| crystalhelix | 01-29-2007 04:26 PM |
Non-metallic Hard Suspension Bushings
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For some of us who can't switch to pillow ball bushings our options are to replace the stock bushings with Poly bushings.
Specifically the TA, LL, and front LCA bushings.
My question is, would there be interest in bushings not made of metal but something harder than the 90D poly that is available? Perhaps Delrin or another plastic with good lubricity.
I just finished reverse engineering my bushings and getting the CAD models done, that's why I am asking. I have full access to a machine shop but I am not going to bother unless people are interested and there is some loot to be made.:devil:
Let me know,
Justin
***************************************
1/30/2007
Ok, so I have some results. What I need to clarify here is that this measurement is of the rubber/poly material only, [b]not a measurement of total bushing stiffness. [/b]
I have further testing I am going to try to do this week (maybe tomorrow during lunch) where I will apply a force from 5 lbs compression until I see a load of 200lbs and will measure the displacement of the bushing in 1 direction. This should be representative of directional loading of the bushing. These results would be more valuable than just knowing the rubber durometer. I also saw some shifting around with the durometer of the rubber. I think this may have to do with the metal content of the stock bushings, or molding effects.
I actually am looking at things and I need to get 1 more STi bushing to test before I 100% trust these results. It will have to wait until tomorrow.
Stock WRX - 64.2 M (from used car)
Stock 04 STi - 76.8 M (from car with 38,000 miles)
Group N - 71.9 M (brand new)
Super Pro - 72.3 M (brand new)
Keep in mind, I sorta mostly know what I am doing here, AKA I didn't bother reading the ASTM testing manual or anything on how to use this gauge, but a technician at work explained it to me.
Justin
data table (format is crappy)
[CODE]Durometer Type M Values - Microhardness Scale
Test Stock WRX Stock Sti Group-N SuperPro
1 61.5 77 71 72
2 63.5 77 74 73
3 65 75 75 72
4 64 77 70 71
5 64 78 74 71
6 64 77 70 76
7 64 79 71 69
8 65 79 72 71
9 65 75 74 75
10 66 74 68 73
AVG 64.2 76.8 71.9 72.3
[/CODE]
1/30/07 Compression Results:
[url]http://www.spryracing.com/projects/20070130BushingTest1.JPG[/url]
***************************************
1/31/2007:banana:
After putting together for a more proper analysis here are my results of the lateral link bushings..
I labelled everything a little better and did a better comparison with the 4 "toe" adjustment location bushings I had.
From the results it looks like the group-n bushings are the stiffest in the toe adjust location (inside-rear) in compression.
For an analysis of the outter bushings I only had my stock STi bushings and SuperPro bushings to compare. As you can see the stock STi outer bushings and Poly bushings seem to have similar compression performance. It actually appears the STi stock bushings would have a better pre-loaded condition due to the diameter of the bushings. The inner bushings share the same characteristics.
[B]Also consider that the SuperPro bushings would provide higher torsional stability based on design (no dips at edge of support thus preventing torsional movement), and they will allow the suspension to move more free, this overall may provide a tighter feel and stability of the links so I am going to stick with installing the SuperPro bushings for now[/B]. This data is provided so you can do with it as you please.
One of my biggest questions comes from the stock STi toe bushing stiffness. Both this part and the WRX part are stamped with identical mold markings/numbers. But the data and physically sqeezing the parts shows the STi is softer for some reason (I did 3 blind tests with co-workers, FTW)
Feel free to ask questions,
Justin;)
SpryRacing.com
Bushings:
[url]http://www.spryracing.com/projects/ToeBushings1.jpg[/url]
[url]http://www.spryracing.com/projects/ToeBushings2.jpg[/url]
[url]http://www.spryracing.com/projects/Outter_InnerBushings1.jpg[/url]
[url]http://www.spryracing.com/projects/Outter_InnerBushings2.jpg[/url]
Graphical:
[IMG]http://www.spryracing.com/projects/20070131BushingTest2.jpg[/IMG]
Specifically the TA, LL, and front LCA bushings.
My question is, would there be interest in bushings not made of metal but something harder than the 90D poly that is available? Perhaps Delrin or another plastic with good lubricity.
I just finished reverse engineering my bushings and getting the CAD models done, that's why I am asking. I have full access to a machine shop but I am not going to bother unless people are interested and there is some loot to be made.:devil:
Let me know,
Justin
***************************************
1/30/2007
Ok, so I have some results. What I need to clarify here is that this measurement is of the rubber/poly material only, [b]not a measurement of total bushing stiffness. [/b]
I have further testing I am going to try to do this week (maybe tomorrow during lunch) where I will apply a force from 5 lbs compression until I see a load of 200lbs and will measure the displacement of the bushing in 1 direction. This should be representative of directional loading of the bushing. These results would be more valuable than just knowing the rubber durometer. I also saw some shifting around with the durometer of the rubber. I think this may have to do with the metal content of the stock bushings, or molding effects.
I actually am looking at things and I need to get 1 more STi bushing to test before I 100% trust these results. It will have to wait until tomorrow.
Stock WRX - 64.2 M (from used car)
Stock 04 STi - 76.8 M (from car with 38,000 miles)
Group N - 71.9 M (brand new)
Super Pro - 72.3 M (brand new)
Keep in mind, I sorta mostly know what I am doing here, AKA I didn't bother reading the ASTM testing manual or anything on how to use this gauge, but a technician at work explained it to me.
Justin
data table (format is crappy)
[CODE]Durometer Type M Values - Microhardness Scale
Test Stock WRX Stock Sti Group-N SuperPro
1 61.5 77 71 72
2 63.5 77 74 73
3 65 75 75 72
4 64 77 70 71
5 64 78 74 71
6 64 77 70 76
7 64 79 71 69
8 65 79 72 71
9 65 75 74 75
10 66 74 68 73
AVG 64.2 76.8 71.9 72.3
[/CODE]
1/30/07 Compression Results:
[url]http://www.spryracing.com/projects/20070130BushingTest1.JPG[/url]
***************************************
1/31/2007:banana:
After putting together for a more proper analysis here are my results of the lateral link bushings..
I labelled everything a little better and did a better comparison with the 4 "toe" adjustment location bushings I had.
From the results it looks like the group-n bushings are the stiffest in the toe adjust location (inside-rear) in compression.
For an analysis of the outter bushings I only had my stock STi bushings and SuperPro bushings to compare. As you can see the stock STi outer bushings and Poly bushings seem to have similar compression performance. It actually appears the STi stock bushings would have a better pre-loaded condition due to the diameter of the bushings. The inner bushings share the same characteristics.
[B]Also consider that the SuperPro bushings would provide higher torsional stability based on design (no dips at edge of support thus preventing torsional movement), and they will allow the suspension to move more free, this overall may provide a tighter feel and stability of the links so I am going to stick with installing the SuperPro bushings for now[/B]. This data is provided so you can do with it as you please.
One of my biggest questions comes from the stock STi toe bushing stiffness. Both this part and the WRX part are stamped with identical mold markings/numbers. But the data and physically sqeezing the parts shows the STi is softer for some reason (I did 3 blind tests with co-workers, FTW)
Feel free to ask questions,
Justin;)
SpryRacing.com
Bushings:
[url]http://www.spryracing.com/projects/ToeBushings1.jpg[/url]
[url]http://www.spryracing.com/projects/ToeBushings2.jpg[/url]
[url]http://www.spryracing.com/projects/Outter_InnerBushings1.jpg[/url]
[url]http://www.spryracing.com/projects/Outter_InnerBushings2.jpg[/url]
Graphical:
[IMG]http://www.spryracing.com/projects/20070131BushingTest2.jpg[/IMG]
| Storm | 01-29-2007 05:21 PM |
I'd take 2 sets almost immediately.....
Jay Storm
Jay Storm
| Scooby South | 01-29-2007 05:58 PM |
what are the grp N durometer ..thats what i use
| sciolist | 01-29-2007 06:08 PM |
In concept, yes.
| crystalhelix | 01-29-2007 06:16 PM |
[QUOTE=Storm;16854058]I'd take 2 sets almost immediately.....
Jay Storm[/QUOTE]
Jay - are the PN's interchangeable? I have all the bush dims for the 2004 STi which should fit a lot of subies.
Jay Storm[/QUOTE]
Jay - are the PN's interchangeable? I have all the bush dims for the 2004 STi which should fit a lot of subies.
| Scooby South | 01-29-2007 06:56 PM |
bushings for all 90-99 legacy
93-05 impreza/wrx
04 Sti
98-07 forester
Are all the same...as far as the rear is concerned...as long as they are AWD...
:)
93-05 impreza/wrx
04 Sti
98-07 forester
Are all the same...as far as the rear is concerned...as long as they are AWD...
:)
| BIGSKYWRX | 01-29-2007 10:07 PM |
[QUOTE=Scooby South;16854522]what are the grp N durometer ..thats what i use[/QUOTE]
same question- I believe that the durometer on the Grp N's vary by bushing location- this is after presing in 100's
which bushings are 90D- Super Pro? Curious what your measuring w/- I've thought about getting durometer- but they are kind of pricey :)
same question- I believe that the durometer on the Grp N's vary by bushing location- this is after presing in 100's
which bushings are 90D- Super Pro? Curious what your measuring w/- I've thought about getting durometer- but they are kind of pricey :)
| crystalhelix | 01-29-2007 10:22 PM |
I got my hands on a group-n rear LL bushing tonight, I will be checking the durometers at work tomorrow between stock, group-n, and the poly bushings...(yes I can do that, as long as I use the tool thingy right, lol)
| BIGSKYWRX | 01-29-2007 11:00 PM |
schweet :)
| STiShawn | 01-30-2007 08:47 AM |
I'd be interested in a delrin set depending on price
| speedyHAM | 01-30-2007 08:54 AM |
You can't go to all delrin bushings for the LL and TA bushings without binding up the rear suspension. You can do one or the other and probably be fine, but otherwise the twisting loads that would be put on the suspension mounts (chassis side) would break the mounts after a short while.
| crystalhelix | 01-30-2007 09:00 AM |
[QUOTE=speedyHAM;16861462]You can't go to all delrin bushings for the LL and TA bushings without binding up the rear suspension. You can do one or the other and probably be fine, but otherwise the twisting loads that would be put on the suspension mounts (chassis side) would break the mounts after a short while.[/QUOTE]
Well, I just took mine off and the metallic sleeve is captured and held stiffly by the suspension mounts....IMO...too rigidly and it prevents fluid motion of the suspension bits because the stock bushings do not allow radial rotation of the rubber around the sleeve. I belived delrin and the poly bushings actually relieve certain stresses on the mounts and this is one of the nice side effects people are actually feeling is that the suspension can move more freely.
I am just trying to learn as much as possible here.
Well, I just took mine off and the metallic sleeve is captured and held stiffly by the suspension mounts....IMO...too rigidly and it prevents fluid motion of the suspension bits because the stock bushings do not allow radial rotation of the rubber around the sleeve. I belived delrin and the poly bushings actually relieve certain stresses on the mounts and this is one of the nice side effects people are actually feeling is that the suspension can move more freely.
I am just trying to learn as much as possible here.
| PhilC | 01-30-2007 09:12 AM |
I'd probably be interested in TA and LCA bushings. Just would have to get off my lazy butt and take the parts off the car to do them.
| Impreza01 | 01-30-2007 10:56 AM |
[QUOTE=speedyHAM;16861462]You can't go to all delrin bushings for the LL and TA bushings without binding up the rear suspension. You can do one or the other and probably be fine, but otherwise the twisting loads that would be put on the suspension mounts (chassis side) would break the mounts after a short while.[/QUOTE]
I believe XSEngineering did it to their WRX. The shop often replaces the bushings with delrin ones for their project cars.
I believe XSEngineering did it to their WRX. The shop often replaces the bushings with delrin ones for their project cars.
| speedyHAM | 01-30-2007 11:22 AM |
[QUOTE=crystalhelix;16861521]Well, I just took mine off and the metallic sleeve is captured and held stiffly by the suspension mounts....IMO...too rigidly and it prevents fluid motion of the suspension bits because the stock bushings do not allow radial rotation of the rubber around the sleeve. I belived delrin and the poly bushings actually relieve certain stresses on the mounts and this is one of the nice side effects people are actually feeling is that the suspension can move more freely.
I am just trying to learn as much as possible here.[/QUOTE]
Poly bushings still have some give to them in forward-aft direction on the LL, allowing the wheel to move in an arc defined by the TA. I agree with you that the radial motion would be improved with delrin bushings if only the LL or TA were connected. But with all delrin bushings the forward- aft play would be gone from the LL and the side to side play would be gone from the TA, binding the whole linkage. If the suspension still moves at this point (with enough load it will move) the play will come from the chassis side suspension mounts.
This is why you need spherical ball joints for an all metal system and not just metal bushings. If you have access to a lathe and can make these bushings give it a shot. If I'm wrong I'll buy a set from you.
I am just trying to learn as much as possible here.[/QUOTE]
Poly bushings still have some give to them in forward-aft direction on the LL, allowing the wheel to move in an arc defined by the TA. I agree with you that the radial motion would be improved with delrin bushings if only the LL or TA were connected. But with all delrin bushings the forward- aft play would be gone from the LL and the side to side play would be gone from the TA, binding the whole linkage. If the suspension still moves at this point (with enough load it will move) the play will come from the chassis side suspension mounts.
This is why you need spherical ball joints for an all metal system and not just metal bushings. If you have access to a lathe and can make these bushings give it a shot. If I'm wrong I'll buy a set from you.
| crystalhelix | 01-30-2007 11:42 AM |
Ok, so I have some results. What I need to clarify here is that this measurement is of the rubber/poly material only, [b]not a measurement of total bushing stiffness. [/b]
I have further testing I am going to try to do this week (maybe tomorrow during lunch) where I will apply a force from 5 lbs compression until I see a load of 200lbs and will measure the displacement of the bushing in 1 direction. This should be representative of directional loading of the bushing. These results would be more valuable than just knowing the rubber durometer. I also saw some shifting around with the durometer of the rubber. I think this may have to do with the metal content of the stock bushings, or molding effects.
I actually am looking at things and I need to get 1 more STi bushing to test before I 100% trust these results. It will have to wait until tomorrow.
Stock WRX - 64.2 M
Stock 04 STi - 76.8 M
Group N - 71.9 M
Super Pro - 72.3 M
Keep in mind, I sorta mostly know what I am doing here, AKA I didn't bother reading the ASTM testing manual or anything on how to use this gauge, but a technician at work explained it to me.
Justin
data table (format is crappy)
[CODE]Durometer Type M Values - Microhardness Scale
Test Stock WRX Stock Sti Group-N SuperPro
1 61.5 77 71 72
2 63.5 77 74 73
3 65 75 75 72
4 64 77 70 71
5 64 78 74 71
6 64 77 70 76
7 64 79 71 69
8 65 79 72 71
9 65 75 74 75
10 66 74 68 73
AVG 64.2 76.8 71.9 72.3
[/CODE]
I have further testing I am going to try to do this week (maybe tomorrow during lunch) where I will apply a force from 5 lbs compression until I see a load of 200lbs and will measure the displacement of the bushing in 1 direction. This should be representative of directional loading of the bushing. These results would be more valuable than just knowing the rubber durometer. I also saw some shifting around with the durometer of the rubber. I think this may have to do with the metal content of the stock bushings, or molding effects.
I actually am looking at things and I need to get 1 more STi bushing to test before I 100% trust these results. It will have to wait until tomorrow.
Stock WRX - 64.2 M
Stock 04 STi - 76.8 M
Group N - 71.9 M
Super Pro - 72.3 M
Keep in mind, I sorta mostly know what I am doing here, AKA I didn't bother reading the ASTM testing manual or anything on how to use this gauge, but a technician at work explained it to me.
Justin
data table (format is crappy)
[CODE]Durometer Type M Values - Microhardness Scale
Test Stock WRX Stock Sti Group-N SuperPro
1 61.5 77 71 72
2 63.5 77 74 73
3 65 75 75 72
4 64 77 70 71
5 64 78 74 71
6 64 77 70 76
7 64 79 71 69
8 65 79 72 71
9 65 75 74 75
10 66 74 68 73
AVG 64.2 76.8 71.9 72.3
[/CODE]
| AtomicRacer | 01-30-2007 12:07 PM |
subscribe...
Your results aren't what I would have expected.
-Paul
Your results aren't what I would have expected.
-Paul
| speedyHAM | 01-30-2007 12:15 PM |
[QUOTE=AtomicRacer;16863706]subscribe...
Your results aren't what I would have expected.
-Paul[/QUOTE]
Not what I had expected either.
Your results aren't what I would have expected.
-Paul[/QUOTE]
Not what I had expected either.
| Scooby South | 01-30-2007 12:36 PM |
hmmm...I wonder what results would be if you left the bushings out in the weather for ohhh.sayyy 6 monthes..;)....
Really surprised about the Grp N's...
Really surprised about the Grp N's...
| Impreza01 | 01-30-2007 12:52 PM |
I'm very surprised the STI has stiffer stock bushings. Is there anyway or reasoning that the supposedly stiffer Group N bushings may be softer (like deterioration)?
| crystalhelix | 01-30-2007 12:57 PM |
[QUOTE=Impreza01;16864381]I'm very surprised the STI has stiffer stock bushings. Is there anyway or reasoning that the supposedly stiffer Group N bushings may be softer (like deterioration)?[/QUOTE]
Hence why in the post I want to test another of my bushings but like an idiot I only brought 1 into work with me. All bushings were at room temp when I took the readings. I will let you know tomorrow around lunch when I bring the other bushing in to double check.
J
BTW - added some more info to orignal post and will update the first post as I learn more and do more testing..
Hence why in the post I want to test another of my bushings but like an idiot I only brought 1 into work with me. All bushings were at room temp when I took the readings. I will let you know tomorrow around lunch when I bring the other bushing in to double check.
J
BTW - added some more info to orignal post and will update the first post as I learn more and do more testing..
| angryfist | 01-30-2007 01:56 PM |
[QUOTE=speedyHAM;16863075]Poly bushings still have some give to them in forward-aft direction on the LL, allowing the wheel to move in an arc defined by the TA. I agree with you that the radial motion would be improved with delrin bushings if only the LL or TA were connected. But with all delrin bushings the forward- aft play would be gone from the LL and the side to side play would be gone from the TA, binding the whole linkage. If the suspension still moves at this point (with enough load it will move) the play will come from the chassis side suspension mounts.
This is why you need spherical ball joints for an all metal system and not just metal bushings. If you have access to a lathe and can make these bushings give it a shot. If I'm wrong I'll buy a set from you.[/QUOTE]
+1
if you can prove these wont bind, then they would be great. i would have had a set on my car a couple years ago if it wasnt for the binding issue.
This is why you need spherical ball joints for an all metal system and not just metal bushings. If you have access to a lathe and can make these bushings give it a shot. If I'm wrong I'll buy a set from you.[/QUOTE]
+1
if you can prove these wont bind, then they would be great. i would have had a set on my car a couple years ago if it wasnt for the binding issue.
| BIGSKYWRX | 01-30-2007 02:59 PM |
exactly what bushing are you measuring?
I've replaced several sets of Grp N bushings into STi lateral links and while there may be a bushing or two that is slightly stiffer than the WRX, none were as firm as the Grp N ones.
There are two bushings in the newer revision D/E's that list no Grp N replacement which tells me they are as (possibly even more?) stiff as the Grp N ones- the rear transverse link bushing (control arm) and the front trailing link- everything else lists a replacement in their Grp N charts.
Is it possible you got them switched?
I've replaced several sets of Grp N bushings into STi lateral links and while there may be a bushing or two that is slightly stiffer than the WRX, none were as firm as the Grp N ones.
There are two bushings in the newer revision D/E's that list no Grp N replacement which tells me they are as (possibly even more?) stiff as the Grp N ones- the rear transverse link bushing (control arm) and the front trailing link- everything else lists a replacement in their Grp N charts.
Is it possible you got them switched?
| crystalhelix | 01-30-2007 03:04 PM |
I am measuring a lateral link "outer" group N bushing?
Is that ok? Maybe there is an issue with age of my STi bushings, hardening up or something, they are rubber.
Is that ok? Maybe there is an issue with age of my STi bushings, hardening up or something, they are rubber.
| crystalhelix | 01-30-2007 04:15 PM |
I have to correct the STi bushing tomorrow and finalize the data but here is a cool graph. This is compressing the bushing with 100lb of force. I will post some pics of the setup when I get home.
1/30/07 Compression Results:
[url]http://www.spryracing.com/projects/20070130BushingTest1.JPG[/url]
for now I am seeing Group N outperform the SuperPro bushings
1/30/07 Compression Results:
[url]http://www.spryracing.com/projects/20070130BushingTest1.JPG[/url]
for now I am seeing Group N outperform the SuperPro bushings
| grippgoat | 01-30-2007 04:30 PM |
How much is 100lbs of force compared to what they'll see in action at the track, though? You can see the Super Pro line crossing the Group N line at about 70lbs... If the operating loads are higher than that, that would mean the Super Pro would out-perform the Group N, while at the same time being initially softer (possibly meaning comfier on the street). Also, the Group N works just like stock, only harder, right? Meaning that the inner metal tube does not rotate freely against the rubber like it does in a Super Pro, meaning the Group N would have more binding?
-Mike
-Mike
| crystalhelix | 01-30-2007 04:35 PM |
ACTUALLY THAT's THE STi inner bushing and shouldn't be compared to the other 3 at the moment. geeze...every time I try to make things clear somebody misses it...
it looks like group n is hardest, then superpro, then WRX
I will have better stock STi results tomorrow.
sorry!
it looks like group n is hardest, then superpro, then WRX
I will have better stock STi results tomorrow.
sorry!
| crystalhelix | 01-30-2007 04:38 PM |
[QUOTE=grippgoat;16867634]How much is 100lbs of force compared to what they'll see in action at the track, though? You can see the Super Pro line crossing the Group N line at about 70lbs... If the operating loads are higher than that, that would mean the Super Pro would out-perform the Group N, while at the same time being initially softer (possibly meaning comfier on the street). Also, the Group N works just like stock, only harder, right? Meaning that the inner metal tube does not rotate freely against the rubber like it does in a Super Pro, meaning the Group N would have more binding?
-Mike[/QUOTE]
At some point you will run out of compression from the rubber, that's why I thought it would be important to compress the entire bushing rather than rely on durometer numbers.
I assume the loading is through 6 points
strut top, and 2 lower bushings (similar case front and rear) so if the car's full weight was on 2 wheels (lateral) than each bushing might support near 500 lbs each..........I am just theorizing here, so it should be less than 500, I could use any help people have to offer..
-Mike[/QUOTE]
At some point you will run out of compression from the rubber, that's why I thought it would be important to compress the entire bushing rather than rely on durometer numbers.
I assume the loading is through 6 points
strut top, and 2 lower bushings (similar case front and rear) so if the car's full weight was on 2 wheels (lateral) than each bushing might support near 500 lbs each..........I am just theorizing here, so it should be less than 500, I could use any help people have to offer..
| AUTOwrXER | 01-30-2007 05:12 PM |
[QUOTE=grippgoat;16867634]How much is 100lbs of force compared to what they'll see in action at the track, though?
-Mike[/QUOTE]
I think this is the important question. First we need to figure out if we should be testing with 100 lbs of force or 1000. Damn it would be nice to have a good model of the suspension...
What is the limit of the test rig?
-Mike[/QUOTE]
I think this is the important question. First we need to figure out if we should be testing with 100 lbs of force or 1000. Damn it would be nice to have a good model of the suspension...
What is the limit of the test rig?
| Scooby South | 01-30-2007 06:25 PM |
[QUOTE=crystalhelix;16867711]ACTUALLY THAT's THE STi inner bushing and shouldn't be compared to the other 3 at the moment. geeze...every time I try to make things clear somebody misses it...
it looks like group n is hardest, then superpro, then WRX
I will have better stock STi results tomorrow.
sorry![/QUOTE]
now that makes sense...hurray for grp N's:cool:
it looks like group n is hardest, then superpro, then WRX
I will have better stock STi results tomorrow.
sorry![/QUOTE]
now that makes sense...hurray for grp N's:cool:
| crystalhelix | 01-30-2007 06:49 PM |
[QUOTE=AUTOwrXER;16868272]I think this is the important question. First we need to figure out if we should be testing with 100 lbs of force or 1000. Damn it would be nice to have a good model of the suspension...
What is the limit of the test rig?[/QUOTE]
I think 2000lbs. We have a 200lb load cell, 500 lb load cell and I think 2k, lol.
But I don't feel good about pushing the limits of bending one of these sleeves on a very expensive piece of equipment I don't own (or bushings I bought).
I think the 100 lb test is indicative of results event at 1000lbs, mainly due to the fact the material can only give so much and then the material would give out. Since it is typically encapsulated in the suspension bits it can't go anywhere.
[IMG]http://www.spryracing.com/projects/0130071546a.jpg[/IMG]
What is the limit of the test rig?[/QUOTE]
I think 2000lbs. We have a 200lb load cell, 500 lb load cell and I think 2k, lol.
But I don't feel good about pushing the limits of bending one of these sleeves on a very expensive piece of equipment I don't own (or bushings I bought).
I think the 100 lb test is indicative of results event at 1000lbs, mainly due to the fact the material can only give so much and then the material would give out. Since it is typically encapsulated in the suspension bits it can't go anywhere.
[IMG]http://www.spryracing.com/projects/0130071546a.jpg[/IMG]
| crystalhelix | 01-30-2007 06:54 PM |
I think I may just do a big DOE on what's happening.
If you think about this for a second, let's say the rear bushings shift more than the front than under lateral loading you will gain toe out, particularily if you are under acceleration.
If you think about this for a second, let's say the rear bushings shift more than the front than under lateral loading you will gain toe out, particularily if you are under acceleration.
| Impreza01 | 01-30-2007 07:25 PM |
Instrons ftmfw!! Does the university (I presume it's at one since those are the only places where I see Instrons) know you're "abusing" the machine like that? Hahah
| crystalhelix | 01-30-2007 07:59 PM |
No, I am a Mechanical engineer, location of work not to be disclosed, but I have access to this pretty much 24/7
FTW
FTW
| Impreza01 | 01-30-2007 08:30 PM |
Cool, now start putting struts in that bitch and tell us which ones are consistant in damping, which ones are consistant in knob settings and which ones are consistent across multiple struts of the same type. Oh yeah, please post up the dyno graphs. ;)
| BIGSKYWRX | 01-30-2007 09:48 PM |
good work- I really appreciate taking the time to do this :)
The durometer does vary on the bushings- even within the lateral links (definitely could be a reason for this :)). The outer ll's are all the same, but the inners differ front/rear.
The STi oe outer bushings are ones that do differ from the WRX oe bushings (diffeent part #'s)- this is the reason they came w/ the v7 SPT suspension kit (just the jdm oe v7 STi). My guess is the oe STi bushing will fall right in between the oe WRX and the Grp N one.
Out of all the Grp N bushings the largest difference is between the oe rear trailing link (the one in the knuckle) and the Grp N one- it a night/day difference.
Keep up the good work!
The durometer does vary on the bushings- even within the lateral links (definitely could be a reason for this :)). The outer ll's are all the same, but the inners differ front/rear.
The STi oe outer bushings are ones that do differ from the WRX oe bushings (diffeent part #'s)- this is the reason they came w/ the v7 SPT suspension kit (just the jdm oe v7 STi). My guess is the oe STi bushing will fall right in between the oe WRX and the Grp N one.
Out of all the Grp N bushings the largest difference is between the oe rear trailing link (the one in the knuckle) and the Grp N one- it a night/day difference.
Keep up the good work!
| Impreza01 | 01-30-2007 10:48 PM |
Hrmmm, carbon fiber bushings ftw! :p
| crystalhelix | 01-30-2007 11:40 PM |
[QUOTE=Impreza01;16870991]Cool, now start putting struts in that bitch and tell us which ones are consistant in damping, which ones are consistant in knob settings and which ones are consistent across multiple struts of the same type. Oh yeah, please post up the dyno graphs. ;)[/QUOTE]
I thought of that but I don't think the machine can hit the max speed to move the strut through it's motions, lol.
I thought of that but I don't think the machine can hit the max speed to move the strut through it's motions, lol.
| GSRNick | 01-31-2007 02:17 AM |
[QUOTE=crystalhelix;16873223]I thought of that but I don't think the machine can hit the max speed to move the strut through it's motions, lol.[/QUOTE]
Yeah I agree Justin, my Chattilon (same thing as an Instron) doesn't go fast enough for (<3in/sec) for damping curves.
Funny that two graduates of Pitt in Mech Eng have apparent rare access to those things...
Theoretically the inner rotation points of a control arm should not see any tension or compression forces, only shear. But obviously we know thats not the case. The strut assembly is going to absorb most of the force but part of the vector in the X direction is going to go straight into the inner suspension point. I think you should do some testing in both compression and tension.
Looking at your test setup in the picture above. Can you make a sleeve to go around the outer portion of the bushing - then attach it solidly to the lower non moving part of the machine? Might want to make it rather thick so you aren't testing the strength of your jig. Then with the load cell side of the machine, just make a yoke and run a bolt through the inner bushing. This would make things a little more realistic.
That setup would be for more exact numbers - what you are doing is good just to compare one sample to another.
Yeah I agree Justin, my Chattilon (same thing as an Instron) doesn't go fast enough for (<3in/sec) for damping curves.
Funny that two graduates of Pitt in Mech Eng have apparent rare access to those things...
Theoretically the inner rotation points of a control arm should not see any tension or compression forces, only shear. But obviously we know thats not the case. The strut assembly is going to absorb most of the force but part of the vector in the X direction is going to go straight into the inner suspension point. I think you should do some testing in both compression and tension.
Looking at your test setup in the picture above. Can you make a sleeve to go around the outer portion of the bushing - then attach it solidly to the lower non moving part of the machine? Might want to make it rather thick so you aren't testing the strength of your jig. Then with the load cell side of the machine, just make a yoke and run a bolt through the inner bushing. This would make things a little more realistic.
That setup would be for more exact numbers - what you are doing is good just to compare one sample to another.
| Scooby South | 01-31-2007 07:52 AM |
Justin....I have a question....Isn't there a difference on how the bushing(s) perform....one way is structural hardness...that measures overall hardness...the other, ...should be Torsional Rigidity??? that measures how hard the particular bushing is to twist or not to twist (Deflection), whichever..???
Just curious...
Sorry to throw more questions at you...I think it great someone actually is doing something to learn..props...
way back when...Whiteline USED to have a chart that had all that stuff on it...but I havn't visited the Whiteline Site(Aus) in good While..
Thanks
Bill
Just curious...
Sorry to throw more questions at you...I think it great someone actually is doing something to learn..props...
way back when...Whiteline USED to have a chart that had all that stuff on it...but I havn't visited the Whiteline Site(Aus) in good While..
Thanks
Bill
| crystalhelix | 01-31-2007 08:46 AM |
[QUOTE=GSRNick;16874460]
I think you should do some testing in both compression and tension.
[/QUOTE]
I think you should wash my car, fix my bar sink, install a new floor in my basement.
the good thing is now you know what it feels like to "want"
fwiw subie bushings are completely collared in the method they are attached...
[QUOTE=Scooby South;16875385]Justin....I have a question....Isn't there a difference on how the bushing(s) perform....one way is structural hardness...that measures overall hardness...the other, ...should be Torsional Rigidity??? that measures how hard the particular bushing is to twist or not to twist (Deflection), whichever..???
Just curious...
Sorry to throw more questions at you...I think it great someone actually is doing something to learn..props...
way back when...Whiteline USED to have a chart that had all that stuff on it...but I havn't visited the Whiteline Site(Aus) in good While..
Thanks
Bill[/QUOTE]
Bill - torsional would be great, I wanted to do something simple based on some direct comparison tool, ie...simple test, crush each bushing and see which is most resistant to crush. Torsional stiffness could play into this though because the superpro bushings all tend to be wider than oem and take out some torsional play. I think Ideally I would like a super pro bushing that allows free rotation but is as hard as the group n bushings.
oh, and on a side note I forgot all teh bushing on my couch this morning so I may dash home and grap them during lunch.:(
I think you should do some testing in both compression and tension.
[/QUOTE]
I think you should wash my car, fix my bar sink, install a new floor in my basement.
the good thing is now you know what it feels like to "want"
fwiw subie bushings are completely collared in the method they are attached...
[QUOTE=Scooby South;16875385]Justin....I have a question....Isn't there a difference on how the bushing(s) perform....one way is structural hardness...that measures overall hardness...the other, ...should be Torsional Rigidity??? that measures how hard the particular bushing is to twist or not to twist (Deflection), whichever..???
Just curious...
Sorry to throw more questions at you...I think it great someone actually is doing something to learn..props...
way back when...Whiteline USED to have a chart that had all that stuff on it...but I havn't visited the Whiteline Site(Aus) in good While..
Thanks
Bill[/QUOTE]
Bill - torsional would be great, I wanted to do something simple based on some direct comparison tool, ie...simple test, crush each bushing and see which is most resistant to crush. Torsional stiffness could play into this though because the superpro bushings all tend to be wider than oem and take out some torsional play. I think Ideally I would like a super pro bushing that allows free rotation but is as hard as the group n bushings.
oh, and on a side note I forgot all teh bushing on my couch this morning so I may dash home and grap them during lunch.:(
| crystalhelix | 01-31-2007 03:54 PM |
Results from Today:
�
�
1/31/2007:banana:
After putting together for a more proper analysis here are my results of the lateral link bushings..
I labelled everything a little better and did a better comparison with the 4 "toe" adjustment location bushings I had.
From the results it looks like the group-n bushings are the stiffest in the toe adjust location (inside-rear) in compression.
For an analysis of the outter bushings I only had my stock STi bushings and SuperPro bushings to compare. As you can see the stock STi outer bushings and Poly bushings seem to have similar compression performance. It actually appears the STi stock bushings would have a better pre-loaded condition due to the diameter of the bushings. The inner bushings share the same characteristics.
[B]Also consider that the SuperPro bushings would provide higher torsional stability based on design (no dips at edge of support thus preventing torsional movement), and they will allow the suspension to move more free, this overall may provide a tighter feel and stability of the links so I am going to stick with installing the SuperPro bushings for now[/B]. This data is provided so you can do with it as you please.
One of my biggest questions comes from the stock STi toe bushing stiffness. Both this part and the WRX part are stamped with identical mold markings/numbers. But the data and physically sqeezing the parts shows the STi is softer for some reason (I did 3 blind tests with co-workers, FTW)
Feel free to ask questions,
Justin;)
SpryRacing.com
Bushings:
[url]http://www.spryracing.com/projects/ToeBushings1.jpg[/url]
[url]http://www.spryracing.com/projects/ToeBushings2.jpg[/url]
[url]http://www.spryracing.com/projects/Outter_InnerBushings1.jpg[/url]
[url]http://www.spryracing.com/projects/Outter_InnerBushings2.jpg[/url]
Graphical:
[IMG]http://www.spryracing.com/projects/20070131BushingTest2.jpg[/IMG]
After putting together for a more proper analysis here are my results of the lateral link bushings..
I labelled everything a little better and did a better comparison with the 4 "toe" adjustment location bushings I had.
From the results it looks like the group-n bushings are the stiffest in the toe adjust location (inside-rear) in compression.
For an analysis of the outter bushings I only had my stock STi bushings and SuperPro bushings to compare. As you can see the stock STi outer bushings and Poly bushings seem to have similar compression performance. It actually appears the STi stock bushings would have a better pre-loaded condition due to the diameter of the bushings. The inner bushings share the same characteristics.
[B]Also consider that the SuperPro bushings would provide higher torsional stability based on design (no dips at edge of support thus preventing torsional movement), and they will allow the suspension to move more free, this overall may provide a tighter feel and stability of the links so I am going to stick with installing the SuperPro bushings for now[/B]. This data is provided so you can do with it as you please.
One of my biggest questions comes from the stock STi toe bushing stiffness. Both this part and the WRX part are stamped with identical mold markings/numbers. But the data and physically sqeezing the parts shows the STi is softer for some reason (I did 3 blind tests with co-workers, FTW)
Feel free to ask questions,
Justin;)
SpryRacing.com
Bushings:
[url]http://www.spryracing.com/projects/ToeBushings1.jpg[/url]
[url]http://www.spryracing.com/projects/ToeBushings2.jpg[/url]
[url]http://www.spryracing.com/projects/Outter_InnerBushings1.jpg[/url]
[url]http://www.spryracing.com/projects/Outter_InnerBushings2.jpg[/url]
Graphical:
[IMG]http://www.spryracing.com/projects/20070131BushingTest2.jpg[/IMG]
| GreasedLightning | 01-31-2007 05:04 PM |
[QUOTE=crystalhelix;16881895]1/31/2007:banana:
...[B]Also consider that the SuperPro bushings would provide higher torsional stability based on design (no dips at edge of support thus preventing torsional movement), and they will allow the suspension to move more free, this overall may provide a tighter feel and stability of the links so I am going to stick with installing the SuperPro bushings for now[/B].
...
SpryRacing.com
[/QUOTE]
Torsional stability is not desired on the lateral links. As the trailing arm moves up or down, the lateral links must bend sideways as the arc of the trailing arm pulls them to the front of the car. Also, the mounts for the inside of the lateral links is very flimsy on my '04 WRX subframe and would fatigue fail if it was the only thing with torsional movement. However, I might be biased because I spent a lot of time installing my Group N bushings. ;)
...[B]Also consider that the SuperPro bushings would provide higher torsional stability based on design (no dips at edge of support thus preventing torsional movement), and they will allow the suspension to move more free, this overall may provide a tighter feel and stability of the links so I am going to stick with installing the SuperPro bushings for now[/B].
...
SpryRacing.com
[/QUOTE]
Torsional stability is not desired on the lateral links. As the trailing arm moves up or down, the lateral links must bend sideways as the arc of the trailing arm pulls them to the front of the car. Also, the mounts for the inside of the lateral links is very flimsy on my '04 WRX subframe and would fatigue fail if it was the only thing with torsional movement. However, I might be biased because I spent a lot of time installing my Group N bushings. ;)
| crystalhelix | 01-31-2007 05:10 PM |
^ Thanks to greasedlightning for loaning me the WRX and group-n bushings
we'll see what I think once I get wheels on the car again...lol
we'll see what I think once I get wheels on the car again...lol
| BIGSKYWRX | 01-31-2007 08:10 PM |
Great! Too bad I've installed all the Grp N bushings I had laying around- I would have sent you the ones you were missing to test.
Just to make sure I'm looking at correctly the oe outer STi bushings and the inner fronts are "identical" to the Super Pro ones (or vice versa :))?
Again- thanks for the good work!
Just to make sure I'm looking at correctly the oe outer STi bushings and the inner fronts are "identical" to the Super Pro ones (or vice versa :))?
Again- thanks for the good work!
| crystalhelix | 01-31-2007 10:12 PM |
[QUOTE=BIGSKYWRX;16885408]
Just to make sure I'm looking at correctly the oe outer STi bushings and the inner fronts are "identical" to the Super Pro ones (or vice versa :))?
Again- thanks for the good work![/QUOTE]
It seems to be the case.:o But I am not the testing god and don't want to claim to be 100% correct, lol.
Just to make sure I'm looking at correctly the oe outer STi bushings and the inner fronts are "identical" to the Super Pro ones (or vice versa :))?
Again- thanks for the good work![/QUOTE]
It seems to be the case.:o But I am not the testing god and don't want to claim to be 100% correct, lol.
| speedyHAM | 01-31-2007 10:25 PM |
[QUOTE=GreasedLightning;16882979]Torsional stability is not desired on the lateral links. As the trailing arm moves up or down, the lateral links must bend sideways as the arc of the trailing arm pulls them to the front of the car. [B]Also, the mounts for the inside of the lateral links is very flimsy on my '04 WRX subframe and would fatigue fail if it was the only thing with torsional movement.[/B] However, I might be biased because I spent a lot of time installing my Group N bushings. ;)[/QUOTE]
This is what I was talking about in post #11.
This is what I was talking about in post #11.
| silver arrow | 01-31-2007 10:46 PM |
Which bushings would be of the greatest benefit to replace?
| crystalhelix | 01-31-2007 11:16 PM |
From what I have read the rear trailing arm stock bushings blow.
And for the lateral links it looks like the toe bushings needs a little help.
Keep the actual deflections in mind though, were talking small differences, but they are different, lol.
While I have the lateral links and TA's off the car I have taken the notion to repaint them. I will post a pic, I think they should look pretty sweet when done being painted.
And for the lateral links it looks like the toe bushings needs a little help.
Keep the actual deflections in mind though, were talking small differences, but they are different, lol.
While I have the lateral links and TA's off the car I have taken the notion to repaint them. I will post a pic, I think they should look pretty sweet when done being painted.
| BIGSKYWRX | 02-01-2007 09:22 AM |
For sure the rear trailing link ones are soft- the fronts on non STi's are pretty soft too.
| RainMaker | 02-01-2007 11:18 AM |
[QUOTE=crystalhelix;16887382]While I have the lateral links and TA's off the car I have taken the notion to repaint them. I will post a pic, I think they should look pretty sweet when done being painted.[/QUOTE]
Was taking them off relatively easy? I have a Perrin adjustable set that I need to plop on the car prior to my alignment. I've assumed its a moderately trivial job, but I hope you can confirm or deny that ;)
Chris
Was taking them off relatively easy? I have a Perrin adjustable set that I need to plop on the car prior to my alignment. I've assumed its a moderately trivial job, but I hope you can confirm or deny that ;)
Chris
| crystalhelix | 02-01-2007 12:14 PM |
I have air tools, so most things are easy but the front-inner trailing arm bolts were mother f'ers..
| BIGSKYWRX | 02-01-2007 12:24 PM |
The front trailing nut is very hard to get to, what I do is nstead remove the entire bracket- three bolts, put the trailing arm in a vice (ofcourse you've already removed the rear bolt :)) take a big breaker bar (sometimes requires a pipe too) and break the nut free.
It's very hard to do on the car- you'll see when you get under there- very little room.
The same can be said for the lateral link nuts- I double up combo wrenches for them- highly recommend six point stuff for most all of the suspension stuff.
It's very hard to do on the car- you'll see when you get under there- very little room.
The same can be said for the lateral link nuts- I double up combo wrenches for them- highly recommend six point stuff for most all of the suspension stuff.
| crystalhelix | 02-01-2007 12:35 PM |
I used a 6point and a dead-blow to break it, now I am ordering a spare to replace it with because I rounded the head a bit...
| RainMaker | 02-01-2007 01:32 PM |
Cool, thanks. I have gone overboard in the past on tools, so I'm cool for air tools, 6 points, etc.
Also, I dont have to remove the trailing arm [B]this[/B] time.
The Perrin lateral arms have Heim joints on 3 out of four ends. The one with the swaybar attachment is poly. I bought the arms for the full adjustability, but I'll be interested to see if the Heim joints improve rear stability or just add NVH.
Chris
Also, I dont have to remove the trailing arm [B]this[/B] time.
The Perrin lateral arms have Heim joints on 3 out of four ends. The one with the swaybar attachment is poly. I bought the arms for the full adjustability, but I'll be interested to see if the Heim joints improve rear stability or just add NVH.
Chris
| AUTOwrXER | 02-01-2007 01:45 PM |
[QUOTE=crystalhelix;16887382]While I have the lateral links and TA's off the car I have taken the notion to repaint them. I will post a pic, I think they should look pretty sweet when done being painted.[/QUOTE]
Ricer
Ricer
| crystalhelix | 02-01-2007 02:08 PM |
[QUOTE=AUTOwrXER;16894176]Ricer[/QUOTE]
don't be jealous of my lateral link hawtness...
actually it was inspired from some reading I did, it will be easier to identify where/when I am getting tire rub or any leaks from cv boots or the diff, etc...just to have a nice bright suspenion....and I did pick a "bright" color, lol....woot for NASIOC yellow!:banana: :lol:
don't be jealous of my lateral link hawtness...
actually it was inspired from some reading I did, it will be easier to identify where/when I am getting tire rub or any leaks from cv boots or the diff, etc...just to have a nice bright suspenion....and I did pick a "bright" color, lol....woot for NASIOC yellow!:banana: :lol:
| AUTOwrXER | 02-01-2007 02:14 PM |
I stand by my original assesment :p
| RainMaker | 02-01-2007 03:40 PM |
you are going to paint suspension parts...........
.....yellow???
huh.
.....yellow???
huh.
| sciolist | 02-01-2007 03:47 PM |
^This might also be a Pitt thing.
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