| makofoto | 02-02-2006 01:10 AM |
Hi Flo Cats for STX
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Not getting much response on the 2.0 Forum.
I need to weld a Hi Flo Cat into my left over SM catless straight pipe.
What's the difference between the inexpensive $58 dollar Hi Flo Cats (I would use model 15033 at the bottom of the page): [url]http://www.a-1performance.com/super_converter/super_converters.htm[/url]
(What's that little pipe thingy sticking out?)
And these $150 dollar Hi Flo Cats: [url]http://www.secureperformanceorder.com/dynatechdragstore/getproduct.cfm?CategoryID=58&ClassID=370&SubclassID=1697&ProductID=6945[/url]
Any recommendations?
I need to weld a Hi Flo Cat into my left over SM catless straight pipe.
What's the difference between the inexpensive $58 dollar Hi Flo Cats (I would use model 15033 at the bottom of the page): [url]http://www.a-1performance.com/super_converter/super_converters.htm[/url]
(What's that little pipe thingy sticking out?)
And these $150 dollar Hi Flo Cats: [url]http://www.secureperformanceorder.com/dynatechdragstore/getproduct.cfm?CategoryID=58&ClassID=370&SubclassID=1697&ProductID=6945[/url]
Any recommendations?
| flyboymike | 02-02-2006 01:45 AM |
$92.00
Sorry, couldn't resist.
Sorry, couldn't resist.
| PossumK | 02-02-2006 02:30 AM |
[QUOTE=makofoto]Any recommendations?[/QUOTE]
Why yes... get the one with a smaller diameter and lower flow capability.
:devil:
Why yes... get the one with a smaller diameter and lower flow capability.
:devil:
| PossumK | 02-02-2006 03:08 AM |
Serious response: See if you can find this Random Technology 7000 series (metal substrate) cheaper:
[url]http://www.dezodmotorsports.com/pd_random_technology_7000_series.cfm[/url]
Otherwise, the $150 Dynatech is a metal substrate cat, while the cheaper Dynomax looks like it uses a ceramic substrate. Some claims are higher flow and longevity with a metal substrate.
[url]http://www.dezodmotorsports.com/pd_random_technology_7000_series.cfm[/url]
Otherwise, the $150 Dynatech is a metal substrate cat, while the cheaper Dynomax looks like it uses a ceramic substrate. Some claims are higher flow and longevity with a metal substrate.
| angryfist | 02-02-2006 09:26 AM |
metal will flow better but are a lot more expensive. i just used a 3" magnaflow cat for $35. there will be virtually no difference with the power we are putting down.
| Crash477 | 02-02-2006 11:13 AM |
[QUOTE=angryfist]metal will flow better but are a lot more expensive. i just used a 3" magnaflow cat for $35. there will be virtually no difference with the power we are putting down.[/QUOTE]
Thats what I was thinking. I am going to do this too.
Thats what I was thinking. I am going to do this too.
| Rasmusson14 | 02-02-2006 12:06 PM |
While on this topic of high-flow cats, where would be the best location to place the cat? I have heard argument for both places, in the shorty dp and the mid-pipe location, and was wondering what the consensus here is.
| Crash477 | 02-02-2006 12:15 PM |
I have heard in the midpipe somewhere. I've heard you want to leave teh DP catless, for better flow.. not sure if that is correct, just whatI have heard. I know mine is in the midpipe..
| fliz | 02-02-2006 12:30 PM |
[QUOTE=Rasmusson14]While on this topic of high-flow cats, where would be the best location to place the cat? I have heard argument for both places, in the shorty dp and the mid-pipe location, and was wondering what the consensus here is.[/QUOTE]
As far away from the turbo/engine as you can legally get it.
Which is 6" beyond the stock location of the third cat.
As far away from the turbo/engine as you can legally get it.
Which is 6" beyond the stock location of the third cat.
| Crash477 | 02-02-2006 12:32 PM |
edit:
[QUOTE]High flow catalytic converters are allowed, but must attach
within six inches of the original unit. Multiple catalytic converters
may be replaced by a single unit. The inlet of the
single replacement converter may be located no further
downstream than 6" along the piping flow path from the
original exit of the final OE converter.[/QUOTE]
[QUOTE]High flow catalytic converters are allowed, but must attach
within six inches of the original unit. Multiple catalytic converters
may be replaced by a single unit. The inlet of the
single replacement converter may be located no further
downstream than 6" along the piping flow path from the
original exit of the final OE converter.[/QUOTE]
| mccanixx | 02-02-2006 12:49 PM |
[QUOTE=fliz]As far away from the turbo/engine as you can legally get it.
Which is 6" beyond the stock location of the third cat.[/QUOTE]
Then why does Corky Bell say as close to the turbo as you can get it? I'm not trying to be contradictry. It's just a question I have.
Actually his logic is to allow it to reach operating temp as quickly as possible. Maybe it's based on an oem style cat. :confused:
Which is 6" beyond the stock location of the third cat.[/QUOTE]
Then why does Corky Bell say as close to the turbo as you can get it? I'm not trying to be contradictry. It's just a question I have.
Actually his logic is to allow it to reach operating temp as quickly as possible. Maybe it's based on an oem style cat. :confused:
| angryfist | 02-02-2006 01:06 PM |
if you want the cat to get up to working temp fast then you want it close to the turbo. better for emissions.
| Rasmusson14 | 02-02-2006 01:46 PM |
[QUOTE=angryfist]if you want the cat to get up to working temp fast then you want it close to the turbo. better for emissions.[/QUOTE]
I was under the thought that the hotter the gases the better the flow which the cat would be a great way to maintain hot gases but then again the amount of restriction it is creating would seem to slow the flow down :huh: I guess the question would be which way is less parasitic or more optimal for the flow of gases. Speed or heat?
I was under the thought that the hotter the gases the better the flow which the cat would be a great way to maintain hot gases but then again the amount of restriction it is creating would seem to slow the flow down :huh: I guess the question would be which way is less parasitic or more optimal for the flow of gases. Speed or heat?
| D_REX | 02-02-2006 01:54 PM |
The cat will not heat the gasses passing through it under full load. The exhaust will heat it.
The farther back the cat is located the slower the exhaust gasses will be flowing and the less restriction the cat will cause.
The farther back the cat is located the slower the exhaust gasses will be flowing and the less restriction the cat will cause.
| fliz | 02-02-2006 01:58 PM |
[QUOTE=D_REX]The cat will not heat the gasses passing through it under full load. The exhaust will heat it.
The farther back the cat is located the slower the exhaust gasses will be flowing and the less restriction the cat will cause.[/QUOTE]
That's always the theory I've heard, and why rally cars run the cat in place of the muffler in the back. Well, that also allows them to whack it with a stick if it clogs.
The farther back the cat is located the slower the exhaust gasses will be flowing and the less restriction the cat will cause.[/QUOTE]
That's always the theory I've heard, and why rally cars run the cat in place of the muffler in the back. Well, that also allows them to whack it with a stick if it clogs.
| Rasmusson14 | 02-02-2006 02:02 PM |
Sorry for the hijack makofoto but thought this would be along the same line of �What flows better�
Thanks for your reply�s and it looks like I may be doing some �modification� to my APS tbe that I just bought. :rolleyes:
Thanks for your reply�s and it looks like I may be doing some �modification� to my APS tbe that I just bought. :rolleyes:
| Zoinks | 02-02-2006 06:56 PM |
For what it's worth, [URL="http://forums.nasioc.com/forums/showthread.php?t=747498&page=3&pp=25"]some of the people in this old STX dyno thread[/URL] making 240+ whp are running the PDE downpipe, which places a highflow cat up towards the turbo. So I dunno how much of a difference location really makes. Hopefully they can chime in and correct me if I'm making a dumb assumption.
| abaxter34 | 02-02-2006 08:01 PM |
[QUOTE=fliz]As far away from the turbo/engine as you can legally get it.
Which is 6" beyond the stock location of the third cat.[/QUOTE]
i moved min to the catback section of my exhaust, just on the opposite side of the flange from the midpipe...which is just within 6 inches of the stock placement.
Which is 6" beyond the stock location of the third cat.[/QUOTE]
i moved min to the catback section of my exhaust, just on the opposite side of the flange from the midpipe...which is just within 6 inches of the stock placement.
| fliz | 02-02-2006 08:39 PM |
[QUOTE=abaxter34]i moved min to the catback section of my exhaust, just on the opposite side of the flange from the midpipe...which is just within 6 inches of the stock placement.[/QUOTE]
Hmmm...When I measured my OEM 3rd cat pipe, there was 7" between the end of the substrate and the flange.
Where did you measure from?
Hmmm...When I measured my OEM 3rd cat pipe, there was 7" between the end of the substrate and the flange.
Where did you measure from?
| thechickencow | 02-02-2006 09:56 PM |
[QUOTE=fliz]That's always the theory I've heard, and why rally cars run the cat in place of the muffler in the back. Well, that also allows them to whack it with a stick if it clogs.[/QUOTE]
I ran mine back there because it was easier to tuck up high too there - straight pipes under the car are less likely to be smashed than a big ol' cat.
I used the $50 3" catco on ebay on the rally car - no issues with it and the car had plenty of power (more than any STX car).
I ran mine back there because it was easier to tuck up high too there - straight pipes under the car are less likely to be smashed than a big ol' cat.
I used the $50 3" catco on ebay on the rally car - no issues with it and the car had plenty of power (more than any STX car).
| abaxter34 | 02-02-2006 09:59 PM |
if i remember correctly i think i measured from the end of the heat shield. its part of the cat as far as im concerned. also, my catless downpipe's flange doesnt came back as far aft as the oem midpipe flange. when i switched downpipes it pulled my exhaust forward and caused it to hit the rear sway bar. plus, the conventional plate type flanges use less room then the oem donut type.
| PhilC | 02-03-2006 09:04 AM |
We're running the PDE with the cat right up close to the turbo. In fact I'm pretty sure the PDE might actually put the cat closer to the turbo than the stock downpipe. Only problem I've had with it so far is that the cat is actually too close to the turbo to find a good spot for a wide band bung to be welded in.
If I saw a car that was winning at a big event with a cat in the cat back section only I'd protest it. I've measured the things too and unless your downpipe moved your flange three inches closer to the turbo there is no way that you're within 6" of the stock cat. The heat shield is most definitely NOT the catalytic converter, the substrate itself is the converter and it's a good 7+" from the stock flange to the substrate.
If I saw a car that was winning at a big event with a cat in the cat back section only I'd protest it. I've measured the things too and unless your downpipe moved your flange three inches closer to the turbo there is no way that you're within 6" of the stock cat. The heat shield is most definitely NOT the catalytic converter, the substrate itself is the converter and it's a good 7+" from the stock flange to the substrate.
| KSwrxWAGON | 02-03-2006 10:22 AM |
[QUOTE=PhilC]If I saw a car that was winning at a big event with a cat in the cat back section only I'd protest it...the substrate itself is the converter and it's a good 7+" from the stock flange to the substrate.[/QUOTE]
Different catalytic converters will have different dimensions of catalyst (radius and length). This is an area that will need to be clarified in the rules. The easy way is to look at a stock flange in relation to the heat shield and then measure the new cat flange distance to the heat shield.
The overall goal is to maintain compliance with emissions regulations. If you measure from the substrate, are you measuring from the beginning or end of the cake? This would have a huge impact on the location if the new cat substrate isn't as long as OEM. In the same regard, if both cat dimensions were the same, moving the flange 6" downstream moves the substrate the same amount, right? :confused:
BTW, I'm not winning any large events anytime soon so I hope someone else does so we can see what happens.
Different catalytic converters will have different dimensions of catalyst (radius and length). This is an area that will need to be clarified in the rules. The easy way is to look at a stock flange in relation to the heat shield and then measure the new cat flange distance to the heat shield.
The overall goal is to maintain compliance with emissions regulations. If you measure from the substrate, are you measuring from the beginning or end of the cake? This would have a huge impact on the location if the new cat substrate isn't as long as OEM. In the same regard, if both cat dimensions were the same, moving the flange 6" downstream moves the substrate the same amount, right? :confused:
BTW, I'm not winning any large events anytime soon so I hope someone else does so we can see what happens.
| fliz | 02-03-2006 11:48 AM |
It's pretty specific. The inlet of the new cat must be no further downstream than the original exit of the final OEM cat.
The most restrictive interpretation of that is that the inlet and original exit refer to the substrate. This is easily measured by sticking a tape measure in the end of the pipe.
You could argue that the "inlet" and "exit" are not the substrate, but where the exhaust necks back down to pipe dimension, which would give you some wiggle room, but still not enough to put a cat in the catback section.
BTW...there was a protest lost on a Civic at nationals last year that moved the cat 9", so the SCCA has a method to determine the inlet and exit of the cat. I just don't know what that is...
The most restrictive interpretation of that is that the inlet and original exit refer to the substrate. This is easily measured by sticking a tape measure in the end of the pipe.
You could argue that the "inlet" and "exit" are not the substrate, but where the exhaust necks back down to pipe dimension, which would give you some wiggle room, but still not enough to put a cat in the catback section.
BTW...there was a protest lost on a Civic at nationals last year that moved the cat 9", so the SCCA has a method to determine the inlet and exit of the cat. I just don't know what that is...
| PhilC | 02-03-2006 01:12 PM |
In the case of the Civic it was an STS car and they aren't allowed to move the cats at all. I had heard that it actually had been moved more than 6" and wouldn't have been legal for STX but they had the header cut apart and welded back together shorter before that car ever ran in STX.
IMHO, the only possible method of measuring where a catalytic converter begins and ends is the beginning and ending of the substrate. The heat shields can be configured any way you want and the necking of the pipe can as well. Where the substrate begins and ends is easily measured and not arguable.
IMHO, the only possible method of measuring where a catalytic converter begins and ends is the beginning and ending of the substrate. The heat shields can be configured any way you want and the necking of the pipe can as well. Where the substrate begins and ends is easily measured and not arguable.
| abaxter34 | 02-03-2006 10:14 PM |
[QUOTE=PhilC] The heat shields can be configured any way you want and the necking of the pipe can as well. Where the substrate begins and ends is easily measured and not arguable.[/QUOTE]
so youre going to take apart the exhaust and stick a tape measuer inside the cat until it hits the substrate to measure for a protest? the heat shield on the stock cat ends at the rear bottleneck, which is a good 3-4 inches aft of the substrate. the cat functions as a unit with the bottlenecks on the steel casing. in my definition, that hole piece, bottleneck to bottleneck is "the cat". when you buy an aftermarket cat it comes built with the bottlenecks, right? (at least the ceramic ones do, not the metal substrate cats) the rule book says, "cat placed not more than 6" after the original exit of the last factory cat". it doesnt say anything about where the substrate gets moved to.
so youre going to take apart the exhaust and stick a tape measuer inside the cat until it hits the substrate to measure for a protest? the heat shield on the stock cat ends at the rear bottleneck, which is a good 3-4 inches aft of the substrate. the cat functions as a unit with the bottlenecks on the steel casing. in my definition, that hole piece, bottleneck to bottleneck is "the cat". when you buy an aftermarket cat it comes built with the bottlenecks, right? (at least the ceramic ones do, not the metal substrate cats) the rule book says, "cat placed not more than 6" after the original exit of the last factory cat". it doesnt say anything about where the substrate gets moved to.
| mccanixx | 02-04-2006 07:47 AM |
[QUOTE=abaxter34]so youre going to take apart the exhaust and stick a tape measuer inside the cat until it hits the substrate to measure for a protest? the heat shield on the stock cat ends at the rear bottleneck, which is a good 3-4 inches aft of the substrate. the cat functions as a unit with the bottlenecks on the steel casing. in my definition, that hole piece, bottleneck to bottleneck is "the cat". when you buy an aftermarket cat it comes built with the bottlenecks, right? (at least the ceramic ones do, not the metal substrate cats) the rule book says, "cat placed not more than 6" after the original exit of the last factory cat". it doesnt say anything about where the substrate gets moved to.[/QUOTE]
I think that this is one of the more clear rules in the book, and my interpretation is also the actual substrate not the housing that it's in.
If that we're the case you could say the downpipe's the inlet and the tailpipe's the outlet. I mean it's all one unit once it's bolted toghther. So with that definition the whole exhaust is "the cat" Maybe i'm on to something.
As soon as someone makes a cat that is small and efficient you won't have bottle necks, they'll be the diameter of the exhaust tubing. The shape of the housing it's in is irrelevant. It's the material in the housing that's the Catalytic Converter.
I also think it would be protestable.
And you wouldn't have to take apart the exhaust to measure in a protest. You could take a 1000 of your year stock Subaru's measure from centerline of axle, or some other fixed point, and that stock substrate would be within mm's of each other everytime.
Measure on protested car same method. If your cat starts more than 6" after the stock cat stops. Hmmmm?
I think that this is one of the more clear rules in the book, and my interpretation is also the actual substrate not the housing that it's in.
If that we're the case you could say the downpipe's the inlet and the tailpipe's the outlet. I mean it's all one unit once it's bolted toghther. So with that definition the whole exhaust is "the cat" Maybe i'm on to something.
As soon as someone makes a cat that is small and efficient you won't have bottle necks, they'll be the diameter of the exhaust tubing. The shape of the housing it's in is irrelevant. It's the material in the housing that's the Catalytic Converter.
I also think it would be protestable.
And you wouldn't have to take apart the exhaust to measure in a protest. You could take a 1000 of your year stock Subaru's measure from centerline of axle, or some other fixed point, and that stock substrate would be within mm's of each other everytime.
Measure on protested car same method. If your cat starts more than 6" after the stock cat stops. Hmmmm?
| PhilC | 02-04-2006 08:00 AM |
[QUOTE=abaxter34]so youre going to take apart the exhaust and stick a tape measuer inside the cat until it hits the substrate to measure for a protest? the heat shield on the stock cat ends at the rear bottleneck, which is a good 3-4 inches aft of the substrate. the cat functions as a unit with the bottlenecks on the steel casing. in my definition, that hole piece, bottleneck to bottleneck is "the cat". when you buy an aftermarket cat it comes built with the bottlenecks, right? (at least the ceramic ones do, not the metal substrate cats) the rule book says, "cat placed not more than 6" after the original exit of the last factory cat". it doesnt say anything about where the substrate gets moved to.[/QUOTE]
In point of fact that is EXACTLY what I would have done in a protest situation, disassemble an exhaust at the stock donut gasket location, it's two whopping bolts, stick a tape measure in and get the definitive answer on where in the pipe the substrate is located in 30 minutes, 25 of which is for the car to cool down so you or the protest committee doesn't burn themselves. In our case where the PDE has a cat up near the turbo I would fully expect that the downpipe would be removed and the substrate would be checked to see if it was actually there. I'd demand a tear-down bond for the cost of a new turbo to downpipe gasket and we'd go ahead with the protest. Tearing down an exhaust is a LOT faster and easier than some of the teardowns that the protest committees have been asked to do in the past. The catalytic converter IS the substrate, the rest is just pipe or heat shield. Without measuring the substrate how would you know if it isn't a gutted cat which is no longer a cat by anyones definition?
If I thought it was necessary I'd bring my stock cat sections to the event with me to have as our comparison since I'm reasonably certain that the factory service manual doesn't give a dimension on that one, or we could probably find a few cars in grid even at Nationals who kept their stock third cat to compare to. I don't think it will ever need protested on a WRX at a big event because you're the only person I've ever heard of putting a cat in the cat back area and thinking it might possibly be legal.
In point of fact that is EXACTLY what I would have done in a protest situation, disassemble an exhaust at the stock donut gasket location, it's two whopping bolts, stick a tape measure in and get the definitive answer on where in the pipe the substrate is located in 30 minutes, 25 of which is for the car to cool down so you or the protest committee doesn't burn themselves. In our case where the PDE has a cat up near the turbo I would fully expect that the downpipe would be removed and the substrate would be checked to see if it was actually there. I'd demand a tear-down bond for the cost of a new turbo to downpipe gasket and we'd go ahead with the protest. Tearing down an exhaust is a LOT faster and easier than some of the teardowns that the protest committees have been asked to do in the past. The catalytic converter IS the substrate, the rest is just pipe or heat shield. Without measuring the substrate how would you know if it isn't a gutted cat which is no longer a cat by anyones definition?
If I thought it was necessary I'd bring my stock cat sections to the event with me to have as our comparison since I'm reasonably certain that the factory service manual doesn't give a dimension on that one, or we could probably find a few cars in grid even at Nationals who kept their stock third cat to compare to. I don't think it will ever need protested on a WRX at a big event because you're the only person I've ever heard of putting a cat in the cat back area and thinking it might possibly be legal.
| The Deliverator | 02-12-2006 08:31 AM |
I'd suggest an Arvin Meritor 'Metalcat'. 200 cell, true metal substrate. You can find 'em for ~$135 shipped.
Random Tech's cats, afaik, are 400 cell and I've had bad experience with 'em in the past. The one I had a few years ago fell apart- first the bottom heatshield fell off, then the top one came loose. Then the brick inside started to disintegrate and when it wasn't rattling around it made for a terrific cork.
The other high flow cats out there also seem to be 400 cell and it's not clear whether or not they have a metal substrate- different vendors say different things about the same part #'s.
Random Tech's cats, afaik, are 400 cell and I've had bad experience with 'em in the past. The one I had a few years ago fell apart- first the bottom heatshield fell off, then the top one came loose. Then the brick inside started to disintegrate and when it wasn't rattling around it made for a terrific cork.
The other high flow cats out there also seem to be 400 cell and it's not clear whether or not they have a metal substrate- different vendors say different things about the same part #'s.
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