Im looking to upgrade my DP, and have heard that the cat it the biggest restrictor in the system. The couple question I have are,
Does a high flow cat make your CEL come one? And do you smell more gas than with the stock cat? And which High FLow Cat is the one to choose so these things wont happen. All I have now is an Exhale from WORKS.

Also with the DP, will it make the exhaust much louder? I plan on keeping the stock mid pipe with its two resonators. Also the DP Im more than likely going to get will be the HKS.

And if all high flow cats are going to be gas stinky, I think I will pass on that and just get the DP.

I will still see some good gains with just a DP, yes?

Thanks

 

I had the GHL exhaust which has the tiniest-highest flowing cat you'll ever see. Most cats are much bigger than the GHL cat.

The GHL cat never gave a CEL or a bad smell.

I doubt there is a cat out there that will give you a CEL. The second O2 sensor is looking for a drop in emissions from the first O2's reading. Any cat is gonna do that for you.

 

where are the 2 o2 sensors located?
thanks

 

One sensor is located just after the blower in the cast iron piece between the blower and the DP. The other one is in the tail pipe after the cat under the car.

Actually, I believe that most after market high-flow cats tend to eventually cause a CEL. I know that mine did in my WRX with a 3" turbo-back system. I've also heard other ppl experience the same thing. I'm going to go with the test pipe and the AEM EMS. This way the CEL will become a shift light

 

I've got my fingers crossed. I just installed the BR 3" turbo back. So far no SES/CEL but I've only got about 100-150 miles under my belt, with about 50 of those miles with a BR flashed ECU. I read that Buschur had a problem with the CELs but supposedly they revised their design to eliminate or mitigate the issue.

 

Which will show a better performance gain - the high-flow cat or a downpipe?? (don't factor the testpipe in)

 

High flow cat will give more hp over a d-pipe.

 

Bull**** down pipe gives waymore. Downpipe alone gave like 21whp and 23ft/lbs cat only gives about 7

 

Really - didn't know that. I'm running 2.5" cat-back exhaust, so was thinking about a DP for my next upgrade. Should I think about a high-flow cat instead? I think they're cheaper too????


Thanks.

 

Which downpipe did you get? Did you install it - it clear everything ok or not??

 

RMR. only clears one lower tie bar. Not a problem but a real difference. I recommend this to everyone. The difference was outstanding

 

Stock cat is very restrictive!!!!!! Never heard of a downpipe giving that much hp. Where did you get your figures from? A chain is only as strong as it weakest link which would be the cat in this case. Anyways a downpipe should give you an average of 5-7hp max from what ive read and heard from repsective tuners.

 

Dude we dynoed before and after this specific mod at Turbotrix in NJ. Dynosheet somewhere. This mod alone is one of the best available. Sure the cat is restrictive. But the downpipe will free more power which is what the gentleman asked

 

Did you have cat-back already? 2.5" or 3"??

 

I still dont believe a downpipe would free up that much hp. The cat can only let so much air through a time , you could have a 5in pipe behind the cat and only so much air would go though it. 21 Whp is a little extreme. I would understand that if you had upgraded the turbo or something of that nature. But from stock there is no way in hell you could gain that much hp from just a downpipe with the stock cat in place. He was asking which would give more hp , well losing the stock cat would up the hp . I have a 3in turboback from buschur with a high flow cat (with alot more mods). I sure as hell didnt gain no 21whp from just a downpipe DUDE. The stock cat is just like a restrictor you can only get so much out of it.