i just bought a j's racing exhaust and i also plan on getting either an amuse header or a toda header. i'm nt sure when i will be getting the header, but the exhaust is on the way. now i was wondering should i get a test pipe now, or wait until i have the headers? or is a test pipe a waste of time in general? thanks in advance.

 

Some people have reported that they lost power by installing a test pipe. You will also have to deal with the CEL by using an O2 simulator.

Then there's the legal and environmental issues...

 

[QUOTE]Originally posted by gernby
[B]Some people have reported that they lost power by installing a test pipe.

 

Dyno # is hard facts. what you feel can mostly be effected by you emosions and is really effected by how much $ you spent.... it seems that more $ the more likely to 'feel' it gives you power..

 

I heard really good things about the Toda Header. As for the test pipe, this guy who i talked to had one and he said, it makes the car get to it's top speed faster than without it. Then again, Speeeding lost power on his n1. I don't know what that means.

 

i used the spoon - test pipe with my j's racing - n1 when i first installed it, but it smelled really bad, so i removed it after about a month and a half.

i cannot tell you about gains though, 'cause i didn't a dyno with it on.

edit: i also removed it, 'cause i got horrible gas mileage.

 

I probably wouldn't recommend test pipe unless you can tune with VAFC, etc., or use an aftermarket ecu.

 

Anything that restricts flow which a catalytic does takes away from performance. The less restriction your exhaust has the better the flow giving your car more power. Its a simple fact. Although no exhaust is the best exhaust. I have no cat. and my exhaust does flow much better. IMO get the the straight pipe. Plus emission is not an issue in Florida since they have removed inspections

 

Ditto...removing cat=less restriction

Normally that means more power and it should give you more power assuming you can fool the stock ECU into reading the correct resistance from the O2 sensor.

Whomever lost power with the N1 probably dynoed the car right after removing the stock catback...it is impossible to lose power when removing the stock cat-back. No matter what dyno you show us, the test parameter were not the same, as far as the stock ECU is concerned. I would bet if the dyno had a wide band A/F sniffing the exhaust, you will find during the N1 run the A/F was probably 11:1 or maybe as much as 10:1 ( I have seen 10:1...that's super rich for turbo cars!). The stock run was probably at 12:1 or 13:1 if it was cold.

Any dyno plot must have a wide band logging the info otherwise you really have no idea what program the stock ECU was running and you are wasting your time. No logging means no data. A dyno is not data.

When you remove the cat, the car will run very rich. Hence the smell and I would bet your rear bumper was sooty and required paint cleaner every car wash. If you lean the mixure (not sure using what) you will gain more power no question. The problem is how do you clean up the part throttle maps. These are the maps that will improve drivablity and you will notice the biggest difference. With VAFC, I believe there was an issue with TPS setting below 50%, where the stock ECU will over-ride the VAFC, but at WOT the VAFC took over.

The only solution is to use a standalone, but that will open a big can of worms.

Truth is, the stock cat is a very high flowing metallic unit. The cross-sectional photos I saw indicate this is no old school brick cat, but a very nicely wound metallic cat that creates the least amount of back pressure (in reference to other cats on the market). You will have to go to a 4" or perhaps 4.5" ID tubing on an aftermarket brick type cat to get any noticable difference in power from the stock which run a 2.5" ID.

Essentially you have to triple the cross sectional area of your tubing (2.5"->4") to gain anything.

My suggestion is, unless you are willing to do this properly (ie. be able to lean out the mixture) stick to the stock cat because simply removing it will not benefit you much.

Now keep in mind all this work of standalone, assuming you go the whole nine yards, will still not yield much(not for me anyway). What do you think a realistic figure is? 20rwhp? Let's assume 20...how much did that 20 rwhp cost you in time, equipment, parts, labor...et cetra? You're talking standalone, you are talking logging and tuning, probably about 80-100 hours, but even if you were able to do it 50 hours (1 week) I think that's too much. But that's my opinion.

cheers

W

 

swapping a test pipe leads to power loss? possbile since stock ECU needs time to "learn" and maybe the car was running too rich after the cat. was replaced

swapping a test piple with aftermarket ECU=a slight hp gain, also no worries of CEL