test pipe questions please?

[1gDsmRacer92]

i went through the search to see if i could find what i was looking for but i couldnt so im going to ask you guys, i was wondering what the pros and cons are of a test pipe over a cat? i have a 96 rs 5spd stock except a magna flow universal race exhaust and a cone filter, just woundering how its going to do for me before i waste my money and get it, and i dont have to worry about emission test cuz i dont have to go through it, thanks.

 

[BigRand]

In my personal opinion, if you don't have to worry about emmissions, go with the test pipe. Way cheaper. As for the gains right now I hope others will chime in.

If your planning on staying N/A I'd buy some headers to go with the test pipe and get em all in at once, that should help get the exhuast air out quicker. not to mention adding a cold air intake or short ram pipe to that filter would help a lot too.

If your going turbo soon, I guess buying the test pipe right now might help, but I'd rather have somone else help him on this.

 

[ShadowWulf]

Ohhhh, in my opinion i dont believe the test pipe vs high flow cat has ever really been adequatly answered with a conclusive dyno graph......alot of people will tell you that on a N/T car you need a certain ammount of backpressure to operate properly, aka from the cat. Removing this can actually HURT performance. Others say that its poppycoks and doesnt matter, remove the cat to go faster.

I personally have a hollowed cat, and its LOUD. Also, its not even close to legal. I noticed a somewhat noticable DROP in my lower range power yet a gain in my higher. You can look over m,y mod list to see everything else i have done, which is alot all except for headers.

Make up your own mind, risk vs reward really. Hell, its an almost free mod but i dont (personally) see it as justifying the time it taks to even complete it. The gains are (again in my opinion) negligable.

 

[bullettdsm]

i went through the search to see if i could find what i was looking for but i couldnt so im going to ask you guys, i was wondering what the pros and cons are of a test pipe over a cat? i have a 96 rs 5spd stock except a magna flow universal race exhaust and a cone filter, just woundering how its going to do for me before i waste my money and get it, and i dont have to worry about emission test cuz i dont have to go through it, thanks.

As I read your question it is the choice of test pipe vs cat. Let's see...? HMM...? What should we choose? I know take the test pipe! In a heartbeat no questions asked! let's see

Cat pros, it helps save the environment (yeah that is a biggie ). It will get you through emissions (for those who need it). Also, uh.. uh.... Oh, it might be easier to sell your car with it on!
Cons it is smelly, it is heavy, it is expensive to replace, it blocks your exhaust path and it is ugly (IMO). If it is old and junky it can set your car on fire (experience).

Test pipe cons; does not save the environment, can set off your engine light, can get your car pulled off the road (for those who worry about emissions), is louder, you can lose low end and may need to make an exhaust bracket.

Pros; louder, inexpensive, looks cool, lighter, no smell, it won't set your car on fire (as long as you install it properly) it has no blockage for your exhaust, you can gain high end.

OK test pipe Winnah!

Now comparing test pipe to "hi-flow" cat is a different story. That's provided that you have a "real" hi-flow cat. I have honestly yet to see it. All that I have seen is basically a resonator being called a hi-flow cat. Same as a test pipe in my book.

As for the back pressure concept, you use 2.5 pipe and some sort of muff you have plenty of back pressure (keep in mind that you will probably lose a little low end).

Ok now, have a nice day,
MB

 

[JRichter]

Now comparing test pipe to "hi-flow" cat is a different story. That's provided that you have a "real" hi-flow cat. I have honestly yet to see it. All that I have seen is basically a resonator being called a hi-flow cat. Same as a test pipe in my book.

As for the back pressure concept, you use 2.5 pipe and some sort of muff you have plenty of back pressure (keep in mind that you will probably lose a little low end).

Ok now, have a nice day,
MB

I think my so called "high-flow cat" is actually a test pipe then. When I got it in the mail along time ago we laughed as you could look right through the thing but the outside resembled a stock cat (you could see some type of mesh along the inner walls of the inside if you looked hard enough).

I definately felt a little loss in low in grunt because it was the last thing put on my entire exhaust swap.

Quick question. Would it make a squat of difference to go from my cheap 4 to 1 header to a 4-2-1 once I get my 60mm t/b put on w/ portmatched itm (turbo kit will be a while off if at all as I'm shopping for another car).

 

[Redmachine]

The Hi flo is definatly a resonator. I just put mine on today,stainless. It looks all pretty mated to the stainless flex pipe, now on the the rest of the stainless exhaust.

BTW I can't tell a bit of difference power wise, It seems louder(louder good *GRUNT*)
I've never heard of back pressure actually being a good thing. Mabey it's a 4 cyl thing. I grew up around v-8's, big blocks small blocks. And nothing ran better than my dads SBC 400 with longtube headers and header mufflers.....and that was it. No exhaust tubing nothing just a big ass cherry bomb right off the collectors.

 

[GSGoinFast]

you guys, those "hi flows" are not hi flow cats. there resonators that look like cats. the term hi flow cat was not just made up for these resonator cat look alikes, they actually do exist i have an ERT one. go to exileracing.com they have 2.5 and 3 inch direct fit ones, although it still set off my CEL after about a month. dont worry, did the resistor mod and no more CEL

 

[Redmachine]

you guys, those "hi flows" are not hi flow cats. there resonators that look like cats. the term hi flow cat was not just made up for these resonator cat look alikes, they actually do exist i have an ERT one. go to exileracing.com they have 2.5 and 3 inch direct fit ones, although it still set off my CEL after about a month. dont worry, did the resistor mod and no more CEL

Yeah I know its a resonator.

You have the instructions on the cel mod? I had them few months ago but they didn't make much sense

 

[GSGoinFast]

Yeah I know its a resonator.

You have the instructions on the cel mod? I had them few months ago but they didn't make much sense

remove your front driver seat(4 bolts, very simple). now lift the slit in the carpet and look under it towards the rear passanger wheel. you should see a cluster of 4 wires going into the floor. cut the carpet enough to get to it and cut the black one and solder in a 1 mega ohm 1/4 watt resistor.

 

[Redmachine]

remove your front driver seat(4 bolts, very simple). now lift the slit in the carpet and look under it towards the rear passanger wheel. you should see a cluster of 4 wires going into the floor. cut the carpet enough to get to it and cut the black one and solder in a 1 mega ohm 1/4 watt resistor.

Thanks man. I'll check that out

 

[1gDsmRacer92]

thabks guys youve actually helped me alot im going to go ahead and get my test pipe, the guy who put my magnaflow on is going to make it for me out of 2 1\4 pipe so it matches my stock exhaust piping and flanges, but i mean if i dont like it all i got to do is bolt my cat back on no biggy and it only going to cost me $30 thats him making it and installing it. thanks again.

 

[wannaspoolRS]

im havin the same delema...its the legality im worried about the cops here are duche bags my friend went with a test pipe in his Lancer OZ and he felt a good increase in HP... hes not turbo either. I think i will go with it though... i have Pacesetter headers and downpipe, and cat-back Apexi N1 exhaust system...i love that N1...lotta power...anyway let me know what you decide to do

 

[1gDsmRacer92]

im havin the same delema...its the legality im worried about the cops here are duche bags my friend went with a test pipe in his Lancer OZ and he felt a good increase in HP... hes not turbo either. I think i will go with it though... i have Pacesetter headers and downpipe, and cat-back Apexi N1 exhaust system...i love that N1...lotta power...anyway let me know what you decide to do

im going to get mine next week so as soon as i get it on and drive her around a lil ill post what she feels like and how she sounds, it should sound awesome with that magnaflow on there, man i love that exhaust, but i will keep you posted it, oh yea how do you like that pacesetter header? feel any gains from it, im always hearing bad things about em is why im asking.

 

[XMasta19]

Bolting on a test pipe always throws a CEL since the o2 sensor isn't hooked up anymore right? If you get one of those "high flow" cats with an o2 bung, will it still throw the code as well?

 

[97eagletalonesi]

on my 97 talon there are no senors on the cat only after it. i removed it and had a pipe welded in its place. no cel. came on once or twice in the month that i had it done i just reset it so far nuthin

 

[XMasta19]

Well yea, the second o2 sensor is in the back part of or behind the cat, it's there to make sure your cat is doing it's job. So, if you remove the cat and it doesn't read what it's wanting, then it throws that cel. Thus, the lifting of the seat and inserting resistor to trick the ecu into seeing the voltage it wants and thinking the o2 sensor is happy. So, does that mean one of those "high flow" ones with an o2 bung won't cause the cel, or will they do it too since they aren't really doing what your stock catalytic converter does, and the o2 sensor still won't read correctly?

 

[Below Ambient]

when i had my N/T with exahsut the biggest thing i regretted was pulling my cat... that thing needed the backpressure... do ask me why... it was alot quicker before I pulled it off...

 

[GSGoinFast]

Well yea, the second o2 sensor is in the back part of or behind the cat, it's there to make sure your cat is doing it's job. So, if you remove the cat and it doesn't read what it's wanting, then it throws that cel. Thus, the lifting of the seat and inserting resistor to trick the ecu into seeing the voltage it wants and thinking the o2 sensor is happy. So, does that mean one of those "high flow" ones with an o2 bung won't cause the cel, or will they do it too since they aren't really doing what your stock catalytic converter does, and the o2 sensor still won't read correctly?

no there is no bung in the test pipe, its after the pipe in the cat-back. the resistor will stop the CEL from coming up.

 

[97eagletalonesi]

the thing is, it throws no cel. did 1 time

 

[bullettdsm]

the thing is, it throws no cel. did 1 time

Hey, lucky you! I wish I was so lucky but I will be doin' the resistor fix when I get a chance, thanks GSGoinfast.

As for Below Ambient, I'm gonna take a guess that you did no porting to the intake or any opening up of the TB. This is what I have learned about the back pressure (but I really can't tell you the science behind it). With the big 8s that we played with if you were running maybe a 650 Holley and cams with a open headers you would stand a chance of suckin' an exhaust valve on de-celeration. If you opened up your intake side (P+P bigger carb) you would probably not have this problem. It had to do with efficient use of the airflow (it has been explained to me by a few people but not to my satisfaction - or maybe comprehension - but it has to do with the high RPM airflow actually creating a vacuum on the EXHAUST side under those conditions). Anyway, I would think that the 4 cyl are under the same rules.
MB

 

[wannaspoolRS]

Bolting on a test pipe always throws a CEL since the o2 sensor isn't hooked up anymore right? If you get one of those "high flow" cats with an o2 bung, will it still throw the code as well?

Get a brand new Bosch Platinum O2 sensor...after i had my headers put on i dont think that the stock one could handle the heat, the Bosch one runs awesome, they are quick install...its matching colors...well unless you are color blind...i had a prob. w/ the black wires..thers 2 of em...go to bosch.com and it'll tell you which is which.