Test Pipes on KA pros cons?

[ZenkiSE]

I was wondering if a test pipe/dump pipe on a NA KA would be a negative mod or a pro mod for this type of set-up ? Ill be quiet now so i may listen to your answers.

[adamhu]

it makes power ....but pollutes

[ZenkiSE]

besides pollution it would be something to look into?

[RBS14]

Why do people insist on putting on testpipes when there are aftermarket cats for cheaper than the testpipes you would be buying? Catco makes a 3" inlet/outlet universal cat for $47 through summit racing. I personally own one of these cats, very nice quality. How hard is it to not dump all ur pollutants into the atmosphere? And not to mention it is a Felony to not run a cat. The other thing about running a testpipe on a NA car is that you still need some back pressure, so assuming you had a free flowing exhaust, the cat is the only other source of backpressure.

[kbounds]

Good advice about the cat, but please don't tell people they need backpressure. That myth has been around forever, please don't spread it. NA needs velocity, not backpressure.

[RBS14]

well it depends if you want any torque, if all you want is top end, yes you are right. Take your stock exhaust off and see how much torque your car has.......... then put it back on and see.

[ZenkiSE]

thank you RBS14 for your input like i said it has been given to me i will be marrying it up to an Espelir catback so i was wondering if this would be a good set-up. I understand about the pollution factor and it is noted as well. BUT i do not live in Cali so i don't really worry about this

[nissantuner22]

...thats because you lose velocity, like kbound said. backpressure= bad velocity= good

[RBS14]

ZenkiSE: I'm concerned about emissions simply because i don't want to get some gnarly disease or cancer in the future from horrible air quality........ not because i live in cali. But that's just me.....

[ZenkiSE]

i wasn't comin at you RBS14 sorry if you took it that way. But i do appreciate your feedback

[RBS14]

nah not at all, no hard feelings .......... i'm just in a bad mood, sorry if i sounded like a dick. I wanna hear a sound clip of that exhaust when you get it on!

[ledzeppelin240]

Vavle Overlap...

You can't control your overlap without changing the cams, but the effects caused by changing the back pressure are the same. When you reduce back pressure, it is equivalent to increasing valve overlap, and when you increase back pressure, it is the same as decreasing the amount of valve overlap. That's why some people will say, "you need a muffler for torque", or, "you'll have more high-end, but less torque, if you run straight exhaust". They are right, but a muffler's purpose is to reduce sound output, not horsepower! By reducing back pressure in an exhaust system, you increase high-end horsepower at the cost of low-end torque.

You can compensate for this by increasing the velocity of the intake charge. Increasing the intake velocity has the added side effect of increasing back pressure, because there is more air to be evacuated during the exhaust stroke. Note that if you increase intake velocity past the limits of the exhaust system, the gains you achieve are diminished to the point of being non-existent. That power will be there when you do upgrade the exhaust system, which is why something as simple as upgrading the exhaust system can result in huge horsepower gains.

You can decrease back pressure by increasing the size of your exhaust manifolds, or using separate tubes for each cylinder (called headers). Increasing the size of the exhaust pipe and decreasing its length also helps, as well as installing high-flow catalytic converters and mufflers. Of course, you could just cut them off. Although it is illegal in the United States to remove the catalytic converter in a registered vehicle, the muffler is a different story...

Backpressure is useless in a car when someone is trying to get more power..Thats it

[KaKa]

Well just to state the obvious and for anyone who doesn't know, it depends if you're actually replacing the cat and not the resonator or "dummy cat". On an S14 the cat is actually bolted right after the exhaust manifold, followed by what looks like a cat. If you have an aftermarket header and don't care abour the air and noise pollution get that test pipe.

[BlackS14]

I just installed a Catco Hi-flow cat a few days ago....coupled with my Hotshot header and Apexi N1 exhaust. I actually couldn't imagine adding testpipe instead....the noise would be unbearable (it was with my damn "hollow cat" on)....not to mention the pollution factor.

Wih the Catco, I doubt there was any real loss of power (if there was...you won't be able to tell) and the way it made the car feel sooo much smoother was the best part. It still has a very nice tone to it and being enviro-friendly is a plus....

-Bill

[ryan hagen]

i have a test pipe, it soudns like ass,so i got this muffler that looks liek a cat from ebay havent tried it yet, it was ment jsut as a muffler but it looks like a cat witha stamped body, i ll get a hi flow cat when i get my turbo stuff done,
oh the reason i took my cat out was i took out my air pump so to stop the cat from pluging i took it out

[nismo2491]

I have a bolt in catco cat, bought the universal one, then got flanges and welded it up. I also have a 3" test pipe. I like the environment but not enough to bitch about shit. usually a day or two before a race I'll swap the testpipe in then swap it out a day or two after. there isn't too much of a difference between the two. I did bracket racing one night and decided to test it out, between my first good run with a cat and the one without it I only dropped .08 seconds. (12.89 to 12.81) but gained almost 2 mph. so its really up to you. I'm not sure if the difference between those two runs (I usually run solid 12.80-12.85) was because of the lack of the cat or just because it was later in the night and was cooler. your results may vary but I'm not about to pay a huge ass fine for not running a cat that doesn't really hurt power too much.
KEvin

[holisticbeatz]

FUCK CATCO.. Test pipe allll way, it's wayyy cheaper than buying a Catco or whatever brand hi-flow cat. It's amazing how an 18 inch piece of piping uncorks so much.. It's way worth it but highly illegal in most states.

[nismo2491]

I'll get some dyno numbers later this month on exactly how much hp is gained between the catco high flow and the test pipe. I doubt it would be any more than 1 or 2 hp (Which isn't much when you are putting 400+hp to the ground on the new setup )
KEvin