apexi n1

[nsng20]

Ok guys im just looking for some input here. Now im thinking of getting the apexi n1 universal muffler for my 96 g20t. You think getting it made custom from the cat back to the n1 muffler is worth it(itll cost between 300 to 400 dollars). So im just lookin for some input. And if anyone has any other ideas please tell me thanks. peace

[paradyme]

Hey nsnG20, if your gonna spend that kind of money you might as well get the 5ZIGEN fireball catback exhaust for $494.00....Check it out at,
www.autocarparts.com

:flash:

[NismoG20]

the N1 sounds good as shit!

i have a freind with the dual N1 on his 240sx and a freind with a just a universal N1 on his 96 G20 and it sounds deep and shit!

[AznVirus]

if you are going to get it, make sure you get it for a NA car, not the turbo one. your going to loose backpressure = less power, if you go with the turbo one. dont make the diameter of the piping bigger than 2 1/4 inch either.

[gdalton]

The 5zigen fireball cat-back says the pipe diameter is 60.5 mm or roughly 2.36 inches do you guys think that might be a little too big. You see I want to keep my low end so do you think a 2" custom cat-back to a fireball universal would be better for low end than the cat-back they already have?

[killick]

Re: the N1, jmgladden (here in AF) has one on his G. Might contact him and see what he thinks of it.

BTW: regarding the back pressure issue ... the whole reason of going with an aftermarket exhaust system in the first place is to REDUCE back pressure to INCREASE power. An engine is just a big heat pump. Back pressure is the pressure in the exhaust system that must be overcome to force the expended byproducts of compustion out of the cylinder. Increased back pressure increases the work required to do this. Power is the rate of doing work.

Hence, increased back pressure = increased power drained to get rid of the crap out the tail pipe. We jump through hoops to gain an extra hp here and another there (CAI, underdrive pulleys). BP constitutes another of those parasitic losses, one that can be reduced with a free-flowing exhaust system.

[killick]

Originally posted by killick
... An engine is just a big heat pump. ...

Oops... sorry... had the terms heat engine and air pump goin' round in my head at the same time... <sigh> been a long day.

An automobile engine is a heat engine not a heat pump. You can think of it as an air pump, however w.r.t. back pressure.

The rest of the post still applies.

[gdalton]

Originally posted by killick


BTW: regarding the back pressure issue ... the whole reason of going with an aftermarket exhaust system in the first place is to REDUCE back pressure to INCREASE power.

Yes I agree with the backpresure argument (less = more hp) however a 2.0l engine needs a smaller diameter exhaust to keep the flow going at a higher rate of speed in other words a big exhaust, like a 3" for example, will cause the gases to swirl at low rpm's because the engine will not put out enough to fill the tube completly. That is the theory that Mike Kojima talked about in a few of his write ups about exhaust. I was wondering if a 60.5mm exhaust might be a little on the big side and maybe going a little smaller like a 2" would help keep the low end power while still giving a little extra on the top end. If I'm completly off base then let me know.

[T4 Primera]

Originally posted by gdalton


Yes I agree with the backpresure argument (less = more hp) however a 2.0l engine needs a smaller diameter exhaust to keep the flow going at a higher rate of speed in other words a big exhaust, like a 3" for example, will cause the gases to swirl at low rpm's because the engine will not put out enough to fill the tube completly. That is the theory that Mike Kojima talked about in a few of his write ups about exhaust. I was wondering if a 60.5mm exhaust might be a little on the big side and maybe going a little smaller like a 2" would help keep the low end power while still giving a little extra on the top end. If I'm completly off base then let me know.

The aim is to get low backpressure and high exhaust gas velocity. The high velocity helps create low pressure areas at the exhaust ports when the exhaust flow is interupted by either the piston slowing near the top of it's stroke, or the exhaust valve closing.

This low pressure can help get rid of the remaining exhaust in the unswept volume of the combustion chamber leaving a more empty space for the intake charge to fill. It can also maintain a low pressure in the exhaust port for when the exhaust valve next opens, so that your engine uses less power to push the exhaust gas out.

The process depends on the inertia of the exhaust stream which is dependant on the velocity. To simulate what I mean, next time the bathtub is draining, place the palm of your hand over the plughole and you'll feel the column of water that was travelling down the drain try to pull your hand in after it - same sort of thing.

2 1/4" pipe is about the maximum useful pipe size depending on how much horsepower you have. It will be adequate for bolt-on type horsepower on an NA engine.

nsng20, I highly recommend you read these articles by Mike Kojima before parting with your money:
http://www.speedoptions.com/ click on the hot tips tab, start at page 12 and work your way to page 1 reading all Mikes articles along the way. If the beginning articles are basic for you then skip through to the exhaust articles.