What exhaust system setup will give me the best power gains for my NX?

[Woodyboy]

I’ll be getting a few quotes for a full exhaust system over the next few weeks – thinking of going with some thing like extractors with 2” mandrel bent pipes. Not too sure if I’m going to get a cannon and if I’m going to get stainless. Just want something not too ricey. Any suggestions/opinions?

[wingnut]

if ot's an sr20
go 2 1/4 it will flow better

[sicknx]

yes i agree with wingnut... i got a 2 1/4 with extractors and goes very well

[NX EXA]

What would you say for the 1.6 litre? 2" pipe?

[GPexa]

ga16de? 2" for sure :)

I'd still say 2" on an sr20, but that's just me, most'll say 2.25"

[rednxcoupe]

depends on the bends
if you go mandrel 2" will do the job just fine:driving:

[Woodyboy]

I booked my car into an exhaust shop to get the new exhaust system put on next week. I’m going with press bends due to being told I would only gain a couple of kilowatts with mandrel bends - not really worth the expense.

I’m still weighing up whether to go with 2” or 2.25”. I’ve been told 2.25 because the extractors are 2.25” and I should go with the same diameter all the way through. On the other hand I was told I would end up with more droning in the cabin with 2.25” - however a longer resonator could overcome this.

Also going with an oval shape stainless steel muffler with probably a 3” tip. I’m getting stainless steel as it’s suppose to have a deeper sound and obviously last longer. The place I have booked it into is going to Dyno it before and after for free as well.

[rednxcoupe]

what are you going to do about the cat
keep the standard or get a slightly larger one?

[Woodyboy]

I was told the standard cat on the SR20DE is pretty good and so it isn't worth replacing.

[DIDZ]

I have Extractors and 2" Mandrel. It's all good to me :)

[iceman]

Woodyboy, ignore that opinion... pretty good doesn't equal perfect. Check out Random Technology, they make high performance catalytic converters, and they're not too bad on the pocketbook either.

If anyone from the US is interested, check out this site: SR20developement (http://www.sr20development.com/SR20/SR20_DEVELOPMENT_PRODUCTS.html) They provide tons of aftermarket support for SR20 powered vehicles. They have some very nice turbo and n/a specific exhaust available and I believe some headers/extractors.

-Ice

[Pretty White]

There is a company in Florida making a cat back in either mild steel or stainless for the NX now. And they are going ot be reasonable, they are the pipes cut in sections. Or full exhaust.
http://www.sr20forum.com/showthread.php?t=65923

[iceman]

May want to contact Andreas Miko if you're checking out that forum, I think he's got an exhaust he makes...and as you're probably aware, he's the man.

[NXT51]

Hey Woodyboy did you get your exhaust done??

I'm trying to figure out what to do with mine.

Already have the extractors (birthday present) but quote for mandrel bent, 2 1/4" minus the tip (I'm gonna buy) is $635. This includes a NEW catalytic converter which I think is about $300 of this price...

What do you guys think?

[tissue]

I just (as in today) got my exhaust done, 2in mandrel bent in mild steel, with new flex pipe, new muffler and 18in resonator, no tip, reuse stock cat converter and i supplied my own extractors (x-force) for $500. Sounds good and looks good too.

2 1/4" is pretty big for mandrel bent, id stick with 2" mandrel or 2 1/4" press bent.

[Lonx]

Good choice.... I would've recommended 2" mandrel or 2.25" press bent but don't check the B13 section as often as I should. Unless u're planning to do a bit of headwork and there's a chance of more after this, I'd stick to this on any SR20DE.

[jazza]

Depends on howw much work your puttin into it.
2.25' mandrel bent is good for anythin around or over 100kW @ wheels.
A filter and zorst will give u around 85-90kW @ wheels in an sr20de.
So if ur goin to change management, do some headwork as brenden said or even proper aftermarket management then ido go the bigger exhaust as it will flow better for abit more power!
Otherwise if ur keeping the mods limited go 2' mandrel, or 2.25' press bent.
Id also be getting the hi flo cat as its just another restriction in the zorst u dun need.

[DangerMouseNx]

take that nasty cat converter out, and smash the guts out of it, not possible if you are in a state that has ppl checking emissions, is possible up here so i did it when i had the 2.25 system put on. ive been told by reasonably good sources, that a cat converter only reaches temperature to operate properly after 300km and is only efficient for 5000 miles. he may have been given dud info, but we smashed mine out, and the one on his bmw 1150 and its definately made a difference, couldnt tell you in kW or anything but it flows a hell of alot better.

[Woodyboy]

Hey there NXT51, I got mine done back in January (check out the images on my CarDomain site if your interested).

From what I have been told I would go with what jazza and a few others have recommended “if ur keeping the mods limited go 2' mandrel, or 2.25' press bent”.

As for the cat converter I guess it’s up to you if you're willing to take the risk of being caught if you do gut it – I think there is some pretty heavy fines if you do get caught but not sure. I was told to keep the original cat because in terms of value for money it wasn’t worth getting a high flow one – just like going for mandrel bends (you’ll only get small gains compared to money spent).

In the end though it’s up to you – Do you want the best performance setup or would you prefer a better value for money setup? Anyhow the price you were quoted doesn’t sound too bad to me.

[wheelspin]

When I had my exhaust done I had a range of different opinions. Some of the dimema's I had were:
- 2" v.s 2.25". Some recommended 2.5"
- Mandrell vs press
- Mild vs Stainless
- Catback vs full system
- original vs hi-flow cats
- etc, etc...

In the end I went for a 2" mandrell bend in mild steel, 12" resonator, 2" straight through mild steel muffler and the original cat. Final result? $250 lighter in the wallet and 89kw at the wheels.

[jazza]

so u didnt get headers? And u have a stock cat, and still 89kw.. damn sr20s no fair!