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How Much Difference Will Swapping Exhausts Make.

SargeRX8

By SargeRX8,
in Engines & Forced Induction

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SargeRX8 Grand Master

SargeRX8

Posted
Posted

Hey all,

Long time since Ive posted here. Anyway just looking to quieten down my car a little. At the moment its got the HKS Silent Hi Power exhaust(the one without the muffler), and its far from silent. Its a 3.5" exhaust pretty much just a long tube to a canon. Ive got another exhaust here which is the 3" Nismo exhaust which has a mid muffler and also the biggest rear muffler Ive ever seen.

If I swap these exhausts out will I notice a big drop in performance? I don't really do anything with the car which needs performance all the time. Just a daily driver to and from work and when out with the mrs. I figured since I granny drive the car I should keep her quiet(after seeing the ACA shit on TV and how cops are going to be cracking down on defective cars and mainly noisy cars, the least attention we attract the better).

I can live with power loss but if its going to cause my turbo to heat up much more rapidly which will raise intake temps and potentially cause det, that is what I can't live with..... We all know how strict HG is about high flowing exhausts with their turbos(SS2).

Any input? Are those nismo exhausts rubbish? Last I heard it on my car, I couldn't even hear the thing at idle and since the stock exhaust isn't even enough to stay legal, this one is quiet enough not to hopefully awake sleepy eyes when I finish those late shifts.

Sinista32 Grand Master

Sinista32

Posted
Posted

Hey Sarge,

What modifications have you got and how hard for how long do you run your Skyline?

Nismo is one of the best quality exhausts.

I dont beleive you will get too much of a drop in performance, the noise is alot quieter.

Hanaldo Grand Master

Hanaldo

Posted
Posted

It's only going to cause a drop in power if it is a restriction. Which I doubt it will be. You mentioned the SS2, is that what you are running? At SS2 power levels, a 3" exhaust should be plenty. Just make sure it is a true 3", a lot of Jap exhaust systems have step-downs to around 2.5-2.75" which may well be a restriction. Not sure if the Nismo ones do this.

AngryRB Grand Master

AngryRB

Posted
Posted

if its quiet it will most likely have a restrictor, when i put my old system on after it had a loud system, the silencer was having effects cause the car was running hotter, not pulling so hard and a couple of times i heard it knocking.. so you may need timing taken out.

SargeRX8 Grand Master

SargeRX8

Posted
  • Author
Posted (edited)

I think TiTAN's statement is correct, its when you find a quiet exhaust with no mufflers(low profile crap you see online) which can shut the sound up but poses a massive restriction. The size of the rear muffler is f**king huge, if you've seen the Nismo exhaust you'll know what I mean. If you haven't its about two times the size of a HKS canon. The mid muffler is nice and big too. The pipes are full 3" all the way to the back. My old HKS was 3" then became 3.5" after the resonator in the middle.

Just fitted on the Nismo, honestly doesn't sound bad at all. It loses that tough raspy sound of the HKS but what I'm left with is a very nice quiet idle and a clean RB note. Only issue now is the damn gasket between the cat and the cat back is shaggered(its the multi plate copper thing). When backing off I can hear the plates flapping around so gonna need to replace it.

My car is all bolt ons(injectors, turbo, dump, ecu etc) for 255rwkw. Most of my drives are on average 15 minutes long. Sometimes the odd 40 minute drive. Never really take it anywhere. When summer rolls by Ill throw the HKS back on if the temperatures are an issue.

Edited by SargeRX8
infamous_t Veteran

infamous_t

Posted
Posted

Main problem with the Nismo 3" catback is the weight (good mufflers!), it flows pretty well.

You'll notice that the exhaust note wakes up after ~4000rpm so it's still good soundwise.

Performance wise you will take a hit from reducing ID of the exhaust, but shouldn't be to noticeable on your power output.

For reference I had that exhaust on my 32R for 4 years while it was daily driven, was a lucky charm with police I reckon because I never got any grief :)

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

Any exhaust system thats going to be quiet, is going to weigh a fair bit... that's just how it works.

You could add a better muffler to the 3.5" system if you wanted. That would most certainly help, two = super quiet.

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