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a nice sounding exhaust for n/a

rainster

By rainster,
in Engines & Forced Induction

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rainster Explorer

rainster

Posted
Posted

hope this helps a few people out there in regards to nice sounding legal and powerful exhaust system .after alot of trial error with mufflers and resonator i have assembled a nice sounding exhaust it comprises of 2 1/4 pipe one 18'' expansion chamber coby muffler fitted where the cat was,as for u guys in oz fitt a shorter resonator 16'' expansion chamber type next in line with cat . run straight pipe 2 1/4 all the way up to the rear of car then either a large body straight through twin tip 2.5'' muffler or a 16'' straight through a 2.5'' core come out at 4'' with a provision for silencer use the silencer, give you enough backpressure to help with scavenge of exhaust gasses and prevents burnt exhaust valves still sound deep at idle and crisp sounding at mid to high revs also run coby extractors make a huge difference slightly in low rev and very noticable in mid to high revs. only adjustment had to do was idle air bleed scew adjustment to give smooth idle due to better flowing exhaust i have found it to have more torque and quicker acceleration .i havent dyno to show figures but works well for me and im very fussy when comes to making cars go well and sound well .also if u use a straight through type muffler comeing out 4 '' make sure u use silencer other wise it is extremely loud

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Screamin' Skyline Rookie

Screamin' Skyline

Posted
Posted

All I got is the standard bore pipe (2" I think) headers and three coby's all about 15" long. The car has made 120rwkw on the dyno with this set up, how ever she only ran 108rwkw the other day :confused:

Anywho, I think the important thing is to avoid using stainless anything on the system as this resonates badly with the N/A's.

Also, a turn-down or dump pipe at the end will keep the bark away too.

I get many comments on how good it sounds :D yay!

rainster Explorer

rainster

Posted
  • Author
Posted
How about a 3" straight pipe? it will sound very mean. Probably be about 110 db.

i think 3'' a bit extreme.your dead right it would be very load it would sound like youre exhaust fell off.also you would loose a heap of power down low,only turbos modified could run that size and sound good,the turbo helps push the exhaust gas out,wear as n/a need a certain amount back pressure and smaller pipe size create scavenging to draw exhaust gas out and give good low down throttle responce .

Jago Mentor

Jago

Posted
Posted

can't have a quiet exhaust which gives good power. Plain and simple.

I'm gettin a 3" turbo back exhaust chucked on an ECCS RB20'd R31 GTS-x, won't be too bad :D

If you want lower pitched sounds then get mild steel, the thickness/density etc absorbs higher frequency sounds better.

dondesoto Community Regular

dondesoto

Posted
Posted

ive got 2 1/4 " pipes 1 x 18 " muffler and the cat converter and extractors . sounds deep at idle up to a great screaming noise at peak revs ,( yeah bit hard to describe exhaust sounds . its a bit loud overall , but tolerable

NA_R33 Grand Master

NA_R33

Posted
Posted

mine used to run a modified 2 1/2" collector off the coby extractors, straight through to a 2 1/2" 16" long cannon no cat... sounded unreal!! though any drive longer then 1/2 an hour resulted in headaches..

rainster Explorer

rainster

Posted
  • Author
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i have being told by a few exhaust shops that you can have two identical models of car fit the same identical exhaust and they could sound totally different,i assume that vairables in engine build,machineing etc could be the cause of that.as for anyone that fits a 3'' system on a n/a car is wasteing alot of money,i no it looks good and at idle sounds good but the power loss at low to mid range is quite bad also take into consideration of fuel waste due to haveing to push down further on the accelerator to make up for power loss, trust me i have being there and tried that.best size pipe i believe is 2 1/2 for rb25 and for rb20 is 2 1/4 for low drone note at 50khm,i no some people like the car loud it draws attention but here in nz it draws the attention eg.police.these skylines are very hard cars to get a good sounding system and good power range without a bit loss in either of these factors its alot of trial error until you build up a system,even now im considering adding another resonator with expansion chamber i have noticed a bit of a loss power low down on hills

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