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Best Way To Improve Exhaust Sound?

Cev

By Cev,
in Engines & Forced Induction

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Deza3000 Proficient

Deza3000

Posted
Posted

NA rb's most certainly do NOT come with 2.5" standard. unless you bought your car new from nissan you can't say that it has the stock exhaust. more than likely your car has the exhaust from a turbo r33, which run 2.5" standard. and make sure you measure inside diameter, as that is what they use when measuring exhaust size.

While installing my muffler the inlet matched the exhaust pipe which was 2.5 inch, the n/a r33s came with 2 different exhaust styles, some came with a butterfly valve from factory(my exhaust), some did not. I know for certain my r33's exhaust is from factory since my friend has the exact same car, and his exhaust is also a 2.5 inch with a butterfly valve on the right tip. I know im right since i actually welded the muffler on myself.

MBS206 Grand Master

MBS206

Posted
Posted

NA rb's most certainly do NOT come with 2.5" standard. unless you bought your car new from nissan you can't say that it has the stock exhaust. more than likely your car has the exhaust from a turbo r33, which run 2.5" standard. and make sure you measure inside diameter, as that is what they use when measuring exhaust size.

as for 2.5L exhaust size vs 3.8L exhaust size, you have to take into account the rev range of the car as well. obviously a smaller engine that revs higher will flow similar amounts of exhaust gas at high rpm, but at the lower rev range it will flow less. the wider the rev range, the harder it is to get an exhaust size right. 2.5" is probably good for a 2.5L engine if you are going to spend a lot of time at high rpm, but if you only cruise around at lower rpm then it will drone like a mofo (as most people find out), as well as not flow as great as a smaller diameter pipe (so give you a bit less torque).

2.5L screaming at max RPM of 7000RPM = 8750 Litres per minute of air ingested (At a perfect efficiency, but in actual fact it will be closer to 80% of that number)

4L (Falcon) tipping over at 6000RPM is 12,000 litres per minute of air ingested.

Take into account they're both NA, exhaust gas temp should be relatively the same, meaning that the exiting gas volume should be quite comparable.

I'd run the 2.5" on the 4L, and a 2.25" on the 2.5L as it doesn't need the high end gas flow, as it just doesn't have the need for it.

mad082 Grand Master

mad082

Posted
Posted

while i agree with the point you are making, you can't simply apply that sort of basic calculation to it. it doesn't take into account the difference in intake efficiency, which then also determines the amount of fuel that will go in and what sort of bang you get.

given that the majority of older commodores and falcons only rev to 5000 (falcons) and 5500 (3.8L commodores) and only put out similar max power to the skyline, they would be put out similar sort of amounts of exhaust gas.

as for the 2.5" stock exhaust, your mate's car may have also had a turbo exhaust put on because they didn't come out with 2.5" stock, as that is the size they used on the turbo skylines. given that on their 2.0L engines (such as the sr20) they weren't even using 2", they certainly wouldn't be going over half an inch bigger for only half a litre bigger engine.

NiHaoMiaoMiao Contributor

NiHaoMiaoMiao

Posted
Posted

4. Don't come back in A months time and complain that it's Droney, audibly loud natro skylines will be Droney on the highway, don't like it keep it quiet it's as simple as that.

+1 to that.

I have a 2.25" mild steel catback, no reso(i know it's silly), and a small muffler (red back i think) and on the highway it is just so droney.

Not worth your money and efforts is my 2c

Deza3000 Proficient

Deza3000

Posted
Posted

as for the 2.5" stock exhaust, your mate's car may have also had a turbo exhaust put on because they didn't come out with 2.5" stock, as that is the size they used on the turbo skylines. given that on their 2.0L engines (such as the sr20) they weren't even using 2", they certainly wouldn't be going over half an inch bigger for only half a litre bigger engine.

Yea you might be right, ill look into it, maybe its just from the resonator onwards thats 2.5inch, rest might just be 2.25.

  • 5 weeks later...
Johnie Community Regular

Johnie

Posted
Posted

Just stay with stock, iv'e currently got a stock system with cannon muffler sounds not too loud but still gets the police attention as i got defected for it and he didn't even hear it.. just asumed its too loud coz of having a cannon..., will be switching the muffler back to stock

drunkn snail Community Regular

drunkn snail

Posted
Posted

Na if you did that you would lose all the backpressures and then lose so many killerwasps.

although everyone know noise=speed therefore more noise obviously = more speed

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