Which Exhausts Systems Are Epa Legal

[xm4tr1x]

Hi Everyone, there seems to a lot of EPA slips flying around and landing on windscreens and in letter boxes.

Question is which exhausts have passed and which haven't ?

There is plenty of different setups when it comes to exhaust and of course depending on whats done to the engine does have a huge impact towards the configuration of the exhaust setup,

So post which mods you have and exhaust configuration including the Db reading for each setup.

Example:

BMC filter

FMIC

EBC

PFC

split dumps > 3" down > 100cpi cat > 3" > resy > HKS HI power muffler

102 Db

running 210RWKW

All else stock.

[xALmoN]

metal plate, + holes.

[Daz]

Standard exhaust that's about it

[R31Nismoid]

The only way you'll pass EPA is this.

3" exhaust

2x as bigger mufflers as possible

hi-flow CAT

The rest is irrelevant.

[Comsic Gate]

Get a Fujitsubo exhaust....they are quite and legal, but are really good exhausts.

[scotty nm35]

I have a Fujitsubo exhaust, it was fairly quiet until I fitted the 1.06 Tial rear housing. There is no way it would pass now.

[vspecIInur]

and I thought my 3.5 inch racepace full exhaust was quiet...until it's opened up at 8k

[Borci88]

I had a Kakimoto catback, 2 large oval mufflers and a standard cat, no chance it would have passed EPA, stock is really your only option on Skylines.

[Takahashi GTR]

I had a Kakimoto catback, 2 large oval mufflers and a standard cat, no chance it would have passed EPA, stock is really your only option on Skylines.

Stock GTR's are over 90 from factory, we are all F#$%#*.

[MUZT3K]

Well if it's over 90 from factory doesn't it make it legal because it's been complied?

[R31Nismoid]

and I thought my 3.5 inch racepace full exhaust was quiet...until it's opened up at 8k

My RP 3.5" (on the 31) is 91-92dB @ 5100rpm. So juuust about legal, but not quite.

Not sure if the GTR version was able to have larger mufflers to get it down further.

Either way enough to have a nice note, but not get attention

[Takahashi GTR]

Well if it's over 90 from factory doesn't it make it legal because it's been complied?

There is a cut off date for the exemption, for instance a 67 Mustang can be 114db and get away with it, just not sure on the exact date.

[emts]

There is a cut off date for the exemption, for instance a 67 Mustang can be 114db and get away with it, just not sure on the exact date.

I wish.....

older than I think it 85 are the older ADR's so we get 94db but that it.

[llama_au]

Get a Fujitsubo exhaust....they are quite and legal, but are really good exhausts.

Mine wasn't legal (I got EPA'ed, rest of the car stock), then again I had removed the centre resonator.

[xm4tr1x]

surely you can quiet down a 3.5" from turbo back?

[R31Nismoid]

Not to a legal standard whilst maintaining the flow of a straight 3.5" exhaust, decent CAT and acceptable ride height etc etc - on a skyline.

People including myself have been there and tried, you come close, but just not enough.

Another car with a different floor pan, then possible if you could get mufflers on there that are larger again... But 2-3dB is actually a substantial amount of noise to soften.

It's the noise of the motor and the 4700/5100 RPM that the tests are done at that sets the meter off. They also measure "back off" noise too, which often a crack/pop will set the meter off over the limit.

3" you can get passed however, as i said in post #4

[vspecIInur]

Nicely explained. If you drive a GTR or something with big flow properties then >90db is far too easily achieved. So annoying.

[xm4tr1x]

A GTR is by default >90db is it not?

[xm4tr1x]

So which 3" configuration do know you of that can pass

which dumps, down, cat, res, muff, material, press, brand etc.

The big question that follows is do you have evidence?

[vspecIInur]

I just find it hard to believe that a stock exhaust system on an R is >90db or is that referring to a particular model - 32, 33 or 34.

The standard 34R system seems pretty restricted to me however, the only good thing about it is the awesome flow properties from the manifold and dumps. Do not change them