Gtr 3.5" Custom Exhaust

[HKS-R33]

Hi,

I'm getting an exhaust custom made for my GTR atm and wasn't sure whether its supposed to be 3.5" ID or OD. The exhaust shop I'm using only carry 3.5" OD exhaust pipe which makes it around 85 - 86mm ID.

Would I be better off getting them to make me a 4" OD system?

Its an RB26 with GT2860-5's

Thanks,

Michael.

[Ziller]

Pipe uses ID nominal bore measurements which is N/A for an exhaust, tube and exhaust tube is measured by the OD.

3.5" tube will be fine, 4" is a pain in the ass for ground clearance when you add in a muffler.

[Hadouken]

It might help to say how much power you want.

But 3.5" should be good for -5's.

[HKS-R33]

Thanks for the replies, looking to get around 350rwkw

[Hadouken]

it will be fine

[Hadouken]

i like your side skirts. what are they?

[SiR_RB]

one of my best mods was going from a twin 60mm into 70mm front pipe and 76mm cat back to Twin 76mm into 90mm front pipe and 90mm cat back

resulted in a 70kw midrange gain and much much better response

[Buraz]

one of my best mods was going from a twin 60mm into 70mm front pipe and 76mm cat back to Twin 76mm into 90mm front pipe and 90mm cat back

resulted in a 70kw midrange gain and much much better response

Is that a full custom system or off the shelf jap exhaust? I'm going down that path very soon, full custom system. Will be interesting to see my results.

[usmair]

one of my best mods was going from a twin 60mm into 70mm front pipe and 76mm cat back to Twin 76mm into 90mm front pipe and 90mm cat back

resulted in a 70kw midrange gain and much much better response

70?

[SiR_RB]

i made the cat back myself, no step downs, mendral bends, one 3.5" straight through mid muffler and 3.5" rear muffler.

yes around 60-70kw midrange gain, and made boost come on MUCH sooner....we stopped (well i did and jez called me a pu@#y lol) at 340rwkw as i didnt want to push any further

Edited September 3, 2012 by SiR_RB

[Hadouken]

so either you had the most restrictive exhaust known to mankind or i smell furfies

[HKS-R33]

Hey, thanks for the replies, I ended up getting 2 custom 3.5" mufflers made and I'm going for a 3.5" system. Front pipes will be twin 3" into single 3.5".

i like your side skirts. what are they?

Apparently they were top secret side skirts but i never seen another pair.

Thanks,

Mike.

[SiR_RB]

so either you had the most restrictive exhaust known to mankind or i smell furfies

these are figures both done on jezs dyno....what benefit do i have in lying?

i had alot of step down, even going from 3" dumps down to 60mm front pipes, hence i upgraded the front pipe and made a genuine 3.5" cat back

anyways good move going 3.5" cat back for 350kw

[Anz32GTR]

What sir rb is saying is true. I was a witness I got my car Dinoed on the same day and saw the results.

[black bnr32]

Pipe uses ID nominal bore measurements which is N/A for an exhaust, tube and exhaust tube is measured by the OD.

3.5" tube will be fine, 4" is a pain in the ass for ground clearance when you add in a muffler.

no, it is not a pain. and, the muffler is not the lowest point on the exhaust.

[Ziller]

no, it is not a pain. and, the muffler is not the lowest point on the exhaust.

Like myself and many others, the OP is using two custom 3.5" mufflers on a 3.5" system. "Add in a muffler" as in mid muffler, it becomes a pain in the ass for legal hight. 4" becomes a total pain in the ass.

I hope this clears things up.