exhaust sizing questions

[BeRad]

ill start by saying ive read numerous exhaust threads on this site over the couple of years ive been here, and learnt alot from it....

now my question is the engine is a 3rzfe so a 2.7 4 cylinder with a r33 turbo at the moment but i cant see that lasting to long once i want to go over 12 - 14psi. so an upgrade will come either being a gt35r or small gt42r... both being able to push out alot of air. so im wondering if i go a 3inch exhaust am i going to starve the engine of power. i see alot of 1j's etc going 3.5inch and the 2j going up to 4inch... is this pure wank factor or gone that big for a reason., the hilux being in between i wouldnt mind going 3.5inch but not if its to no advantage.


so is a 3inch going to restrict me in time to come or will it be fine.


thanks

[kingmick]

3inch should be fine! whats Hp it making now? and what boost?

[BeRad]

not running yet but going in for a exhaust next week. the previous owner who i bought the turbo kit from , hes running the same ecu as me same everything with a 3inch exhaust and made 220rwkw on 12psi.


move up to a gt42 or something and the skies the limit so thats all im asking.

[kingmick]

if you not going to go much 300kw 3inch will do the job. I take its a stock motor? and you are going to go 16psi or so?

[BigWorm]

I'd recommend 3.5", my mates 1J Cressida showed a huge improvement with a 3.5" pipe with a 5" catco stainless cat over my 1J with 3" and cheapo "hi-flow" ceramic cat, although I'm sure most of it came down to the cats.
Mine makes 11psi with no boost controller whereas his was hitting boost cut with no controller, so it's flowing enough to make at least an extra 2.5 psi.

Goes to show how much effect exhaust flow can have.

[kingmick]

But as your doing, think down the track a bit and it will help decide between 3 and 3.5inch. If you want to bump up the HP in a year or two and change things chacing bigger HP you wont have to change the exhaust then.

[YelloRolla]

I suggest 3.5". I see 3" working nicely on 1.8 and 2 Litre engines and your engine is 50% larger than my 1.8. The 3.5" has approx 36% more flow area than the 3".

Bear in mind that the turbine housing and exhaust manifold are going to be experiencing considerable exhaust pressure when under boost. Expanding the area behind the turbine is quite beneficial to building boost quickly and making the turbo system more efficient.

[BeRad]

ok thanks guys. i think ill go the 3.5inch gives me a bit of play in 12 months when hopefuly i can afford to build the engine... bloody more money haha.


thanks everyone.

[Aust162]

I'd would be saying 3.5" berad. Knowing you, you went pretty nuts on your gt2 so you will most likely do the same on your hilux

I went 2.5" cat back for my gt2, and i sort of regret it. should have just done 3" now the car's approaching 200kw atw.

[Draven]

if you go gt42, I would very seriously consider the 3.5" - that's a big turbo you're playing with there

[-==L=a=N=c=E==-]

3.5" berad, mines running that as far as i know, and it sounds tuff.

Goes hard too.

[Draven]

although that said, I think Miss 2J was running a 3" zorst and 380rwkw

[kingmick]

ten char

[30psi 4agte]

just thought id chuck in my 2 bob worth.
Go 3.5 m8 that way you wont need to mod / change it in a hurry.

I just went 3.5 off the back turbo and deff dont regret it !!