New Turbo Set Up Gt35R. How Much Power Before I Should Upgrade From Stock Exhaust Manifold?

[ursin]

i see a lot of people on here are running the stock cast exhaust manifold with a external wastegate welded on. im about to go that route but i was wondering at what power will this start to hold me back. my set up is going to be a stock internal rb25 with a gt3582r 740cc injectors and nistune. i would like to make between 400-450whp just making sure that will be possible with that manifold. i have a greddy intake manifold q45 tb. 3.5 inch straight pipe exhaust. my motor is in very good shape, great compression, everything has been inspected and it has been run for a year with the stock setup and made great power on the stock turbo but its time to upgrade. i don;t think its really necessary for me to go with a tublar manifold untill i build the motor and look to squeeze more power out of it. but since it is only in a tiny s13 400 is going to be a lot. looking to run probably around 16psi on the turbo, if i have to i may put a set of some less aggressive cams in or get my stock ones reground. any ideas people have for me feel free to throw out. i undertstand the gt35r is probably a little overkill for my power goals. but i got it for a great price and i would like to have the room to grow in the future. thanks for looking and for any help!

[zebra]

Gt35 really is too big for the standard exhaust manifold, a 3076 would have been a better choice imo.

But as you said you will want more later so save up for an ETM or 6 boost manifold

[ursin]

well heres the other thing. i also have one of those manifolds that i've seen like 10 different companys names on but its really just a cheap ss tublar manifold with a t3 flange and a bottom mount 38mm tial wg flange. prob is like most turbos the clearance isn;t so well. the compressor cover hits the valve cover just slightly. but im unsure about how anyone has modified it to work. it also seems that the turbo sits very high and im worried about hood clearance... if i absolutely have to i will go with the rawbrokerage manifold that just came out.

[zebra]

Forget the cheap stainless crap.

6-boost or ETM or whoever else is doing custom manifolds will be able to build one with plenty of bonnet clearence.

eg I had a TD07S on a 6 boost manifold on an RB25/30 and it cleared the bonnet fine in my R33

[R31Nismoid]

stock manifold is too small, most setups have issues around the 300rwkw mark.

given a GT35 will make around 360-380 on most setups, thats well above

[l0WRB]

Forget the cheap stainless crap.

6-boost or ETM or whoever else is doing custom manifolds will be able to build one with plenty of bonnet clearence.

eg I had a TD07S on a 6 boost manifold on an RB25/30 and it cleared the bonnet fine in my R33

like anything cheap if done correctly it can work.

Just dont go bolting it on and expecting it 2 do its job

[SimonR32]

You will probably spend more time and money stuffing around putting it on the standard manifold than if you just bit the bullet and went a decent high mount manifold...

Plus then you are not going to have restrictions on power!

Also a GT35R on a RB25 on 16psi will be a dog

[KiwiRS4T]

Better to use the stock manifold than a cheap stainless one that cracks. Run the external w/g off the turbine and save up for a 6boost or similar later. let us know how it goes with the stock manifold.

[ursin]

^^ thank you best reply so far. i guess people are missing the point. its not that i cant afford the 6 boost or a better tublar manifold i was asking which was better. i know the 35r is gonna be a dog, but its gonna be better than the stock turbo. my set up is going to be tuned with nistune and im not building the motor yet. i have too much other stuff to do to the car this year so its just not in the budget. its not like this is going to be the permanent set up just wondering which would be the best way to go about it at the moment.

[bubba]

My opinion is to do the turbo swap properly.. go the decent high mount manifold and set it up for that otherwise you'll be dicking around with cooler and dump piping again when it comes time to put a proper manifold on.

[ursin]

well the other thing is i can/have fabricated everything on the car i don;t care if i have to tweak a down pipe later on. and i also can modify the stock manifold for the price of the wastegate flange and pipe for it. but idk everyone is raving about aftermarket manifold i'll see what i can find, 6 boost seems hard to find in the US

[SimonR32]

well the other thing is i can/have fabricated everything on the car i don;t care if i have to tweak a down pipe later on. and i also can modify the stock manifold for the price of the wastegate flange and pipe for it. but idk everyone is raving about aftermarket manifold i'll see what i can find, 6 boost seems hard to find in the US

Plus you have to factor in the costs of...

New oil and water lines

New intake pipe

New dump

External Wastegate

Spacer for the turbo

Second Gasket for the spacer

Screamer pipe

Plus I would actually debate that a GT35R on 16psi would be better than a stock turbo

[bradsm87]

Smaller turbo, more boost FTW!!!

http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT30/GTX3071R_803712_1.htm << BUY BUY

[Harey]

What exhaust housing do you have on the GT35?

0.63 housing will give you good response and up to 300rwkw. 0.82 will have some lag but will be great once you build the engine and decide to push things. 1.06 will be VERY laggy and not recommended.

What you could do is throw the 0.63 on while the engine is standard, then upgrade to a 0.82 when you build the engine.

Brad, I would argue for the GTX3076 over the GTX3071 as he plans to build an engine later on.

[KiwiRS4T]

well the other thing is i can/have fabricated everything on the car i don;t care if i have to tweak a down pipe later on. and i also can modify the stock manifold for the price of the wastegate flange and pipe for it. but idk everyone is raving about aftermarket manifold i'll see what i can find, 6 boost seems hard to find in the US

Well if you are in the US you might as well buy one from Sinco Customs (as per my pic above):

http://www.sincocustoms.co.nz/

If you tell him what car and what engine he will be able to make one that will fit for around NZ$1500. (Aussie dollar is quite strong at the moment so Sinco from New Zealand probably better value for you than 6boost from Australia).

[R31Nismoid]

Plus I would actually debate that a GT35R on 16psi would be better than a stock turbo

Same.

Rather pointless IMO.

[Harey]

Same.

Rather pointless IMO.

Not if its a 0.63 rear! Plenty making 300rwkw with good response.

[zebra]

Good response compared to what though a T04Z?

[Harey]

Good response compared to what though a T04Z?

r33cruiser, on 28 May 2010, 10:36 PM, said:

full boost (16psi) at 3600-3800. Pulls HARD, all the way to 7500rpm.

No more than ~200rpm difference between a GT30 0.82 and a GT35 0.63 on a stock RB25.

[Rolls]

it is still not optimal, for 300kw you are better off getting a smaller turbo, more lag for no good reason.