ghost vh sle

looking at twin turbo package for a 253 holden v8 as far as i know no has tried this before ive already sourced manifolds need information as to turbo sizing(looking for about 8-12psi as this is a street package)and also the right compression ratio and someone to provide a suitable efi conversion package. any feedback and oppinions would be grealy appreciated.

_Daniel_

Just guessing but shouldn't it be the same as the 308 package? Just use smaller injectors?
A common upgrade is using a 308 manifold on 253 when wanting to go to four barrel carby, therefore the same manifold from the 308 package can be used.

A general responce to this thread will be why bother with the 253 when you could use the 308, when spending that kind of money on turbo set-up it must be a question you ask yourself...

v8tfcorty

what manifolds did you source ???? The factory ones be swapped from left to right can't they.

BossHoggett

Its been done 100 times
standard engine... ? if so.

GT35/40 with 60 - 80 turbine A/R or with a 60 it will move at about 1800-2000 rpm. (80) @2500-2700
Expect 280-300hp @ 4800rpm

Intercooler. get a purpose bult one. or GTR intercooler. the Ebay End tank design is shit.

Make some decent exhausts and keep them as close to the cylinders as possible, not long spaghetti things. Steam pipe is best as it holds the heat into the exhaust system. Hot air has more energy.

The Trimatic vacumme modulator doesn't like full boost. so you need to make a 1m bleed hole from the modulator to inlet manifold so the trans can see atmosperic for kick down.

Decent quality pistons not forged. with good rod bolts. Full Engine balance.
if you want decent life out of the motor, LPG seats and steel exhaust valves.

Camshaft: +10 degrees on the advertised and .50 durations on the inlet. wide lobe separations 112-114

In the future you might want to consider a 3.48 inch stroker crank. or higher revs then go the GT40

ghost vh sle

yeah ive been told the gt 35/40 but that seems a bit overkill for twin turbo set up. the exhaust manifolds are already made they were custom jobies but they are steam pipe and the clearences are right. efi conversion is the head ache atm and incase anyone else was wondering the reason for the 253 is because not everyone does it and im out to do something different.

BossHoggett

Please pass on my sentiments to the bloke that said you need two turbochargers capable of 500hp each or approx 60lbs of air at atmospheric pressures ratios of 2.8 or 26.4lbs of boost that hes a ****head.

For twins youll find GT20's more your liking.

For your hip pockets sake go and talk to some people in the industry for a second opinion. I think youve been fed a bit of misinformation.

ghost vh sle

sorry didnt mean to add more confusion i thought u were recomending the 35/40 as a single but i was after twins for response ive looked at the 20's as well but just fimd anything in the garret range way over priced for the applications i hav in mind. atm my vh is completely restored original inside and out the motor is slightly tweaked but thats irrelivent as i will be changing to low comp pistons more appropriate cam and exhaust package and a supra five speed most of these parts have already been aquired and pretty reasonable prices as i said before really struggling with the efi conversion and i dont just want to hand the car over to an engine builder and right a check there is enough wankers doing that in the magazines

BossHoggett

Try T3 .55 trim .64 turbine A/R its a thrust bearing comes in T25 flange. or 30lbs air
or go the 60 trim .64 at 35lbs air. combined is 60 or 70lbs of air at about 15-18 lbs boost.

ghost vh sle

thanx all the info is much appreciated