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Hi all,

I'm just after some opinions of what turbo's (read low mounts that bolt to stock manifolds) would be best for me. My motor is freshly built with all the good stuff, and just in the process of getting the head ported and installing some cams (still undecided, need suggestions as to what would work best)

I want 700awhp @ 2bar max and i was thinking either the HKS GT-RS or Trust T618Z, redline is set at 7500. What are peoples experiences with these turbo's, and what are their characterisitics i.e when do they come onto boost, how much can they flow @ what boost etc. Also the car's being set-up for track & hill climbs, so i require half decent response.

It'd be ideal if someone could suggest what turbo and cam combo will be best for my motor and power goal.

cheers

Shane
 

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Heres a link to a dyno graph and info on the set-up with Trust T618Z turbo's, is this a better result than what could be achieved with the HKS GT-RS?
http://www.skylinesaustralia.com/forums/index.php?act=Attach&type=post&id=21103
From what I've been told, if you've got 2.8ltr or more of displacement, the twin HKS GT-RS offers great overall performance. Peak power and response is simply a compromise in tuning and both combinations could get you the 700hp-750hp to the engine (assuming you are not fussed with the small torque benefits of a ball bearing cartridge).

Check out the HKS web site for a dyno graph but take with a grain of salt as the quoted torque figure is very high for those turbos at 1.8kgf/m boost:

http://www.hks-power.co.jp/products/turbo/turbinekit/ac_gtrs/img/gtrs
 

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You've got conflicting interests. 700ATW, 2 bar boost and 7500RPM redline doesn't normally come in a user friendly package.

Whilst IMHO the optimum capacity is 2.7L, this is based on having a willingness to allow the engine to rev. A properly rebuilt engine with billet crank good rods/pistons etc. will easily take 9000RPM longterm.

If you really want to stay down at 7500 I assume you have gone for a bigger capacity engine. If you have, then bigger capacity also gives you the option to run a single rather than twins, T51 Kai maybe? Otherwise its something like GT-RS's or bigger running fast spool exhaust wheels, but watch the efficiency maps as frequently around 1.6 is the optimum.

Irrespective, having targetted and built for 2Bar boost, the turbo(s) will probably come on like a steam train, so think in terms of going from say around 200ATW to 700ATW in the space of 1000RPM.

Think you can handle that?
 

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Hes gone 3litre, he said that.

If his car goes 200-700 in 1000rpm then he has some patheticly long duration peaky cams that are awful on the road and are no use on a 7500rpm engine anyhow.

With the right cams and right turbos (i cant comment as never looked into twins as i think they more trouble than they worth) he could have 700ATW at 7500rpm but 200ATW by 3500rpm at most, so a nice big powerband with lots of midrange, and not a peaky nightmare like most GTR engines.

Main thing is with 2bar of boost youve potentially got a lot of torque.
 
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