My GTM Supercharger Review

RCZ

Other than getting LTH's to work, what's the purpose / expected gains? I heard there wasn't much at all to be gained from fiddling with the system since it already does a pretty damn good job from the factory. Don't get me wrong, I'd be all for running LTH's.

Staples

No no... this is actually remarkable because the problem with the VVEL system from factory is that it has an extremely aggressive cam duration of about 300, yes 300. This in turn causes valve overlapping which means the intake valve and the exhaust valve are both open at the same time and when you're pushing a high amount of air - like with forced induction, you're actually not able to make the full amount of boost because it's being pushed through head so fast it doesn't give the bottom end enough time to compress it. Turn the cam duration down and in turn you'll be able to use more of the air that's being forced into the engine. That's why you see the same stage 1 kit on the 350z HR putting down 470+whp on 14psi, the same exact kit that's available to the VHR motor that is only seeing 8psi (same pulley being used between both motors)

This is what my input is at least on the matter, I'm sure Sam could shed a lot more light on this then I can.

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'08 Infiniti G37s - Forced Induction Fed

Buddy Revell

Whoa. A VQ35HR is strong enough to handle 14 psi?

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'08 IP G37S/GTM Supercharger/20" DPE SP-5 Wheels/ARK GRIP Exhaust

kevin1985912

I think it's because VQ37VHR has higher compression than the VQ35

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Staples

Displacement and compression both play a factor in the VHR compared to the HR. HR has a 10.5:1 compression ratio, our motors are 11.0:1... We'll make more power on the same amount of boost.

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'08 Infiniti G37s - Forced Induction Fed

Buddy Revell

I didn't know the HR engine in the 07-08 Zs had strong enough internals to handle 14 psi even with the lower comp ratio. I had read the older DE engines in the 03-06 Zs w/ stock internals had trouble handling over 10 psi and they had even lower compression than the HR.

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'08 IP G37S/GTM Supercharger/20" DPE SP-5 Wheels/ARK GRIP Exhaust

1slow370

rods in the hr are pretty much the same as ours, pretty much everything is actually the same in the shortblock for the most part our stroke is just a we bit bigger.

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Staples

It seems they changed a few things for the better.

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'08 Infiniti G37s - Forced Induction Fed

Staples

I don't know from a supercharger standpoint, but I've seen a 350 with an HR put down 500whp and 430ft-lbs on 10psi with the Greddy 20G kit. He daily drives it at 8psi which hovers around 450-460whp.

They've really upgraded the bottom end in the 08 350z compared to the older DE non-rev and rev-up motors.

GTM ran a 14psi pulley on their test Nismo 350 on 100-oct and it put down 487whp and 365ft-lbs.

With a fairly conservative tune on 93 oct I'm sure it could be daily driven with no issues. It obviously wouldn't be 490whp, but I'm sure it would be fine at 450.

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'08 Infiniti G37s - Forced Induction Fed

Mr.Squeeze

The same 8PSI pulley on the VHR made 11PSI on the HR.

1slow370

this was thanks to poorer flow, smaller displacement, and less valve overlap(the HR's dual cvtc is tuneable)

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Mr.Squeeze

I am aware of this and is the reason I posted it VVEL is the problem

theDreamer

VVEL does not have much to do with LTHs.
It is more on the side of cams and such, it will help those with more open exhaust setups probably but maybe not. Right now they are going to use the FCON by HKS to test tuning with VVEL.

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