How much boost pressure can a built VQ37VHR withstand?

phunk

it goes way back. it was a major problem with DE's and effected all the early builds. Guys were chasing all kinds of non-existent issues like boiling coolant etc trying to figure out why it was happening. Some were even going so far as replacing the coolant plugs in the head with giant allen bolts and torquing them down to create pressure on the headgaskets between the cylinders (LOL). Eventually everyone went to 1/2" headstuds, boom, problem solved. Until the L19s came out which allowed getting real torque on the head studs without drilling and tapping the block.

I forget, what is the torque spec on the standard ARP? 65-75lb ft? Thats not going to cut it. At least, it didnt on my 350z. Made it about 5-6 blocks from the dyno. Then I swapped the block for one that was drilled and tapped for 1/2" studs, and now we are about 10 years since that engine went in the car and its still doing great! So, I like to get about 90-95ft lb on the headstuds (with moly lube).

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tturbo370z

Other than being an expensive unicorn and handling so far 26psi of boost. I would wait for Charles, specialty Z or someone else to make a worthy intake that is proven to make power. I have no before or after dyno so I cant tell u if it helped me make power or the opposite. I do know that I had to have custom billet fuel rails made to accomadate the intake conversion as well as repipe my charge piping. Save your money and wait. Plus I doubt anyone will ever see another one come out. I may be wrong and for me rarity is better. Waiting will provide proven results and more bang for your buck IMO. But who knows when that will be...

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37winner

Thanks for the info! I'm curious as to when your saying worth intake. Is something wrong with the gtr intake manifold? I figure going from plastic to whatever material the gtr material is, it would be much better.

So how did you get that conversion made? I'm very interested! Please do share!

Rid3_FaM0uS

I just finished installing mine here about 4 days ago and they call for 3 equal steps to 85ft-lbs. I didn't feel that was too bad I could most definitely understand concern if it were only 65ft-lb though! God yes. Iirc the ones I installed are indeed half inch now ill look into that though to make sure I'm not just blowing smoke out my @ss to you!

On topic; OP I must agree with my man Charles though approach boosting your factory block. Hell I would still be on my factory block had I had a competent tune done. After having rebuild both my DE and VHR blocks now I can tell you there are several stout improvements in our block. I can assure you technology in both the bottom and top end of the block in our car has definitely been improved.

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phunk

85ft lbs should be good to go. Perhaps they raised the torque specs or changed material of their standard studs to allow more torque? Because I am pretty sure that the stud threads and length and everything are the same as the DE arent they? Its been many years, its just burned into my brain that all the 2003-2004 DE builds were blowing headgaskets with the normal ones and then it became a non-issue when we all went to 1/2" threads.

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Wattles

My built engine was a big investment, but siting at nearly 600whp at 13lbs boost on 91 octagon fuel is very nice. It makes me comfortable I can beat on the engine on hot hot days without worry.
When I upgrade my fuel system to deal with any starvation I will push her higher to 18ish. 650-700whp should be fun.

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G37Sam

One of the reasons people build their engines is to drop compression to a decent enough level for boost. The OEM compression ratio is too high for pump fuel.

You also need to keep in mind that traction is a major issue on our cars, and the increased torque makes breaking parts in your drivetrain much easier. If you're building a dyno queen you'll be fine but anything you plan to race requires serious consideration in terms of traction and strength.

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Nuc370z

What would you recommend upgrading for the drivetrain? Eg. Clutch (which brand is best suited for high torque spikes), driveshaft, differential (I plan on an OS giken, but any suggestions?), gearbox, etc.

Thanks!

megalapagas

But see he's a 7AT, where are you going ro get the valvebody to help your tanny hold all that torque??? As far as I've read through here our 7At tranny can only hold up to 400 torque and that's pushing it if it was on a good tune? Unless I missed something please elaborate as I too plan on going boosted...Btw between ID's and Bosch injectors whoch would you go with and what about Deatschwerks??? I plan on going with 1000cc for E85..

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Mitco39

I am running 13PSI peak (settles in around 12.5 under most scenarios). I had to upgrade to the CJM return fuel system to be able to support fueling at that boost (the stock system would drop ~15psi under boost). Car has been running great. Nissan did right with these engines in my book.

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Rid3_FaM0uS

Bosch is who designs the cartridge for both Injector Dynamics and Fuel Injector Clinic. IIRC each company only merely designs their own spray nozzle if I were you I would go with one of the two. They are top dogs in the injector market ID being flow balanced to 1-2% and FICs being balanced to no more than 3%.

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Rid3_FaM0uS

Charles. I still haven't had time to measure the studs to get you an answer sorry but I do believe they changed to their ARP 2000 grade material for the studs so that could be where the much higher allowable torque specs are coming from. both my mains and heads were torqued 3 equal stages @ 85

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Diabel

So, getting back to topic - how much boost pressure can a built VQ37VHR withstand? 16,17 psi ?

Mine block is 9.0:1, arps l19, without e85 or water/meth injection.

Isn't the stock intake plenum the max limiter of boost we can go with?

Chuck33079

That's not a question that can be answered without a lot more info. 25 psi out of a tiny turbo is a lot less air than 25 psi out of a large one. The motor may hold up fine with 15 psi out of a gt28 and explode at 15 psi out of a gt42.

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jwick

It's all R&D at this point. No one knows. **** none of us actually know where the stock block limits are yet.

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