VQ37VHR Build Potential

[hazesleepgod]

I've been doing some research on the VQ37VHR, and my main goal is to make at least 425whp on natural aspiration. Meaning, about 450-475 to the crank given some mental estimates. In my case, the wheelbase is going to be shortened around 9.1in (100.4in --> 91.3in) to an exact. Added, a lighter flywheel, lighter driveshaft, etc. With all of this unadded load-travel, for a lack of better words, put me a little closer to that number? If needed more info on what exactly I'm adding to the drivetrain to achieve this, let me know and ill update with a more thorough list.

 

((edit; Z31-t chassis already has a curb weight is about 3,285lbs. My main goal with the chassis as well is to shed just shy of a grand in weight. This will be achieved with the full fiberglass (carbon fiber if time and money are right) silhouette with a full roll cage going through the cab. Firewall forward, and rear struts back minus the hatch will all be chopped off and replaced by rollbars and gussets. The attempted end goal in terms of weight is going to be 2,500lbs.))

 

With that, I don't expect to come near this number on decreasing the travel distance of power. The second question is, with this considered, would it be possible to comfortably make this power output, without tapping into the bottom end or increasing the displacement?

 

The modifications I have planned for the top end includes, but isnt limited to,

E85 tune, Billet Fuel Rails, Upgraded injectors, High-Pressure Fuel Pump, Performance Ignition Coils, Performance upper/lower Intake manifold, Cold Air Intakes, JWT V2 Cams, Valves, Ported & Resurfaced Cylinder heads, Dry Sump Crank Pulley, Dry Sump Oil Pan* (Kinda cheating with this one). 

 

I think this number is decently achievable, but the more research I do, leads me to finding less and less 400hp N/A VQ37s, at least those without tens of thousands of dollars invested. Don't get me wrong, the estimate is close, but not just for an engine.

Apart from the questions above, I guess in general, is it even feasible? Does my theory hold any ground here? Will I need to start looking into the bottom end being build to make said power output? 

 

Any help/comments/opinions would be greatly appreciated!

 

Edited January 24 by hazesleepgod
Missing context

[dprada01]

I think the VQ37VHR is a great swap. Trying to make over 380whp is going to be a nice challenge. I would say possible, but the juice may not be worth the squeeze. 350-380whp is going to be bananas on an s30 chassis that is dialed in right. I would still jump into doing the swap even if 350whp was only decently achievable. 

[hazesleepgod]

@dprada01 Thanks for the input! Actually, much of this build is inspired and assisted by a fellow builder doing that exact project on his 240/280. I always loved the VQ, and the main goal is to overbuild (Originally, I was looking to attempt the 5XXhp mark and detune to 425*hp) and make a more reliable number as opposed to the constant breaking point. I also recently edited to add, this car will be about 900lbs lighter (3250 --> 2500*), due to it getting the full IMSA/GTO car treatment. Maybe I'll have to shoot a little lower, and hope for the best lol. I feel like I should also clarify, I'm dropping this in a Z31 chassis. The 80's odd child has a special place in my heart. 

[Sanchez]

@hazesleepgod
I’m in the midst of a VQ37VHR swapped 240Z at the moment, and while I’m still in the body and rust repair stage of mine I have gotten my VQ running on a palette with wiring and ECU done by Hexa Garage. Z1 sells what they call a 400hp package which is rated at the crank and most people I’ve talked to who dropped $5k on a tune, plenum, and exhaust combo (absurd price for stuff you can do if you are competent or go to an exhaust shop) said it woke the car up noticeably, but couldn’t help feel like they got robbed a bit. And some dyno charts show that the Z1 dyno results maybe on a dyno that reads high, as most purchasers dyno closer to 320 at the wheels after some dyno tune sessions.

 

Ive put in tons of research to getting the most out of the VQ engine using NA power and ultimately one would spend thousands on the engine to reach over 400hp/tq to the wheels. The few I’ve seen doing this are dedicated race cars that need to meet class restrictions, and to get there they are going full race mode with crazy cams, oversized titanium valves, heavy valve springs with titanium retainers, heavy head porting, completely revised/custom intake plenum and lower manifold or ITB’s, and a number of other expensive modifications that require taking the engine apart like high comp pistons and even stroker kits. This equates to a car that that would be unbearable as anything other than a track car with $15-25k spent on an engine that loses a bunch of reliability because that peak power requires spinning it out to 9k RPM (lots of power up top, but not much under the curve). Ultimately you will have more reliability, more power, and better drive-ability with any forced induction at 1/3 the cost of making 400 to the wheels NA. I think Z1 sells a 

 

I decided that the VQ will be an absolute blast completely stock in any S30 chassis, at least that’s what I want. A few bolt-ons and a good tune can free up some power and get you over 300hp/tq to wheels especially with some lightened rotating mass via flywheel and rim/tire choice. Some intake plenum and lower manifold porting, headers (though the factory ones are already basically tubular stainless), less restrictive MAF tubes and air filters, and a free flowing exhaust can be done without opening up the engine and net you about 300-320 to the wheels. If you did want to go a bit further and open the engine you probably wouldn’t hurt drive-ability too much with a set of mild exhaust cams which might get you around 340-350 with the previous modifications to engine parts and drivetrain. If you wanted to go further and still have the car keep its manners some 12:1 pistons could get you right around 360 to the wheels though you would need access to high octane fuel or ethanol blends, upgrade the fuel system, and could never throw forced induction at it with out removing those pistons. The last 40hp to get you to 400 is where the prices and effort starting getting absurd and not worth it unless you race professionally or want to excuse to never have to go on a car cruise with your friends.

Edited March 1 by Sanchez

[A to Z]

I don't know if you have ridden in modified Z cars, but 240Z's are LIGHT.  320 to the wheels it's basically a widow maker.  Overkill on power is overkill on power.  You reach a point where more power is useless, as you can't put it down, and the car is already dangerous as-is.  It's a street car.  With the power level you are talking about, additional bracing is necessary in the subframe and rails.  Do you like reliability?  Stock=reliability, modifying it for 40-50 horsepower could take away the reliability.  stock 370Z engine is fine power wise bone stock for a 240Z. A lot of the modern cars with all the horsepwoer....that's in a car that weights OVER 4000 pounds.  2 tons.  Completely different deal. Your weight is about half of those.  Be sensible.  Live Longer.  And this setup....stock brakes are NOT good enough, nor is a stock suspension.