Juztin

iTrader: (9)

Question folks,

I've already done the poor mans 37VHR stock crank in a 35HR stroker route. But I'm going to be looking at rebuilding to go to a closed deck block as my car has some overheating issues that we think might be head gasket related. So might as well upgrade the bottom end a little while at it.

The real question is, can I roll with a VQ37VHR stroker kit that has a crank with a 92mm stroke in the 35HR without issue?

The 37VHR stock crank was drop in, but I wonder if the 37VHR stroker cranks (which seem to go above the BC 86.4mm stroke of the 35HR) are compatible with a 35HR?

I'd like to go with a 92mm crank with a 96mm bore to be just about 4.0L.

Any ideas if it's safe to go with a 37VHR 92mm stroker crank, VHR rods (5.886" vs HR 5.974"), and HR pistons and not contact anything?

I've seen a YT vid of a VHR block getting some slight shavings on the cylinder walls on the bottom to clear a BC 4.2x crank (which I'd imagine is a 92mm).

I want to get away from the GTM GT2860RS's and go the GTX3076R (maybe even a GTX3582R if the 4.0L won't take ages to spool); but either way could use the extra displacement to spool those suckers faster, and get more power overall aside from the bump in low end torque.

venture210

You'd very likely have to do serious clearancing of the block. Stock hr pistons and vhr rods will extend past the deck by 3mm at the top of stroke and break off the oil squirters at the bottom. That's IF the crank and big ends of rods don't contact anything in the bottom end of the block to cause binding.

I have seen a vq37vhr with hr heads though... that would make the 92mm stroker easier with the larger block and taller deck height. Only problem with that is your entire engine would be taller and might be really close to the strut tower brace.

For my own curiousity, at what average rpm do the 28's fully spool?

Juztin

iTrader: (9)

With the .82 AR stage 2's from GTM from back in the day. They feel like they hit full boost around 4.5K when getting some fun run's on the highway without brake boosting (not setup for it).

Thanks for the info Venture, definitely things to ponder; didn't think about the VHR block route. I figured the blocks were the same but sounds like the VHR is taller.

venture210

No problem J. I forgot if you have sleeves or not, but have you considered boring out your cylinders for larger pistons and upping the compression ratio a tad? That will increase your displacement as well as a your torque curve

Juztin

iTrader: (9)

Negative on the sleeves, it just seems that there is a lot of general 'dislike' in the community with running them but I have thought about it; and still will need to. But yea I run e85, right now 9:1 on the motor in my car. Thats a good point, what kinda comp on an E85 100% of the time car do you think is pretty good to go with? 10-11:1?

Conway_160

iTrader: (1)

A lot of the really big HP Supra, Lambo, Vettes, run 11.0+ compression.

venture210

+1 to Conway.

If you were on pump gas, yes stay with a low compression piston set. Since you are already on ethanol, take advantage of it and bump up that compression! You can make a really aggressive tune with E85 and still be safe. Passing 700whp shouldn't be very difficult at all.

About the sleeve comment, who dislikes sleeves??? While there is no real need to install them unless around 800whp, they still allow for much larger pistons, reduced "ovaling" wear, and make your bottom end borderline indestructable when paired with forged rods and pistons. If you have the coin, I say sleeve it and shoot for the moon. THEN you will need the larger turbos.

Juztin

iTrader: (9)

@Venture: Do you know the deck heights of each? I see the block heights for both the 37VHR and 35HR as 8.795" so at least from that aspect they look the same. Supposedly the vq40de has the same block height as the HR and it's got a 92mm stroke which is the same idea I'm floating around in my head.

It would be awesome to get away with using the 35HR block with custom pistons to clear everything; granted if the block needs more clearance grinding for the rest of the rotating mass.

Having to go through multiple sets of rods/pistons to try to find a working combo is not something I'd like to waste $ on. I could always stick to the poor man's stroker I'm running now, but damn it'd be great to eek out 4L.

I'm a little hesitant on the VHR block route in the event that it renders my elite 2500 ECU not compatible as it's only wired right now for HR stuff. I'm not sure if sensors and all that are the same on the VHR to the HR?

Start thinking about stuff like going with a shorter rod and thicker piston comp height for more strength for boost, but then that may likely be heavier pistons and need more balancing weights... I'm curious how the VHR block does it's oiling vs the HR in regards to considering piston clearance with oil squirters etc.

The more I think about it, the easier (cheaper) it is just to stick with the 3.7 route and run a 11:1 CR setup on e85.

MM'08_350Z

iTrader: (5)

HR and VHR Blocks are one in the same...

venture210

Hmm I couldve sworn the vhr had a taller deck. I guess not!
The hr/vhr transmissions have the same bolt patterns. My only concern would be the water pump and oil passage castings. If those are the same, then I don't see why a vhr stroker kit wouldn't work in a hr block. The vq40de crank though, I'm not sure the journals would be the same diameters. The vq35de crank has smaller journals than the hr crank.

All that being said, my vote still goes for the high compression pistons and e85 route. Simple and should get you solid results.

Juztin

iTrader: (9)

Yea, just mentioned the vq40de as it has the same stroke that I would intend to run (and supposedly same block height), so it would seem that Nissan did it OEM style.

But yea for now just likely looking at the high compression E85 route with the VQ37HR. I don't feel like being the guinnea pig with my wallet for the rest of the community lol.

Thanks for the confirm Manny. Does anybody know the stock connecting rod length for a VHR? I'm curious to compare that against the posted length of the brian crower stroker kit. I wonder where they run different sized components from stock to make it work.

MM'08_350Z

iTrader: (5)

I believe it is 5.886"... hey Juztin how was the 37VHR stroker on the HR and boosted? What compression were you running and what numbers did it put down?

- Manny

Juztin

iTrader: (9)

It varies Manny power wise as we've been touching the tune trying to fight the overheating issue that seems to be WG related at this point... but my car was gimped because of my turbo's and clutch as they are the Achilles heel's. But basically it was just a VHR crank with VHR eagle rods and CP 35HR pistons. 9.0:1 compression and a GTM 272 turbo cam (stock heads / valve sizes). E85 is mid 660 hp / 560 tq with a brief spike to 18 ish in the mid range but it drops like a rock to 11psi at redline. Turbo's seem to be at their witt's end.

The turbo's are GT2860RS's with .82 AR so fairly small and already seem to be about 750 bhp so well above their rated 700. This time around I'll just go same 3.7 stroker setup with just carillo rods, 11:1 compression and re-use my cam but upgrade to GTX3076R's with .82 AR. I'm definitely interested to see how the high compression on e85 affects the power with the much larger turbo's. I'm thinking for that setup to have WG springs of 14# to start and see where it goes from there. I gotta roll with a clutch like yours too though, looking at the P-trim or SS trim like yours. Definitely gotta get away from the southbend stage 5.

Otherwise though I love the little stroker setup. It was easy to do last time I recall without much thought needed. I would be game to go 3.99L with the 96mm bore and 92mm stroke but too many unknowns right now how hard that is to do. From old GTM posts where they ran up to 96mm strokes, it sounded like even for 92mm strokes they talked about using longer sleeves. So if you have to do a sleeve job just for 92mm stroke then that sounds like more pain that its worth to try to be the financial guinnea pig for that. If it was something as easy as a certain combo of crank, rods with a select custom pistons that would be much more palatable. I still wonder though... would the 92mm BC crank with VHR rods and 35HR pistons push out the deck considering both HR/VHR have the same block heights? If it would work then that would be a super easy 4L stroker. 5K is a lot to sink on an unknown though, rather put that into the GTX3076R upgrades

What is your E content in your area, mine has been stable at E70 on my gauge since I started running the E85 setup. Not sure how much that will affect running the 11:1 compression like a stock VHR though. Another buddy in the area has a stock VHR with stock compression on E85 in the boost range of around 16psi, think he's around 670 or 680 hp. He has the same E content most likely as me (there's only 3 stations in Albuquerque) so I figure that amount of boost should still be safe on 11:1.

MM'08_350Z

iTrader: (5)

In my area we only have 1 HEB that sells E85, and the content gauge always reads E85 did you have to modify the VHR crankshaft to fit in he block like clearance issues at all?

Juztin

iTrader: (9)

No machining at all from what I recall.

HOODEY

Can some one explain clearly the 350z hr block with, with hr pistons and 370 crank and rods? What needs to be done and what capacity is created? This kind of got lost in the entire discussion.

I've already done the poor mans 37VHR stock crank in a 35HR stroker route. What pistons are used? What is the compression ratio? What else was required.

Juztin

iTrader: (9)

The 3.99L with stock-ish 96mm bore and longer stroke (92mm) I still haven't got past the concept phase. I have to have a builder measure it all out and work with BC on a custom piston to play nice in the block or at least see if it's possible.

I'm still enjoying my current motor build (poor mans 37VHR crank stroker) and first going to upgrade turbo's before getting serious about building up the 2nd block to shoot to go the 3.99L stroker route. If anybody else wants to pioneer the route and post the piston specs for custom ordering, by all means

But I'm a ways off still, likely either late this year or early next year.

HOODEY

What is the poor man poor mans 37VHR crank stroker?

Juztin

iTrader: (9)

Poor man's stroker is just a 35HR block w/ 37VHR crank as it drops right in; so a cheap .2L bump. I'd do a 3.8L GTR crank but from what I have heard it will require some machining to make it fit, and since doing that I'd rather just go with a bigger stroker bump with a 92mm stroke instead for the pretty much 4L displacement.

Conway_160

iTrader: (1)

Would this work for a DE as well? I belive the DE and HR use the same block.