It would appear that what I had previously read was incorrect. I’ve verified now a number of times that the HR pistons are not required to run the VHR bottom end with HR pistons. Here is another video recently posted that confirms the same.

So I believe this to be the way to go for an NA build, and I also believe with the right cams, exhaust, and tune that this combination will yield a reliable 350whp result.

So far I am confident that the formula requires
- VHR block and complete rotating assembly
- HR heads, upper/lower intakes and fuel rail.

I am still trying to collect information on which versions of the timing cover, timing chain, VVL actuators, oil pump, and rear coolant cross over are required to make it all work. I’m guessing that all of the HR stuff will be required. I doubt that the VHR stuff will work with the HR heads. I was hoping it would be a simple as just bolting the HR heads to the block, but I doubt that’s the case. It is shaping up to look like one would need to really purchase both engines to make it all work.

 

all good information -

Im not trying to poo poo on your build but full bolt-on 370z/g37/q cars are seeing 330hp after being tuned. And this is with taking them up to 7600rpm and higher … so 350hp is achievable if you want to spin the motor well past 9k rpm and/or if you want to use a saturated correction factor. Another thing you mentioned was reliable - I dont think these motors do well with constant high-end rev’ing. I suspect the VHR oil pump is better than the DE / DE RU / HR but I dont think they were made to be bouncing off 8k rpm. Locally, I see guys spinning bearings (for whatever reason) quite often (albeit they are very hard on their cars).

Itd be wise to replace the gallery gasket too of the donor VHR.

 

Yes I agree. I’ve accepted what others have stated. 8000rpm on the VQ platform, regardless of which engine, or combination of parts, is not feasible on the street. I do not want the additional cost of adding a dry sump system. I think a 7300-7500 redline is doable for a street engine that won’t spin at that for sustained periods of time. This is also why I think the better flowing HR heads and cam options available are going to be needed to achieve a reliable 350whp on the VQ platform.

 

Going to be critical again … take no offense and if there is anything I can help with along the way please let me know. I run a VQ specific parts website and happy to get you anything and everythig you need, I have (atm) one blown VHR if you need parts, I got that little CNC if you need something cut out of aluminum, if you need anything welded, anything and everything I can help you with I’m willing to help.

You’re not going to make anywhere near 350hp on an NA setup, especially if you are going to bring your revs down to the 7500 range … your only hope to make that much power was to really push the motor into the 8500 to 9500rpm range. I know I’m in colorado but my vhr made 295hp at 7600rpm with full bolt-ons

Are the HR heads more efficient?

I dont think cams will help either - cams and VTC (I suspect) will optimize torque. And if it an Achilles-heal of the VHR its that torque falls on it’s face past 7k rpm. You simply cant open the valve long enough with respect to how fast the piston is moving down to get sufficient air into the cylinder.

in for the build though …

 

All this is just a bunch of work to get 350whp, that may or may not happen.
The whole thing will probably match the cost of a low boost setup that would be equally reliable.
From my understanding the HR valve train is superior to the VHR but still.

 

I dont know how to explain this to people other than telling them to get into a 370z / g37 and floor it … yes, low and midrange torque are amazing and the use of VTC and VVEL is pretty sweet but these engines fall flat on their face past 5800 to 6k and the torque just drops off …

so, yes - 300 to 350hp sounds really cool but it’s really not when the lose the feeling of being pulled-back into the seat you go limp pretty quick…

and Im not a huge fan of running a car too much past it’s peak torque … rarely on my z do I shift past 6300 to 6500rpm.

Let me talk out of the other side of my mouth:
I do love the VHR and I think it’ll go down as one of nissan’s best engine (especially in it’s OEM form and when turbo’d) - guys are consistently getting 600 to 700hp out of them with a turbo kit and e85. The VR38 will likely be the king of the hill for time to come and the VR30 is plagued with issues.

 

Thats a fair comment. I know not many people see the point of building an NA VQ, or any NA engine for that matter. I prefer NA engines for how I use my car. It’s as simple as that.
I don’t think I agree that 350whp is not going to happen, when I’ve found more then one example of cars doing that, or very close to that.
If this build formula works out, I think this setup is an overall better engine to build NA or boosted than my DE. If my opinion changes down the road, there is still the option to boost the 37HR engine after it is built. The benefits I see over the DE are:
much better flowing heads (proven by Sasha)
stronger bottom end
better cooling design
larger displacement
better flowing intake design
I think all of those would be beneficial to an NA or FI build.

 

And please dont take anything I say as negative.

By all means, do this build - it will make you a better mechanic, engineer, designer and you never know what you’ll discover along the way.

There are things that I’ve done in the past that many people told me it was dumb/not smart and I did them anywas … sometimes it worked out sometimes it didnt

so, if you think you can hit 350hp without taking the engine to the moon using OEM components I would highly highly advice you to do it and prove me wrong and prove me dumb. You may get close many people do but anything over 330hp you are spinning the engine past 8k and you are compromising longevity. And look at what torque the engine makes at 8k (it’s like 200ft-lbs … you are a mile out of your efficiency range).

I’ll push back and say that the DE is a better engine (apples : oranges). Which engine makes more torque? Peak torque is a sign of efficiency and despite .2liter more displacement, exhaust timing and variable valve lift, the VHR only makes 2 more ft-lbs of torque (these are OEM numbers and not real life numbers). One reason I think the DE does better is the single intake/throttle body vs. the dual. Single throttle body means faster air charge through the intake and plenum - faster intake charge means air enters the cylinder faster and fills the cylinder better (There are obviously 1000 variables I’m not considering).

definately a stronger and significantly better bottom end.

Better cooling?? Ehhhh?? Maybe? Nothing that the pathfinder mod can’t fix and cooling has never been an issue for me.

More displacement, obvioulsy

Better technology, yes

dual throttle bodies is sorta a plus and minus (as talked about above)

VHR and it’s ECU also utilize a MAP sensor in the intake

The manifold is plastic which is lighter and I think absorbs less heat soak compared to the aluminum on the DE

Dont confuse a better flowing intake/head with a more efficient flowing intake and head. The VHR can consume more air than the DE but this equates to more horsepower at a higher redline but does not mean more peak(midrange) torque >>> which leads back to efficiency.

If the VHR intake and plenum was significantly better, you’d see more torque - bc the intake could fill the cylinders more efficiently.
(And who know? Maybe both intakes are designed to fill the cylinders as efficiently as possible, and there is simply no gains to be had??)

But torque is practically the same between the two engines.

DE: 274tq
VHR: 276tq (nismo z)

Something else to consider is look at the tq : hp

DE: 274tq : 287hp = .95%
VHR: 276tq : 350hp = 79% (and this is the nismo z, its lower for the other VHR equiped models)

and this is with more displacement and better technology …

 

Beall I think there are 2 points to be made here, and if both of you haven't see the video where Sasha first talks about (and breaks in) the 4.2L do so.
It's interesting and he hits on redline, head design and the changes between the two setups.

1. A larger (by any means necessary) HR is superior to a VHR, the VVEL heads are finicky and probably the cause for the lackluster high end torque.
2. I will always agree with the DE>HR argument, because let's face it, neither engine will lead to a fast car in NA form (acceleration time, not track time) both can get to about 350whp if your pockets are deep enough.
Id be willing to bet a lot of money that if you have a 350whp DE it will be a better driver's car than a 350whp HR.
Why?
Simple, the DE is made for torque (truck engine) and to get to 350whp it would need more displacement and ITBS.
That car would have significantly better response than the HR with the stock intake manifold, now it will be more expensive tho.
I think OP needs to get in a boosted Z if he hasn't before making any decisions lol

 

I have. I get it, you guys love boosted DE’s. That’s totally cool. I’m seeking information on an NA build. Last I check I wasn’t anyone to spend their money.

 

Researching, wrenching, and tinkering is the best part. Boosted DE's on these platforms are boring to some people now. A VQ37HR would be epic.

 

This was posted last year by Z1
I haven’t found any DE that come close to these numbers in NA form without ITBs. The closest comparison is Micheal Gardners engine (formerly Sasha’s)
that motor was big bucks custom eagle rods, 12:1 pistons, head work, dry sump, and race fuel. The peak torque was 278. The HR above with completely stock bottom end cams and bolt ones, put down 295 peak torque at a lower rpm. My concept is to replicate the same idea but add a slight increase in displacement, and slightly higher compression ratio with off the shelf parts, and avoid the substantial cost involved like the DE above. I would rather not have to purchase the JK transmission as well, but that would still be cheaper then what’s required to build the DE to that level. I have another theory to get HR heads on a DE block utilizing the 7/8th Gen Maxima engine, but that is whole other topic…

 

So you want to do research, and try to shut down any statements contrary to what you think is true, and if 350whp NA would cost more than 350whp boosted, you rather spend the money on NA.
Got it, so if you know it all, why are you here?
Just do it and prove us wrong, not like we haven't seen everything under the sun in the 10+ years we've had our cars lol.

 

I’m not trying to shut anyone down. You’re just not offering anything relevant to the question by just repeating that you don’t think it’s worth it compared to a boosted build. I didn’t invent the idea of the 37HR, I’m just looking for information on how to do it properly. I know the easier and cheaper route is likely to follow your advice. I’ve never argued against that.

 

From the sounds of it, you’re not looking to put the cash in the engine as to what this guy did:
Boundary Oil Pump $400 to $1200
JWT Custom Cams $1600
Spring Assembly $400
Z1 headers $1500
Tomei Exhaust $1300
Refresh $1000
Gallery Gaskets - Priceless
(not to mention labor and tuning at Z1)

Add the wire harness/ECU/Uprev/Tune,
Cost of the Donor Engines/parts
Ported Manifold
75mm TB kit
Intakes

and you gotta be approaching $10k. All so you can be wildly disappointed when you see 330hp on the dyno.

I hope Bridge does this … I really do - I wanna be wrong!

Its sooooo true…

We know…

To answer your question: Just go with OEM HR MLS head gaskets. Head gaskets are important, but your head studs play more of a role in how well your head seals

We know…You watched a handful of youtube videos, have done hours of research but it feels like we’re telling you the answers you dont want to hear.

You want the answers that you do want to hear.

You’ve been here a few years, you got 36 posts - I would invite you to hang around longer because these types of dream-builds come up every time. I love these cars and these engines and that’s probably why I’m investing this much time into the discussion but the more you talk about it and the less you are doing it. Go out and get this build rolling! Lets go!!!! I wanna see your 350hp NA build!

Just start … start doing it and you will get the answers you need to build it.

 

Well if this prices you mentioned are correct then I’m not far off. Like I had said before, the budget number I mentioned did not include the engine/trans/wiring. That was for parts only. It doesn’t include labour either as I said. I already have long tube headers and a good exhaust.

 

It's not that you invented it, but you are certainly the only one I've seen trying to do it in a DE car!
If this was an HR car its a no brainer, but there are not a lot of 100% functional HR swaps at all.
There are people here that know more than me that say it's not worth it, so I'll believe them.
At the end of the day I understand it's your money, but can't you admit that spending $6k+ for a chance at 350whp is a bit nonsensical when that same price can get you to 350+ with boost?
You can say you don't like it all you want, (I don't either) but it's principal of dollar per HP and the ability to have overhead or not.
I came from a 8600 RPM redline to the VQ, I get it, but I also have a mk7.5 GTI as my daily and it's very much almost as fast as my Z with FBO + tune and it barely has an intake and exhaust, a tune would get me another 100ftlbs of torque and will cost me like $400.

 

Thats a really good point … you hear and see quite a bit but you dont know what went into it, you dont ‘really’ know how it’s working, and you dont know how long it worked. I know were a dying breed here and at some point in time FB will consume us all but I dont think there are any active members who have done this and are here to show us how…

Agreed - I tell my car buddies twice as much and twice as long as you expected.


My pushback Dark, is that, it’s his money … he can do whatever he wants, (and where I agree with you)but dont try to convince me it’s a good idea, or it’s redily available and people are doing this with guarenteed sucess … nonsensical is the best way to put it.

I’ll say this again - I wanna see some progress Bridge - do it! Start your build lets see how this plays out. I would channel everything that is being throw at you use it to propel you in this venture. Go get a donor VHR and HR heads, get the guilty garage wire harness. This is your time to shine.

 

You know, funny and off topic but I was watching the Z1 video about their supercharger kit for the 370Z and they are like "full complete packages, bolt on 300hp"
They are being coy, they even said the stock cooling could be enough for the street, NOT A CHANCE IN HELL!
Only if you never use the power, and if you use it, how long will it last?
Nothing is free, extreme NA is no more reliable than mild FI, it very much depends on use case.

 

100% agree … the most stress on any engine component is the split second when it was going up and now it’s going down. And the stresses on the bearings, rod bolts, wrist pins are exponential as revolutions climb linearly.

I sorta thought this was common knowledge?? But I guess not?