Compression ratio

Forum for Infiniti M35 and M45, and Nissan Fuga owners.
TPRadiographer
Posts: 22
Joined: Thu Aug 30, 2018 9:46 am
Car: 2006 Infiniti M35x with Tech Pkg
Akebono BBK
Upgraded sway bar bushings
08-10 Sport bumper
Custom CAI and exhaust
UpRev tune
5/16” plenum spacer
Fan pulley delete
Location: Oregon

Compression ratio

Postby TPRadiographer » Wed Jan 30, 2019 5:05 am

I apologize if this has already been asked but I have had no luck finding an answer.

I am looking to replace my 222k engine in my 2006 M35x with one built to higher specs. I have low compression in one of the cylinders and I am considering the Stage 2 VQ35DE from Import Parts Pro with the S2 cams. I want to continue to daily my car and I run 92 non-ethanol (the highest I can get where I live).

Can I run the 11:1 pistons (with a tune) that they list or should I go with more like a 10.6:1?

http://www.importpartspro.com/st2vqloblni3.html

Thanks.


EniGmA1987
Posts: 2010
Joined: Tue Apr 28, 2009 5:13 am
Car: '06 M35 Sport

Re: Compression ratio

Postby EniGmA1987 » Wed Jan 30, 2019 8:20 am

11:1 is probably fine with street gas. With cam changes and piston changes you are going to be doing a major tune anyway so it can be tuned properly.

Not to discourage you, but thats a lot of money spent for the car. Are you sure you want to keep it with looking at spending $9k? That engine costs $7150, then you have shipping costs and then installation and tuning costs. At that point it also seems like such a waste to just do a new built engine ready for 650whp and not have anything that takes advantage of the extra durability. It just begs to have some major intake mods done. Step up to a Kinetix velocity manifold, move to a 90mm throttlebody, do custom 4-5" intake piping with maybe even dual cones on the end for extra airflow. All that with the oversized pistons and high compression would probably get you around 350whp. Maybe even more if you have them increase the rev limit to 7.5k. With the oil pump upgrade and the new valve springs that should be plenty doable. Would definitely have to open up that intake system though.


If all you need is a new block I believe I still have a spare one laying around. I never actually used it as I bought it at a great deal, but then found a much better engine a couple months later. It is a rwd VQ35DE with stock everything except the rods have been upgraded to H-Beams. It doesnt come with intake manifold or anything, it is just the block, crank, rods, and pistons. So whichever shop you are having this done at will need to scavenge things from your current engine to put on this one. Since you just have a block issue causing low compression you shouldn't really need anything more though.

CarGuy87
Posts: 52
Joined: Wed Dec 26, 2018 9:12 am
Car: 350z, G37s, M35s

Re: Compression ratio

Postby CarGuy87 » Fri Feb 01, 2019 5:35 pm

As listed above, you can run both, specially since you should tune it with either one. Since you are doing this go all out and do 11:1. I also own a Z and I would refer you to the All motor forum in my350z . com The VQ guys there are pretty knowledgeable.

TPRadiographer
Posts: 22
Joined: Thu Aug 30, 2018 9:46 am
Car: 2006 Infiniti M35x with Tech Pkg
Akebono BBK
Upgraded sway bar bushings
08-10 Sport bumper
Custom CAI and exhaust
UpRev tune
5/16” plenum spacer
Fan pulley delete
Location: Oregon

Re: Compression ratio

Postby TPRadiographer » Thu Feb 07, 2019 6:30 am

Thank you both for the info.

I'm seriously thinking of doing the work myself on a spare motor but not sure how much needs to be changed for the AWD on the 2WD engine. I'm seriously trying to find out about what it takes to do the oil pump upgrade and the info on specs to grind out the block for the HR style coolant setup that is mentioned on the importpartspro website so that I can have a local shop do that part as well as the 0.020" overbore, milling the block and shaving the heads. So far I have found little.

I have a friend that may port and polish the heads while I plan to do the same to the intake manifold/plenum. I've got the 70mm TB on order and will be doing the fan pulley delete maybe this weekend.

TPRadiographer
Posts: 22
Joined: Thu Aug 30, 2018 9:46 am
Car: 2006 Infiniti M35x with Tech Pkg
Akebono BBK
Upgraded sway bar bushings
08-10 Sport bumper
Custom CAI and exhaust
UpRev tune
5/16” plenum spacer
Fan pulley delete
Location: Oregon

Re: Compression ratio

Postby TPRadiographer » Thu Feb 07, 2019 6:31 am

EniGmA1987 wrote:
Wed Jan 30, 2019 8:20 am
11:1 is probably fine with street gas. With cam changes and piston changes you are going to be doing a major tune anyway so it can be tuned properly.

Not to discourage you, but thats a lot of money spent for the car. Are you sure you want to keep it with looking at spending $9k? That engine costs $7150, then you have shipping costs and then installation and tuning costs. At that point it also seems like such a waste to just do a new built engine ready for 650whp and not have anything that takes advantage of the extra durability. It just begs to have some major intake mods done. Step up to a Kinetix velocity manifold, move to a 90mm throttlebody, do custom 4-5" intake piping with maybe even dual cones on the end for extra airflow. All that with the oversized pistons and high compression would probably get you around 350whp. Maybe even more if you have them increase the rev limit to 7.5k. With the oil pump upgrade and the new valve springs that should be plenty doable. Would definitely have to open up that intake system though.


If all you need is a new block I believe I still have a spare one laying around. I never actually used it as I bought it at a great deal, but then found a much better engine a couple months later. It is a rwd VQ35DE with stock everything except the rods have been upgraded to H-Beams. It doesnt come with intake manifold or anything, it is just the block, crank, rods, and pistons. So whichever shop you are having this done at will need to scavenge things from your current engine to put on this one. Since you just have a block issue causing low compression you shouldn't really need anything more though.
How much are you asking for the block and where abouts do you live? I'm near Portland, OR.

EniGmA1987
Posts: 2010
Joined: Tue Apr 28, 2009 5:13 am
Car: '06 M35 Sport

Re: Compression ratio

Postby EniGmA1987 » Thu Feb 07, 2019 10:12 am

TPRadiographer wrote:
Thu Feb 07, 2019 6:30 am
Thank you both for the info.

I'm seriously thinking of doing the work myself on a spare motor but not sure how much needs to be changed for the AWD on the 2WD engine. I'm seriously trying to find out about what it takes to do the oil pump upgrade and the info on specs to grind out the block for the HR style coolant setup that is mentioned on the importpartspro website so that I can have a local shop do that part as well as the 0.020" overbore, milling the block and shaving the heads. So far I have found little.

I have a friend that may port and polish the heads while I plan to do the same to the intake manifold/plenum. I've got the 70mm TB on order and will be doing the fan pulley delete maybe this weekend.
The reason I specified RWD engine is because there are two versions, the FWD and RWD. They are incompatible with the different platforms. SO you cant stick out RWD engine in an Altima or Maxima. They use the 90 degree rotated FWD engine version. The AWD platform we have will use the same engine as we have in the RWD, but I am not completely sure there is no difference whatsoever. They may have additional small tweaks that need to be done for mounting.

With the overbore, that would bring you to the same 96mm piston size that I have. You will need new pistons when you do that. I have heard good things about the Weisco pistons with the ceramic coating.

The stock throttle body is 70mm made by Hitachi. Hopefully you did not buy another 70mm? Otherwise there wont be much difference. My current engine is using a 70mm Mustang TB, but there is no real reason to do so. I actually just bought a new GM 90mm throttle body that I plan on putting on the car *soon*. But first I have to get quotes from shops on doing custom fabrication work to replace my current intake tube between the TB and the manifold, and then make me a new intake pipe from outside air to the TB. Ill probably do that with tax return money. Most people who have tried this end up going with a GM LS2 throttle body, and you can either do the custom pinout yourself or there is a company that sells that custom adapter for doing this. You do need to do some significant tuning work to make this work though. I dont think you can use the stock ECU with UpRev, not enough control. My GM throttle body is being phased out so its a bit hard to find, but it is made by Hitqachi and uses the same sensors and actuator as our stock TB does, so it doesnt require nearly as much tuning as an LS2 throttle body.
TPRadiographer wrote:
Thu Feb 07, 2019 6:31 am
How much are you asking for the block and where abouts do you live? I'm near Portland, OR.
I am in So Cal. So not too far. I sent you a PM with some more details.

TPRadiographer
Posts: 22
Joined: Thu Aug 30, 2018 9:46 am
Car: 2006 Infiniti M35x with Tech Pkg
Akebono BBK
Upgraded sway bar bushings
08-10 Sport bumper
Custom CAI and exhaust
UpRev tune
5/16” plenum spacer
Fan pulley delete
Location: Oregon

Re: Compression ratio

Postby TPRadiographer » Thu Feb 07, 2019 12:20 pm

Thanks for the heads up. I was going on the specs found while looking up new/refurb TB’s for the M and they all stated 65mm. I just double checked and was able to cancel the adapter bracket and harness. The TB I bought on eBay for ~$60 so no big deal.

dragmyr1
Posts: 23
Joined: Wed Jan 01, 2014 8:31 pm
Car: 2006 infiniti m35

Re: Compression ratio

Postby dragmyr1 » Sat Feb 09, 2019 11:50 pm

Hey I am looking to go the same thing with my engine.well maybe not replace,bit rebuild with oversize pistons. And then get my crank balanced.

EniGmA1987
Posts: 2010
Joined: Tue Apr 28, 2009 5:13 am
Car: '06 M35 Sport

Re: Compression ratio

Postby EniGmA1987 » Mon Feb 11, 2019 8:00 am

dragmyr1 wrote:
Sat Feb 09, 2019 11:50 pm
Hey I am looking to go the same thing with my engine.well maybe not replace,bit rebuild with oversize pistons. And then get my crank balanced.
VQ35DEs have a ton of mods for the engine you can do. THanks to it being the engine that was in the G35 and 350Z for so many years. It really is a great platform. The most I saw someone get was 2100 wheel horsepower from these engines. lol. Most people typically just do rods, pistons, valves, and cams and then throw a turbo on it though. That would get you easily 600+ whp with a mid size turbo

From what I remember, you can do 96mm pistons (a .5mm oversize) without having to sleeve the cylinders, but if you go larger to 96.5mm you will have to.
I havent done it, but I have heard people have been able to use the crank and crankcase from the VQ37VHR engines onto the VQ35DE, and basically get a mini stroker kit going and give themselves and extra .2L displacement just like the bigger engine. If you are already going to do stuff around that area and it has to be dropped anyway for piston and rod install then you might want to look into that. The longer stroke will give you a very nice torque boost in the low RPM range.

TPRadiographer
Posts: 22
Joined: Thu Aug 30, 2018 9:46 am
Car: 2006 Infiniti M35x with Tech Pkg
Akebono BBK
Upgraded sway bar bushings
08-10 Sport bumper
Custom CAI and exhaust
UpRev tune
5/16” plenum spacer
Fan pulley delete
Location: Oregon

Re: Compression ratio

Postby TPRadiographer » Mon Feb 11, 2019 8:58 am

I wonder how much work is involved in the VQ37 bottom end swap would be. That would be an awesome idea. Do they use the same connecting rods as the 3.5 or the 3.7?

EniGmA1987
Posts: 2010
Joined: Tue Apr 28, 2009 5:13 am
Car: '06 M35 Sport

Re: Compression ratio

Postby EniGmA1987 » Mon Feb 11, 2019 10:23 am

Im not sure on the work involved. A really good shop like Specialty Z or JWT might know. And you would need to use the rods from the 37 engine, or aftermarket rods for that engine.

TPRadiographer
Posts: 22
Joined: Thu Aug 30, 2018 9:46 am
Car: 2006 Infiniti M35x with Tech Pkg
Akebono BBK
Upgraded sway bar bushings
08-10 Sport bumper
Custom CAI and exhaust
UpRev tune
5/16” plenum spacer
Fan pulley delete
Location: Oregon

Re: Compression ratio

Postby TPRadiographer » Tue Feb 12, 2019 9:41 am

Does anyone know of an ideal spark plug for an 11:1 compression ratio in the VQ35DE? I’m currently running 1 colder than stock (heat range 6) with my tune because I was melting the electrode on stock.

EniGmA1987
Posts: 2010
Joined: Tue Apr 28, 2009 5:13 am
Car: '06 M35 Sport

Re: Compression ratio

Postby EniGmA1987 » Tue Feb 12, 2019 11:56 am

TPRadiographer wrote:
Tue Feb 12, 2019 9:41 am
Does anyone know of an ideal spark plug for an 11:1 compression ratio in the VQ35DE? I’m currently running 1 colder than stock (heat range 6) with my tune because I was melting the electrode on stock.
Not sure. The shop that helps you with tyhe engine and tuning could help you out with that. Plugs are cheap so its not a really big deal.

My car when it was all stock before it ever got a tune it was actually very lean from the factory. At WOT it never got below 13.5:1 ratio, so you engine may be similar so your engine might be running hot and causing the spark plug damage.

TPRadiographer
Posts: 22
Joined: Thu Aug 30, 2018 9:46 am
Car: 2006 Infiniti M35x with Tech Pkg
Akebono BBK
Upgraded sway bar bushings
08-10 Sport bumper
Custom CAI and exhaust
UpRev tune
5/16” plenum spacer
Fan pulley delete
Location: Oregon

Re: Compression ratio

Postby TPRadiographer » Wed Feb 13, 2019 9:30 am

Any ideas on what the stock injectors can handle hp wise? Should I upgrade to something like 440cc?

EniGmA1987
Posts: 2010
Joined: Tue Apr 28, 2009 5:13 am
Car: '06 M35 Sport

Re: Compression ratio

Postby EniGmA1987 » Wed Feb 13, 2019 9:53 am

That really just depends what you are shooting for on horsepower. Im pretty sure the stock injectors can handle anything you can produce without a super or turbo. You could look up Fatboy's threads and see if he replaced his injectors or not. He was the only one to put a supercharger on his car, and he made 450whp. I dont remember if he said he replaced the injectors or not. Typically even for significant mods with staying NA you wont even make 400whp. From what I remember the VQ35DE only makes around 220 or so wheel horsepower at stock.

Though if you are doing injector changes you probably also want to replace the fuel rails. Our stock setup isnt really that great. The driver side rail bridges off the passenger side rail, and the passenger rail has a weird little 180 degree bend in the line between the rail and other stuff in the engine bay. That bend was pretty kinked on my far and definitely constricting flow It wasnt like a full kink that could cause a block, but the line definitely was flattened in the bend area. You could either fix just that area with some custom fabrication work or replace the rails entirely with larger capacity and better designed ones

TPRadiographer
Posts: 22
Joined: Thu Aug 30, 2018 9:46 am
Car: 2006 Infiniti M35x with Tech Pkg
Akebono BBK
Upgraded sway bar bushings
08-10 Sport bumper
Custom CAI and exhaust
UpRev tune
5/16” plenum spacer
Fan pulley delete
Location: Oregon

Re: Compression ratio

Postby TPRadiographer » Wed Feb 13, 2019 10:57 am

Thank you again EnigmA1987. Everyone has been very helpful.

I’m hoping for around 300whp so I don’t create more trouble than it’s worth for me (ie. broken divetrain components or needing to make other upgrades) and I want to maintain it as my daily. I was thinking that the next step up in injectors (440cc) was a bit much tbh but a 360cc-380cc might be cool (haven’t seen them though). I will however look into the fuel rail setup for smoother flow to the left bank.

TPRadiographer
Posts: 22
Joined: Thu Aug 30, 2018 9:46 am
Car: 2006 Infiniti M35x with Tech Pkg
Akebono BBK
Upgraded sway bar bushings
08-10 Sport bumper
Custom CAI and exhaust
UpRev tune
5/16” plenum spacer
Fan pulley delete
Location: Oregon

Re: Compression ratio

Postby TPRadiographer » Wed Feb 20, 2019 10:14 am

I successfully removed the fan pulley and bracket. I used the shorter belt with the spacer from Infiniti for the P/S pump mount. Everything went very smooth and the car seems a little more responsive. I think it helped that the fan pulley bearings seemed to be making some noise when spun.


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