i don't quite think the VHR is a disaster. They tried to build on the original 35HR which they did. I atribute the heating issues to not enough R&D and more of 'lets get this thing out to the public pronto' type of scenario. If nissan deems it profitable they can still massage the VHR...of course they won't.

 

not necessarily..

4.0 v6 Nissan Frontier
4.3 v6 Chevy S10 - replaced by Colorado
4.0 v6 Ford Ranger

 

HR and VHR have the same redline. Yet, the VHR overheats much faster. VVEL is the culprit to many many issues with the engine. The slightly longer stroke doesn't help, but I would conjecture a 3.5 with VVEL would overheat as well, and that a 3.7 with a traditional head design would not overheat as quickly.

 

I agree VVEL is the culprit for the VHR. again. not enough R&D. but i think nissan was aiming for more useable power for everyday drving. the power curve on the VHR is the most linear compared to the DE, Rev-up, or HR. of course the undesired effect is the rapid overheating we find on the track.

I think a 3.7HR could have made just as much power in lieu of the 3.7VHR. of course you get a less refined feel as opposed to the power 'swell'...lol.

would you like the 3.7 if it had v-tec mike?

 

I think the VQ has an amazing pedigree and history. I still actually enjoy driving my 4th gen Maxima. There wasn't much available in '95 anywhere close in it's class that could touch it IMO. It was very innovative then. But so was the Discman, Windiws 95, and this newfangled technology called a Digital Video Disc. It's had a great service life and I think Nissan's done a good job of trying to keep it up to date. But technology and innovation and competion in the industry has grown exponentially since then and I think it's time to see what the engineers can come up with to push the envelope fir the next generation.

 

VVEL is supposed to have all the pros and none of the cons of VTEC. Supposed to, being the key word.

 

YouTube - G37 Vs. 335i - Infiniti and BMW Face Off At The Track! Pt. 2

The 335 overheated and the g kept going

 

Lets not forget that the N54 has been revised since then, while the VQ37VHR has not.

 

what is your take then on a 3.7HR motor with a high and low cam config like v-tec? i'm sure the displacement would stil make it use-able around town, while having the high cam gets it closer to 100hp /liter. but the power deliver would not be as linear. i wonder what if nissan went that route...(seriously)

the N54 has more problems than just heat issues...the HPFP issues are ludicrous even for a german car. it is not uncommon for 07s to 08s have their engines replaced numerous times. it's even occuring in the 09 models. at least BMW has put a 10 year 120K warranty on the 07-08 models....

if it wasn't such a buggy motor i'd be a 335i owner in a second.

let's see what the N55 holds...

 

As previously having a 08 G35xS with the VQ35HR and currently having a 2010 G37xS with the VQ37VHR motor - I can say a few things ...

1. The VQ is no where as smooth as the three Honda V6s I drove (2002, 2004, and 2006). The 2006 Honda 3.0 V6 was truly incredible - torquey enough around town, and when it hit that 4950 rpm VTEC switch-over - it was just fun - sounded incredible and was smooth as buttah'. I do think the 3.7 is smoother overall than the 3.5.

2. The 3.7 with VVEL feels very odd. Coupled with the shorter gearing of the 7AT, this motor should feel much more responsive than the 3.5 with the 5AT - and it doesn't overall. This thing should be RIPPING around ... and it doesn't.

3. YES I agree - you truly only feel mega power and extreme responsiveness of the 3.7 when the tach hits 5,000 ... at least that engine speed. Today I shifted down to 2nd manually just to hear the motor and to feel the power surging while I got on and off the throttle (5,500 - 7,000 rpm ... it's a truly incredible sensation). I have written in other posts that the 3.7 is overall more torquey in the lower rpms than the 3.5 was - but it just doesn't FEEL that way. Very odd. Bad programming??

4. Innovation: The VVEL system is innovative, but I don't think it means better either. Yes, I believe the VVEL contributes to increased efficiency. But, I just miss the regular 'ole feel of power from the 3.5. Last week I drove my partner's 2010 M35x - I couldn't believe how much fun it was to drive. The 3.5 felt so responsive (even in a car that was 250 lbs. heavier than my 2008G35xS with the same 3.5 and 5AT).

Long in the tooth? IMO - yes.

 

I must be really easy to please. The car goes fast, the engine doesn't have problems, and all I have to do is feed it fresh oil every 3 months or so and I can keep driving the hell out of the car with no issues.

It's not as smooth as the engine in my IS350, but it's also a lot more fun. The G has a coarser engine than the competition, but for me that makes for a more visceral experience. That coarseness only comes on when I'm really getting into it at 5k+ RPMs, and a little bit of thrashing seems perfectly reasonable at high revs.

No complaints here. As a matter of fact, the "issues" that people bring up about this engine are really the things that put a smile on my face and brought me to Infiniti in the first place.

 

id rather feel the engine than be numbed and isolated from it. the 37hr is by no means a disaster. the potential to put 500+hp to the wheels on stock internals has me planning a tt upgrade very soon. being a g35 owner previously, i can absolutely say that i prefer the 37hr over any of the 35 iterations. every one of the 35's i drove were weak and anemic and imo no more refined than this new motor.

 

VTEC on a 3.7? Since VVEL theoretically uses the "ideal" lift and timing at all points in the RPM range, output wouldn't go up. Instead, area under the curve would decrease...

Note the huge "gap" in power when VTEC hits. This is more for marketing purposes, the bump would be completely smoothed if the transition is lower in the RPM range. (This is done almost universally for s2k's with any sort of tune) VQ35HR dyno included for comparison.

F22C1 is bone stock. VQ35HR has intake, exhaust, and HFCs. Both cars are on summer blend CA 91 octane. Note that this was the most powerful NA VQ35 that showed up to this dyno day. The DE's were dynoing anywhere from 250 on up depending on the mods.

 

sacrifice under the curve and eliminate VVEL..in turn no abrupt overheat? of course in theory will not be as efficient as VVEL throught the rpm range. i've seen the vtec transiton soothed out by using hondata on some engines ala K20s, the power curve gets pretty linear.

 

I love the sound of the motor when i rev it up. It loves to be revved i mean after all its called HR (high-revving) engine.

But i do find it ironic how we have a 3.7L V6 compared to the new BMW e92 4.0L V8. Nissan pushed every little bit of power they could out of this motor while BMW throws a small high revving v8 into the M.

I would be happy if we got small displacement high-vevving v8....or a turbocharged I6.

-Tom