Lastchance

ADD HFC, Stillen Gen 3 intake, an exhaust and a reflash.....

bunluvsvw

iTrader: (1)

I think they did that on purpose cause alot of ppl were complaining about how the g35 was very torquey off the line, actually too torquey off the line, making it a very rough off the line, jolting all the passengers. Im guessing they tried to smooth it out so it gets the high class feel, nice and smooth and not just blunt speed. but I can be wrong.

SilverRSXJezus

Refer to my posts and some other people's posts on the first page.

JohnEnglish

Yup, this is why people love turbos and superchargers. They usually give you a nice flat torque curve throughout the RPM range.

shabbo

this is the first production VVEL HR so perhaps Nissan was also conservative. I think the peak torque could have been increased too, because

1) larger displacement
2) higher compression
3) VVEL
4) higher rpm

only to flatten the torque curve?...which is nice for a luxury ride. But IMO along with a flatter torque curve the peak could have definitely increased (gives 6MT a sweetspot), and the reason I see Nissan not going all out is to market the vehicle according to Carlos Ghosn plans...

1) better power, response
2) better emissions
3) better reliability
4) pricing....

Pricing is critical because this car is already priced higher that g35, and adding more power means added costs , higher MSRP and insurance , and perhaps lower sales, and safety ratings etc....

I like the added HP though. Anyways....Intake, exhaust and flash will easily and reliably untap what we're looking for.

shabbo

with simple ECU flash alone is seems like the torque curve even extends past 8000 rpm besides giving a big sweet spot between 5K-6K... this is what you want....nice and flat with a juicy lump in the middle !!

with this kind of a torque curve you really only have to shift once from 0-60 !! you can blow away many a mustang muscle with this :-) just get wider tires if you want a better launch. :-)

vinnys coupe

iTrader: (1)

i still think we could use more torque with a smoother curve or w,e you guys are talking about.. if we had the smooth curve with more tq i guess thats all we need.

shabbo

it seems to me that the VQ37 max HP is kind of limited given the relatively large bore sizes of the cylinders. Even with the sophistication of the VVEL at high rpms, rapid airflow into the cylinders will be slower than an equivalent cc V8 or V10 thus limiting the possibilities of sustaining torque at the higher rpms without a turbo.

And without going turbo or SC, the flash,intake,exhaust route is about all there is for torque that can be sqeezed out of this engine.

Unfortunately the torque limit governs acceleration and for a heavy car like this it ain't going to get much faster without a bigger NA engine. But the ability to already keep a decent torque output past redline (thanks to VVEL) really makes this car feel like there's a small turbo that keeps pushing.

okay...i talk too much..

trebien

If the torque into redline was so great, this thing would be putting out more than 330HP near redline... only 89 HP/liter.

Seriously, it's a good engine, but considering all the VVEL technology, you'd expect higher numbers across the board.

I know it's a very different engine/animal, but let's compare the 3.6 liter GT3 engine that puts out almost 300 ft/lbs between 5000 and ~7200 rpm. Now that's fat.

And at 7500 rpm, outputs 415 HP. Seriously, it's already putting out 330 HP before 6000 rpm.

Now, compression ratio is 12:1. Given. But the 3.94 x 3.01 bore/stroke... a much shorter stroke compared to VQ37 3.76 x 3.39", which should favor the VQ in terms of torque.

You have an engine with a fairly "square" design... but it seems the torque is not quite up to par for an advanced 3.7 liter engine.

And check out the new 3.6 liter 911. It has 345 HP at 6500 rpm and 288 ft-lbs from 4400 to almost 6000. Thank you, direct injection. Nissan needs to put that in high gear. More power, and better fuel economy.

It just feels like the VQ37 is being held back a little bit in it's current form. That's all...

SilverRSXJezus

Can you explain specifically as to what the VVEL mechanism does? I'm not completely clear on it, but does it operate by using two different camshaft profile lobes, one less aggressive/less lift lobe for lower rpms, and more aggressive/more lift at higher rpms, sort of like a VTEC or VVTL mechanism from Honda/Toyota, or is this something different?

soldier9599

people need to read the posts before theirs before posting

PearlG37

C'mon, I realize that you bolded "Very different engine", but you can't compare a GT3 to a G37. There is a reason why the GT3 STARTS at around $110k.

Also, I guess I don't completely understand why some G37 owners seem disappointed with the amount of power the car delivers. It's not like it was some kind of secret that the car wasn't blowing away every car off the line.

shabbo

I agree with this VERY interesting comparison! Now given that the GT3 is such a highly tuned engine it'll be nice to see the VQ engine produce tighter results in comparison...and the $110 $$$ of the porsche doesn't mean that VQ cannot be compared. It won't win..but common sense dictates that it can be compared.

Imo the 2008 GT3's performance comes mainly from it's higher compression 12:1 and shorter stroke formula, This is a disadvantage at lower rpms but when the engine starts to suck in the air the 12:1 really produces more force and the shorter stroke allows the engine to reach higher rpms symbiotically to about 7600 rpm........after which we kind of see the same disadvantage at the VQ37, having larger cylinders displacements vs. air flow restrictions.

Nevertheless with this, the GT3 can sustain the maximum torque of 300 lb.ft all the way t0 7000 rpm!!! so this is a winning race formula and explains the 415HP number at 7500rpm. if the VQ37 were able to sustain it's 270 lb.ft till even 7500rpm it would be making 380HP which is still better for an 11:1 compression...

it's interesting to note that the GT3 torque is only 150lb.ft at 3500rpm and increases to 300lb.ft at 5000rpm. So below 5000rpm the VQ37 will be much better and faster.... but GT3 is a track car over 5000rpm and a normal street car below 5000rpm. The G37 is impressive everywhere.

Now with a simple tadashi ECU tune, intake and exhaust the VQ37 is apparently extremely responsive! decent torque increases past 8000rpm and I DON't want to claim anything but I feel that the numbers will trail respectably to GT3 in HP at least, and beat the stock GT3 between 1000-5000 rpm

This stock VQ37 engine is very underrated and torque can be pushed to 290lb.ft with an ECU, intake and exhaust.

Direct injection is clearly the next logical step to better torque and efficiency.

trebien

I wasn't bitching about the G37 not blowing doors off of other cars.


I was having an intelligent, thoughtful adult conversation as to why it appears in my mind the VQ37 still has headroom that Nissan didn't take advantage of...

As for VVEL, the nice thing is that it is "variable"... not just 2 simple profiles to switch between. This is the new "vtec"... like Vanos on BMW and Variocam on Porsche, etc. In the past, it was just 2 profiles to switch between. Now, it's variable profiling and it's intake and exhaust side.

SilverRSXJezus

Gotcha.


Problem is, the whole notion of "taking advantage of extra power" applies to many cars, and there's plenty of reasons for bottling it up. Number 1, don't want to possibly eat out their own sales, like the Cayman vs the 911. Number 2, marketing standpoint. This car has to be affordable to a certain type of buyer, so they can't just keep on adding parts to make more horsepower and end up with a more expensive car than they planned.


It seems like the VQ has a great torque line that is sustained all the way until redline. Has there been any aftermarket companies looking into parts like valve springs/retainers, cams, and other valvetrain/head modifications? Because I'd be curious as to see how long the VQ could sustain its flat torque line as it goes up into even higher rpms.