Really dumb question..........

[cheapazz]

I keep hearing about different engines for the G, whats the difference? How can I tell if I have what in my car? I only ask 'cause I've read that doing the spacer mod is really only effective on the ?rev-up? motor?? Is that right? Or is there a thread I can be directed to?

[WESIDE]

You have a 2005, correct? Is it manual or an auto? Coupe or 4-door?

[cheapazz]

Yes, 2005, auto, coupe.

[all G'd up]

I believe to tell if you have the rev-up motor your RPM redline will be at 7k instead of 6500. I'm not really sure what they did to the motor to increase the redline...

[CYO44Baseball32]

I keep hearing about different engines for the G, whats the difference? How can I tell if I have what in my car? I only ask 'cause I've read that doing the spacer mod is really only effective on the ?rev-up? motor?? Is that right? Or is there a thread I can be directed to?

Not stupid question so don't feel bad

[WESIDE]

I believe that you have the rev-up motor. Double check..

[cheapazz]

OK, I looked, and the actual redline as printed on the gauge is at 6,650 but I can hold till my rev limiter hits at 7,100 or a bit higher.

[rmezz13]

The spacer does nothing in the Rev-Up motor but decrease torque. The rev up has a different lower plenum/manifold, which has shorter runners, thus increasing HP but reducing torque. The non-rev-up have longer runners, with more torque but less HP than the rev-up, so buy adding a spacer you increase HP's. adding a spacer to a non rev-up would take you up to the 300hp the rev-ups have (example being 350Z). But you already have more torque so there fore you will be more powerful than the rev-up's for $200-$300. Being an Auto 05' coupe you probably don't have the rev-up motor set-up. The Auto Z's (base model) didn't have the rev-up in 05.

[cheapazz]

rmezz...........thanks, just what I was looking for. Spacer it is!

[C-Kwik]

But you already have more torque so there fore you will be more powerful than the rev-up's for $200-$300. Being an Auto 05' coupe you probably don't have the rev-up motor set-up. The Auto Z's (base model) didn't have the rev-up in 05.

Not necessarily. Having more peak HP is only one aspect of making more power. The rev-up motor has three-stage variable exhaust cam timing, in addition to the infinitely variable intake cam timing, which allows for a broader torque curve (think area under the curve here). So there is likely more HP available in the rev-up around the peak as well. I doubt a spacer would provide as much average HP, even if the peak HP is the same.

Not to say that a spacer is a bad thing. More power is more power. But its misleading to give the impression that it might be as good as the rev-up unless it actually is.

[rmezz13]

well.... stock vs. stock from people who have owned 03-04 Z's (non-rev up) and 05-06 Z's (rev-up) have said the stock* 03-04 feels more powerful thru all the gears, and they said it is more fun to drive all around because of this factor...... I read this on a poll taken on another forum about a year ago........ Thats stock against stock 350z's rev-up and non rev-up....... The higher torque seems to be the factor. More power you can feel! The true test is always to drive the car, numbers are just numbers......

but thanks for the technical side c-kwik.....

[joe603]

Check out the G-series FAQ for model year differences in the engine. (in my sig)

[Sentientbydesign]

To sum it all up.

You have a non rev-up motor. The spacer should yield you some more power. It will unlikely produce the same power as the rev-up.

The 500 or so RPMs to redline will also make a difference in the HP.

[C-Kwik]

I'd be much more inclined to believe dynos than a driver in this regard. Also, this also says nothing of power anyways as the 350Z's and G35's with the Rev-up motor gained some weight when they were released as well. Acceleration may have changed very little as a result. Keep in mind that the Rev-up motor makes up for the difference it lost in peak torque at higher RPMs.

The non-rev-up makes 287 HP at 6200 RPM. The Rev-up makes 300HP at 6400 RPM. It would be safe to assume that the non-rev-up makes no more than 287 at 6400 RPM and likely makes less. But for arguments sake, lets assume that it makes 287 at 6400 RPM. That would be equal to making 235 ft-lbs of torque at 6400 RPM. The Rev-up makes 246 ft-lbs of torque at 6400 RPM. The difference is about 11 ft-lbs IF we assume that the non-rev-up makes 287 HP at 6400 RPM. It is likely less, but how much is not known based on manufacturer specs.

Looking at the data even closer, if you compare the peak torques to their respective torque levels at their peak HP RPMs, you'll notice the torque is dropping off much more rapidly in the non-rev-up motor. The typical advantage of variable cam timing is to broaden the torque curves. I'd speculate that the difference in torque at 6400 RPM would be much greater than it is at 4400 RPM. Add to that the Rev-up can hang onto the gear for a few more MPH in each gear and its torque multiplication advantage will probably become more apparent. Now if Nissan/Infiniti could have done this without adding the extra weight, the Rev-up probably would have shown some incremental improvement in it's acceleration performance.

[rmezz13]

i re-read my response to your post, i didn't mean for all of that to be directed towards you, just adding to the post in addition to what you said, i kind of came off as cocky and don't really know what i was thinking when typing it. Sorry, and you know already that your right on both counts.....

[C-Kwik]

Most of that post was a general response to the comparo betwen the rev-up and non-rev-up. Plus, I was pretty bored at the time I wrote it so...

So I wasn't trying to be argumentative. Just spitting out somewhat useless facts. =P