Revup heads vs Non-Revup Heads

[simmode1]

I searched NICO and google and couldn't find any solid info. I'm curious on what advantages (if any) does the Rev-Up VQ have over the earlier Non- Revup VQ's.

Of course the Revup has a higher power rating and redline, but specifically I'm inquiring about the variable valve timing on both the intake and exhaust sides. What real value do this provide? Is it just improved gas mileage or is there a performance benefit? And how has the aftermarket responded to the variable exhaust timing on the Revup?

[simmode1]

No responses?! That's weak, guys... I had to go ask a Honda guy.

[tollboothwilley]

I know that the REVUP has different rod bolts and springs. It also has variable exhaust valve timing which the DE does not have. Better oil pump as well. Those things allow it to rev a little higher and get more power.

[BusyBadger]

No responses?! That's weak, guys... I had to go ask a Honda guy.

That's a great way to ensure people don't help you out in the future, at least around here. Some of us actually have a life out outside of here and don't hang out 24/7.

So, how did the Vtec sermon go anyway?

[simmode1]

That's a great way to ensure people don't help you out in the future, at least around here. Some of us actually have a life out outside of here and don't hang out 24/7.

My bad. I just didn't realize how sparse the visitors to this board were compared to the some of the other boards on Nico. I guess I'll ask in the Gen forum next time.

So, how did the Vtec sermon go anyway?

Went pretty well. It explained why many ppl say the earlier Z's are quicker off of the line (besides the weight difference). As I understand it in the simplest of terms, variable timing on the intake side apparently promotes low end torque production, whereas the addition of variable exhaust timing promotes more top end power, which why the Rev-ups shine more in the higher RPMs.

Now understanding the differences in dyno graphs between early VQde's and Rev-ups seem to make more sense to me now as a result. If I were planning alot of high RPM driving, like drifting for example, the Rev-up would be slightly better suited. But for my needs, the early VQ35de model's low end torque will be just fine. No need for me to plan a head swap.

However, I did separately search for the differences between Nissan's CVCT and Honda's V-Tec. There are big differences, but the fundamental point of varying the timing on intake and/or exhaust sides seems to be the same: To define an engine's character by promoting either low-end torque or top-end horsepower

[BusyBadger]

Despite giving some ground down low to the regular VQ the RevUp has a little bit more room up top. The engines in base trim are pretty even provided you have a RevUp and managed to dodge the oil-burning bullet.

Where the VQ really shines is when it comes time for forced induction as its got a beefier components than the regular VQ.

[simmode1]

So was it just the Revup that had the oil burning issue? Can't seem to confirm if the early model had that problem too...

And what is the source of this oil buring problem? I'm sure it must have been diagnosed by now, right?

Nevermind... I searched some more and found the answer.

[PEZi]

Nevermind... I searched some more and found the answer.

i don't like searching.... wanna shed some light?

[simmode1]

Well, ppl on this board say the problem is rare and confined to the VQ35 Revup motor only, but google search reveals otherwise.

Basically, it seems that all VQ35DE's may be susceptible to massive oil consumption issues. I found posts where this affected Maxima drivers, Altima drivers, G35 drivers and more dating back to 2002. For a long time Nissan denied there was a problem, simply replacing problematic motors.

I searched and searched for the actual cause of the problem and finally found this thread from a very well respected NICO member:

zerothread/323273

Hey gang,

I haven't written on this particular section of NICO before. There are a few things on the VQ Im sure you may want to know. If you already do, then disregard this information, but this is good information.

1) If your VQ is losing/burning oil, it is NOT because of the viscosity. The problem lies in the taper of the cylander bore. All VQ engines have a tappered bore, and on some, it is excessive, to the point where the secondary rings and oil control rings are not making full contact with the cylander walls. Durring heavy deceleration, or high rpm deceleration, the vaccum in the cylander draws oil past these rings. In a situation where you are losing 1qt every 1000 miles, you can be sure to find secondary rings that show minimal signs of wear. (since they are not in contact with the walls, why would they wear?)

And more from that thread...

The taper is there for a reason. The update to the engines was a different set of piston rings. The secondary rings origionally had insufficient tension against the cylander walls. All new engines and remans are comming with the updated piston rings. As far as minimizing the oil loss.....best thing I can tell you is to just keep an eye on it. If you have it, it's like cancer, it will eventually get worse. Sorry

I'm still searching for independant confirmation of this info, but it seems like this is the only true solution to the oil burning issue is to replace your old piston rings with the updated set of rings. I'm not sure what all that involves on the VQ35, but it sounds like damn near a full rebuild.

I wonder about this as well: In regards to all the VQ35 motors that have blown up under boost, I wonder how many of those can be attributed to premature detonation due to excessive oil loss? Hmmm...

I'll also add that VQ30DE(K) Maxima drivers seem to be unaffected by this, but I'm still searching for confirmation of this as well.

[BusyBadger]

i don't like searching.... wanna shed some light?

The oil burning on the RevUp was due to the piston rings and the finish on the cylinder walls.

[PEZi]

Basically, it seems that all VQ35DE's may be susceptible to massive oil consumption issues.

see this is what i thought

The oil burning on the RevUp was due to the piston rings and the finish on the cylinder walls.

not this

that's why i was confused

[BusyBadger]

My information comes from a a couple of Nissan techs, one in Dallas and another in Indianapolis - I doubt that they're in collusion.

Outside of the info from the techs I've only got my firsthand experience (and some secondhand experience from a couple of friends running various versions of the VQ) there's no oil burning with any of us. It's odd that Simm mentions all VQ's as the only TSB I've seen released by Nissan regarding excessive oil consumption was specifically in regards to the RevUp engine.

I did have my oil level drop abnormally when I was "thinking with my dipstick" during a moment of weakness and I used castrol Syntec instead of my normal Mobil 1. I switched back and everything was back to normal in no time. Don't think it didn't get me started on the oil burning research though. That's the reason I initially chatted up the couple of techs that I did. I've read through countless posts on forums all over the place and I'm not saying it's hasn't happened but given how many VQ's are out there if the oil consumption was as widespread as it sounds there should be a lot more complaints out there.

That being said I've probably jinxed myself with my lack of oil consumption and I'll probably walk out to my car in the morning to find it sitting in a puddle of oil.

[simmode1]

It's odd that Simm mentions all VQ's as the only TSB I've seen released by Nissan regarding excessive oil consumption was specifically in regards to the RevUp engine.

Thanks for the additional input, it's really something to consider. I am in no way proclaiming my statements to be fact. I'm simply sharing the info that I've found around the net from different forums. It's all debateable, I suppose.

Here's a few links regarding other VQ35 equipped cars with oil loss issues. If you saw these same links in the other thread I posted them in recently, it's because I just copied and pasted. If you want to see more, just google search 'VQ35 oil loss / consumption'. There are quite a few more.

3.5L Altimas with the problem...http://www.nissanclub.com/foru....html

VQ35 Maxima's with the problem...http://forums.maxima.org/5th-g....html

Non- Revup G35 Sedan with the problem...zerothread/139103

[bmike818]

VQHR FTW!

[simmode1]

VQHR FTW!

Very true, but unreasonably expensive to swap into a 240 at the moment... at least for me anyways.