Looking at the EM sections for the 97 maxima and the z33 '05, I see that the rev up exhaust cam is positioned in the head with the dowel pointed at the bottom of the head. The vq30 exhaust cam is positioned with the dowel pointed towards the top of the head. So obviously the exhaust spacer would have to have two holes. One for the rev up exhaust cam and dowel, and one for the vq30 exhaust cam sprocket and dowel. Right?

Additionally, the fact that two holes would have the be drilled in the spacer would give you a lot of room for adjustment. The vq30 stock cams have 6 degrees of overlap and the rev up cams have -4. I have been thinking about retarding the exhaust cam 10 degrees to keep the same amount of overlap.

From what I have been reading, its not the opening of the exhaust cam that matters as much as when it closes, i.e. how much overlap it has. Obviously if it opens way too late or way too early, there will be problems. The exhaust centerline would only be a few degrees different from stock.

The modified timing would be as follows.

Intake_Opens: 2º ATDC
Intake_Closes: 70º ABDC

Exhaust_Opens: 60º BBDC
Exhaust_Closes: 8º ATDC

Overlap: 6º

I think keeping the stock overlap of 6 would still allow me to take advantage of the scavenging effect while preserving the car's idle. I also don't want the exhaust valve to close too late or I risk pulling exhaust gas into the cylinder on the intake stroke. My question is what would this do to the power band? Also, is this more trouble than it's worth? Should I just rotate the exhaust sprocket 180* and live with the -4 overlap?

 

Just live with the stock rev-up cam overlap, its the way all of us run them. These cams are made to breath up to 7500rpm

 

As far as cam timing goes:

Advance pushes the powerband to the left, and retard pushes the powerband to the right.

As for overlap...



Wider LSA (reduced overlap) improves low/midrange power, tighter LSA improves top end horsepower.

Less LSA (increased overlap) also reduces idle quality because there's not enough vacuum at idle.

More details here:

http://www.enginebasics.com/Advanced...%20Tuning.html

and here:

http://www.ls1tech.com/forums/genera...erts-come.html

What is your desired rev range and what software are you using? You can add some fuel at idle to reduce the "lope" from the cam and a relatively low LSA. It's hard to predict how the RevUps will shift your powerband with the change in duration & lift but according to the preceding information, keeping the standard overlap would be better than pushing it to +6 degrees. This is because if you increase the overlap this much it may push your power delivery too far to the right and you'll lose more idle than necessary.

(wishes VQs could get adjustable cam gears)

 

adjustable cam gears or just use the 3.5 VTC.

 

Doesn't the RU engine have CVTC on both I &E as well? V-manage .

 

who has a dyno of REAL gains or how it shifts the powerband in a vq30?

i tried searching but i coudn't find anything

 

"Just use the 3.5 VTC?" Yeah, why don't you just use it, just like you would casually change from CAI to short-ram. Try that on your 3.5 swap please.

These cams are going in a VQ30. None of the VQ30 has CVTC, the adapters used are Stephen Max adapters for 3.5 swaps that allow the cams with CVTC sprockets to run STATIC timing. V-Manage is just a piggyback so you'd need a previously existing VTC signal to manipulate. It will not adjust anything by itself.

Nobody barely ever puts cams in a VQ30.

 

No shat ...

Point being, in order to optimally use them, one would need A33B software coupled with said V-Manage . ...

 

Sorry I didn't respond to your PM earlier. I've hardly been on the org lately and my e-mail notifications aren't working for some reason.


I've handled the rev-up exhaust cams and they are definitely installed straight up. Their dowel placement is the same as non-revup VQ35/VQ30 exhaust cams. It's the intakes that have the larger dowel in the different orientation.

 

To run the CVTC you'd need to swap out all of the electronics from an engine with the system. Also, isn't there a fitment issue with the rear head? (RWD head on a block mounted laterally) This is far beyond where I plan to take this car.

Crusher,

As far as the rev up cams breathing at 7500 rpm, I'm sure the overlap is being changed by the CVTC system at that rpm. In other words, it's not -4.


Moncef,

I realize that a large amount of overlap will push the power band to the right. I only plan on taking the engine to 7000 or 7200 with an EU. I would not consider 6 degrees to be pushing it. That is the vq30 stock overlap.

Modified rev up timing

LSA-240
Intake centerline-124
Exhaust centerline-244

Stock VQ30 timing

LSA-226
Intake centerline-113
Exhaust centerline-247

As you can see, the LSA is 14 degrees greater with the modified rev up timing. According to Moncef, this would be conducive to low rpm power. We already determined that the overlap is the same as stock, so I don't see that being a concern with regards to idle. We don't really need to talk about intake centerline by itself, as it will be unchanged. The exhaust centerline, however, is almost exactly the same as stock VQ30 cams.

From my research, it seems that a lot of overlap is 40 degrees or so. 6 degrees is not going to give me loopy idle. Also 6 degrees won't really negatively impact my low end because it's the same as stock. The increase in lift would surely give me more low end in the end.

Comments?

 

Sounds good to me. What about high RPM power? The increase in duration over the stock DE cams will allow for efficient breathing to 7-7200 rpm, correct?

 

no love for the vq30 not even a dek?

 

to be honest if u are putting this much thought into it just go buy some really aggressive cams and work with those, we sure could use some more information on the JWT C series cams.

 

Yeah the C series that requires valve clearancing before installation...

 

This whole thread is about the VQ30, we are tryin to make some lovin to this motor

 

no ****. i have an extra set of VQ30 heads if he wants to try it thou.

 

That's what I would think. At high rpm the increased duration and 6 degree overlap would both get air into and out of the engine better. The added lift does hurt.

But then Nismology comes and rains on my parade. I was writing the last post when he posted so that information did not figure into the last post by me.

Nismology,

we are talking about the engine being at tdc on compression of cylinder 1, correct? The z33 fsm shows that the rev up exhaust cam small diameter dowel is pointing down and on the intake cam, it is pointing up. The regular vq35 and vq30 cams are installed with the dowels both up. So, if vq35 cams are installed dowels up in a vq30, and rev up cams are installed exhaust down, intake up in a vq35, doesn't that mean the rev up cams are exhaust down, intake up in a vq30? In other words, if a given cam is installed one way in a vq35, doesn't that mean that the cam would be installed the same way in a vq30?

 

the cam on the left is a rev up the one on the right is a normal DE they are pretty much configured the same:



The VQ30 cams are the ones that are different from VQ35 cams period, but from what i have seen all VQ35 cams are stats quo.....

 

That's way beyond the scope on my project. The rev up cams are appealing to me because I know that if properly timed, they will play nice on the street. I don't mind thinking, I can do that for free. C series cams, on the other hand, are 1200 bucks!

I'm sure I'll see good gains by installing the rev up cams with the timings as described in the FSM. But I would like them to be installed in such a way that makes sense considering the cams were designed to be used with a dual VCTC system, ans I will not be using one.

Half the fun of figuring out this problem is figuring it out. I had to learn about cam timing at some point.

 

what most of us do which is lazy is just set the idle a little higher lmao. when i get this thing up and running, it use to idle at around 500-650rpm, i will bump that up to 800-900 just to make sure there are no problems.

somebody correct me if im wrong what from what i have seen when they are comparing dynos to the changes in timing CVTC has made, at about 5000 rpm CVTC has came back to normal timing thats when in most cases peak power is about to be made., no advances and no retardations and stays that way till redline.

 

RevUps shouldn't have too much lope anyways. But if you're running EU you can add a little bit of fuel at idle to smooth it out.

 

At TDC with everything lined up the large dowel hole will be facing up on the exhaust cams. This corresponds to the the slot on the top side of the VQ30/VQ35 non-revup exhaust sprockets. All you need to do is insert VQ30/non-revup exhaust dowels. Unless you were thinking of enlarging the small dowel hole to change the cam timing. You would then of course need to modify the exhaust sprocket like dandymax did to his intake sprockets.

 

Those are intake cams. From what I understand, he was asking about the exhausts.

 

I think i have a pic of the exhaust cams, they were the same as I set them up just like a normal DE cams i didnt have any timing issues.

 

Exactly the point of my post. They can be installed straight up like non-revups without having to modify anything.

 

But this brings up an interesting idea. If you just drilled a hole next to the smaller dowel hole (wouldn't require as large a change in cam timing vs drilling next to the larger hole) you could made a corresponding slot in the exhaust cam sprocket and change cam timing that way. But the fact still remains that you don't HAVE to modify anything to make them work.

 

well u can buy the cheaper JWT spacer instead

 

VQ30


VQ35DE


Rev Up


So obviously I'm missing something here. I'm not saying you guys are wrong. I know guys have used these cams with good results. I just don't understand why the rev up exhaust cams are installed with the dowel down in the vq35, and the non rev up cams are installed with the dowel up.

I guess I'll ask Stephen Max to make me the same adapters that I would use to install non rev up vq35 cams.

 

ajm8127 I see where you are getting confused. The FSM chose to designate the hole pointing down as the "dowel hole" but in reality you can make the hole facing up your dowel hole by simply sticking a dowel pin in there and installing it normally. Relative to other VQ35 exhaust cams, the large hole is in the normal location. Nissan just decided to add a smaller hole 180* from it for their own reasons.

 

remember one thing with the 350Z Rev-ups, CVTC are on both Exhaust and Intake cam(so its going to be wacky). Normal DE its only on the intake put the Exhaust cam's timing moves in sync with the intake.

 

Not sure how that relates to altering the exhaust cam timing.