VVEL control unlocked

JC671

I just recently got an etune from Uprev and Randy says they do not offer it yet and he said that the VVEL is tuned good from the factory that after some runs they were unable to get any gains with a bolt on Z.


So far only one I've seen is John@Z1 offer this and has seen some gains from it.

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AlexRaymond19

Thanks for the info!

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2010 370Z Touring MT | Stillen | Motordyne | Momentum| Z1 | Fast Intentions | Advant Garde | RE11 | Swift | SPC | Quaife | Whiteline | Evo R | 322RWHP 259ft-lb Mustang

370zrider

I saw in UpRev's Facebook that pro tuners have the Beta version for VVEL tuning.

Hope someone in this forum that has had any experience with this would comment about it.

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Baer383

The VVEL is really going to shine with the guys who have FI,you N/A guys aren't going to gain that much at all.

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2013 ZL1

754 rwhp 747 rwtq

Sh0velMan

How do you figure?

How does changing the profile of the intake cam more dramatically affect the FI systems for the 370 than N/A?

The TT guys maybe could tweak it to add duration and lift earlier and spool faster? Maybe?

I dunno, you can't make it open any further or anything than it already does, that's why Uprev is saying they weren't able to get much out of it. They smoothed the curves a little on my car, but that's about it. It already goes to maximum (safe) lift and duration on the stock tune.

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DIGItonium

How about those with lower CR builds. I'm assuming the piston has a deeper dish, so would not increase valve travel clearance?

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SS_Firehawk

With Superchargers, there is a lot of blow through through the heads and makes it difficult to build pressure. Reducing the overlap and running a less aggressive profile will allow the SC's to get boost up quicker. Don't quote me, but I don't think turbo's have this same problem. It's also a big reason why long tubes weren't making the same power as a stock header because the heads and exhaust were too efficient. It made more power per lbs of boost, but not enough boost to make more power than the stock headers. I feel being able to control VVEL will be a big deal for supercharged cars. Maybe we can reduce overlap to increase pressure, and open it up progressively so it gets top end efficiency. Just a theory, but it sounds good lol.

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Jordo!

Yep, there should still be some advantages NA, but FI greatly changes optimal valve timing. The ideal angle will change significantly as you force a greater volume of air into the cylinder.

Essentially, as I understand it, you want just enough overlap for achieving peak torque -- wrong timing means you just lose boost, blown out before it has a chance to build peak pressure.

With turbos I believe you want as little overlap as possible, as you want to get exhaust gasses flowing as much as possible. I'm more familiar with SC's, so someone correct me if I'm wrong.

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Z370Z011

Hmm, i was actually told the opposite. I had met some guy with a high horse power Z, and told me he supercharged his Z because the VVEL made turbos less efficient than a supercharger as far as reliability goes.

Dont hang me for this, just sharing what i was told lol

which actually made me re-think going TT. idk,

SS_Firehawk

NP, I was talking to Mike@GTM over the phone about it and my long tubes. It's what he told me. Not the VVEL tuning piece, just the blow through effect and long tubes being too efficient. Likewise with a high flowing exhaust. The heads on the 370Z flow really really well.

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Baer383

Firehawk said it well,plus saved me allot of typing.

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Sh0velMan

All of these comments about blow through would be perfectly valid if we were talking about a system that does anything to the exhaust cam.

Until the variable phasing on the exhaust side is tunable, I don't see how it's relevant.

I don't see how holding the intake closed until the exhaust has closed would net you any real benefit since you'd be waiting until the piston was already on it's way back down before you open the valve. Surely any small gain you get from preventing blowthrough would be offset simply by there being far less time for gasses to enter the cylinder?

I mean, testing and time will tell, of course. Maybe they can work some magic?

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SS_Firehawk

Reducing the duration will increase pressure because less air is being blown through. With boost pressure just being a measurement of resistance, being able to modify how far and long the intake valves open should effectively change how and when the superchargers are reaching peak efficiency. The problem is there is too much overlap. The combustion process is still happening as usual, it's just when both the intake and exhaust valves are open, it's open for too long and reduces pressure. Getting more pressure built up on the intake side should allow more air to be pressurized in the combustion chamber when the intakes do open. Sorry if I'm talking in circles, I'm just trying to hit all the angles.

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Sh0velMan

You could, in theory, make a funky intake cam profile that would work under boost, the problem is that it would be awful off of boost. Like, be a total misery to drive at anything less than 3/4 throttle and up.

Retarding the intake opening would make for some serious drivability issues, if taken too far (read: far enough to make any difference).

This is all in my estimation, so feel free to prove me wrong, GTM!

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SS_Firehawk

GTM hasn't talked about VVEL tuning with me, just the blow through effect. I have no idea if they tried tuning VVEL yet. I have no idea what the tables would look like for VVEL, but I imagine it can be tuned for all types of driving, NA, or FI. I wish there was more public info on the topic though.

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