so if you have a 4000 or 4500 stall the vvt is useless

 

Exactly. I think it's great in a factory car, but a hot rod should always have the proper converter in it anyhow. Of course everyone is after something different with their own car, but I found out long ago that making power on the bottom doesn't seem to make the car faster, so I don't bother with it. It might be fun to roast the tires, but again, with the proper converter you will do that on the street anyhow. At the track, the shift recovery point is never low enough to need "low end". Just my opinion, and it only applies to the way I use a car.

 

the other thing is piston to valve clearence. when running aggressive cams, the piston to valve clearence is tight enough allready, then add in the cam phazer advancing/retarding the cam furthers the problem ESPECIALLY when there is no mechanical control of the phazer, to garanteee that piston to valve contact doesnt occur.
I like the idea of VVT, and I beleive it will work fine on mild(small cam) applications, but if you want an aggressive setup, eliminate it. my.02

 

That's the point... with VVT, what you get with a mild cam would take a much larger cam on a non-vvt motor.

Every major auto manufacturer (including Ferrari, FYI) has implemented a VVT system of some type in their engines, so the benefit is obviously there. Just take a look at the GM High Tech article on the cammed L92 engine. The "large" Comp Cam that they use yields marginally more performance (like 5-10hp if that) over the "smaller" cams that were tested. All VVT cams of one sort or another are certainly small by most SBC guys standards.

I'll have a dyno chart up of my VVT LY6 before too long... coming from a cammed LS1, I like my LY6 a lot better.

 

There is a lot thats misunderstood about VVT that for sure. For drag racing it doesnt really make a heap of difference granted. Theres no pro stock engines running VVT for instance but its banned from Formula One racing engines as there is a lot of benefit for it in these applications where your up and down the RPM range. A street car that wants to be always "on" so to speak or a road racing car that needs to be on the cam at all times will really appreciate VVT. It just adds a multitude of variables to ensure that your getting as much as you can out of your engine at any given RPM. What VVT does NOT DO is add much peak hp so the comments made above about drag racing and how more power down low not being required is absolutely true.

If your building a drag only car its really pointless to add VVT imo. For any street car the ability to have more with less so to speak is a welcome addition and will make the car more fun to drive in general as the throttle response and pull from corners and roll on pulls will all be noticeably improved. So what this means is if you take two identically prepped manual trans street cars yet one has VVT and one doesnt. You roll away from the light up and then hammer it the VVT car will present more torque and roll out a bit better and pull a bit harder through more of the RPM range than the car without.

Anyways nothings perfect but VVT on a street/strip car is a nice addition but for all out drag racing its not really beneficial as you can just let the stall or the slipper clutch make up for the loss of power down low hence my mention of a manual trans above to make my point. But if I was building an all out drag car I'd be adding boost like crazy and could care less about anything other than peak hp and then work the car out around the engine.

All said and done for street use VVT is a nice thing to have and will add to your smiles per mile. Plus the side benefit that the car will run more efficiently and get better fuel mileage

Im running it on this next build

 

cam, very well put - If you're running an all out drag car (where you're never low in the RPM's and you're running 8's) it probably isn't extremely beneficial. However, if you're running a street/strip car as most of us are then in most any situation you're in, it will be a better performing car. If you have 3.42 gears and your motor bogs off the line, it will help shore up your numbers by giving you more power when your motor is revving lower.

Just some food for thought.

 

I use our Pantera EFI IGN-8 controller for the "Carbed" LS-92.
I use the GMPP intake ($275.00)
I use a Crower Cams camshaft (232/252@118c/l)
I use the "yellow" springs.

DO NOT USE the CompCams "phaser limiter", they allow for FULL advance (108-114) ONLY on a 118 C/L stock camshaft and they seem to "stick" at FULL advance.

The best part of this "bit-of-kit" is that the VVT controller is included as a standard feature of the IGN-8 Ignition System.

Lance

 

Hey Lance have you tested the Comp Phaser limiter to be no good?

 

Ahhh Lance I see what your saying now after chewing on it a few minutes and a discussion or two later its starting to become clear. I am going to run that Comp limiter kit and a cam specifically ground to work with it. The cam I'm running has as much advance ground in it as possible and I only need to retard it as it revs so it should work out very nicely ( so long as that Comp Limiter doesnt hang up and get stuck as you mentioned )

In fact Im going to be taking a VERY close look at the internals of that phaser when I get it open and see if i can find out how/if the Comp kit can get stuck or hung up on anything. Might have to make a part or two new but meh thats custom car bui8lding for ya.

Regardless Lance I'd like to hear about your issues that you had with it mechanically speaking and whether or not your fixed it. Thanks