-TheBandit-

iTrader: (1)

Comp Cams has four shelf grinds and Mast has two. Is there anyone else I should be looking at for a VVT cam?

I'm curious if either company's lobes were designed with AFM/DOD in mind and if so what sort of compromises were made (if any) to that end. I'm also curious how the profiles vary in order to accomodate the VVT. Obviously the cams are ground with lower lifts that similar duration non-VVT grinds. I presume this is to prevent piston-valve interferance during VVT operation, but I also wonder if the ramp rates had to go down to prevent the VVT mechanism from losing control of timing.

Any info is appreciated. I don't want this thread to be a pissing match of VVT vs. non-VVT - I'm more interested in knowing what differences are incorporated into the lobe profiles.

Sales2@Texas-speed

iTrader: (5)

In all of our testing, the best gains were had by deleting AFM/DOD and just retaining the VVT so that we could use more aggressive lobes and more lift! Back to back, the same duration camshafts, one with at or under .500" valve lift and the other up near .600" (1.7 rockers), the higher lift made significant power gains all the way from idle to redline!

Our testing, as was backed up by Comp Cams' testing, revealed/confirmed that those stock AFM lifters will have a significantly shorter life (some ending catastrophically) when run over that magic .295" lobe lift (.500" valve lift on a 1.7 rocker)!

-TheBandit-

iTrader: (1)

Can you confirm if the Comp Cams lineup (for example 156-403-13) is designed for AFM or no AFM? Based on your response, I would say no AFM since they all have over .500 valve lift.
http://www.compcams.com/Technical/Ca.../pdf/page9.pdf

Jason 98 TA

iTrader: (4)

You have to be very careful selecting a vvt camshaft. L99 and other vvt ls motors have different phasers so the cams aren't compatible.

Also keep in mind tsp is the only vvt camshaft provider that includes the phaser table when you order a camshaft.

We engine dyno tested our camshafts at each rpm to create the best possible phaser tune.

Who wants a phaser camshaft that doesn't include a updated phaser tune?

Checkout our engine dyno vvt data I posted compared to other camshafts your considering. We have several options for afm/vvt or just vvt.

One of the camshafts even makes over 100 flywheel horsepower gains! That's what's going in our shop 2010 l99

Jason 98 TA

iTrader: (4)

The cams with lower lift isn't because of the vvt, it's for guys with the crap afm lifters. . Afm lifters don't really like going past .500" lift.

The vvt only camshafts are much closer to typical ls camshafts, but some vvt minded tweaks!

toyin

I'm not trying take away from your thread or what your looking for but if you don't mind i have a quick question.

How do these VVT cams work in a turbo set up? Going to run a LY6/TC76 turbo. Would i want to run a VVT cam or go to normal LS style cam for my set up. It's NOT going to be a race car or weekend drag car. It's built to drive on the street with limit track days.

-TheBandit-

iTrader: (1)

Where can I find info on your vvt cams? I tried milling around on your website, but I couldn't find anything.

cam

iTrader: (9)

The tuning is what has everyone freaked out about VVT cams. VVT is better than no VVT even if its not a huge gain its still going to gain with VVT all other things being equal.

Once the tune "secrets" become more available you'll see a ton more VVT stuff happening. Its still kind of new and tricky which scares most people away.

If you want a cam that will fit your needs exactly get Patrick G to spec you one

Coban

iTrader: (14)

Yes, this. I don't see any VVT cams listed. If ya'll are offering the timing tables, you might have me sold.

Not to mention the fact that you actually recognize the phaser change GM did. Every other site has no idea what I'm talking about when I try to get the VVT cam on the 189 core.

Sales2@Texas-speed

iTrader: (5)

Precisely, very few are actually taking the time and spending the money to test their camshafts, much less new VVT stuff! We spend both and developed phaser tables that we send with each of our VVT cams to ensure that part of the tune is dialed in properly!

We're getting very close to launching our new website, and they are on there....we just haven't had alot of extra time to keep updating the old site when the new site is so close to being ready! Feel free to call us anytime though and we can discuss your options!

cam

iTrader: (9)

Odd isnt it? Something new and better comes out and most people **** all over it simply because they dont understand it.

He who cannot recall history is condemned to repeat it

Enjoy your carbs fellas LOL

-TheBandit-

iTrader: (1)

I really don't want this thread to be a pissing match of VVT vs non-VVT. Please keep that kind of rhetoric outside of the thread.

I have decided to use the VVT so I am looking for tech info on my options for VVT cams. I PMed TSP and they would not share their cam specs (lift, duration, LSA) citing concern that their cam design would be stolen. It puts me in a tough spot as a customer because I have no way to judge their cam or compare it to offerings from other cam manufacturers. I will call to get more info from TSP tomorrow. At the very least it's good to see there will be more VVT cam options in the near future.

-TheBandit-

iTrader: (1)

Comp Cams talks about the cam & phasor change in their catalog. I would be interested to know why GM made the change.

pillagenburn

iTrader: (2)

I believe that most VVT cams available are going to be small-ish (224/230 ish) by comparison to non-vvt cams because of concerns of PTV clearance. You won't see tremendously high lift cams because of this, but I think with VVT it simply won't matter all that much. In the GMHTP L92 cam upgrade article, they didn't realize much greater gains with a "bigger" cam once tuned, so I don't think having a tremendously massive cam on a VVT motor makes a lot of difference; I would think head/intake/exhaust flow has more of an impact. In the case of my LY6, after it's been mail order tuned by Patrick G and all of my bolt-ons have been done, it feels like it makes most of its torque almost immediately and pulls really hard... MUCH harder than my old F13 cammed LS1 Camaro. I wish I could get dyno data but there are no dynos around me for some 60 miles.

edit: oh and my LY6 does all of this on 87 octane... I doubt one point of compression (and another $8 at each fill up for premium) makes all that much of a difference.

Coban

iTrader: (14)

I was under the impression they were just selling Comp's SPR cams. They have their own grinds? And I know the way you feel. I'm not a cam expert, but I don't want to be completely taken out of the process.

I would as well. From my reading, it looks like they also reduced the total movement from 52 to 42 crank degrees.

The phaser limiter kits seem like they should have to account for this, but I've never seen a limiter kit for the new phaser yet.

Sales2@Texas-speed

iTrader: (5)

You are on the right track, but not right on yet. Just like in a non-VVT camshaft, max lift on a VVT cam actually has very little to do with piston to valve clearance because the piston is around half way down the cylinder when max lift is reached. That doesn't change with VVT. And the more aggressive lobes DEFINITELY make more and better power than the mild low lift lobes do on these VVT cams (same as the non-VVT stuff actually!) The only reason you see some of these VVT cams with such low lift is to keep the AFM lifters that come in some applications (L99 Camaro for instance) happy and alive. That is why TSP is releasing VVT/AFM cams as well as plain VVT cams, so if you chose to ditch the AFM, you can make that extra power via the better lobes!

cam

iTrader: (9)

Remember GM uses the VVT on these V8's mainly for fuel mileage purposes and the phaser differences are likely attributed to that.

There are always custom grinds available for those interested contact Patrick G ( im starting to feel like a broken record here ) He has some interesting options available for VVT applications that are a far cry from what the shelf cams offered are.

pillagenburn

iTrader: (2)

Matt, yeah a bigger cam will be beneficial for sure, but from what I recall, the phase limiter is used specifically for the reason of PTV clearance. If PTV clearance wasn't at all an issue then why would a phase limiter be needed? At what lift point does a phase limiter need to be used on a non-AFM VVT motor?

As far as using a bigger cam, I was referring to the diminishing returns that I saw in the GMHTP L92 article. It seems that with the cams that they used on the L92 (all comp products, different companies may yield different/better results?) you really reached a point of diminishing returns, but there was never a sacrifice at the low-end and you even saw gains at the low end. This indicated to me that they were reaching the limits of the untouched L92 head with the cams they were using. This leads me to believe that head porting might be necessary if you really want to maximize what a bigger VVT cam can do. Again, I'm not sure if using a cam from a company other than comp, on untouched L92 heads, would yield different results; I was just going on what I saw in the article.

But thank you for furthering the use of VVT though - you're doing a huge service for the LSx community.

Sales2@Texas-speed

iTrader: (5)

I'll check into the valve drop info when I get back to the office on Monday!

Jimbo1367

Anybody have any problems with the phasers granading with a aftermarket VVT/springs? I read somewhere that it happened to COMP CAMS when they first started the VVT cams. Something about too aggressive springs.

Who knows what if fact or net rumors..