TO VVT or NOT TO VVT?

mark underwood · 01-11-2010, 01:15 PM

I have a l92 and want to keep the bottom end stock and put ported heads and ls3 intake on it... This is the easy part....

Now i don't know weather to switch to LS3 cam setup or leave the VVT..

All the info i have read and called about Seems to counter what the previous guy says...

I don't have a harness or computer so i can go either way MAst or jusrt Ls3..

Why do VVT cams not have as much lift as the LS3 cams?

What dyno numbers prove you make more torque with VVT down low and have good top end?

I am not shure the extra headach of vvt is worth it... And then you have to find a tunner who can tuen it correctly..

Thanks
Mark

pillagenburn · 01-12-2010, 08:12 PM

use an e38 ecu and get a factory harness reworked, dont go with Mast unless there is a specific reason to.... check Comp Cams xfi lineup of vvt cams. GM High Tech Performance stuck a comp VVT cam into a L92 and made 500hp.

cam · 02-02-2010, 12:06 PM

Well heres how I see it. VVT is superior it offers more technology to deal with issues that static cam shaft designs simply cannot handle. For example with a conventional static cam you either go for a smooth idle, decent low end torque at the sacrifice of top end or vice versa a cam that SCREAMS up top but has no grunt down low. Or somewhere in the middle etc but theres always an element of compromise. VVT helps minimize that compromise but its new tech, not widely used and understood yet so your going to run into tuning trouble ( who tunes them? Where? How good? ) and so on. In the future Im sure we'll see a TON more VVT set ups making the impossible possible so to speak ( consider comments about about static cams ) but for now? Might be a little more grief to get it working as you want but Im sure the market and knowledge base will only grow to support it as time rolls on and you'll have a platform all set up, ready to make some killer power.

If it were me starting from scratch now? I'd stick with VVT and try and make it work its not like your out a whole ton of extra coin and if you decide you cant deal with it later on its not a giant expense to swap it out.

Patrick G · 02-02-2010, 07:02 PM

I'm such a big fan of VVT that I sold a perfectly good 2007 Suburban with a 5.3L and bought a Denali with a 6.2L VVT motor just so I could master tuning the cam phaser. The potential these motors have with VVT is astounding. You can run higher lift if you want. The Comp cam phaser limiter is a good idea to keep from running into P to V issues.

Find a tuner willing to spend the time to dial in your cam combo. It would be totally worth it. Ditching VVT on a 6.2L is like ditching fuel injection and going back to a carburetor.

chevellepowered · 02-02-2010, 08:08 PM

i had this same problem too.with ly6..vvt.. i had the crank pully off and the cam cover off,to paint it..lol.. and i had an ls3 cam sittin on the shelf.. i was going to swap it out,, but at last minute deciced to just keep the vvt.. reason i did, is even if valve lift is low,, the heads still flow 280-290 cfm around .450 lift.. pretty stout.. and i wll be adding boost to this vvt engine.. i want to be first with totaly stock ly6 boosted..just to see number's..

cam · 02-03-2010, 10:29 AM

After some thoughts last night about it when/if GM starts putting VVT in performance platforms I think thats when we'll see a big surge of aftermarket performance support. As soon as we see a VVT set up in a Vette or a new Camaro the appeal to make these things work better will really fire up. As of now its only the swappers and the trucks who are playing with it and as a result the market for hi perf VVT is moving slowly.

Also made me think of another craze that literally makes my skin crawl when I hear this acronym.... VTEC

If I had a nickel for every time some brain dead bench racing fool mentioned to me how his turd would smoke *insert ridiculously fast car* once his VTEC kicked in.... ayayayyyy

chevellepowered · 02-03-2010, 10:44 AM

sir dont compare a gm to a honda.. .no comparasion at all...

cam · 02-03-2010, 11:01 AM

Quote:

Originally Posted by chevellepowered

sir dont compare a gm to a honda.. .no comparasion at all...

LOL Blaspheme!!!! I never "compared" I would never do such a thing! I merely commented for the sake of babble, my memoirs of a lesser species and about acronyms of an extremely annoying manner.

mark underwood · 02-03-2010, 09:41 PM

I wraped up the VVt parts and placed them in a box on the shelf for down the road..

I went ls3 to keep it simple...

Sid447 · 02-04-2010, 12:46 AM

How reliable is the VVT set-up?

Anyone having problems with it?

I remember the early VANOS system that BMW started fitting in 1992. It was a little troublesome and needed piston seals to be replaced quite regularly. It still isn't the last word in reliability. That IIRC worked on a similar principal. If BMW couldn't get it right first time maybe this is why GM decided not to fit it across the range because of potential reliablity issues?

pillagenburn · 02-04-2010, 11:35 AM

I'm going to see how much my LY6 Firebird picks up from a tune... it's on a factory tune with bolt-ons. How much do bolt-on LS3's pick up from a tune I wonder? I know L99's pick up a lot.

chevellepowered · 02-04-2010, 03:32 PM

ive seen ly6 from mast,or somewhere else they keep stock cam ,sell whole motor as package, with tune , makin 420 hp at crank..stock intake.. probly conservitive tune...i dont kno..

cam · 02-09-2010, 11:35 AM

Patrick G is the a software advantage for VVT tuning with efi-live? How much gains did you get out of your Denali?

Patrick G · 02-09-2010, 02:47 PM

Quote:

Originally Posted by cam

Patrick G is the a software advantage for VVT tuning with efi-live? How much gains did you get out of your Denali?

EFI Live does a great job with VVT. HP Tuners also can adjust VVT although I have not seen that it can adjust some of the key VVT timing tables. Perhaps they now have it covered with a newer beta version.

We picked up around 40 lb ft of torque in the mid-range by playing with cam phasing on the Denali. We also gained around 20 rwhp at 6000 rpm by retarding the cam more than stock.

cam · 02-09-2010, 03:19 PM

Interesting and definitely impressive! So im thinking here why are these phase limiters nec if you can tune in the retard of the cam? Cant you just digitally "limit" it so to speak?

cam · 02-09-2010, 03:57 PM

I googled it and came up with a GM high tech article saying the limiters are in case of mechanical over rev as a bit of an insurance policy so you dont put valves into pistons

cam · 02-10-2010, 05:40 PM

Well I was driving along minding my own business and all of a sudden Im at a wreckers and....

filmjay · 02-10-2010, 06:38 PM

Hmmmm.....I'm going the other way and wondering how VVT would work in my LS3. ('08 C6)

cam · 02-11-2010, 09:56 AM

I'm sticking with VVT also.

I called Mast and asked about the cams and from what the tech told me the stock VVT lifters, timing chain, and push rods are fine running their cams with a redline of 6800RPM. I'm not certain about the pushrods as I'm always a fan of buying the beefiest and most durable items for all valvetrain so a little more research is in order here.

Patrick G wanna spec me a cam?

pillagenburn · 02-12-2010, 07:55 AM

I wouldn't think that the timing chain/lifters would be that much of an issues. I believe they're simply LS7 lifters since that's the GM OEM replacement for everything lifter-wise nowadays. Timing Chain, I would assume, is similar in strength to the LS2 piece. Pushrods and valve springs, however, I would most certainly upgrade before attempting a 6800 rpm run. You will destroy those pushrods almost immediately.

if 40rwtq is attainable from simply adjusting the cam phaser versus a stock tune, then there is a LOT of potential from a stock-ish VVT motor. GM is undoubtedly very conservative in their tuning (as we've seen F-cars and Holdens make an additional 20-40hp from a tune) and I think the presence of VVT only compounds that.