Give him a break hes new and trying to help.

Keep reading posts on this website and you'll be up to speed in no time. Its the best site to learn REAL technical information.

 

So I'm interested in keeping VVT but am picking up GMPP harness/ECU LS376/480 (19258267) for $500 from a local guy. Anyone know if it can control VVT? Or do I need to have a specific ECU?

 

I've been e-mailing with HPTuners asking about this. Bill at HPTuners says that HPTuners has added everything that they have found related to VVT to the PCM's that can control VVT. He did note that it's possible that they haven't found everything yet, he seems pretty confident that I should be able to enable it in my E38 in my 2010 Camaro. So that said, I believe the harness you have listed here is an E38 setup.

Regardless of that, if you can't enable it with the operating system in that controller, you can most likely overwrite that entire controller with that of a VVT vehicle. It's a little easier when you're working with an older vehicle. I can't just overwrite my car's tune file with one for another car as I have to keep my VIN number in my car for inspections.

 

I think the answer to your original question in post 1 is that it will be faster with the vvt working. But the thing is, that is only with the same cam. Once you get into aftermarket vvt vs non-vvt cams, things get very different. The grinds are different, and it is easier for most shops to work without vvt and get great results. Also I have yet to see anyone prove that aftermarket vvt cams on an LS motor get better results compared to aftermarket non vvt cams. including low rpm torque. So why add the complexity and risk of not getting it to work right?

Some people on hear are talking about fear, but it's not, it's experience. Talk to your local shops with experience. VVt on an LS motor is nothing compared with independant intake and exhaust vvt that you will find on 5.0's, toyotas and bmws. There is a reason it is not used on gm's highest performance ls engines, LS9s, LSAs, and LS7s and LS3s. I don't regret for one second removing my vvt, and I have the results to prove it. Now if Texas speed was in my back yard, and they could tune my car, I might have tried them, but I know of another shop on here that is a sponser that had to remove a clients aftermarket vvt cam in order to get it to run right. If you need that extra 1 or 2 mpg, sure the vvt will help, but you wanted to know about the track. Also, the bigger vvt cams will need a converter just like their counterparts.

 

I'm not so sure about this. The specs for the TSP cams have been slowly finding their way around the internet. The VVT-2 that I got recently has specs in the same neighborhood as your nonVVT cam. I don't know how the lobe profile compares exactly, but looking at the lifts, advertised durations, 050 durations, and LSA they are close, at least close enough to compare. Here is a post with the specs on the VVT-2: https://ls1tech.com/forums/15834038-post17.html

VVT-2
futureuse's nonVVT cam

There's nothing voodoo about tuning these. Once the phaser timing is determined (TSP provides this, though it wouldn't be hard to tune as shown above by SweetS10V8), you tune it like any other non-VVT engine.

All this talk about "complexity" and "risk of not getting it right" are in my opinion just fears of the unfamiliar. You made a decision based on what your local tuner was familiar with and there's nothing wrong with that, but there is bias on their part that you can't extract that from their recommendation. You did get great results, but there is currently no data to say you would have had better or worse results with a comparable VVT cam like the one I chose. If I ever get my build done, we can compare our timeslips, dyno charts, and whatever other performance data is relevant - I doubt it will settle the discussion, but at least we'll have something tangeable on VVT cams that you or I can use to make our points.

It is true that the independently variable cam timing on engines like the ones you mentioned are superior to the LSx VVT system, but that doesn't mean LSx VVT has nothing to offer over fixed cam timing. I think this article explains it best: http://www.hotrod.com/techarticles/e...t/viewall.html

People have been playing with adjustable cam gears on traditional small blocks for decades. Cam timing is an effective tuning tool. As long as the cams are comparable, which I believe we now have offerings that are, VVT should provide an advantage.

 

Was the root cause ever determined? What was the setup on the engine? Was it a factory or aftermarket ECU? Stock or modified wiring? Was the correct phaser & cam core combination used? Was there something wrong with the grind? There are plenty of cases of nonVVT engine builds where the tuner can't get the engine to run right until they stumbled on something that wasn't compatible, a setting that needed to be changed, something wasn't assembled right, or there was a faulty sensor. Was VVT really the culprit in this case?

And no offense to our sponsors (I dont' know which you're referring to anyway), but just becoming a sponsor on a website like this doesn't make you good at anything. Yes there are a lot of great businesses sponsoring this website, but as far as I know there's no application process where LS1tech evaluates them on merit.

 

What I think will be cool is when someone outs in a set of pistons on avvt engine. Lots of PTV means you really could bump uo the cam size, or run withou needing a limiter.

 

Good to hear...I'll probably run a 3 bolt cam for now but keep my VVT stuff. I already have everything laying around to delete VVT. Just wanna get car up and running quickly.

 

It isnt hard to flycut the oem pistons, how did you setup your vvt engine?

 

Ive never had a VVT engine. Ive done TONS of R&D on them at work.......

After learning and playing with VVT, I mean "working" with them forever, I WISH I had VVT.......

 

Where did/do you work?

 

Ive already reavealed all I am going too......

 

I'm building my L92/L99 with Mahle -12cc inverted dome pistons (http://www.race-mart.com/Mahle-MAH-L92314070I12.html

and the TSP VVT2 cam.

I'm still running the Comp limiter because I'll be running a T56 manual trans and it better having the mechanical limiter in case anything happens.

I'm all about keeping as large of a PTV as possible..

 

I'm playing the safe card as well. I'd rather lose a negligible amount of compression and have more of a safety margin in case of valve float etc. There's no point running a 500hp engine on ragged edge clearances. I flycut my stock pistons because my heads are milled .035" and i'll be using a VVT3 cam since i've already paid for it and my PRC heads came with the springs to match the combo. Exhausts already had the relief of course, but I figured while I was making a mess it wouldn't take much more effort to cut a .045" relief for the intakes as well. That'll leave me with more PTV than an engine with stock deck, head and head gasket.

 

From what I have been reading the biggest problem they are having with the VVT is the Hydraulics from the oil system keeping it steady or consistent. Is this correct?

 

Read the article above that Bandit posted from Hot Rod. It is excellent. Think about this:

That is an 11.4:1, 416 with cnc ported LS3 heads. While the results are good, they can be better without vvt. The thing is they limit their cam to .600/.618 because the phaser has trouble controlling the cam timing with the big springs, especially above 5000rpm. My bet is if they could have put some double valve springs, a c5R timing chain and a cam with a more aggressive lobe and lift, they could have made more torque and more horsepower, doing it safer, without moving the power band up. It would be less fuel efficient, though.

On the overhead cam engines, the phaser(s) only has to control the intake or exhaust valves, not both. This and the fact that gm excludes vvt from all out performance applications reinforces my argument. It really comes down to what you're using the car for. For the track, which is what you asked about, I think deleting vvt is better. If it was better for the track, gm would have used it on the c5r. If my Camaro was a daily driver, I would have kept the vvt, although it could still easily be a daily driver.

Bandit, I will try to get more info on what you asked about. The shop was Vengeance. And I hope you get great results! I kept my vvt parts.

 

That part of your statement is not true, the 5.0L Ford DOHC engine in 2012+ cars has 4 cam phasers...

 

Well, the folks over at Dodge (SRT) felt compelled to include VVT on the Gen IV Vipers...I'm not saying it is the end-all, be-all of performance, but the 600HP/560TQ is nothing to sneeze at (neither is the 24MPG I've seen on the highway). It is the same engine used in the Viper ACR as well, which is about as close to a street legal race car as you can get. Not apples to apples, but this is one example of a performance application where your argument breaks down.

They got a little fancy with theirs...it is a cam-in-block engine, yet they only control the exhaust valves. How?

http://www.mechadyne-int.com/vva-home/dodge-viper

The technology may not be perfect for all applications at this point in time, but I have a feeling the OEMs will continue to develop it due to the huge advantages it provides.

 

Why would my argument break down? I don't know how this technology works with dodge, but I assume that it is a 2 peice cam where the exhaust lobes can move indepandantly of the intake valves. Half of the cam is fixed to the timing chain and the phaser only works half on the valves, which is a double advantage. It is always better to vary intake valve timing independently from exhaust valves and it puts less demand on the phaser. Brilliant move for dodge.

Also, I doubt that the vvt works only on the exhaust valves here. It probably only works on the intake valves just like the early vvt systems on on dohc engines.

 

You said that GM excluded it from all-out performance applications, so I took that as a blanket statement that VVT wasn't good for any performance application, but you likely were only referring to how GM implemented it.

Nevermind me...I've become more of a Mopar fanboi than Killemall.