VVT vs VVT delete
01-22-2012, 11:25 AM
#41
Launching!
Thread Starter
Join Date: Jan 2012
Location: Disneyland or St Louis
Posts: 234
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
01-23-2012, 05:31 PM
#42
TECH Addict
iTrader: (4)
Join Date: Feb 2002
Location: Enumclaw, WA
Posts: 2,566
Likes: 0
Received 0 Likes
on
0 Posts
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?
01-23-2012, 07:02 PM
#43
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.
01-23-2012, 08:26 PM
#44
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.
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.
Last edited by futureuser; 01-23-2012 at 08:34 PM.
01-24-2012, 09:59 AM
#45
VVT-2
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
Among the valve events in a four-stroke internal combustion engine-intake valve opening, intake valve closing, exhaust valve opening, and exhaust valve closing-most engine builders agree that intake closing is king. In fact, some contend that intake closing is more important than the other three combined.
To facilitate the passage... read full caption
To facilitate the passage of oil, VVT camshafts (left) feature gun-drilled hollow cores. To take full advantage of the VVT system, the cam used in our test was ground on a 116-degree intake centerline, which is 6 to 10 degrees more retarded than on the average non-VVT cam. Since the ability to retard the cam improves high-rpm power, Mast's VVT cams don't require as much intake duration, which improves idle quality and low-rpm torque.Simple physics dictates why this is the case. Internal combustion engines are nothing more than glorified air pumps, and the opening and closing of the intake valves determine how much air can be drawn into the cylinders on the intake stroke. With a typical performance camshaft, it's not uncommon for the intake valve to close up to 60 degrees after bottom dead center, which means after the piston has already started to move up during the compression stroke. This isn't ideal at low rpm, as the pistons will push the air/fuel mixture back past the intake valve and into the intake manifold, which hurts low-end torque and idle quality. On the other hand, a delayed intake closing point is exactly what an engine needs at high rpm.
Read more: http://www.hotrod.com/techarticles/e...#ixzz1kOPVCn41
To facilitate the passage... read full caption
To facilitate the passage of oil, VVT camshafts (left) feature gun-drilled hollow cores. To take full advantage of the VVT system, the cam used in our test was ground on a 116-degree intake centerline, which is 6 to 10 degrees more retarded than on the average non-VVT cam. Since the ability to retard the cam improves high-rpm power, Mast's VVT cams don't require as much intake duration, which improves idle quality and low-rpm torque.Simple physics dictates why this is the case. Internal combustion engines are nothing more than glorified air pumps, and the opening and closing of the intake valves determine how much air can be drawn into the cylinders on the intake stroke. With a typical performance camshaft, it's not uncommon for the intake valve to close up to 60 degrees after bottom dead center, which means after the piston has already started to move up during the compression stroke. This isn't ideal at low rpm, as the pistons will push the air/fuel mixture back past the intake valve and into the intake manifold, which hurts low-end torque and idle quality. On the other hand, a delayed intake closing point is exactly what an engine needs at high rpm.
Read more: http://www.hotrod.com/techarticles/e...#ixzz1kOPVCn41
Last edited by -TheBandit-; 01-24-2012 at 10:11 AM.
01-24-2012, 10:20 AM
#46
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.
01-24-2012, 04:16 PM
#48
TECH Addict
iTrader: (4)
Join Date: Feb 2002
Location: Enumclaw, WA
Posts: 2,566
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
01-24-2012, 08:48 PM
#53
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..
01-25-2012, 12:24 AM
#54
Vvt ptv 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.
01-25-2012, 12:54 AM
#55
Launching!
Thread Starter
Join Date: Jan 2012
Location: Disneyland or St Louis
Posts: 234
Likes: 0
Received 0 Likes
on
0 Posts
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?
01-25-2012, 06:34 PM
#56
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.
Last edited by futureuser; 01-25-2012 at 09:06 PM.
01-25-2012, 07:37 PM
#58
On the overhead cam engines, the phaser 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.
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.
01-25-2012, 08:10 PM
#59
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.
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.
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.
Last edited by futureuser; 01-25-2012 at 08:21 PM.
01-25-2012, 08:24 PM
#60
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.
Nevermind me...I've become more of a Mopar fanboi than Killemall.