VVT vs VVT delete
#61
Good article on the Vipers cam in cam http://www.thehemi.com/news.php?id=20080211-1
http://www.youtube.com/watch?v=0uiDmcPEekc
http://www.youtube.com/watch?v=0uiDmcPEekc
#62
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.
http://www.motivemag.com/pub/feature...xplained.shtml
#63
Good article on the Vipers cam in cam http://www.thehemi.com/news.php?id=20080211-1
http://www.youtube.com/watch?v=0uiDmcPEekc
http://www.youtube.com/watch?v=0uiDmcPEekc
#64
I was thinking early vvt on single bank engines. The fact that 4 phasers are used in the 5.0 is interesting. I think some dual bank (V) engines only use two phasers.
#65
GM's intention with VVT was to take a fairly small cam profile that they used and have a good bit of advance ground in, and retard the cam timing in higher VE conditions to have a broad powerband with something that gets good fuel economy. And, in mid range cruising throttle conditions, commanding 20+ degrees of cam timing retard is going to produce EGR (Exhaust Gas Recirculation) by hanging the exhaust valve open as the piston is going back down in lower VE conditions, will pull some exhaust gas back into the cylinder and reburn any unburned gas providing cleaner air for emissions, and it also reduces engine vaccum at part throttle which reduces engine load also improving emissions. In a nutshell, GM used VVT for emissions, not to make more power.
However, VVT can make more power globally with any cam, and even more with the right cam. But, more importantly, proper installation and calibration is the key. And, with our findings, if we sold our kit to someone and told them the way we do it, and what to do, anyone will have a hard time making sense of it at first, so we chose to keep it install only, plus the fact we have hundreds of hours of testing to come up with the solution in the way we did it, so if we announced what to do, it would be like throwing the money away for our R&D for someone else to just copy. With our method, any cam can be utilized to to have it's advantages with VVT, but we tested multiple thought out profiles and came up with one that was fairly universal making a lot of power and amazing drivability, so that is what we use, and what is still in my 2010 Camaro SS which has gone 11.41 @ 119.8mph, full weight with stock heavy rims. The VVT is worth about 2 tenths and 2 mph out of how fast my car is. And, I have all the data, especially the dyno data. Someone in this thread mentioned Darin Morgan, when his car was in our shop, we demonstrated it for him, showing him multiple install methods and what does what and why, but we have since then found a lot more power in the calibration, which I know he is aware of now as well.
However, VVT can make more power globally with any cam, and even more with the right cam. But, more importantly, proper installation and calibration is the key. And, with our findings, if we sold our kit to someone and told them the way we do it, and what to do, anyone will have a hard time making sense of it at first, so we chose to keep it install only, plus the fact we have hundreds of hours of testing to come up with the solution in the way we did it, so if we announced what to do, it would be like throwing the money away for our R&D for someone else to just copy. With our method, any cam can be utilized to to have it's advantages with VVT, but we tested multiple thought out profiles and came up with one that was fairly universal making a lot of power and amazing drivability, so that is what we use, and what is still in my 2010 Camaro SS which has gone 11.41 @ 119.8mph, full weight with stock heavy rims. The VVT is worth about 2 tenths and 2 mph out of how fast my car is. And, I have all the data, especially the dyno data. Someone in this thread mentioned Darin Morgan, when his car was in our shop, we demonstrated it for him, showing him multiple install methods and what does what and why, but we have since then found a lot more power in the calibration, which I know he is aware of now as well.
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#67
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Then when you get into performance, at the low end you advance the intake just like the GM VVT, but you keep the exhaust advanced too. This way your events are advanced and you have a tighter LSA, both good for low end. As you go through the RPM range, you retard the intake and retard the exhaust even faster. Now your events are retarded and the LSA wider at high RPM, again very good for power at high RPM.
The 3v Ford was SOHC with 2 phasers.
#68
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Mike@newera yes that was me that meantioned Mr. Morgan. It was through his posts that I heard about what you guys had discovered thru R&D. 11.4's is exceptional with a full weight car. What are your supporting mods?
I hope I can get my brother to take a road trip to NY lol
I hope I can get my brother to take a road trip to NY lol
#69
TECH Junkie
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Though VVT is an awesome technology, and can give you great benefits, it is pretty much in its infancy in LSx aftermarket products, and therefore not very many people can tune properly for them.
In the 70s people took of their HEIs and put back on points
In the 80-90s people removed their fuel injection and went back to a carb.
Today people remove VVT, because they dont understand it. Have fun removing awesome technology. Ive heard many many stories of guys that raced in the 70s trying to make their engines VVT, but couldnt. Because they understood the advantages of having the cam advanced for low end and retarding it to keep top end performance. Now that the OEMs have spent millions and brought the technology to the masses everyone is afraid of it.
In the 80-90s people removed their fuel injection and went back to a carb.
Today people remove VVT, because they dont understand it. Have fun removing awesome technology. Ive heard many many stories of guys that raced in the 70s trying to make their engines VVT, but couldnt. Because they understood the advantages of having the cam advanced for low end and retarding it to keep top end performance. Now that the OEMs have spent millions and brought the technology to the masses everyone is afraid of it.
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.
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.
I love mopar stuff too. The modern hemis seem to get similar results to LS engines with less cam, which could mean better flowing heads. Also could mean vvt might work better, because less cam means less spring, which means less hydraulic pressure for the phaser. You might be right about the viper only varying exhaust valve timing which has me scratching my head.
#70
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Mike@newera yes that was me that meantioned Mr. Morgan. It was through his posts that I heard about what you guys had discovered thru R&D. 11.4's is exceptional with a full weight car. What are your supporting mods?
I hope I can get my brother to take a road trip to NY lol
I hope I can get my brother to take a road trip to NY lol
Transmission and converter specs are currently in the experimental phase and are being changed / tested regularly, which is where a lot of our focus is right now.
#71
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Mike @ New Era thank you for the thought out response and great information. I appreciate you sharing your direct experience with LSx VVT along with the great tech.
Do you have any comments on the phaser control issue? Have you had any problems with the cam timing jumping around as SweetS10V8 described?
EGR is used to reduce combustion temperatures to prevent formation of NOx.
Do you have any comments on the phaser control issue? Have you had any problems with the cam timing jumping around as SweetS10V8 described?
EGR is used to reduce combustion temperatures to prevent formation of NOx.
Last edited by -TheBandit-; 01-26-2012 at 04:20 PM.
#72
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I believe that what he meant was that each phaser only has to control 1 set of valves...not that each cam isn't controlled...so they can independently control intake and exhaust valves, and each cam has less valves/springs following it meaning life is probably a little easier for each phaser...I guess my concern would come with changing to dual springs and seeing a lot more pressure on the cam from the lifters...is the GM phaser strong enough at that point, and if not what can we do to upgrade it?
#74
At first we had some issues but we made a design change and fixed it, however it does effect the MAF transfer a little bit, as almost any aftermarket induction system does. We tested the MAF sensor in 25+ locations in 3 different prototype designs before we found the best location to measure airflow and make maximum power with a minimum effect on torque calculation. But, quite commonly the MAF sensors GM uses can read 10% off from the next one, which could require tuning if this is the case. We have installed and tuned upwards of 50 of them since 2009, never had a problem.
#75
Mike @ New Era thank you for the thought out response and great information. I appreciate you sharing your direct experience with LSx VVT along with the great tech.
Do you have any comments on the phaser control issue? Have you had any problems with the cam timing jumping around as SweetS10V8 described?
Do you have any comments on the phaser control issue? Have you had any problems with the cam timing jumping around as SweetS10V8 described?
#76
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I have a forged 402 LS2 in my '00 C5. I have been reading a lot on the VVT system and have been thinking if converting to it would be worthwhile. I am fairly certain that the stock '00 ECU won't be able to handle VVT and would need to upgrade the ECU. I know that mechanically I can fairly easily convert to VVT, but would you have any suggestions about what to do for controlling the VVT?
#77
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The phaser control stability is slightly effected above 6000 rpms with the components we use, maintaining +/- .2-.4 degrees of cam timing there which can be seen by simply logging Intake cam desired angle/Intake cam angle/Intake cam error for anyone that has VVT. This will create extremely small fluctuations in power on a dyno graph, because 1 degree of timing can be worth 8-12 rwhp, depending on your cam profile and engine rpm, but my car has over 10,000 miles on it, over 500 WOT dyno pulls, 150+ track passes, and was driven from Rochester, NY to Indianapolis, IN last October to race in 2 classes all weekend at the LSX shootout, without any issues.
If the timing really is fluctuating, I wonder if additional oil pressure or flow would be useful or if the control system just can't respond fast enough to spikes and pits in the cam drive torque that are experienced as the lobes actuate the valves.
#78
TECH Junkie
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I agree re the instability of the VVT although mine is not yet dyno tuned so we can verify my efforst beyond seat of the pants I have noticed that just from each romp to the next there is one in about 5 passes that SMOKE man lemme tell ya she FLIEEEES but there other 4/5 are just okay.
I think it comes down to how minute the phasers control is. Seriously your trying to control 20 plus degrees of cam timing with about 1/4" of valve plunger movement? Thats too small to control perfectly. If the phaser valve and servo were over an inch of throw and had a more solidified connection rather than the plunger/needle deal I think it would function a lot more accurately. Regardless its still fun as heck and the insane amount of bottom end GRUNT this thing has as a result of the VVT? I'll suffer with a little inconsistency over 6000 RPM so long as it goes faster I dont care so much.
My only worry is dropping a valve from the single beehives. Im old school and come from the camp of theres never too much valve spring, only not enough lol. But there are some compromises that must be made when running this system of VVT. If I get through this season without a catastrophic failure im going to try duals next year and compare results.
As for the MAF? LS7 maf card is the trick with LOTS of straight pipe before, and after the maf. Then it all comes down to the tuner if he can scale it properly and dial everything in as should be.
Im going to be playing a lot with my L92 swap this summer. Keep your eyes peeled
I think it comes down to how minute the phasers control is. Seriously your trying to control 20 plus degrees of cam timing with about 1/4" of valve plunger movement? Thats too small to control perfectly. If the phaser valve and servo were over an inch of throw and had a more solidified connection rather than the plunger/needle deal I think it would function a lot more accurately. Regardless its still fun as heck and the insane amount of bottom end GRUNT this thing has as a result of the VVT? I'll suffer with a little inconsistency over 6000 RPM so long as it goes faster I dont care so much.
My only worry is dropping a valve from the single beehives. Im old school and come from the camp of theres never too much valve spring, only not enough lol. But there are some compromises that must be made when running this system of VVT. If I get through this season without a catastrophic failure im going to try duals next year and compare results.
As for the MAF? LS7 maf card is the trick with LOTS of straight pipe before, and after the maf. Then it all comes down to the tuner if he can scale it properly and dial everything in as should be.
Im going to be playing a lot with my L92 swap this summer. Keep your eyes peeled