Another L99 cam question....VVT!

[toehead93]

Originally Posted by Ace

I am just waiting on a date to drop it off! They are deleting DOD/AFM and the VVT won't be active either.

What do you mean by deactivating the VVT? That is what most people are doing but we're discussing the advantages of keeping VVT. It sound like once you make the conversion you're talking about you'll have an LS3 with LS7 lifters. The VVT is what makes the L99 uniques and VVT is why the L99 makes better power under the curve! Good luck with you're build you'll no doubt have serious power but I prefer to wait it out and see who else jumps in the L99/VVt mix. I've seen what Mast has done and I'm excited. I'm looking forward to seeing InjectoinConnections Comp set-up. I'm interested to see how the difference principals in VVT limitations convert to power and if they come across any unique tuning issues.

[Ace]

Toehead93...yeah, I know there is a lot of potential with the VVT but as of right now it doesn't look like some of the issues are cleared up working a cam with it. I plan on doing a lot more down the road so in the long run I am not too concerned about keeping the VVT. I know it is what makes the engine unique and I have a little concern just getting rid of it...but at the same time, the parts that are going in are really going to beef up the engine and make it stronger. The cam they are putting in is better at keeping a broader torque curve as well so I still should have plenty of torque down low. Plus, I have the money right now to spend on this and need to get it done!!!!

[Sack Rat 2SS]

The article in GM High Tech did not address the tune for each motor which still leaves us in the dark. Also, they did not address whether they changed out any of the lifters related to AFM or not and whether it could operate if desired. They did the dyno runs up to about 6800 rpm on all but baseline pull of L99. That is why I ask about the lifters and if they were changed out or not. I like the test but still many questions up in the air. It is only a first step and I will look forward to seeing a VVT test on someons L99 using Comp Cams version. It is nice to have choices in life.

[cam-]

Originally Posted by PatrickfromMD

Cam,
What you describe about the phasing effect on the fuel and timing explains a lot. I keep wondering why cam designers do not spend more time working with the phasing tables as they design a VVT cam so they can take better advantage of the technology. (though Mike at New Era claims to do this). If phasing, timing and fuel tables are wacked out all at once, its like solving math equations with 3 unknowns (e.g. the need for lots of trial and error) Add to the mix that by the time someone chooses to add a cam to their car, they already have a number of other bolt on’s. This would seem to require a comprehensive custom tune for each application.

So, I received my GMHighTech mad yesterday, along with a very interesting article on Mast cams in brand spanking new LS3 and L99 motors on an engine dyno.
They tested stage 1,2,and 3 cams on both the L99 and LS3 (L99 and LS3 cams are different for their respective motors)
There were impressive gains, but as we know, there is no specific tuning of the VVT for their L99 applications. One of the limiting factors Horace mentioned to me (in addition to piston to valve clearance) was that the VVT is not strong enough to overcome light lift and aggressive lobes, thus necessitating the special springs. A better oil pump can help (as you know the VVT operates from oil pressure), but there is not a lot of aftermarket in that area.
BTW- the article was even more interesting in its comparison between the L99 and LS3 (stock 466hp/465tq vs. 477hp/456tq respectively on the SF-902 engine dyno). When cammed, the L99 outpaced the LS3 up to 5100rpms in both hp and torque.

For me, who wants to keep the door open for FI in the future, I want to stay on the milder side of the cam selections (there was a Mast cam just below stage one 218/230 and 564/578 that was recommended to me), but I would really like something that was designed around a phaser profile optimized for the cam (retarding, advancing, or both). I suppose such a package would require some time tuning the timing and fuel tables, but if the phase profile is proven that’s half the battle.

So tell me about this cam solution from EPS? Do you know if the VVT can function with this lobe design? Have they been designing their profiles in conjunction with manipulating the phasing tables? What drew you to them? Is it primarily the lobes?
BTW- thaks for sharing all the good info you have found out there.

Good point about the phaser power limitations and as of now theres a few theories floating around. I've heard that during COMPS cam testing on VVT grinds in durability tests they firstly blew the hell out of the stock AFM/DOD lifters and as of this time I am unaware of any end user having a lifter failure but the buzz is that they are definitely not up to the task for high perf use based solely on COMPs testing. Secondly the reports on the phaser itself were that it has to work against the valvetrain to move the cam position so big dual springs pose a problem and should be avoided if retaining VVT. Its because of this info I opted for the PAC 1518 single beehives instead of a nice set of duals ( which i prefer just for various reasons Im a bit old school that way ) You can run the COMP 918 beehives and these were recommended to me over the PAC springs and on paper the COMP 918 is superior to the PAC 1518 but I've seen one too many horror stories and a few too many lame excuses pop up over why the 918's fail time and time again. One bad tale? Fine installation or user problem but theres been too many for my liking so I opted for the PAC as the feedback on them has been good. Besides just because "on paper" the 918 claims its superior doesnt make it so. How does the saying go? You sell the sizzle not the steak...

Regarding the oil pump? Im not certain at this point whether upgrading the oil pump will solve the problems being reported with phaser control. I've spoken with just about everyone out there whos doing VVT development ( MAST, Mike at New Era, Lance at pantera efi who is a practical genius IMO that guy is something else ) Anyways everyone has their own opinions of whats working, not working, and why. Unfortunately none of these opinions match up they are all from various angles and different theories. So my thinking is simple.... GM has to deal with warranty and reliability and all of these much bigger mountains of responsibility than any horse power seeking specialty shop so Im sticking with the proven as much as I can and I'll change things one piece at a time as I see fit. Im in no rush here ( clearly as I've had the cam for over two months and its still in its box LOL ) One thing i should note is I did hear that the COMP phaser limiter can be prone to getting stuck and locking the cam in full retard or full advance... Interesting...

As for what got me onto EPS? Well its a bit of a tale actually. I ran a TR224 cam on my old LS1 and LOVED that thing for a DD car it was perfect IMO. Had decent bottom end but not so much it would blow off the tires too badly but it pulled superb through the mid range and had decent top end pull as well. All in all it is the best all around DD LS1 cam ever made. But as time goes on I am always looking for more. My end goals are to have a solid daily driver naturally aspirated ten second car that gives up nothing in terms of calm road manners and driveability. I've had the BBC solid cam high compression monsters and I've run turbo cars both domestic and exotic and for my "smile per mile" factor as I like to call it, nothing beats a well built naturally aspirated set up. The trick is to keep it mild but when you mash the go pedal it turns WILD Kind of like the best wife scenario: "Betty Crocker in the kitchen, Jenna Jameson in the bed room"

So I've been planning this new build for a few years now. Considering my goals of a ten second DD car with decent road manners VVT started to look very attractive as it salvages bottom end yet produces the same top end as static cams would and this has a lot of appeal for DD use. I had a few things all happen at once this winter that really timed out perfectly for me to go for this build now so I did. I decided that the only way I was ever going to get to my goals was to master tuning this stuff on my own and thats what this season is all about, learning. So after all my research and thinking about what I want I decided to see if we could make a cam that mimicked the TR224 for a 6.2L with VVT yet make as much HP as possible. None of the off the shelf offerings have this, Comp wouldnt grind me a custom VVT cam so I hired PatrickG ( Admin and cam spec guru over at LS1tech ) to spec me a custom cam and thats when Geoff from EPS got involved. Low and behold dont I then find out that Geoff is formerly of Thunder Racing fame and to make it even better he designed the legendary TR224 so a few laughs and lots of conversation later and the cam I mentioned above is the cam they spec'd out for me.

Initially I was pushing them for more duration as at that time I didnt truly understand how tight the PTV issues are and I thought that VVT could "tune" out more cam harshness. I've since come to realize that isnt really the case but more of how the engine behaves in terms of power output vs RPM as this is truly where VVT helps out a lot. In a nutshell a lumpy, radical cam VVT or no VVT will be just as lumpy and radical. What VVT will do differently is make more power under the curve than a static cam will but the overall cam behaviour remains the same. So that led me on many MANY hours of cam research on LS3's over at Corvette forum and the like trying to see who made the most power and what constants seem to win time and time again. What I noticed was high lift and relative low duration is a real benefit for not only power but owner satisfaction. A lot of guys made GREAT power with huge duration cams but they all complained about having to buzzit to 7500RPM to make the number and sacrificing good manners as all the bucking and surging and the like. Plus its not like these huge cams were really destroying these "milder" cams they were only 10-20 hp off in most cases and when we're in the 450+ range thats not a lot of gains for the compromises involved. I also started noticing that LSL lobes were just killing it on these smaller cams and again EPS lobes are in fact LSL lobes which initially I didnt know.

Moral of the story is; Custom grind cams are so completely worth the extra 50 bucks LOL. Besides I've never seen a thread with a PatrickG cam where anyone complained about it. In fact quite the opposite everyone seems to love the cams he spec's and considering that this is really just a learning curve for me I figured i had nothing to lose.

So back to my ten second goals? After this build and I master this VVT tuning and whatnot Im going for cubes. Hopefully VVT works out well and survives the punishment Im about to put it through ( and you better believe it will be punished hehe ) I hit the limiter daily on my LS1 and will do that and then some with this one. A nice 414 cid na build with ported heads and another custom grind cam outta put me into the tens with ease. Maybe next year on that but this year mid 11's will suffice

[JustinCesler]

Great discussion!

To keep everything in one place, please check out my post here for more information about this test.

Thanks,

Justin Cesler | GM High Tech Performance

[cam-]

Cool info. It seems they have changed some things over there at MAST. When I spoke with them their Phaser limiter was 40 degrees which i guess was installed on the original design according to that quote mentioned from Horace there are a few different phasers produced by GM.

What I'd like to know is if one is stronger than the rest? Im sure this will bubble up over time but as I mentioned earlier if someone else has done their homework and discovered the winner Id really appreciate knowing about it. Maybe i should place another call to MAST and see if they feel like talking. Too busy now I'll look into it next week

[Geoff]

For the record: The 'EPS' lobes that I am selling are NOT LSL lobes. They are my proprietary design and have some influence from the LSK and LSL designs, but they are different. These lobes do not have as much lift as either the LSK or LSL. They also have MUCH smoother acceleration than either of those designs. Patrick and I have been working on some copy to explain the benefit of these lobes and a bit of history on how they came about. I will try to have it posted on my site in the next week or so. If anyone has any questions plese feel free to contact me.

[trudawg660]

Originally Posted by Ject

Wonder what their price on that is.. my biggest thing is labor costs. The parts in general are cheap, but labor is the killer.

the price is pretty damn steep this is including labor and parts

http://www.livernoismotorsports.com/...t.phtml?p=1958

[IConnection]

Geoff are you using the STOCK L99 lifters with your VVT stuff?
Just curious, Always had good luck with your stuff when u were at TR

[Geoff]

Originally Posted by InjectionConnection

Geoff are you using the STOCK L99 lifters with your VVT stuff?
Just curious, Always had good luck with your stuff when u were at TR

Depends. If you are using AFM (I.E. L99 Lifters) then the EPS Lobes are a no go...too much lift. If you are ONLY doing VVT with conventional lifters (no AFM) then the EPS lobes will do fine.

I can do cams that will work with either AFM or VVT or both. Just ask

[SS-screamer]

Originally Posted by trudawg660

the price is pretty damn steep this is including labor and parts

http://www.livernoismotorsports.com/...t.phtml?p=1958

That is actually not too bad considering that price includes ARH headers as well as cold air intake. On top of that it includes installation for all of it and tuning. Looks very reasonable when compared to other places in my opinion. I just wonder how much to transport there would be though.

[Ace]

Originally Posted by trudawg660

the price is pretty damn steep this is including labor and parts

http://www.livernoismotorsports.com/...t.phtml?p=1958

No, it is not bad and I received estimates from a couple of shops and they were all pretty much the same. My car is being dropped off today to start the work and hopefully I will have it back at the end of the week. Of course I will post the results and driving impressions! It is going to be a long week of waiting.....

[cam-]

Originally Posted by Geoff

For the record: The 'EPS' lobes that I am selling are NOT LSL lobes. They are my proprietary design and have some influence from the LSK and LSL designs, but they are different. These lobes do not have as much lift as either the LSK or LSL. They also have MUCH smoother acceleration than either of those designs. Patrick and I have been working on some copy to explain the benefit of these lobes and a bit of history on how they came about. I will try to have it posted on my site in the next week or so. If anyone has any questions plese feel free to contact me.

Sorry for mis-quoting Geoff I was yakking with Patrick in another thread over at tech about LSL lobes and thought he had said they were the same hence my comments above. I re-read the post now and see that he did say they were similar but also mentioned softer off the seat for easier valve control and whatnot.

So much info to retain man... As I said above too this is the season for learning for me and Im still sorting out a ton of stuff.

Regardless EPS lobed cams have been making damn impressive results on a ton of set ups that i've read about. Cant wait to get mine going

[StlRomAniaN]

Originally Posted by Ace

No, it is not bad and I received estimates from a couple of shops and they were all pretty much the same. My car is being dropped off today to start the work and hopefully I will have it back at the end of the week. Of course I will post the results and driving impressions! It is going to be a long week of waiting.....

What are you getting done?