Another L99 cam question....VVT!

[SS-screamer]

So L99 heads are L92 heads and vice versa. Wonder what else I don't know...

[IConnection]

Sure there is a learning curve with tuning a VVT but in the end I think the L99 might be a diamond in the ruff compared to the LS3.. I do agree the larger lift cam is a good thing with a L92 head but how will it effect VVT lifters over time?

I wont be going over .560 lift
I will stay around 224-236 duration

[2010 SSRS]

L92

[litle88]

YOu guys are forgetting another weak point on the l99'S!

Thats the damn mechanical lifters that BREAK!!
They would need to GO ASAP!

[2010 Bumblebee]

Originally Posted by Ject

I dunno about easiest, it is sure a large cost of $$ though.
My estimate is running about $4k-$5k counting labor to do the full LS3 conversion. At that rate I could just slap a Super charger on for more power.

Why don't you just buy a crate LS3, and sell your L99? Wouldn't that be cheaper?

I think a s/c is the best bang for the buck.

[toehead93]

Originally Posted by InjectionConnection

Sure there is a learning curve with tuning a VVT but in the end I think the L99 might be a diamond in the ruff compared to the LS3..

I agree and now there is hard evidence to support this...
http://www.camaro5.com/forums/showthread.php?t=82272

[cam-]

Originally Posted by SS-screamer

So let me see if I get this right. If I change out my heads to L92 then I can run a Comp cam/phaser combo which allows more lift and better potential performance over the Mast cam/phaser and may be easier to tune?

"Wish someone had done all this homework for me before I started LOL " That's what I'm banking on you for.

Sort of. First off as mentioned the L92, L99, LS3, LY6 are all the same head casting the only difference is the valves and springs but nothing to worry about performance wise they are all as good as the other in terms of flow. The LS3 does get lightweight valves though but the stock L99 ( L92 ) valves are pretty decent pieces as well.

As for the easier to tune comments. What I was referring to deals with two issues in the approach I mentioned that will be easier. The MAST cams are big on duration and bigger duration = more challenging tune VVT or not big duration cams can be a biatch to dial in nicely. Also the MAST phaser limiter has more phase movement which your going to want to control so that also adds complexity to the tune. When running the COMP phaser you can simply order a cam with the advance ground in and then tune the phaser to retard the snot out of it as the RPM climbs so your only dealing with one aspect of VVT and if you match the cam up properly it wont lose anything down low over the phaser as you have the same advance just ground into the cam vs using the phaser to advance it. Make sense?

Plus Im not a fan personally of big duration cams on the L92 heads for street use ( or any heads for that matter ) as once you crest the 230 duration range you migrate the cars purpose closer to a race only weapon as the civility and street manners will become pretty harsh. Over 230 duration you can expect low speed bucking and surging and a pretty harsh idle so A/C and the like will be difficult to use at idle etc. Most of these things can be dealt with if the tuner is amazing but in my case I tune my own and would rather avoid the difficulties. Plus it sure doesnt seem to take donkey dick cams on L99's to make AMAZING power and they do respond very well to more lift over more duration and you simply cant have both with VVT due to the piston to valve clearance limitations. In my case the cam I had spec'd is .600 222/230 but I have very hot lobes ( LSL ) which work very well and I might be leaving a but up top over say a 230/240 XER but not a whole lot and I would have to cut down on lift to use that much duration and retain VVT so Im pretty excited to get this cam installed and dyno it as Im expecting decent numbers.

[SS-screamer]

Originally Posted by cam-

Sort of. First off as mentioned the L92, L99, LS3, LY6 are all the same head casting the only difference is the valves and springs but nothing to worry about performance wise they are all as good as the other in terms of flow. The LS3 does get lightweight valves though but the stock L99 ( L92 ) valves are pretty decent pieces as well.

As for the easier to tune comments. What I was referring to deals with two issues in the approach I mentioned that will be easier. The MAST cams are big on duration and bigger duration = more challenging tune VVT or not big duration cams can be a biatch to dial in nicely. Also the MAST phaser limiter has more phase movement which your going to want to control so that also adds complexity to the tune. When running the COMP phaser you can simply order a cam with the advance ground in and then tune the phaser to retard the snot out of it as the RPM climbs so your only dealing with one aspect of VVT and if you match the cam up properly it wont lose anything down low over the phaser as you have the same advance just ground into the cam vs using the phaser to advance it. Make sense?

Plus Im not a fan personally of big duration cams on the L92 heads for street use ( or any heads for that matter ) as once you crest the 230 duration range you migrate the cars purpose closer to a race only weapon as the civility and street manners will become pretty harsh. Over 230 duration you can expect low speed bucking and surging and a pretty harsh idle so A/C and the like will be difficult to use at idle etc. Most of these things can be dealt with if the tuner is amazing but in my case I tune my own and would rather avoid the difficulties. Plus it sure doesnt seem to take donkey dick cams on L99's to make AMAZING power and they do respond very well to more lift over more duration and you simply cant have both with VVT due to the piston to valve clearance limitations. In my case the cam I had spec'd is .600 222/230 but I have very hot lobes ( LSL ) which work very well and I might be leaving a but up top over say a 230/240 XER but not a whole lot and I would have to cut down on lift to use that much duration and retain VVT so Im pretty excited to get this cam installed and dyno it as Im expecting decent numbers.

I can't wait to see how yours turns out. Keep us up to date with how it goes and maybe a video of the finished product.

[third1]

What he said

[IConnection]

The XER lobes make power but there noisey
I like the LSL (LSR CAMS) lobes better as there quieter and quicker on off the seat, u are on the right track..
I also believe the big cams are not needed for a heavy street/strip setup (Camaro)

We have proved this on the dyno with the LS3
We have made 475RW with a CAM ONLY LS3 SETUP running a 222-234 566-578 113LSA

This was with all the other boltons too..
So I am hoping for 440RW out of my L99 if done correctly

I will be going to a cam similar to this grind in my L99
It does lope alittle bit but no hunting,surging of anykind and make serious power.

I also agree the Comp stuff looks nice
We are direct with Comp and Mast but I get better pricing from Comp so thats who I will use for my setup.

Cam, Good luck with your Cam setup

[thesnoopster]

This is some good information cause im currently cam shopping for my L99.... and this VVT stuff is new to me .... but it is also catching my eye as well. Im more in the hunt for that street drivability with the option of a S/C later in life (funding pending ) and great power. I will also be doing the DOD/AFM delete as well with all the new upgrades thats recomended (springs, trunion kit, pushrods and lifters and whatever is needed). Still deciding on either Comp or Mast or a good stick thats on the market ...I know their both good but I am gathering much information as I can...

[Ace]

I am going with the Livernois Motorsports 2C cam. 224/236, .612/.612 lift, 117 LSA. I am just waiting on a date to drop it off! They are deleting DOD/AFM and the VVT won't be active either. They replace all the internals necessary of course (using LS7 lifters)...if you look at their website the L99 camshaft package lists all the parts they use.

Send it Livernois snoopster! They are fantastic to deal with and of course they have a great reputation and well deserved!

[Ject]

Originally Posted by Ace

I am going with the Livernois Motorsports 2C cam. 224/236, .612/.612 lift, 117 LSA. I am just waiting on a date to drop it off! They are deleting DOD/AFM and the VVT won't be active either. They replace all the internals necessary of course (using LS7 lifters)...if you look at their website the L99 camshaft package lists all the parts they use.

Send it Livernois snoopster! They are fantastic to deal with and of course they have a great reputation and well deserved!

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

[PatrickfromMD]

Originally Posted by cam-

Yeah this is the main VVT issue. Tuning.

The real problem is you cannot ( as of yet ) adjust the cam phase without having that affect ign timing and fueling as well so it adds a real mountain of complexity vs a conventional non VVT tune. Mast runs a phase limiter but they still retain both advance AND retard features of the VVT. COMP on the otherhand also sells a phase limiter but theirs locks out all advance so the cam sits in a zero position and only allows retard phasing. Both MAST and COMP phasers limit total cam retard phasing to 20 degrees but MAST also offers 20 degrees of phase advance for 40 total degrees whereas COMP only offers 20 degrees of retardation as the phaser limiter prevents all advance. The unfortunate reality we all live with is piston to valve clearance so there is no perfect way BUT....

What Im seeing so far is this. The L92 heads really seem appreciate lift and the MAST cams are all around .560 which is about as much as one can safely run and still allow the phaser so much room to operate without bif'ing pistons into valves. If you run the COMP phase limiter with its 20 degrees of phase movement then you can safely run .600 lift cams and gain the advantages of the L92 heads a bit more. Plus you can order a cam with as much advance in it as you can possibly clear on ptv concerns.

So this is the route that i am going and I will post results. Initially I was a little confused as to what the limitations were and why but after a couple of three months of digesting these thoughts and the limitations at hand I feel that this route should net both more peak hp than a MAST cam plus it will be a lot easier to tune as I have less phasing to deal with AND less duration to smooth out. So my strategy at this point is to leave the cam phasing tables stock and let the phaser do its job and just tune the a/f in a conventional way. Once I have that done I will dyno and post results. Then Im going to take the rest of the season to play around with the phasing tables and see if I cant squeak more out of it which I'll also post up about. Of course i have to get the car together first. Anyways this is probably a bunch of jibber jabber but I hope it makes sense to you guys.

Sooner or later we'll have enough if us guinea pigs that test out this stuff and find what works out best. Wish someone had done all this homework for me before I started LOL

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.