Tune necessary for L99 -> LS3 conversion?

[fastbroshi]

Hey guys, the temps got down to the lower 30s today here in Dallas and my L99 sounded like it had backed off the retaining nut from one of the rockers this morning. It pretty much went away after I got up to operating temperature, but that sound was scary. I think everything's ok as I'm not getting any CELs or anything, but I want to convert this thing as soon as I can before it grenades.

Even sometimes during the summer, when I started it up after sitting for a day it would clatter a little until it warmed up.

So my plan is to do it as cheaply as possible (myself). I don't take it to the track or anything, so power isn't the ultimate goal but if I can get rid of VVT and AFM, and put in the stock LS3 cam I'd like to do that.

My main question is in doing this, will I need to do a tune so it'll run right? Anyone have an idea of people to do that in the Dallas area, and how much that would cost?

[Dmpsix]

Why are you doing an LS3 conversion and swapping into an LS3 cam?

[frankwjr]

get with dynoSteve, RDP....he will answer all you q's...look for his Q&A thread...

[camarosspower]

I wouldn't do all the work for a stock cam

[hrpiii]

Originally Posted by camarosspower

I wouldn't do all the work for a stock cam

this. if you are breaking into to upgrade it, then upgrade it. Cost of parts is not going to be that different.

[InFiD3ViL]

Originally Posted by frankwjr

get with dynoSteve, RDP....he will answer all you q's...look for his Q&A thread...

Agreed. I am working on a custom email tune with him, and he has been nothing short of awesome when it comes to communication. Very professional and will answer questions before the sale has even completed...which not everyone does.

[Davidd_SS]

Dude, while your in there might as well change out the cam.
Do your research before deciding, L99's are no joke with a good vvt cam and tuning.
Try to stay away from remote tuning after engine work, you need dyno or street tuning.
Talk to the guys over at Gpi Gwatney Performance for a good Vvt cam. You could go with a vvt ss1 on a stock converter and have good street manners for daily driving plus, an .11 sec car on the 1/4 with the right set up if you ever decide on a track day.

[Pro Stock John]

I've been running a performance VVT cam for 2 years and it runs 10's. VVT works.

[hammdo]

2 years here too VVT cam -- Road Racing and Supercharged...

-Don

[fastbroshi]

To answer one of the earlier questions, the reason I'd like to just go to LS3 is cost. Not just the extra I'm going to pay up front, but all the money that I might have to spend down the line to address any weak links, e.g. valve springs with more agressive cams.

These cars are plenty fast for me from the get go and I don't need a buttload of mods mechanically to make me happy.

And I have read about how fast the autos can be, but that's not really a priority. It's a daily driver, not a daily racer. I have motorcycles to to feed the can't-leave-well-enough-alone bug when it hits.

How much does a good dyno session actually cost anyway?

[2010reddevil]

Well if that's the case, then just get a good tune and call it done. No sense in spending thousands of dollars to open up a perfectly good running engine and downgrade it's performance. These guys are right, if you're just so dead set on cracking the engine open, then stick a GPI VVT1 or 2 cam in there. That will eliminate the afm crap and give you more power to boot, under the curve where you need it. Otherwise, just tune it and call it done. You're throwing money away. Instead of doing that, how about making a charitable monetary donation my way, I'll definitely put it to good use haha.

[JCunningham]

Dyno will cost you $450-$500. keep your stock VVT cam and VVT or get a custom VVT cam. there's no weak link to it. the weak link in the L99 is the AFM lifters. I wish I could add VVT to my LS3.

[fastbroshi]

Originally Posted by 2010reddevil

No sense in spending thousands of dollars to open up a perfectly good running engine and downgrade it's performance. These guys are right, if you're just so dead set on cracking the engine open, then stick a GPI VVT1 or 2 cam in there. That will eliminate the afm crap and give you more power to boot, under the curve where you need it. Otherwise, just tune it and call it done. You're throwing money away. Instead of doing that, how about making a charitable monetary donation my way, I'll definitely put it to good use haha.

It's not like I want to get in there just for the hell of it or anything; I want to eliminate the AFM lifters. And I'm not sure how it would be a downgrade in performance. Aren't the LS3s rated a bit stronger on dynos? Every thread I've seen about L99 dyno numbers has them consistently putting down 40hp or so less than the LS3s. The implementation of VVT is IMO a concession to the weaker cam of the L99. So maybe I can keep the VVT and convert to LS3 cam, I'm not sure. But I think I read that to do so, it's recommended to upgrade the valvesprings.

Sure I could put in a stronger aftermarket cam, but that would likely cost me another $350 on top of the cost of LS3 cam gear, which I understand can be had relatively cheap. Not to mention those cams typically require stronger valve springs, so there's another $400 or so there. Pushrods too maybe? The list goes on and on.

Either way it sounds like GPI has a good conservative VVT cam. I'll probably give them a call and pick their brains about it to weigh the pros and cons.

[2010reddevil]

Originally Posted by fastbroshi

It's not like I want to get in there just for the hell of it or anything; I want to eliminate the AFM lifters. And I'm not sure how it would be a downgrade in performance. Aren't the LS3s rated a bit stronger on dynos? Every thread I've seen about L99 dyno numbers has them consistently putting down 40hp or so less than the LS3s. The implementation of VVT is IMO a concession to the weaker cam of the L99. So maybe I can keep the VVT and convert to LS3 cam, I'm not sure. But I think I read that to do so, it's recommended to upgrade the valvesprings.

Sure I could put in a stronger aftermarket cam, but that would likely cost me another $350 on top of the cost of LS3 cam gear, which I understand can be had relatively cheap. Not to mention those cams typically require stronger valve springs, so there's another $400 or so there. Pushrods too maybe? The list goes on and on.

Either way it sounds like GPI has a good conservative VVT cam. I'll probably give them a call and pick their brains about it to weigh the pros and cons.

The L99 vs LS3 main rivalry is the cam only. But, if you look @ the fast list, it is dominated by the cammed L99 cars for a reason. They make more tq under the curve. VVT is a good thing. My 2012 Silverado had the LMG 5.3L also with VVT and I can attest to how well it worked on that turd of a motor. It worked wonders. The 5.3L was no longer a torqless wonder. It had some grunt. I highly recommend a GPI SS1 or 2 cam. The 1 just requires VVT lockout and of course the requesite lifters swapped out. There are a lot of guys here running 10's with the VVT, that means it flat out works, as long as you have a person who can tune it right like Rino or the others on here.