I just installed a new LS6 in my 99 SS ragtop but no gain in performance. I suspect I need to reprogram the computer but the GM service rep is not much help. Any help would be appreciated.

Thanks
Ray

 

Yes, you need to reprogram right away. The LS6 does not take the timing that the LS1 does - you are probably getting some knock retard killing your performance.

Don't let it go long - mine had a bad tune (using LS1 timing) in it for about 1,000 miles, and I am now rebuilding a brand new LS6 due to detonation damage. I couldn't hear any detonation or see much in the way of KR, so don't just go on indications.

The LS1 tuning has as much as 5 degrees more advance than the stock LS6 tuning - right in the heart of the daily driving range (1,800 to 2,200). That will do damage in short order.

I would get it to someone who tunes with LS1 Edit - they should be able to look at the stock LS6 timing tables and copy them into your PCM. Then they need to also work on fuel tables.

Hope this helps!

 

I have never heard of detonation damage. Unless you have a knock so bad you can hear it a mile away you might crack a piston. But other than that...

 

I had stock tuning in my 01 SS with a LS6 crate, not even a hint of detontion... even without tuning it still put down 390 rwhp... and from what I hear thats low for that swap! id say check the install!

 

Well, it happened to me.

And, yes, you can have detonation damage going on and not have knock so loud you can hear it. Ask any proffesional engine tuner and they will tell you that. I took shortcuts and went with inexperienced people on my tuning to save money, and it ended up costing me a lot!

If you look at the timing tables, you will see that the LS6 takes much less timing than an LS1 - mostly in the lower RPM ranges. So, yes, you may have good peak power, because they are only off by 1 or 2 degrees up high, but down in the daily driving range, they are way different - up to 5 degrees more advance on the LS1. Maybe you just got lucky and didn't do damage before getting the tuning right. Maybe KR saved you. I suspect that the idiots that wrote my tune also reduced my KR as well, but that is hard to tell at this point.

You don't have to believe me if you don't want to, but I have the damaged pistons to prove it - obvious detonation marks all over them with the worst being #7 having chunks out of it that got smashed in the chamber of my nice new LS6 heads.

Everything else has been checked over. The injectors were flow tested and everything. When the shop working on my car now saw the difference in the LS1 timing in my car versus the LS6 timing, they said right there is the answer.

Just trying to save someone else the pain and suffering that I went through...

 

What is described here is probably true also when milling LS-1 heads and doing !EGR. Check part throttle timing and KR.

 

This makes sense since the LS6 has a higher compression ratio than the LS1. Something has to give somewhere; get better gas or install a cam with more valve overlap to bleed off some cylinder presure in the low r's.

 

Hey Blk02wsr:
I just put Ls6 heads milled .055 and a cam 220/220, 564/564, 112LSA in my SS.

I have no tuning yet. Do you think I need a tune?

Cam is very mild and I assume the stock knock retard would kick in if there was a problem....

CR is 11.4 to 1. No audible knocking and car runs great!

 

Well, I'm no expert by any means, so my first advice is take it to someone who is! I would say you probably do need some work.

From what I understand, it is really the design of the LS6 head that raises the issue - more so than the compression ratio. That is why there will be guys on here that have milled LS1 heads that can run more timing than an LS6. The LS6 heads are a "fast burn" design that won't tolerate the advance like the LS1 design.

Your PCM knock retard may cover you depending on how much KR is needed to keep you safe - from what I understand, the max KR you will get is 4 degrees (can anyone verify that?). If that is true, and you have more than 4 degrees of retard needed, then you could be in danger.

I can tell you that there are areas in the stock timing tables (comparing LS1 and LS6) where there is as much as 5 degrees more advance in an LS1.

Also - just because you can't hear it, doesn't mean you don't have detonation. I never heard so much as a ping out of my car during the short 1,000 miles it lived - but when I took the heads off, there was definitly damage.

Also, not all means of monitoring KR will give accurate results. From what I am hearing and reading, it seems that maybe Autotapping with only minimal data being logged at one time may be the way to go. I would like to hear others weigh in on this. I did not have Atap, I was trying to use a live scantool - not next time.

The biggest problem I had was that the tune in my car was written by so-called proffesionals and it turns out that they used the stock LS1 timing instead of the stock LS6 timing - and to make matters worse, it seems they somehow reduced my KR, so I didn't have the stock protection.

My plan for tuning when the motor is finished is to get real tuners with a proven track record (I've already been discussing the job with them) to write me a tune in LS1Edit which will include the entire stock LS6 timing table.

They will go safe on the fuel, and lean as required on the dyno with a wideband. The hard part with fuel is that the LS6 and LS1 are very different in the tables and don't really correlate due to the different MAF. You can't just copy the tables over. I have suggested going with a stock Z06 MAF (not calibrated for the LS1), but they say with my other mods (headers), it will be just as easy for them to work with the stock LS1 tables in my PCM and go from there.

Probably, most of you doing LS6 swaps and using the stock tuning may be alright until you get a tune due to your stock KR taking care of you. It seems mine was not that fortunate. Besides, I would not want to rely on that anyway. I was advised to put the tune with the LS6 timing in before I ever crank the motor over! After the money I've spent, I'm gonna follow that advice!

Sorry to go on and on, but I hope this helps someone.

 

WOW; that is some story!

...were your monetary damgages covered? How did you decide to install a new LS6 engine, anyway?

My freind A-Tapped my car; would the knock be detectible using this software? What do you log and how do you tell if knock is ocurring?

 

"were your monetary damgages covered?"

-No, they say it must have been my fault and they have all kinds of disclaimers anyway - use at your risk...

"How did you decide to install a new LS6 engine, anyway?"

-Long story, but to make it short - I race the car and had mods - I damaged the engine through my ignorance, so didn't feel it was right to attempt a warranty claim. Needed my car back quickly, so I decided the crate engine swap was better for me at the time than a rebuild.

"My freind A-Tapped my car; would the knock be detectible using this software? What do you log and how do you tell if knock is ocurring?"

-Like I said above, I am not an expert by any means. You should try to find out from those that are. I am doing that at this time myself. From what I understand, you would log KR. And the fewer parameters that you log at one time, the more accurate it is (??). I'm trying to find out more on this too. Maybe we should start a new post on the capabilities of A-Tap.

I do not have A-Tap as of yet. I am going to get it or access to it before my engine goes back in. If I had been A-Tapping before, I may have caught the KR before I got the damage.

 

WOW that blows...

...i think you should request that the tuner replace all the bad damaged stuff...

...is the new engine under warranty ...or do you have to install it in a Z06 to get coverage from GM?

 

I think you might to check your tune and your fuel system I don't think 28 degrees of timing running thru a LS6 is gonna detonate, what did you break exactly a ringland or burn a head gasket?

 

The ring land - small pieces of the piston came off around the top and bottom (6 & 12 o'clock). Not huge chunks, but big enough to cause noise when the piston smashed them on the flat part of the chamber.

It was on a wideband and plenty rich. I had the injectors all flow tested - they are good. I will check the pump, but suspect it is good too.

Why do you not think 28 degrees will cause detonation - an LS6 only calls for 22 degrees in the majority of the table. 6 degrees advanced is a lot if you ask me!

When you compare the LS6 & LS1 tables, you will see there is a very big difference. LS1's are 2 to 5 degrees advanced over an LS6 everywhere in the table. The place that is putting my car back together now (not the ones who gave me the bad tune) looked at the tables and said without a doubt that was the cause of my damage.

Like I said earlier in the other post - the other thing that I think did me in is I suspect the "tuners" did something to reduce my KR in the tune. The reason I say this is because you would think with the detonation damage I have, you would have seen some KR - even on the scan tool I was using, but I saw very little (1 to 1.8 here and there).

 

I feel bad for you and I hope you have better luck with your new motor, But I still question timming was the issue with your piston damage. I'm a mechanic and have built over 100 engines. I run all the timming I can get on my LS1. When I go too far performance drops and the pinging starts, I can hear it easy over noise of straight pipes. Been running it like that over 10k miles with no problems.

 

Well, I just installed an LS6 intake on my 2000 LS1. I also deleted the EGR system.

I autotapped my car and I am getting a insignificant amount of knock retard. No more than I used to get with the LS1 manifold. I am also running MORE timing than a stock 2000 LS1. Up to 31 degrees at WOT.

I think the issue is problably A/F tuning. Maybe the LS6 intake leaned your car out, which helped cause the detonation. Coupled with the higher compression ratio.

But I still find it odd because if you wew truely using a stock LS1 tune, your car should have been trying to run rich at WOT since it thinks your injectors were smaller than they actually were...

In any case, our computers can certainly retard timing more than 4 degrees...

Good luck.

Tommy

 

How about your part throttle KR ? Though, you have Hotcam which contributes to less efficient cylinder filling around ~2000rpm and thus likely more tolerance to high advance there.

If you have small or stock cam, milled heads and !EGR watch out around ~2000. Part throttle advance can be up to 41 degrees for EGR cars. And nothing you can do for closed loop fueling...

High stall can make ~2000 always a light load RPM which helps the situation.

 

When I replaced my LS1 with the LS6 crate, the mechanics said all performance features were identical between intakes, and recommended I reuse the LS1 intake because of the diffent number of cooling lines.

Are the LS1 and LS6 intakes different, and if so, by how much? Shound I have used the LS6 intake? They looked the same when I compared them.

Also, I never checked casting numbers or anything else on the LS6 crate engine when I bought it. How would I verify I got an LS6 engine vs an LS1?

Regarding my original post, I was put in touch with a programmer in Mena, Arkansa, and am currently waiting on my new computer chip. Will update you on performance gains shortly - I hope.

Anyone interested on specific issues encountered during the swap? - read on. The original oil pan, motor mounts, exhaust manifolds, front pulley, intake (questionable) had to be reused. Biggest problem for my builder was he had to make a roll-around platform to move the new engine around.

During engine swap, decided to have tranny rebuilt - mainly due to occasional 3rd-gear grinding. Found the spine between 5th and 6th gear 50% gone - $2300 in damages. Fine job of overhaul though.

If anyone is looking for an experienced (1 time) LS1 to LS6 swapper, I would recommend them (also the 6-speed tranny shop.

Thanks for all who responded. Will update performance as soon as new chip arrives.

Ray R

 

IMHO, its a real bummer to lose an engine that way but if anything the tuning had a lot to do with it.
Also many times lots of mods are added but people refuse to see they really do need larger injectors and its clear that if piston 7 was fried that engine was way too lean.
7 is common to fry, I have seen it several times with shops that install superchargers and then do lousy PCM tuning.

My stroker engine has 11.3:1 compression and using only Ca smog gas and sees 6,800 RPMs all the time with 28 degrees of timing at PE/WOT with very little low knock or none at all most of the time.

I've tuned many LS6s that were stock or had mods and not one has had a problem with 28 degrees at WOT.
A decent PCM scanner is the cheapest tool to own with these powertrains today and inform you way before most damage could occur.
Problem is many people rather save $50 and buy junker scanners and you get what you pay for.

GM sets the PCM to allow as much as 15 degrees of timing retard under knock and also has a safe timing table (low octane) so it had to be the tuning that limited how PCM reacted to knock and when it was to react what it would command and how long to be in that state when knock was reported by sensors.

LS6 intake allows a bit more total airflow but not enough to cause engine damage. My PCM is a 1999 yet it still functions correctly with all the mods powertrain has so again its the tune and it is required when making any real changes to the engine to achieve best performance and to assure motor is not a timebomb.