Ok I know this has been beaten to death about how much timing to pull with how much spray. My issue is that I see “stock timing” literally all over the place! Searching the net I see 24-28° and even some more or less here and there. I had a tune on my 2000 corvette when I got it so I don’t know what stock was. I had a respected tuner since note that early stock ls1’s had a lot of timing and mine should have been 28°. He has since done a mail order tune and his tune removed 4° at WOT from 3k onward from 28°. I did not pull my plugs (br7ef), to check as I don’t track and it’s just a street car running a 100 shot occasionally from a roll. I could find a place and do a launch to 1/8th mile mph if necessary to check plugs but I’d probably have to leave in a hurry and not have time to pull over after an immediate shut down 😆 With all that said is there a max timing I should have it set at other than my 26°? I have hptuners arriving any day now so I’ll be able to monitor KR and log but I prefer safe. I also have an ln2000 I can pull more timing while spraying if necessary. Don’t think I’ll spray a 125-150 but it’s not off the table either. I’ll also be picking up a wide band. Thanks!

 

If you have an lnc2000, then I would have your tuner leave your timing alone, and use the lnc to handle the timing.

 

There is really no set timing amount to pull based on shot size.. The old "2° per 50 hp worth of nitrous is kind of crap" and can put you in a bad spot. The timing a motor wants/needs is dependent on fuel and the heads. A more efficient head/combustion chamber will need less timing as compared to a less efficient head.

 

I think I’m going to do like said and put the timing back to stock at what I believe is 28°. If anyone has an earlier LS c5 and could verify that would be great. I’ll use the lnc 2000 for retard purposes however what gets me is the starting point. I know the old 2° per 50 rule is kinda crap but at least it was a baseline of sort. Having mine setup for 24° sounds safe to me but it may not be. Some say you can’t tune nitrous on a dyno and in don’t have a place to make a run and immediately pull over to check plugs. Maybe at some point I can get to the track but without all of that how does one know? Measuring KR could be a disaster waiting to happen. Idk, I’m open of options lol.

edit: I’ve noticed a shift in tuning since the last time I ran nitrous (like 20 years ago). Looks like things are less timing and leaner now. Is there an afr that I should be aiming for? General of course. 12.5?

 

By pulling plenty of timing and setting the afr at what the motor runs at, or just barely richer, you'll never hurt the motor.

 

Perfect and what I was looking for. Since the 2000’s were timed a bit aggressively I’ll knock another 2° off and have it at 22° while spraying. My hptuners arrives tomorrow and I’ll log some WOT and part throttle/idle once I figure it out. I’m running br7ef’s and my idle isn’t as smooth as it used to be with stockers so I’m sure I’ll have some work to do to get them to run better also.

Since I’m green with hptuners I’ll probably leave the tune alone until I’m a little more confident and just pull another 2° with the lnc2000. I’ll work with my tuner too to get my feet wet. Thanks for the help!

 

Not sure I get the logic here. You have a device to pull timing when nitrous is active. Yet you are driving around excessively retarded and pulling more timing? Why do you want it at 24*? Where did you pull that number from?

Most of the standard LS stuff Is happiest around 28*. It will vary the more you rev it and “upgrade”. But I don’t think you want to drive around 24*, then pull 2 more degrees? If you run decent 91-93 octane, I’d set it at around 28* from 5k to redline. Pull 2* with the n20 activation and call it good. You are likely costing yourself 15-20+hp with the current setup. If you wanted to be super conservative. leave it at 28* NA and pull 4* with the N20... then read a plug and bump timing back in it until the plug ground strap reads happy.

 

Ok let me try to answer all of this. The tune was done before I had the lnc2000 to pull timing. It was tuned by someone who’s been tuning LS for a very long time and active on many of the forums. The 24° was partially from the old starting point of 2° per 50 shot. I did not have hp tuners at the time so I just ran with it. The extra 2° (total 22° with the lnc2000 was that 2° per 50 when running a 150 shot). I’ve been looking over all the stock timing tables for c5’s throughout all the years since purchasing hp tuners and 97-00 have 28° while 01+ are down to just 17°. I know they have the ls6 intake on them but not too much more so I’m not sure why they’re even that low? Possibly some other timing modifier that adds on top of that which the earlier years like mine don’t have? I’m not really sure on that one.

Anyway I just finished my VE table and going to scale the MAF next. I’ll more than likely bump my timing back to stock and use the lnc2000 to just take 4° when spraying. I have to find some time to hook a meter up to it to verify it’s pulling timing as it does not log it. The ECM doesn’t know that it’s modifying timing which is a little annoying but nothing to write home about.

 

I'd log the total timing and verify. There are many parameter that change timing. So while it may state 17*on the map for the 01+, I can’t imagine that’s the actual total number. I’d assume other tables come into play and add to that 17* base number. IE coolant, IAT, maf loads etc. 17* is likely the base timing it reverts to if there is a problem. CEL etc. Where the older models didn’t have that ability.

 

Right I can’t imagine that 17° is total and I’m sure like you said it’s modified by something else. Mine is stupid haha. I do log timing and will have to go over those too. Life is so busy anymore it’s crazy. I only ran 2 bottles of nitrous and I’ve been sitting on one now with like 3lbs left. It’s $16/lb here so it’ll be a while until I fill it anyway. Thanks for the help too. Appreciate it.