I could have posted this in the tuning section... but I really only want to hear from those that are boosted. Obviously there is a TON that goes into this... local fuel that's available plays a huge roll.

I don't know that I've ever seen a thread like this on this forum, and a quick search didn't find me much.

So here it goes. First I think we should make some ground rules and require that certain info is shared. If you have any suggestions or stuff I may have missed by all means add it!!

I'd like to see:
How much boost
what type of boost
What type of fuel
target AFR
compression - along with that details about the engine you run... heads etc.
max timing - maybe how that changes with RPM too if that is important

I'll start off. I have a cam only LQ9 (stock heads and bottom end) with LS9 gaskets (should still be 10:1) running about 13# max boost with a maggie 1900. I run 100% VP meth with an alky control kit that kicks on at about 5# and 93 pump. It's hard to know exactly how much meth I am spraying, but I target 10.9-11.0 AFR on the gasoline scale of lambda. I have gotten away with 14.5* of timing at about 3600 and higher and no signs of KR.

I do hope to bump it slightly, but not by much. Maybe 16* or so. I figure why push my luck too far... I'd like to know what others have gotten away with and what others run on a daily basis. As far as I can tell I am safe where I am, but Id rather not find out the hard way that I'm not.

Clearly everyone needs to take the info in this thread with a grain of salt... just because someone else gets away with a certain amount of timing doesn't mean you will. There are a lot of good tuners on here and I figured we may as well have some place to aggregate data like this. Like any other data there will be outliers... please keep that in mind if you go back to tweak your tune. Not that I think there are a lot of people who will do that... but I felt it had to be said.

 

Interesting thread. If i go lower than 14* of timing i get KR. I usually run around 16* without issues.

 

I'm running 21* at WOT running 9-10 psi of boost. I'm running a stock LQ4 long block with 1* overlap cam. I run 93 octane with 50/50 methanol/water being injected progressively starting at 1 psi and 100% @ 8.5 psi.

I will see 0.5*-1.0* change in timing over a WOT run locked in 3rd.

 

Each build will like something different. Mine likes low timing and runs great on it. I savy leave the timimg low and go up in boost, but wuth a maggie, a lil more timing may be your best option. Heat will be your enemy. Pay a lot of attention to the iat pulling table.

 

Hmmm....

How much boost: 21-27psi
what type of boost: s482/96 T6, A2A
What type of fuel: pump 93, 100% meth, plus some c16
target AFR: 0.7 lambda
compression: 9:1, L92 heads, 0.080 gaskets, 22cc pistons
max timing: 18 or so around peak torque, 20 at max power. Usually pull 2 degrees if I dont add any c16 to the tank.

 

Your combo should run best somewhere between 16-18 degrees at WOT. I'd also bet that your IAT adder is pulling timing where it doesn't need to.

 

How much boost: 12psi
what type of boost: turbo, A2A
What type of fuel: pump 93 (No meth)
target AFR: 0.78 lambda
compression: 9.4:1 stock bottom end 4.8L, stock heads, LS9 head gaskets
max timing: 14* right now but haven't pushed it past that. I'm sure it could go


With E85 in the tank, I was running 16*-18* without issue and it ran its *** off. I think AKlowriderZ71 nailed it. Your truck will like 17* or 18* with meth.

 

How much boost: 12psi (14psi spike on 2-3 shift)
what type of boost: turbo, A2A
What type of fuel: pump 93 (No meth)
target AFR: 11.8-12.0
engine: stock bottom end 5.3L, stock heads, LS9 head gaskets
max timing: 14*

there is zero KR with this boost/timing combo. we didnt see any KR with 17 degrees timing either, but i didnt feel comfortable with it that high without meth or e85. even in the southeast texas summer months (100+ degrees)

 

That's a pretty aggressive tuneup.

 

It runs pretty good