Timing Advice

[ngc1068]

Hey guys, I have a 2.9L Whipple on an LS3. Its a Chevy SS. It has the 4.000 pulley. I have Doug Thorley Tri-Wye Headers and DSX aux fuel pump.

I had it professionally tuned and ran on a Dyno. It put down about 490WHP and 490Ftlb of Torque at WOT and 6500. It is logging around 8psi of boost, or 154kpa on the MAP.

I see on a few websites a Whipple pulley vs boost chart for the 2010 Camaro SS (I think should be similar for my LS3) and it shows around 565RWHP at 18deg for a 4.000pulley and 9psi. Even at 7.5psi, they show 545RWHP.

I don't see any KR in any of my logs. The tune is commanding AFR of around 11.5 under PE and delivering within a few % of commanded out to redline.

Should I be looking to command a little bit leaner AFR? Should I be expecting more HP? I am not a HP, dyno number obsessed person, but it seems like I'm quite a bit below "normal" for my setup?

I've never actually done any timing tuning, but I'm nowhere near seeing the 18deg in the table. My log shows timing advance never more than 14-14.5deg from 3000 to 6500rpm.

Any thoughts appreciated!

[kingtal0n]

leaner isn't meaner

and never push timing unless you have to for some reason, for example if the EGT seems like its rising very quickly during a WOT pull, you might consider trying an extra degree or two to see if it helps keep the EGT down. If not, take the timing back out and use water injection to bring EGT down instead (the right way).

[5FDP]

That fueling is safe. Sometimes it's better to be safe than it is to go for every last bit of power. Often times engines can make more peak torque at a richer air fuel ratio than at a leaner one. Of course this testing is best done while on the dyno to see where things end up.

So changing the commanded value to something like 11.7-11.8 may or may not do much.

That timing is also very safe. Likely why it was left there. Hard to know how the shop ended up there. They could have taken it slow from say something like 12 degrees and went up from there. Watching horsepower/torque increase per degree of timing. Then once they got over 15-16 degrees the gains were less and less each time, so they dialed it back to 14ish degrees. Or they just slapped it with 14ish degrees and called it good LOL.

I'd say feel free to play with it. Add a degrees or two, see how it reacts. It's not the most scientific way of doing things but you could watch some of the horsepower/torque based channels in the scanner to see if doing certain things shows a result there.

[SultanHassanMasTuning]

we all have different methods of tuning, but usually more manufacturers advertise on 93oct

depending on the quality of your fuel will dictate your power and how safely you can reach it.

[asquinton]

The hp seems a little low but dynos are all over the place when it comes to hp (assuming aftercooling). It may be a conservative dyno. My '05 NA 6.0 LS2 GTO put 440 hp to the tires on what I've been told is a conservative dyno.

If this is not a race car, I'd limit timing to 15 deg under boost on 93 octane at 8-10 psi. Timing above that can be a problem quickly if you have any issues. Your 14-14.5 deg timing feels right to me. 11.4:1 A/F is right on as well in my opinion. You can chase numbers but things can go south quickly with detonation leaner and more advanced.

Dynos vary but the ET tells the story. Is the car slower than expected?

Good luck with it!

Hey guys, I have a 2.9L Whipple on an LS3. Its a Chevy SS. It has the 4.000 pulley. I have Doug Thorley Tri-Wye Headers and DSX aux fuel pump.

I had it professionally tuned and ran on a Dyno. It put down about 490WHP and 490Ftlb of Torque at WOT and 6500. It is logging around 8psi of boost, or 154kpa on the MAP.

I see on a few websites a Whipple pulley vs boost chart for the 2010 Camaro SS (I think should be similar for my LS3) and it shows around 565RWHP at 18deg for a 4.000pulley and 9psi. Even at 7.5psi, they show 545RWHP.

I don't see any KR in any of my logs. The tune is commanding AFR of around 11.5 under PE and delivering within a few % of commanded out to redline.

Should I be looking to command a little bit leaner AFR? Should I be expecting more HP? I am not a HP, dyno number obsessed person, but it seems like I'm quite a bit below "normal" for my setup?

I've never actually done any timing tuning, but I'm nowhere near seeing the 18deg in the table. My log shows timing advance never more than 14-14.5deg from 3000 to 6500rpm.

Any thoughts appreciated!