Need a rough timing estimate comparison.

[slowgsr]

s258, stock motor, arp headstuds, 94 octane, 75/25 meth/water, aem ems.


Hi, I had my car 'tuned' last year.. I made less than good numbers. I installed a bigger turbo and retuned the AFR's myself, and now its better (old turbo blew), and my timing LOOKS very conservative.

Heres what I got.. (I wish i could post a screen shot). I run around 24lbs and trap 118mph in a 90 tsi. Car went 12.2 2nd pass..

I wish I had a screen shot but I don't so please just let me know what you think roughly.. seem very conservative to me.

Im using stock knock, i plan to upgrade to a 2nd gen w/ the aem ems, it works wayy better, the 1g isnt sensative enough.. so keep in mind i can't properly detect knock other than checking plugs. Once i get the 2nd gen knock sensor in (few days), I will tune timing for knock basically and keep my current boost level because i feel this is way too conservative and killing my power.

at 19psi. I see 15deg from 5000rpm to redline straight across.
at 22psi. I see 11.8deg from 5000rpm to redline straight across
at 25psi. I see 9deg from 5000rpm to redline straight across
at 28psi. I see 7.6deg from 5000rpm to redline straight across


before 5000 i see a slight increase, but I never see that boost before 4200ish anyways.

down at 10psi i see about 19.6deg
and at 16psi i see 17.1deg

The car was tuned to 22psi on the old setup, Id like to see how fast I can go on the stock block though so I might run high 20's.

So whats the best thing I should do here, just get the proper knock detection and just tune for knock? Than set up a safe timing retard incase of knock detection?

Any advice apreshiated!

 

[Black_Bullet]

As much timing as you can squeeze per rpm for the boost level your trying to run. Afr should be between 11.1- 11.3 in my opinion. Thats really all there is to it, youll have to get your feet wet.

 

[whitedawg]

I would say you're limited by the type of gas you're using, even with the meth. I bet if you switched to E85 or C16, you could get your timing numbers in the upper teens.

 

[slowgsr]

Thanks.

Still with a 75/25 meth/water mix and a big jet and 94 pump, @ 22psi 11.8deg just seems so little to me, and at 25psi only 9deg. Just seems very conservative.

I have been doing a bit of reading, and with the 2g knock sensor, 0.5-1.5v on a pump gas stock piston motor seems to be safe knock sensor voltages, maybe even as high as 2.0v some have tuned to.

The AEM seems to read knock different than the oem box, and it will only do what you tell it to and exactly that.. I just have to figure that part out.

My EGT's are also about 700deg C on a 3rd gear pull to 7500rpm.