GT-ER

Jerry has been continuously reflashing my car for the past few months so that I can get my tune as perfect as possible before I head off to the dyno and the track. Street tuning is the best there is I'll tell you that...

Anyways, My car is currently running mid a 11 A/F ratio and pushing a max of 14.5psi. My ECU is commanding 20-21deg all the way to redline ( only drops when the car upshifts ) and I get ZERO deg. of timing retard.

This is on 93oct and the ambient temps at 95* with my IAT's going from 100* to 150* by 120mph.

How does all this sound to you? I find 21* to be pretty decent for pump gas and even though I see no knock I'm kinda wondering if anyone thinks that advancing timing even more would be a good idea.

Thoughts?

whipplem104

I was wondering what the optimal timing on these engines is. I can not believe that the combustion chamber is so inefficient that more timing is required. I know for instance that the two 4 valve motors I do tuning on, both boosted, one is an Audi an one a Mercedes tend to like around 15-18 degrees of timing and really stop making anymore power above that. This is where the dyno comes into play big time.

adianaty

21 is way good. Peak power for me came at 19 with a 180 pulley and 91 pump. Remember these cars are ultra sensitive too it due to our crappy pistons so you shouldn't push it. Not to mention the gain will be small considering the abuse the motor will take with the increase in cylinder pressure.

GT-ER

This is exactly what I'm thinking. I'm want to know what other people run to see if I'm far off.

cij911

Currently I am seeing 19 * max, but I am on 91 octane...I doubt the 2* difference seriously makes more than 5 or so hp. Frankly I would rather run conservative timing map and run more boost.

I am surprised you are seeing 14.5 psi, I believe my 175mm is more like 13.x psi peak and more like ~ 12.x .

layzie12g

What program do you guys use to log? Do you need the STAR tool?

GT-ER

I guess I can agree to this.

I'm using Auto Enginuity.

99lightning

are they ramping the timing or locking it throughout? what is the timing at lower loads? thats what makes the car feel good too the part throttle spark with some boost but not floored.

cij911

No, it is not a steady 19*.....The EC tune is very smooth and appears to ramp similarly to the factory.

To the person who asked about logging - I use the Innovate LC-1 (wideband) & OT-2 (OBD2 logger).

skratch77

Iv been running stock timing for a while now,Im down from 600ftlbs in the low end to around 530-540 but my car makes power till the rev limiter.

On the street I can beat the hell out of it and I never feel heat soak even in 90d weather

My latest dyno and Im looking to up to a 185 and see how it looks,I finally got the low end a/f perfect also

Aknight was there when I had this run done and he can vouch that I litterally drove an hour to get there and right when I pulled into the lot it was my turn to dyno and this was done 100% heatsoaked with zero cool down.

GT-ER

How much is stock timing?

Toadster

mine was 20-26 today - but it's 105 outside, and IATs were about 126!

cij911

No way in he<< that stock timing is 26* at redline on 91 pump under WOT (full load)...

GT-ER

You must be talking about part throttle, I'm talking about wide open throttle.

Toadster

Yes, sorry should have stated that... First day logging and it ended up being 108 outside!!!

PACougar

That's weird, I haven't noticed any heat soak

Toadster

LOL you're cheating! (um, winning!)

Exotic-metal55

Those are great numbers and I would not add more timing. Timing should drop some at 140 deg iat as well. Most cars even in great cold conditions pull timing over 19-21 degrees.

How are you logging knock retard?

You guys seeing 26 degrees, please remember that we are talking numbers at wide open throttle , not part throttle. You can see 30 deg at part throttle, if you look hard enough.

99lightning

any push it on a race tune to see what kind of power say with 104 unleaded race fuel?

Bramage

18-20 seems to be the sweet spot. On 91, the best power is found right about 19. When you go up, power drops off.

I did a race tune that used 21, but again, as soon as we added timing, we dropped off on power. So I guess the moral of the story, at least for these cars is "less is more"


I see maniacs running 28+ degrees on twin turbo motors, but that just does relate to our configurations.

skratch77

my car loves 17-18 and we upped it from 16 at around 5.5k to 18 and you can see the dip in the graph and it litterallay just keeps making the power to redline and zero knock

GT-ER

I'm logging it with auto enginuity.

Here is an interesting bit of information. My car used to be running at mid 9's A/F ratio and I would be seeing anywhere from 4-6* of knock retard. AS soon as Jerry pulled fuel out and I got into the upper 10's my knock retard completely disappeared. Just to show that being to rich can also be a bad thing.