Optimum A/F Ratio

[Newbiewan]

OK for all you 1MZFE tuning experts out there...
(Assuming stock heads and internals)

1. What's the best A/F ratio for Max Power?

2. Does this vary significantly with RPM?

3. Is this A/F ratio to close to detonation to be safe for a daily driver (92 Octane) , if so what is a good compromise A/F ratio?

4. How did you come up with your answer? (Actual dyno time, seat of the pants dyno, just a gut feel, etc)

[wiz2]

This is off topic.
Your car kicks azz. Very well done !! Hope I can check it out the next time Im in ATL.

[StockSolara]

I know some people are running 11.5:1 I don't know personally cause I haven't tuned my car

[Akfahad]

right now, I'm running 12:1 ratio (which gave me 286 whp on the dyno with 6lb pulley)...that was based on others recommendations, however as people started to learn more, I think the optimum A/F ratio is in the 11's I think. Hopefully Joe will hop on and answer your questions ten times better

Josh

[DatSRBoi]

Doesnt it changes in different rpm range and throttle? I think its 12:1 too. Thats what I see allot of people do on the dyno tune.. hearing them say allot is it running around that and all...

[Newbiewan]

Good stuff guys...keep it coming.

BTW...I shared the news about the Supra TT MAF mod offered on this forum with the V6 guys on the MR2OC and MR2Board forums. It's great getting to benefit from parallel development from two different car camps!

I will probably wait and see if I run into the same tunability issue at high RPM's before I slap on the Supra MAF (I have no reason to believe my car will be immune, I just want to see exectly what the differences are)

Akfahad - 286 whp sounds amazing for 6 psi! I think that a couple of MR2 guys have dyno'd their setup at 4 psi and are running (220-230 rwhp). I suppose that the combination of optimizing the tuning w/ the piggyback AND the 2 psi increase in boost can really make a difference. I'll let you guys know what I end up with. I am doing a basline dyno soon and then I will be doing periodic dyno runs between mods.

wiz2 - let me know next time you are in town and I will be happy to show you my baby

[JoeB]

My car has had a LOT of dyno time. When I was running stock internals with stock 10.5:1 compression, I found the best safe power at about 11.8:1. The dyno testing is different for manuals and automatics. Where with a manual you can roll it into 3rd and start the test at a lower RPM flooring it, you can't do that with an auto. With the auto, you have to get it up to about 78MPH before flooring it or it will just downshift into 2nd. The problem is, the RPMs start higher and it is more difficult to see that portion of the RPM for tuning. Plus the transition from closed loop to open loop happens much later doing it that way so what you see is a drop from 14.7:1 to the desired AFR later in the RPM.

Of course that is only dyno. I have TONS of money in monitoring/logging equipment and do a lot of my own tuning. I can get a better tune for the lower RPMs doing 1rst-3rd pulls on the road and recording it.

By the way, the 11.8:1 number came from a tune that Pual Efantis did for me. If you don't know Paul, he is the owner/driver/mechanic for the worlds quickest street tire Supra (now being driven by his brother Krys) and Pual now has the Lucas Oil sponsored Solara.

The tuning was with 93 octane pump gas. I like to have the AFR drop down to that point from about 12.5:1 at 4000. I like it richer near red-line. Lots of tuners just like to use the standard 12.5:1 as a general number but our car engine seems to like it a little richer up top. -JoeB

[Newbiewan]

Thanks Joe. How do you like your Innovate Motorsports setup? I just installed a LM1, AUX Box, and XD1, but had to send back the AUX Box b/c I managed to scramble the firmware. I can't really start playing with the tuning until I get it back.

[JoeB]

Thanks Joe. How do you like your Innovate Motorsports setup? I just installed a LM1, AUX Box, and XD1, but had to send back the AUX Box b/c I managed to scramble the firmware. I can't really start playing with the tuning until I get it back.

The Innovate is an AWESOME setup!! That's the same setup I have. If I could figure out how to get it to log timing, it would be PERFECT!

By the way, I haven't said it yet but welcome to Solara Guy. I really like what you've done with your car! -JoeB

[gLok]

Just to be safe, i tune mine to 11.5 to 11.8 using a plx R-500 wideband. Im running a 2.6" pulley right now on 93 octane.

[SC V6]

I;'ve got a supra MAF setup for sale if you know someone who wants it