Help with a/f ratio and timing for 30psi & m/i with 118 octane!

[92tsifwd]

I have a 1g and mods are:
580cc injectors, walbro 190lph, 43psi
small 16g ported, exhaust man ported
2.5" o2 housing back (no cat)
2.5" upper ic pipe
1g bov modded
Fidanza flywheel
Awd tranny for low gear & strangth, ACT 2600
2g mass, k&n
2g tb inlet
cyclone intake
methanal injection 300cc nozel running -25 fluid injecting at TB
completely stock long block exept
ballance s/ elim, ported exhaust runners on head
exhaust cam retarded 3.5*

Right now I am running 21psi falling to 18 at red line on 91 octane

My limitation is my stock ic, I was thinking 12.1 a/f & 18* total timing with 118 octane & as high as I can get the boost cause it won't hold it anyway.
I want it to be very safe yet make good power because once I get to the track I have no control over timing & fuel. Let me know any info is good.
So far I have 12.1 a/f & timing is from:
3k 10*
35k 11*
40k 12*
45k 13*
50k 14*
55k 15*
60k 16*
65k 17*
70k 18*

 

[zippyshoe]

If you plan on sticking with your small 16g turbo, I would probably advise against setting your boost much above 21 psi - at higher boost levels, the small 16g is probably working outside of its efficiency range. If you try to run higher boost levels, you will probably shorten the life of your turbo. If I were in your shoes, I would keep the boost at 21psi and datalog carefully to monitor your injector duty cycle and for any knock. Then, you could probably shoot for at least 16* timing and the leanest AFR you can get away with without detonation with a bit of safety margin. If your future plans require 30psi of boost, then I would consider a turbo upgrade.

 

[90laserRSfwd]

great response from "zippyshoe" I agree, don't even bother going over 21 psi. If you want to make some more power on race fuel (this is what I assume you are trying to do) upgrade your turbo like zippy said. what horsepower are you looking to get?

 

[92tsifwd]

Ok, I have been dataloging up to this point runing a 11.1 a/f and 21* total timing I sucsesfully run 21psi daily no knock or problems using 91 octane and meth inj for the record. I have heard of alot of people runing 22-24psi on a small 16g and that is where I heard the little 16g peaks out in efficincy. I have drag radials and barely turn them over on the street aired up at 30psi by the way. They hook awsome! What I want to know is, what is a good timing and a/f ratio to be around for this setup with 118oct? To answer 90laser's question I would like to hit a high 12 sec et or make 350 hp at the crank.

 

[Black95TSIawd]

I wouldn't push the AFR's much past high 11's, maybe 12:1. Even on racegas. Timing is where the power is at. The small 16g is efficient right around 23psi, possibly 24. With a nice racegas setup, I would tune for a 11.8:1 AFR and get as much timing as possible without knock. It probably would be somewhere in the low 20's before knock. On pumpgas, I don't see why you wouldn't be able to run anywhere from 18-20psi with a low to mid 11 AFR and timing maxing in the high teens.

 

[92tsifwd]

Ok, Do you think 12.1 a/f & 18* total timing is going to be ok then? Because I can run 22psi now on pump & no knock with a 11.1a/f & 18* timing with meth inj. I think I understand what your saying now. Basicaly I need to shoot for around 21* timing to make maximum power & might have to run slightly richer to do so, like say 11.8 a/f.

 

[Black95TSIawd]

First of all, 11.8:1 is leaner than 11:1. Not richer. You should be able to run nearly 12:1 with the meth injection. What nozzle do you have and what meth mixture?

 

[92tsifwd]

First of all, 11.8:1 is leaner than 11:1. Not richer. You should be able to run nearly 12:1 with the meth injection. What nozzle do you have and what meth mixture?

(Methanal injection 300cc nozel running -25 fluid injecting at TB)
(I know 11.8:1 is leaner than 11.1:1)

Well, I went to the track & like it or hate it I had a best of 13.84@ 99.89 mph with a 2.07 60 ft. Next time I am getting real slicks and rear shocks!! I spun all the way through 1st and part of 2nd! The 12.1 a/f was way lean and I ended up puting back in the 11.1 a/f & 18* timing pump gas chip. I did however mix 1 gal of 116octane in with 1 gal of 91 & was able to run 23psi but, only for a second and then it bled to 15 by redline. Also my atilag was not working, it was knocking if I let it build boost so I could not leave under boost. I probably should have dialed in my chip for a 11.5 a/f intead of 12.1. But mabey next year with the fresh motor (200,000 miles) & decent ic & full slicks I can get that 12 sec et. I was curious if someone had a calculation of whp with my [email protected] run? Full weight car!