What air fuel ratio's are your cars tuned to on C16 and high boost (25-30psi) I've seen cars tuned in the 10.8-11.0 range and others tuned in the 11.5-11.9 range.

Also, let's say you are at 4000rpms and floor it in 3rd gear. What air fuel ratio's do you see until you hit full boost.

Thanks,

Anthony

 

If I understood what you asking then anywhere from 13.5 to 14.0 at no boost to 10.8-11.0 at full boost.

 

Thanks for the response Crispeed.

The 2nd part of of the question was basically what air fuels do you tune for going up into the higher boost areas. Keep in mind I'm running pure C16, not mixed with 93 and 10.5 plugs. What do you think of the air fuel ratio's below?

0-10psi - 12.0-12.5
10-15psi - 11.7-12.0
15-20psi - 11.5-11.7
20-25psi - 11.1-11.5
25-30psi - 10.8-11.1
30-40psi - 10.8-11.0

Anyone else? Even if you don't tune your own car please chime in as well with what A/F ratio's you see on your car.

Anthony

 

12.0@27psi

 

12.0.1 across the board up to 32psi

 

I've also spoken to a few others about this and it's funny how everyone is on one extreme or another.

Some tune to 10.8-11.0 and others to high 11's or 12.0 Even in NY, some of the tuners are in the 10's and others closer to 12.0

I guess it's just a matter of preference. Thanks for the responses.

Anthony

 

*

 

I did a bunch of dyno testing/tuning on my turbo car a couple of years ago, and I used a really cold spark (NGK 13.0 Heat Range) with VP C16 with very good results. At first I ran the stock GSL-SE style plugs with pump gas, and it made decent power, but when I changed to the colder plugs, and the C16 fuel it made a huge difference. After all the dyno time, and testing I did we ended up with 11.1 to 11.5 AFR, and made reliable horsepower with no problems.

There were a couple of problems we did notice when I started tuning the car with Race Gas, and the colder plugs it burned the O2 sensor out very quickly. My wallet was also much lighter after the cost of that damn fuel. Works well, but very expensive compared to pump gas.

Good Luck

 

Anthony, most tuners will tune a car a bit richer for the obvious reasons.
Since you tune your car and have access to a dyno aim for 11.0:1 A/F @ 30psi and slowly lean it out depending on hp gains.
The proper way is while on a dyno, monitor both A/F and EGTs and make adjustments based on the gains/ losses.
11.5:1 A/F is the number I'm conforatble with on most set ups.

 

Good topic Anthony, now what about timing can we get into that subject or is it still a touchy subject with most of the tuners?

 

Another point also just don't go off of what's done on the dyno.
Actual load on the street or track is much different.
EGT's play a much more important role on the street or track especially under heavy load for instance in 4th and 5th gear.
You can tune for a certain A/F mixture but your egt's might still sky rocket so you have to compensate.
My tuning setups are done to be very safe in the knock zone of the rotary. I always run richer and more retarded in that zone. It works very good for me especially when you're pushing the limit of pump gas.

 

Anthony,

10's with C16 is way too rich...
i would tune it to 11.5 and you would still be very safe.

 

Their's nothing touchy about it... Every car/setup is different.
you want it tuned properly you bring it to a dyno with the proper equipment.

 

Yes, I agree mainly on rotaries !!!
My 11.5:1 A/F is on C16 and on the street, since that's how I do most of my tunning.
I've see many tune on the edge on the dyno then blow the motor on the 1st full boost pass on the street or track.
On pump gas I have no problem doing 3-4-5th gear pulls @ 20psi but with a 10.8-11.0 A/F. That extra fuel helps keeps things under control.

Anthony, start rich and work from there with caution....rather loose a few hp then have the tune in a danger zone.

Good Luck
JD

 

I see some of the hardcore guys sharing information, VERY nice!

 

tuning AFRs isn't all too difficult, tuning ignition is a bit more complicated.

 

Can we get into ignition/timing? I know timing should be done on a dyno but not everyone uses a dyno to tune there FDs...

 

Well, if you want the proper igniton map for your engine and mods the dyno is the key.
What may work for someone's motor may not work as well with yours.
Same goes for trailing split.

JD

 

JD, please check your PM's.

 

I think what people are asking is how to identify when to add or remove timing while tuning

 

I dont' know what you want to hear then...
your going to need some method of measurement.

If your a consistent driver you could do it at the track for wot only, your still going to need a dyno for all other sites.

So in the end if you want a properly tuned ignition map your going to need a dyno.

 

This is exactly what i'm asking about. On the dyno where can we see when to add or retard timing to get the best results for each setup? Maybe someone can lead me to a nice article/thread on tuning for split and advancing/retarding timing.

 

What octane are you using for 20psi on pump? And are you using any added injection such as water, alcohol or meth?

 

I can probably answer corectly to say that he's using 93 octane with no additional power adders or knock prevention devices. I know this because my car was tuned by him and I've seen up to that much amount of boost with no detonation or pingin as well on 93 octane gas as well, motor is still alive and ticking years later. I will say that when tuning on pump gas the key is to be safe with the A/F ratio, my car will dip into the 10.9s at peak hp/tq/boost, but I know it will live to see another day, leaning it out a bit isn't worth gambling on your engine.

 

John is old school like myself. Running 20 psi on pump gas is the norm around here for we old schoolers!