fuel curves for blown alcohol

I have a few questions on what you do with the fuel curve going down track
I know for the most part your rich off the starting line to take away some power but if you didnt need to do that what would a typical fuel curve look like would you be leaner in low gear rich on the shift to high . powerglide trans and would you maintain rich right to the end of the track or is there any part of this where you might be leaner etc.. . Our personal experience is the car will run like crazy a little leaner in low gear and likes lots of fuel when shifted to high gear but our mph to the eigth is still down about 5 mph we pick up 43 mph from the 1/8 on which is about right for us but losing from the gear change to the 1/8 . Our 60 foots are good 330s a bit weak but mainly losing our Et to the 1/8 so any wisdom would be helpful car currently runs mid 6.50s at 2450 lbs at vegas altitude . it should run mid 6.40s our mph is only 167 to the 1/8th . we find the car likes lots of fuel lots of timing for high gear but just havent been able to find exactly what it likes between the 330 and the 1/8th . procharger on m5 alcohol 9.5 to 1 compression 420 cu" ford thanks for your help .

 

We run a kam system and everything is fully logged except we dont have a G meter . as boost goes up fuel pressure goes up to accomodated the Extra boost maybe Im asking to much on here without actually being able to see a fuel log of what we are doing . Our system is EFI we have a seperate map we can put in for low gear and hi gear we are close just trying to find the last tenth and it seems to be from the first second shift to the 1/8 mile we shift approx 1.7 seconds into the run . We know the car requires alot of fuel when it shifts or it just lags but still not picking up as much mph as it should to the 1/8th . our finish Line Egts are quite good now below 1100 and its picking up 43 mph from the 1/8th on which is pretty good so really just the one area we need to work on .I guess my basic question would be is after the low to HI shift when we run it rich is there an area in there that perhaps could be a bit leaner or would it require more timing?

 

I run an F3R ProCharger on gas. But it's like Mike says, you'll have to test to find your personal tune up. I can tell you it will most likely want a little less fuel and most likely a little more timing before you get into high gear.

Your 9.5 compression on alcohol leaves a lot of room for more power potential. That could also be hurting you where your trying to pick up.

ProChargers are real sensitive about converters too. To loose and it blows the tires away, to tight and it kills your 60' to 100' times.

Where you have your cam degreed will also be a tunning factor where your trying to pick up.

Blessings............Ron Clevenger.

 

we have found it wants more fuel going into high gear or the engine just flat lines we know this to be a fact for our setup in low gear if we run it too lean it makes stupid amounts of power our short times are very good and we drop about 8 lbs on a gear change we run .983 and 2.74 to the 330 the 330 being a little soft but our main thing is the 1/8th of only running a best of a 4.20 we should be around 4.15 at around 173 to 175 instead of 168 of which we are running now . here is a question we have the abilitly to put in a variable timing map so would putting more timing in at the gear change as it does drop boost be a good idea then take it out variably as engine rpm and boost climbs be a better alternative . our other option is to change the trans from a 1.8 first gear to a 1.69 first gear what are your thougts on going this way? low gear and hi gear in this car are two different animals .Ps what does this hi gear leanout I hear that some of you top alcohol guys run what is the purpose of that and where is it employed during the run?

 

So your saying the 330 to the 660 is where you feel it's soft. I'm wondering if it's related to the engines recoverability after the shift?

Maybe someone can chime in on ...if the 9.5 cr ratio on alcohol would have a tendancy to have a soft recovery after the shift....??

First gear would have the gear/torque multiplication factor to help overcome the low compression, and in high gear once the boost got up high enough it also would help overcome....is my thinking anyway.....??

You didn't say how much or what kind of ignition your running?

The high speed lean outs are related to the mechanical fuel injection. With your EFI and fuel MAP capabilities that's a little different deal.

Blessings...........Ron.

 

A high-speed lean-out is used to take away fuel at high RPM when the efficiency of the intake system falls off. As Ron says, it's primarily used on mechanical injection.

He maybe onto something; your (low) compression ratio affecting engine recoverability after the shift. Do you have some boost/RPM figures you can compare between low and high gears?

Paul.

 

Thanks for your help we think our problem is boost level . Here is what happens we shift at 2.2 seconds into the run boost falls from 45 lbs to 36 lbs and to the 1/8th the car only picks up 300 rpm and 3 lbs of boost to 39 lbs . we fall from 8500 on gear change to 7300 and by the 1/8th we are only 7600 rpm we can either spin the supercharger faster as option one or perhaps put in a looser convertor if we spin the super charger faster we should only drop to 40 lb on a gear change as well as the convertor should become a bit looser as more torque what are your thoughts on this ? the igntion has 8 individual coils its a Kam system and its fully tuneable . Our problem all this year was due to a solenoid vibrating and shutting the igntion on and off we since eliminated that with a master cut off switch to power up the igntion and fuel and that problem has been elminated a simple 100 dollar part cost us two engines live and learn I guess . also in lbs per hour of fuel for lets say 2000 hp and adding lets say 500 hp to turn blower what should fuel usage be is the formula of approx 1.3 lbs of fuel per hp . be in the right ball park?

 

What fuel injection do you run? what does the motor fall at the gear change, I have a small block ford and run a Procharger and we literally have changed 10 converters to get exactly what I want and mine falls 2#'s of boost on the gear change and recovers very quickly! If you want give me a call or e-mail me and I can help you out with a killer converter aracerx41@aol.com
(815)703-4345
AJ Powell