50% Nitro Blown - BAE 526 PM

A quick question if I may......

A friend is contemplating 50% nitro for his Promod for ADRL next year. His current deal is a Promod legal 526, 14-71HH, BAE, hemi deal. Any suggestions regarding how much to cut back the static compression? We are assuming that the static compression will have to be cut down, or are we wrong in this regard?

Any suggestions would be appreciated.

 

I think you need 50% to see much performance improvement and have to really cut back the compression. My guess is the most you want is 8:1 and take out the transmissionor hi gears and 2 speed.

 

this might give you some ideas http://fuelinjectionenterprises.com/nitro_new.htm

 

This seems like some good info but deals mostly with n.a. motors. On the blown deal, I think if you could get away with loading the motor hard, ie high gears, slider clutch you'll want lots of fuel pump and a bdk valve. Just a guess but say 30some gallon use most of it at the hit, like a pump shot, knock it back at say .8 second and roll it back in going on down the track. Sounds like fun!!! Dont forget big ass wrist pins.

 

50 %

it is a major change to do this and the only aplication is pro extreme. operating costs are many times higher. MANY!!
24 to 28 gallon pump. bigger tank. 7-9 gal per run. coated pistons. more pistons to replace burnt pistons. change oil and some bearings every run. stainless ex valves as ti burns w/ nitro. about twice the nozzle area and a few degrees more timing as nitro burns slower. (but it does burn everything)
35-40% more power is possible, but hard to use. much cheaper to buy a good screw charger like most others.
3-5% will crisp up an alky motor a few hundreths and is easy. anything past 12% needs coated pistons to avoid piston and sleeve damage.
if you really want to do 50% and can afford it, i could be hired to help make it work. the screw is still cheaper and a lot less work.
chuck

 

Another mag? If you go with the screw get the gizmo. 80 over drag boats doing 5.11 217.

 

I am currently running a 511" blown hemi with Walt Austin heads on it, 8-71 Hi-Helix at 70 over making 42lbs of boost, Enderle 1100 pump, 9.9:1 at 30% nitro, and can change to 8.9:1 for 40% nitro. I also run this with a lencodrive 3 speed and 3.90 rear gear.

Around 8:1 is the most compression you would want to try. Now the tuning window for these medium amounts of nitro is actually large as far as burning the motor up. However if you are a little too lean you will beat up the pistons and rods. Case in point...I ran my last 2 races at 30% nitro and nipped 2 plugs just a hair. We fattened the motor up and the car ran great. Hell I qualified number 2 at that race. Well the car ran great at the next race so we thought it was all good. Nothing looked burnt or hurt, but the pistons were collapsed .015"-.016" because of how lean we were. If the compression was lower we probably would have gotten away with it, but the performance would suffer. So while I said you have a wide tuning window, you really have a narrow window to keep the motor happy. Now I have a bigger pump on coming so I don't run into this problem again. You would really need a Waterman Red pump or equivilant to get enough fuel in the motor.

 

TOL
This is the way I see it. NHRA/IHRA is your grandma ADRL is your grandpa. Why use grandmas combo at grandpas race? Why would grampa suggest 50% if he didnt want you to try it? 5%-10% probaly would wake it up a little, maybe .05 second. 30%-33% you have to change pistons/coated and or rods to lower the compression. Its sort of a give and take though, look at nitro coupe not any faster than IHRA at the time. Except for a couple cars. Rumor that Bill Kuhlman was cheating when he ran 6.01 and when he burned his car to the ground tank inside a tank or something. Another concern when using very much nitro. BIG FIRE SYSTEM!!! funny car style.
Please post or pm me if anything comes of this as it is very interesting.

 

nitro

How would a screw blower work with nitro? say 5-10%?

Sean

 

Id say why not you might need it.
http://www.promodzone.com/showthread.php?t=15494

 

Finally. Some new ideas . I will predict that A/PM will not be as quick/fast as PM for quite some time to come.....