Head flowing

building my first blower engine and confused on what to do with heads.
eng. specs;
11.8 to 1 comp
736 lift rollor cam
12-71 alcohol blower[25% od]
enderle "big&ugly" injector hat
mallory super maglll
enderle 110 pump


the heads i have are bordix 2-plus;;should i spend the $1000 to have heads flowed or save my money?i'm on a very tight budget but don't want to cut corners either.how much advantage will this $1000 on heads give me..i think i already know answer but would like to hear from experiance blown alcohol engine builders.as i stated--first blower and first alky engine.

 

The best bang for your buck is in your blower. Spending that $1000 on a bigger and/or better blower will gain you far more HP than a port job.

Once you have a running engine, you need a properly tuned fuel system to maximize the power potential of those parts you've already paid for.

 

I agree if you feel you are short on air spend your money on the top. 30% wont cost much more

 

Save your money and put it into completing your ride. You can always spin the blower faster for the price of a pulley.

 

update on engine specs that may or may-not make a differance.it is a 540bbc[4;25 stroke and 4.50 bore]11.8 is my static comp before boost and below is cam card specs

 

I think you will be plenty happy with the HP you get out of your combo no matter what head you have on it. What kind of power are you trying to make? How many rpm are you going to turn?

Your cam is just a touch short of where mine is but I dont think thats a big issue.

 

i'd like to see around 1200hp. if possible without hurting parts.but know how hp. is the more the merry but don't want it where i'll be taking down everytime i run it.just want to play hard..have fun..not be embrassed to run it..

 

I would think that setup should be good for at least 1400hp, now keeping it happy is gonna be your job. There are alot of high power cars out there that are fairly maintaince free, if built right yours should be too.

 

A good fuel tune up is what mostly keeps them "Happy"

I would use a 990 pump because that's what I'm used to, although I'm not saying a 110 won't work. Somewhat depends on how good the 12-71 blower is that you have. Can you explain it a little? pie shaped exit, large opening, etc??

 

it is a old style std large opening with std rotors.just got it back from littlefield.so it is a new fresh blower.mounting on a BDS tented comp. intake with injector ports but haven't plained on using them unless it is needed.do plain on sending complete fuel system in to be flowed.

 

I use the 110 pump, no loop, .096 pill, gets me 130lbs fuel pressure with my nozzles. Im using a 28% over 871. I agree with SoDak big pumps are good don't short yourself on fuel.

 

hhhhhhmmmmmmmm

Me and a buddy of mine were just debating this same scenario. If you had the same bottom end, same blower, same hat, same O.D., compression....etc... blah blah blah, How much are good heads really worth on a blower setup? Lets say Big Chiefs that flow 540cfm vs Dart 360s that flow 440cfm? Would there be a change in boost levels for the less restrictive heads?

 

Theres no doubt better flowing heads will make more power. But for me a pound of boost is worth about 20HP, I don't know how much head CFM (on a flowbench)it takes to make 20 HP??? But I think it takes a lot of CFM increase???
Your biggest gains are in blower and fuel system.
I am now playing with heads/intake since I think I'm getting maxed out in the above. But I don't yet have dyno data only track/fuelflow data.
This weekend will be the first on the new intake/head combo on top of a new short block. I guess we'll see if it burns all the fuel I give it

 

Boost pressure is the air that isn't going into the motor, so better flowing heads would read less on the boost guage because more air going into the cylinders.

 

So you could make more power with less boost with a more efficient head design? That makes sense.

 

Thats a proven fact, a better head makes less boost and more power.

 

And a smaller engine makes the head and blower more efficient

Personally I would use a bigger pump than a 110 on that set up.

I dont think you should have a problem making 1200 hp

 

We use the 110 pump on 517 BBC with a 14-71 turning at 38% & 28 lbs at 8000rpm in a circuit boat with no issues. If you run a 990, will you run a pump loop or sizer ? If so,why do you do this? Dont they make all the different size pumps so you can fit the right one?

 

Yes, but I look at it this way...

If you need to decrease the HP in the lower RPM range (for traction control, drivability, etc) the extra fuel is available to do so.