hp estimates 509 bbc blower motor

[taps]

i am building a 509 bbc blower motor trying to make `1000 to1100hp,here are the specs give me some estimates.dart block steel cap,4.5bore ,4"stroke callies crank,6.385 eagle rods l19 bolts,crane 714-714 lift solid roller [email protected],114 lobe sep.afr 335 full cnc i think they flow i little over 400 intake,bds stage 2 871,2 1090 dominators on race gas,have pulleys to make 10-15psi boost.flat top piston,122 chamber..give me some suggestions and hp estimate.

[wizbang]

I did a 572 back in 1995, made 975 hp @ 6500 on pump gas , 14 lbs, EFI and emissions legal in California. I did the dyno work in Huntington Beach on Pfaff's Dyno.

4.5 bore
8.0:1 dish
4.5 stroke
STOCK 076 GM aluminum head 2.19/1.90 , they were port matched, but no port work done.
Crane .708 lift, 274-280 @ .050 110lc
BDS manifold
10-71 Mooneyham
Bird with 16 nozzle EFI , Lee Performance ECU

It made equal torque also.

[OneBadGMC]

i am building a 509 bbc blower motor trying to make `1000 to1100hp,here are the specs give me some estimates.dart block steel cap,4.5bore ,4"stroke callies crank,6.385 eagle rods l19 bolts,crane 714-714 lift solid roller [email protected],114 lobe sep.afr 335 full cnc i think they flow i little over 400 intake,bds stage 2 871,2 1090 dominators on race gas,have pulleys to make 10-15psi boost.flat top piston,122 chamber..give me some suggestions and hp estimate.

I'm going to guestimate 700-800 crank HP.

Hard to get to your goal with a small blower and carbs.

[wizbang]

I totally agree on the lack of air from carbs. A Bird is like 4500 cfm or something.

I also, no offense, wouldn't try it with the BDS blower. It is a street car blower, not something you want to use if your looking for boost.

[taps]

i had a simular combo in my beretta 2500lbs with me it went 162 mph best hp calculater says about 800hp,that was with same carbs and blower on 468 with 630 liftcam and stock rectangular port edelbrock heads,i was hoping this motor would be better.

[OneBadGMC]

i had a simular combo in my beretta 2500lbs with me it went 162 mph best hp calculater says about 800hp,that was with same carbs and blower on 468 with 630 liftcam and stock rectangular port edelbrock heads,i was hoping this motor would be better.

The motor isn't the limiting factor, the blower is. A blown motor will only make what power the blower pumps through it. The smaller the blower on a larger cubic inch motor, the faster the overdrive has to be to pump more air.

Pumping more air, less efficiently means more heat in the intake charge because the rotors are beating the snot out of the air. The more the air is heated, the less that gets into the cylinder...

It all comes down to the blower. If you left the carbs and blower alone, and increased the motor under it, chances are it's not going to be any faster than before.

It would be a LOT faster if you put 2 alky carbs on it, simply due to changing the air intake temperature.

[taps]

i agree with air temp and air density issues,but not having run the blower more than than 14 over i dont think i have reached the limit of the blower yetand as you know a better breathing motor does not bhave to make the same boost to make the same power.thanks for your input i will post how it turns out.

[OneBadGMC]

Keep in mind that when you get past 15 PSI at 7000 RPM those carbs will be choking the power.

[kwkracing]

After reading this, i guess i feel lucky my steel headed blown bbc 468 made over 1300hp at the crank. Your main limiting factor is boost and static compression thou.

[OneBadGMC]

http://www.yellowbullet.com/forum/showthread.php?t=154775

Another thread just posted regarding a similar combination...

[taps]

found a formula to figure cfm on blown motors,when i did the numbers on my combo i came up with 2318 cfm for 509 running 7800 rpm at 15 psi boost.

[OneBadGMC]

[(CIDxMax RPM)/3456] x [(Boost/14.7)+1]=CFM Required

That formula?

Didn't you say you had two 1090s? 1090 x 2 = 2180?

As long as you keep it at or below 7300 @ 15 PSI you won't starve it for air. Thats the point at which those carbs become your power restrictor.

[taps]

the carbs are king demon rs i am going to change to the 1195 venturi and recalibrate.that is the formula i used.any thoughts on jetting and timing,what about a boost timing master?

[OneBadGMC]

the carbs are king demon rs i am going to change to the 1195 venturi and recalibrate.that is the formula i used.any thoughts on jetting and timing,what about a boost timing master?

Jets, no clue. Maybe 80 square in both carbs?

Timing, start at 30 and read the annealing mark on the ground strap. Closer to the plug base, the safer the tune and less fuel required. The closer to the end of the strap the more timing and more fuel required. The closer it is to the end of the ground strap, the closer you are to burning stuff up.

Timing retard isn't needed with race gas. Taking timing out will simply kill power.

[ashbros]

OneBad

You are hitting the NAIL on the HEAD...........

I have seen so may blower motors choke on the dyno because of the limited capability of air intake when using the incorrect sizing of carbs..

When you fire them up you can actually hear the motor trying to breath & it just can't.

I can't tell you how may blower motors I have worked on that have incorrect carbs on them. Its amazing. Its my opinion that a lot of guys, by the time they are ready to purchase carbs are so tapped out of capital to finish their build that they purchase what they consider a reasonably priced set of carbs for their build based off the information from an inexperienced sales rep on the other end of the phone line...

In the back of their mind they are thinking I still have to buy plumbing, regulators, fuel pressure guages, braided line and fuel pumps. It's quite a heavy burden for the budget builder who's looking to tear up the streets or have thier day at the track...

Bottom line is; "Most guys just don't know", but thier ride looks bad as all get out with dual carbs & that massive blower sticking out of the hood.....

I had a similar build on a 515 BBC on Pump Gas 8/71 and only 5 lbs boost. With a healthy set of Jimmie Evans blower carbs on the motor I produced 789 hp @ 7400 rpm, I jerked the carbs off and swithced the motor over to injection , 851 hp at 7200 rpm. Go Figure...

[OneBadGMC]

Ya know, looking at the original parts list again...

If he ditched the gas carbs, got a good blower, mechanical injection, and added more boost, the HP numbers could go from 700-800 up to double or more.