Anyone know the BSFC for a rotary on E85?
 

Anyone know?

I've read that turbocharged rotaries on gas is somewhere in the .77 range, so would adding the 32% make our BSFC around 1.09?

Trying to use the below calculator to figure out how much pump and injector I need for 600 whp.

http://www.eastcoastrollingthunder.c...r/finject1.htm

Aeromotive A1000 is listed at a 700 Lb per hour pump, but I'm not sure how that translates into liter per hour.

I read somewhere .80 for forced induction. I went with .85 when sizing my system.
I'll see if I can find the page again.

Not the exact page but has the info

Estimating Fuel Injector, Carburator and Fuel Pump requirementsFuel injector, carburator jet sizing and fuel pump requirments, can be estimated by using the following rules of thumb as a starting point. For a Naturally Aspirated (NA) engine (carburated) on gasoline most need a Brake Specific Fuel Consumption (BSFC) of 0.50 lbs of gasoline/hp/hour. On E85 the same NA engine would need a BSFC of about 0.65 lb/hp/hr.
Turbocharged engines typically need BSFC fueling of about 0.60 lb/hp/hr, a reasonable first guess for fueling required on E85 would be 0.77 lb/hp/hr.
For a simple conversion to replace gasoline with E85 take the current "flywheel hp" as a reference point. With E85, power should increase by about 5%, so the estimated E85 fueling would be:
(BHPgasoline x 1.05) x BSFCe85 = Estimated E85 fuel requirements


http://www.poel-tec.com/english/e85.php

Awesome, thanks.

I thought it would be higher than .85.

A interesting reply from crispeed, based on his 1.9 finding with methanol. I thought we would be somewhere between .77 and 1.9.

What fuel pump are you using?

Tell me if I’m doing this correctly,

Using this calculator http://www.eastcoastrollingthunder.c...r/finject1.htm

This says my A1000 will only handle 485 whp with the following inputs.

485 WHP
.85 BSFC
18 PSI Boost
Rated Fuel Pressure of injectors 50 psi
Rated Fuel Pressure of Pump 50 psi
Actual Fuel Pressure 50 psi
Number of injectors (6)

Suggested fuel pump size 441 lph

I’m getting the LPH calculation by multiplying the LPH by 1.58 to get my lb/hr.

I’m running (6) 1680cc injectors and a A1000 fuel pump, which is good for 700 lb/hr

Let me know if I’m doing this wrong because 485 whp is not even close to enough…. For me

i have no idea as to the BS in your app but i can tell you what you need for E85 600 rwhp.

the rotary needs 1.92 CFM to make one rwhp.

so 600 X 1.92 = 1152 CFM

1152/14.471 = 79.6 lbs per minute call it 80

so 80 pounds of air per minute at an AFR of 10.8 equals 7.4 pounds per minute
of gasoline. ( if you plan on running a different AFR it is easy just to adjust the bottom line on this calculation)

7.4 pounds per minute of gasoline to make 600 rw rotary hp at 10.8

of course you are running 15% gasoline and 85% alcohol.

gasoline has 18,400 BTUs (energy) per pound
alcohol has 9500 BTUs/lb

7.4 pounds per minute times 18,400 BTUs is 163,160 BTUs to make 600.

gas weighs 6.25 lbs/gal so it would take 1.184 gallons per minute to do 600
alcohol weighs 6.55 lbs/gal so it would take 2.622 GPM to do 600

mix them at 85/15 and you end up at 2.405 gallons per minute or 546 liters per hour.

that's 9103 CC/Min at 100% duty at 10.8 AFR to make 600 rw rotary hp. you are at 10,080 CC/Min and probably should have another injector.

think that's alot of injectors? my friend runs 14 1680 injectors to 85% duty and makes well over 1000 rw on his 2 rotor... that's 23,520 CC/Min at 100% duty.

howard

Sounds about right....When I did my math for at least 500whp on E85....I tossed out the idea of a A1000 pretty quick because I got a similar number to what you did. I went with twin Bosch -044's, one running all the time...one coming on under boost.

My friend from PR has two bosch -044 and one A1000 for about 1000rwhp on a 20b...just to give you an idea.

Chris

Thanks Howard, I was hoping you would chime in. I knew that you would break it down for me. :):icon_tup:

I have (2) extra 1680cc injectors installed, I just have them unplugged. So, I should have enough injector for what I need.

I'm just curious about fuel pumps. My pump is supposed to handle 700 lb/hr. Do you know the coorelation between lb/hr and liter per hour?

I thought that I would be able to handle 600 whp (barely) with this pump. Looks like I need another one. :(

http://www.magnafuel.com/



1 lb/hr is about 10.5 cc/min depending on fuel

1000 cc in a liter

700 lb/hr = 7350 cc/min

700 lb/hr = 7.35 l/min

700 lb/hr = 441 l/hr

Sounds correct?

2.405 GPM X 60 = 144.3 GPH

.15 X 6.25 = .9375

.85 X 6.55 = 5.5675 + .9375 = 6.505 weighted weight per gallon of E85

144.3 X 6.505 = 939 lbs per hour

Alright, so the A1000 pump is rated at 441 LPR.

That means it's only good for 485 whp.

So, to make a decision. Get another A1000, or sell my current one and buy a bigger single pump. :dunno:

Thanks for the help guys, I do appreciate it.

There is also an issue with going bigger and bigger with a single main pump and that is fuel heat. The bigger the pump the more the energy it puts out and all this works to over heat the fuel when sitting still or when not using all the volume. It will gradually heat the fuel in the tank then the pump gets noisy....etc...and the fuel looses some of its cooling capabilities. That is why many people go staged....or you could go bigger and install a speed controller.



Chris

Okay, well I'll probably just get a 2nd A1000. That should give me more than enough fuel for my needs.

What do you guys think of this kit? Tripple 255's that will flow 765 LPH, enough for 800 whp.

http://www.glennsperformance.com/ima...tom)%20(3).JPG

Interesting. I ened up using 2 bosch 044's and 1 apexi bncr33 pump and got them to fit intank.
Last fall they were holding pressure with my 3x 2200cc and 3 x 1680cc injectors at 72% duty cycle at 25psi boost. We will see this year once my rebuilt motor is fully broken in.

Custom kit Eric? I was contemplating using CJ's twin bosh assembly...craftsmanship looks nice.

Glenns Performance sells the above kit for $639

http://www.glennsperformance.com/pro...roducts_id=148

The also sell the manifolds and fittings for $149

http://www.glennsperformance.com/pro...products_id=92

For that kind of money have you thought about one big pump and a speed controller for it? Personally I'd rather have a single pump than 2 or 3. Just seems like a big problem waiting to happen at some point.

I had thought about that also. I'm still debating whether or not to just throw another A1000 on it and call it a day since I've had good luck with these pumps.

I know you want to switch EMS as bad as you want kicked in the nuts but the newer Haltechs as well as some other brands have definable rpm v. load maps for a PWM output. Since you started talking about this I realized this would be a great way to have a built-in speed control for a large fuel pump. I've used this output to run methanol injection pumps through a solid state relay. There is no reason you couldn't do the same with the fuel pump. Set a low duty cycle on the pump at low load/rpm and as those parameters rise the fuel pump would come up to full power. Doing the same thing as what something like the Aeromotive controller does (though that just bases pump duty cycle off of rpm) without the need for a 2nd box. Just thinking out load...