johnrx2

The car makes 500 whp at 21 psi. The previous owner/tuner stopped there because the injectors are not big enough for any more boost. 850 pri. 1280 secondary.
The car is tuned great runs on e85 and has pre turbo water injection for added safety.
The turbo is a gt 40 w .84 a/r. Is what I was told by the old owner.
My question is if I went w id 2000 injectors would this turbo make much more power at 25_28psi. Or would it run out of air.
I also have a barrel of e98.
Thanks for any replies
John

Howard Coleman

iTrader: (6)

"how much power from a gt 40 e85?"




the simple answer is... 550 rw rotary hp SAE at 22 psi.

(73 pounds per minute X 14.471 = 1056 CFM/ 1.92 = 550)

this of course assumes you can drive the turbo to the end of the map.

you are at 21 PSI making 500 so you are not yet at the east end of the map.

as to injector requirements:

let's use 11.0 AFR for our calculations. should you wish a diff AFR simply do an adjustment.

500 hp

66.33 pounds of air
6.03 pounds of fuel

6.03/6.35 = .949 gallons per minute = 3441 Net CC/Min to make 500 @ 11 AFR

you have 4260 Gross injector capacity at 3 Bar static or 3706 Net after 13% lag.

the above calculations are for gasoline.

E85 has approx 82,000 BTUs per gallon V gasoline at 116,000.

you need approx 35% more volume of E85 to make the same power as gasoline.

adjusting to E85...

500hp gasoline requires 3441 CC/Min net of lag. you have 3706 net of lag at 100% duty.

3441 X 1.35 = 4645 CC. that's for 500 rotary rwhp at 11 AFR, 13% lag, 3 Bar static fuel pressure on E85.

you have 3706.

all calculations have some wiggle room... you may be running a higher fuel pressure, a leaner AFR, your power may be in STD rather than SAE which adds a magical 10 hp at 500 etc.

it seems to me either your 500 # was on gasoline, which would put you around 85% Duty Cycle or your 500 is a bit high.

last April i was in your situation on E85. around 550. i had switched to the new Bosch alcohol friendly "1650" injectors only to find that the rating was at 4 Bar (58 psi static) rather than the norm 3 Bar (43.5 psi). deliverability varies w the square root so the adjustment 1650 X .866 = 1428 CC.

so at 1428 X 4 = 5712 x .87 (lag) = 4969 i was out of injector at 550 approx.
you were at 500 so 4969 X .9 = 4472... that is pretty close to my 4645 calculation above.

Executive summary

GT40, E85 maxxed out...

6000 Gross Injector would work well.

Howard

johnrx2

Yes my current injectors are maxed out. But w id 2000 injectors could I get to 550. Rwhp. . I know the current set up is maxed . I dont want to go to a bigger turbo this one is fairly responsive and fun to drive on the street.
As far as 500 whp. I bought the car the way it is and was not there when it was tuned. But I did see a video of it and it shows the dyno screen.
I will say my old car w a s300 tuned by steve kan made 424 on pump 15 psi and people said no way so I put it on another type of dyno and it was 418. .
I drove that set up for 3 years and this car is way faster so my but dyno says its way more than 418 or 424. Maybe it would be 475 on another dyno not sure.
John

johnrx2

Would two id 1000 pri. 2000 secondary be good then.

Howard Coleman

iTrader: (6)

yes, they would work well for you.

johnrx2

Thanks for the replies howard. The previous owner who built the car said he followed many of your threads and info when building the car. I am content w car for now but in a year or so may swap injectors and push for a little more. Also does anyone run duel fuel systems,where u could cruise on and light load idle on pump and be on e98 only past a certain boost level. If so which ecus would run it correctly.

John