Quote:
Originally Posted by Stielow
Will
You are correct a CTS-V pump does hit the internal pressure relief at around 65 psi. These pump are sensitive to voltage. At 60 psi the pump will flow 482 lbs per hour at 13.5 volts and 615 lb per hour at 15.7 volts. With my system running at 13.5 volts I would be right on the edge for fuel flow. I need about 850 lbs per hour. So with a 20% safety factor I need about 1000 lbs per hour of fuel flow for E-85 to support 1150 HP piston HP. I'm right at 1000 HP at the flywheel and need 150 HP to turn the blower.
I built a test rig (Stop watch and a bucket) to verify I have sufficient fuel flow as installed in the car. I could not maintain 60 psi and the flow rate I needed without the boost a pump. I ended up with two Vapor Worx models and one boost a pump because a boost a pump can't handle more than 30 amps. Both pumps pull 44 amps so I'm just boosting the voltage on the 2nd pump. I stage the pumps with a Hopps switch. Once it hits boost the 2nd pump with the boost a pump kicks in. With two Vapor Worxs system the fuel pressure stays rock solid at 60 psi all the time.
On a side note we integrated a GM truck E-85 sensor so the E67 controller reads the alcohol content off the sensor and adjusts the pulse width and timing accordingly. Our pump E-85 in MI is not always 85% alcohol and if a gas station does not have E-85 I can run 91 - 93 octane.
Because I read the CAN data I can display the alcohol content on my dash. I know all of this is geeky engineer stuff but it is cool.
The car pulls hard on E-85 and I see no spark knock activity. On 93 pump fuel I can see small traces of knock that we pull timing for.
It takes a bit of getting use to the smell of the E-85. It is different not bad just different. So far it has been a very fun experiment and I'm looking forward to taking it to the track. Also the $2.10 a gallon is kind of cool also for E-85.
Mark
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I appreciate the lengthy response and can also appreciate the nerdy engineering stuff as well.
I have virtually the same tank you do with dual V pumps and may have to look into the BAP mod for mine. Reading this I'm slightly worried E85 may be out of the question for me as i'm expecting to be in the 1000rwhp range on pump gas (93). Not sure those pumps will be able to be pushed enough to safely support the additional power E85 will make.
I like the idea of integrating the E-85 sensor, makes it easy to play it safe with the inconsistencies of E-85 from the pump!
Maybe I can work out two BAP setup on mine to see if I can get both to push at 15.7V when required. Then the issue becomes the effectiveness of an injector when instead of 60psi differential, you're looking at it's flow on a 45-48psi differential.
What injectors are you running on this car for 1000flywheel?
William
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