911 RSR Clone Track Car to Convert to E85

[lonestarrpm]

I picked up the car a few weeks back -- engine in pieces
so some of my details are still to be proven out.

3.8L NA with Ross Pistons -- 12.4-12.8:1 CR

TWM Throttle Body and Motec M48 ECU system.
Not sure of the fuel injectors used -- but I suspect they
should have plenty of juice for the required larger flow rates.

I know it has a fuel cell and previously ran 110.

Seriously considering re-tuning to run E85. Been doing a lot of reading.
Seems like the perfect application. A very high CR NA engine
that needs to be detonation proofed.

Anything I should consider when doing the engine rebuild
or fuel system, please let me know.

thanks,

Mike in Austin

[jackdidley]

Sounds like you have a good plan. Probably not required but I used teflon core braided fuel line. Ive run up to 70# fuel pressure with no problem.

[adamsvega]

AT HIGH FUEL PSI A TEFLON BRAIDED LINE IS A MUST . carb systems can last alot longer at low psi with lessor hose
the solid plastic (oem) is good too but must be formed and spliced .
go to any hydrolic shop to get your lines custom made for cheap .
depnding on age of eqpt. your regulator and pump might not b alky safe . definily will need a flex fuel or methanol fuel filter . injector size need to stay at 80%duty cycle at max tq. rich wide open under hardest load .so you will need to know the flow rate of pump at preset psi and inj. size to program the ecu

[lonestarrpm]

Jun 15, 2011 17:36:30 GMT -5 lonestarrpm said:

I picked up the car a few weeks back -- engine in pieces
so some of my details are still to be proven out.

3.8L NA with Ross Pistons -- 12.4-12.8:1 CR

TWM Throttle Body and Motec M48 ECU system.
Not sure of the fuel injectors used -- but I suspect they
should have plenty of juice for the required larger flow rates.

I know it has a fuel cell and previously ran 110.

Seriously considering re-tuning to run E85. Been doing a lot of reading.
Seems like the perfect application. A very high CR NA engine
that needs to be detonation proofed.

Anything I should consider when doing the engine rebuild
or fuel system, please let me know.

thanks,

Mike in Austin

Circling back -- I ended up building up a street 3.6L while I sorted what was going on with the original engine.

They had cooked the heads and had piston issues. Fortunately the jugs look good.

Now it is time to explore converting the original engine to E85.

I need to source new pistons and want to know what CR ratio I should shoot for.

This is a track only 100% race car -- I will be driving it in Porsche Club events. Typically 30 minute sprints or 90 minute enduros (with a required 5 min pit stop -- which could be for fueling)

I have a motec 48 ECU.

The heads are twin-spark and I am running with ITBs, but might consider going to a slide intake. I believe I have enough fuel pump and fuel injection bandwidth to support the extra E85 requirements.

I want to remain NA as forced induction moves me up at least 1 or 2 classes -- and the speeds/$$ to be competitive are intimidating.

I'm looking to get the most HP/Torque out of the car I can reliably.

I can add a E85 quality sensor to alter/change mappings.

Bottom line -- since I am going with new pistons -- what CR should I shoot for.

Any other engine build/mechanicals I should consider while doing the paper build for this engine would be greatly appreciated.

thank you,

Mike

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[butterbean]

IMO as much compression as you can, compression makes hp and E-85 is good up to 15:1 so I say go for it and make big HP, good luck