Changes to Use E-85

[Tom Oxner]

My off and on 930 project is back on again. I have a basically stock 3.3 liter with SDS EFI using a Carerra manifold. The intakes ports are matched to the Carerra manifold. What changes would I need to make to use E-85. I know I will need larger injectors. Are the stock fuel lines and fuel rails adequate? I did a search but did not find a thread on this. If there is one I missed, please point me toward it. Thanks in advance for your advice.

Tom

[Ken911]

yes stock fuel lines and pums should be ok dependingo n the horsepower your after. Basically e-85 requires 20% more fuel for the same HP.

[xbmwguy]

20% more fuel is about right,but the ability to run more timing and boost is where the benifit is, not to mention the cooling benifits from the alcohol. afterstarts with a warm to hot engine (heat soak) can be a chalenge due to the correct wall wetting quantities but can be tuned around with the right ecu and software. and that oh so awesome smell with white flames instead of orange

[Tom Oxner]

I had not considered E-85 as it was not locally available (driving 30 miles to fill up with fuel did not sound like a good plan). Now that it is locally available, it is much more attractive. I am hoping to get 450 flywheel horsepower with the limited modifications to the engine. Since detonation is pretty much fatal in a 930, the additional octane and cooling seemed like a good idea.
I guess I now need to look for larger injectors (I guess around 70 lb.)
Thanks for your advice,

Tom

[nocarrier]

Is anyone running a flex fuel sensor?

It would be nice to know what the exact ETOH content in the fuel at the pumps are. I suppose you could tune for e10 and then tune for e85. Then let the sensor and the ecu interpolate for whatever blend you have in your tank.

The price of these have come down quite a bit. I'm going to try one out but haven't gotten to that point yet.

[sjf911]

I'm running an ethanol sensor but have not run e85 yet. I changed out all of the flexible fuel lines to alcohol compatable hose. I have to replace the stock Carrera FPR as the fuel pressure is too low for my injector size before I can run e85. It will be a project for this winter.
By the way, I currently see an average of 8% ethanol in our premium.

[nocarrier]

Very cool! I haven't fired up my efi build yet but have added a honeywell pressure sensor to monitor the fuel pressure. I plan on running 80lb injectors.

What are you seeing for fuel pressure with the carrera fuel pressure regulator?

sorry for the thread hijack

[sjf911]

The Carrera FPR is set at 36 psi or 2.5 bar and I need at least 3 bar to meet e85 fuel volume requirments at current horsepower.

[Tom Oxner]

Does anyone have a suggested source for 70-80 lb fuel injectors (high impedence). Thanks,

Tom

[nocarrier]

Oh wow I had no idea the carrera fuel pressure is that low.

[rsscotty]

750cc/72lbs New Generation U.S. CAR Fit - Fuel Injectors MOD Sets - Siemens Injectors & Lucas Injectors - Racing Fuel Injector Sets - 013US750, 72lbs/hr

[sjf911]

Originally Posted by Tom Oxner

Does anyone have a suggested source for 70-80 lb fuel injectors (high impedence). Thanks,

Tom

I'm using Injector Dynamics 725 series which were recommended by one of the big EFI 930 tuners.

Injector Dynamics - Injectors

[xbmwguy]

I am using Siemens deka 80# and am at 85% duty cycle in the upper 500s. Will be going to the new Bosch 90s which are supposed to be very stable at low pulswidths

[TurboKraft]

Originally Posted by nocarrier

Is anyone running a flex fuel sensor?

Yes, on a few cars now.
Pic from the latest build:



Tom: we have the 80# Siemens injectors in stock, they supported over 540whp/550wtq on a recent BTR engine we converted to EFI. That was using the 964 FPR.

The 964 FPR is a direct fit replacement for the 3.2L regulator and bumps up fuel pressure about +1bar. The only change is the return (lower) port has M16x1.5mm threads on it, not a hose barb. If you're upgrading/replacing your fuel lines, this is no big deal.

Your stock Turbo pumps will be fine if they are in good shape and getting full voltage.

[sjf911]

Chris, do you have a pic of a 964 FPR on a 3.2 manifold?

[TurboKraft]

Looks the same, only a threaded fitting on the bottom, same as the threaded fittings presently on the sides of a 3.2 regulator.

[sjf911]

Thanks!

[Pimpim]

I've convention off my 930 to E85 o have not had any problems with it .. I changed the injectors to 1800cc and use Red Line SI-Alcohol.

[Tippy]

My MegaSquirt II allows E85 using a GM E85 flex fuel sensor.

From what I read, I leave base map alone. Fuel map 2, just copy/paste fuel numbers in it, then multiply by additional fuel required (20% as said here?).

Once on, I assume based on content will run an algorithm to interpolate between the 2 maps.

[BoxsterGT]

The factory main tee hoses on the 3.2 Carrera were made long before E-85 was on the market, so those hoses are not likely to be E-85 compatible. Also, during the time this system was designed & produced, Porsche (or Bosch) used both M14 and M16 fittings & corresponding hoses. The supply from the filter starts with M16, then goes to M14 and back to M16. The entire fuel system from the pump through the tunnel uses M14 fittings w 7.5mm hose.

Only when Porsche introduced the 964 did they go to M16 fittings & 9.5mm hose throughout.

Len