E85 requires A LOT more fuel. I will be putting this to the test to get some real life data. Im thinking of running 14+volts right off the alternator to get a little more juice to it. I hope it doesnt max out at 600whp. We will see though. Still curious to see if anyone else has though.

 

You definitely want to rewire the pump with 10ga or larger so it gets full voltage. DSM guys pretty much all do that. If you ever saw the flow data showing how crappy your fuel pump flows with the stock wiring, you'd never want to run one on a small wire again.

I used to run a Denso 150lph fuel pump in my DSM. It's rated at 150lph at 43 psi and 12 volts. With stock wiring it was only seeing 10-11 volts, and the flow was down around 105lph, which is the stock fuel pump rating for those cars at 43psi/12v. At 14.4 volts with the rewire, that same Denso fuel pump was pushing 190lph at 43psi.

For the record, I've seen numerous cars running rewired walboro 255s with over 500awhp...

 

Wow thats some neat info on the wiring, I never did any measurement or calculations on that. Big thanks for the heads-up, will definitely be on the "to-do" list for my e85 setup.

 

Yeah it's definitely worth doing, and it's really easy. All you need is a relay with an amp rating high enough to handle the pump load. I think I used a 30amp relay, wire the factory fuel pump wires onto the coil side of it, and run a 10ga from the battery positive to one relay contact, and from the other relay contact to the fuel pump. Then a 10ga ground from the fuel pump to a bolt back there and it's done.

I honestly won't ever run a high horsepower car without a rewired fuel pump. The factory wiring is just too small for the load the fuel pump sees.

good info on flow rates here
http://www.roadraceengineering.com/f...pflowrates.htm

Oh, and if you look at that page, you'll notice that the denso twin turbo Supra pump flows better than the walbro 255 does. It's also quieter. I could never stand the noise from the walbro pumps, I'd be running a supra pump over a walbro if it fits...

 

I have the Walbro 255 and am over 600whp on 110 race fuel and I haven't had any problems, with the stock wiring or anything. I think it is good on the F20 for around 650 whp before you really need to upgrade.

 

good to know. everyone was saying that i wont get more then 600 out of it but i know on a bseries you dont need to upgrade till you get to the 650-700 range. Glad to see there is someone out there making 600+ on stock wiring too.

 

spooling are you still on the stock motor 3mm headgasket?
im making close to 600hp on a 255 walbro re-wire on my dsm goin with dual 255s this year just for safety.

 

When King did my tune with my SOS setup it was dropping off at the top end. I talked to Chris at SOS and he told me to rewire it. They do it all the time on the cars they build. He said it would fix my problem.

 

interesting to note.

how much power are you pushing? boost? compression? etc?

my kit should be here very soon. maybe i should rewire mine as well.

 

Really this is just simple math, since I could never find any kind of pump curve I would assume that the 255LPH is a close representation of acutal flow at 60PSI and the stock wiring and pressure drop.
(Road Race Engineering Verified)

255lph = 4255 cc/min so using 1000cc/min injectors with a concervative BSFC of .6 and VE based on actual dyno's, 15% drive train loss you should be able to lay down 600 WHP.

Now if you lower the factory fuel line pressure drop, increase the pump voltage and have a good tuner there is more availibe.