Had my car tuned on E85 at FFTEC yesterday. Sean also tuned it on 91 almost a month ago with identical mods except for adding the Omni 4bar MAP sensor for the E85 tune. Weather was not drastically different on the two days- we are blessed with relatively mild and consistent weather in the Southest Bay Area.

This is not a drag car, and I am not after the highest possible dyno numbers. I intend to autocross and learn to road race with this car. With this in mind, transient response, very fast spool, loads of torque down low, and a smooth predictable power curve is what I want. Sean took this into account and did not tune for maximum power but rather the most usable and reliable for my intended use.


According to Sean, the fuel pump was dropping voltage in the upper RPM range. I'm not sure if it is really losing voltage and/or it would benefit from rewire and/or having the relieve valve modified. With this corrected I think the car could have made a little more power.

I am very pleased with how the car drives. It exceeded my expectations in how it feels and the numbers it put down considering my minimal mods. Thanks to the crew at FFTEC for their great service and tune.

MODS:
03 Evo GSR
Stock block
Kelford 272s
GSC valvesprings
L19 head studs
Perrin intake
ETS LICP
ETS 3.5" FMIC
Works TB shaft seals
IX DV (uncrushed)
MAP O2 housing
Cobb TBE with FFTEC test pipe
FIC 1100cc high impedence injectors
Single walbro 255-maxed out. need more pump
Grimmspeed EBCS
Omni 4 bar MAP (E85 tune only)
ACT HDSS clutch
ACT Streetlite flywheel
Quaife front diff
Shep 12 plate rear diff
JRZ RS coilovers
265/35/18 dunlop Direzza Z1 (HEAVY)
18x9.5 TE37

E85
Boost spikes to 30psi. I'll get my logging equipment setup soon to be sure but it seems like I reach full boost around 3800-4000rpm


91 oct
boost spikes to 24psi

 

There is no way a single walbro is maxed out with the stock 9.8 turbo on E85. Espically at this power level. You have about 80-100whp and much more lb/min to go before it maxes.

Are you sure it's a real Walbro?

 

Pretty darn sure. I was surpised too. It's not rewired and losing voltage. Maybe maxed out isn't the right term, rather it won't deliver any more fuel due to the voltage issue. There was a slightly leaner spot that just would not go away, right when voltage drops. Ideas?

 

So you have a voltage log? What RPM? If its a voltage problem, a larger or secondary pump won't help. You need to find this issue before you throw more money at it.

Like I said above, a single *real* walbro with a healthy fuel system is 100% fine for what you have, and even for 80-100whp more and more lb/min then what you currently have.

btw, welcome to the E85 Army.

 

Thanks for the reply Bryan. I guess it is possible it's not real. I'll have to check. I don't have a log. Sean was showing me during tuning. I'm new to logging and just got my gear this week, so I honestly don't know how to log voltage yet. I'll try to get ahold of it ASAP, but I'm addressing other things with the car today.

 

How old is the pump?

Check your alternator too if your getting voltage drop, may be a charging problem!

Good power though, e85 ftw.

 

Bryan is correct.

A healty walbro should support more power. We have supported 455hp on 1050cc's with a double pump fuel system while using E85.

Battery volts are 13.9-14 during the log.

We have experienced several cars over the past year that have had low voltage at the pump. We have somebody check the volts during dyno testing at the fuel pump hanger. The lowest we have seen is 10v after the ECU switches the pump to full voltage. This seems to happen more with the older 03-04 evo's but is not isolated to them.

In Uuri's case we didn't have somebody check voltage @ the pump. It's easy to judge by the fuel map that fuel pressure is falling off.

 

Yea I got tuned with about the same amount of power on E-85 except I was running a 10.5 stock turbo, stock intercooler, and stock cams.

 

thought this car would've made more than that.. especially since you have cams.. but great post though.

 

I think I installed it in late 07 or early 08. I have noticed that the dash clock and other power accessories do tend to suffer a little bit when others are used. I also just switched to a Deka ETX14 mini battery, although I woud think the alternator is more the culprit.


Keep in mind this was not tuned for max power as I said, and it's on a Mustang, not a Dynojet. This could have read 400whp on a DJ. Not that I really care all that much.

 

Have you verified that your uncrushed IX diverter valve can hold that much boost?

 

I considered crushing it but we agreed it would be best not to for drivability reasons. Surging/bucking is a major hindrance and is problematic in autocross. It seems to reach and hold bost just fine. I'm not willing to sacrifice driveability for power, even if it is leaking a bit. I don't think it is though.

 

Ruu: Before going to the additional expense of replacing your existing fuel pump with another, more expensive unit, why not try modding your Wally by simply punching its pressure relief valve? This will probably resolve your lean issue at WOT. At least its worth a shot, don't you think? And best of all, it won't cost you a dime.

 

Looks like fun uuri. Be careful on all those fun west coast tracks!

d

 

If you rewire the single 255 with a relay it will bump the base fuel pressure up about 10 psi since it will not be using the low voltage relay anymore, however it will not overrun the fuel pressure regulator. I did this on my car when I switched to E85... may be a cheap solution if you find out what the voltage drop problem actually is.