e85 ON STOCKER
Aug 16, 2009, 05:11 AM
#2
The stock VIII pump is pressure-limited (it has a bypass valve that prevents you from running more than around 67psi of fuel pressure, or around 24-25psi of boost), but as long as you can keep boost down around 20psi, it can flow around 170lph, or around 700 cc/min per injector. (The IX pump will do the same up to around 70psi of fuel pressure, or roughly 27psi of boost; up at about 80psi FP/37psi boost, it's flowing around 600 cc/min.)
The stock injectors are rated by ND at 560cc/min. That's pretty well-matched to the injectors, as I've mentioned here before; assuming the injectors are sufficient, the pump will keep up.
The question, then, are the injectors large enough. I'm having a hard time locating what airflow rate a stock, untuned Evo VIII will produce, but let's assume for a moment that the stock VIII did as well as today's X, which pushes about 33lbs/min in stock form (it's a high estimate, obviously). That makes those 560cc/min injectors just about perfect for pump gas.
And about 33% too small for E-85; you want to assume, all other things being equal, that you'll need about 1/3 more fuel for E-85 (that percentage actually moves around a bit, and has a lot to do with your target AFR, but it's a safe number).
Summary: get larger injectors and a higher capacity fuel pump. The sizing of those upgrades is left as an exercise to the reader.
(I could have just said "no, you need injectors and pump", but hopefully some folks will read this and understand how to work this kind of thing out themselves. The fuel system is one of those few areas of the car where an average person with a calculator and Google can figure out a reasonable configuration ahead of time.)
The stock injectors are rated by ND at 560cc/min. That's pretty well-matched to the injectors, as I've mentioned here before; assuming the injectors are sufficient, the pump will keep up.
The question, then, are the injectors large enough. I'm having a hard time locating what airflow rate a stock, untuned Evo VIII will produce, but let's assume for a moment that the stock VIII did as well as today's X, which pushes about 33lbs/min in stock form (it's a high estimate, obviously). That makes those 560cc/min injectors just about perfect for pump gas.
And about 33% too small for E-85; you want to assume, all other things being equal, that you'll need about 1/3 more fuel for E-85 (that percentage actually moves around a bit, and has a lot to do with your target AFR, but it's a safe number).
Summary: get larger injectors and a higher capacity fuel pump. The sizing of those upgrades is left as an exercise to the reader.
(I could have just said "no, you need injectors and pump", but hopefully some folks will read this and understand how to work this kind of thing out themselves. The fuel system is one of those few areas of the car where an average person with a calculator and Google can figure out a reasonable configuration ahead of time.)
Aug 16, 2009, 02:01 PM
#3
I'm not disagreeing with logic's conclusions, but I think the simple answer to your question is: YES.
Plus, there are other reasons for running E85 than simply making maximum power.
Politics - perhaps an EVO owner may simply wish to send less of their hard earned money overseas for mid-east crude oil.
Environment - perhaps an owner might want to consume less crude oil and use significant amounts of renewable energy in their car.
I am still convinced that even with all of the caveats mentioned by logic, a bone stock EVO would still make more power on E85 than on gasoline. Even if the boost had to be turned down to accommodate the 30% fuel flow issue.
So far, to my knowledge - and I have searched, no one has tuned a bone stock EVO on E85. All it would take is a tune and maybe an MBC. I'd love to see a shop do this. Probably not a good idea for a EVO owner with absolutely no tuning experience, however.
Plus, there are other reasons for running E85 than simply making maximum power.
Politics - perhaps an EVO owner may simply wish to send less of their hard earned money overseas for mid-east crude oil.
Environment - perhaps an owner might want to consume less crude oil and use significant amounts of renewable energy in their car.
I am still convinced that even with all of the caveats mentioned by logic, a bone stock EVO would still make more power on E85 than on gasoline. Even if the boost had to be turned down to accommodate the 30% fuel flow issue.
So far, to my knowledge - and I have searched, no one has tuned a bone stock EVO on E85. All it would take is a tune and maybe an MBC. I'd love to see a shop do this. Probably not a good idea for a EVO owner with absolutely no tuning experience, however.
Aug 16, 2009, 07:57 PM
#4
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I ran my Evo on Denso 660 injectors and a walbro for 6 months. The injectors were max'd at 120% duty cycle according to EvoScan. Yes it can be done, but you'll just be limited on how much boost you can safely run. Typically, injector duty cycles at 80% or below is a safe zone. So, me running at 100+% is something i don't recommend....
Aug 16, 2009, 09:04 PM
#5
Simon, how much boost were you running at 100%+ duty cycle? Were you hitting the 120% at peak torque, or at peak RPM? I assume that was only briefly? 
Jim
Jim
I ran my Evo on Denso 660 injectors and a walbro for 6 months. The injectors were max'd at 120% duty cycle according to EvoScan. Yes it can be done, but you'll just be limited on how much boost you can safely run. Typically, injector duty cycles at 80% or below is a safe zone. So, me running at 100+% is something i don't recommend....
Aug 16, 2009, 09:06 PM
#6
Does anyone know the answer to this: if 100% IDC means the injector is fully open, then does 120% mean that the ECU is capable of increasing the fuel pressure?
If not, how can the injectors flow 120% of normal max?
Or is this simply a calculated number in EVOscan, as opposed to a direct reading of injector voltage? Or is the ECU capable of increasing the voltage to 120%, but in reality the injectors are not flowing any more than they are at 100%?
Just curious.
If not, how can the injectors flow 120% of normal max?
Or is this simply a calculated number in EVOscan, as opposed to a direct reading of injector voltage? Or is the ECU capable of increasing the voltage to 120%, but in reality the injectors are not flowing any more than they are at 100%?
Just curious.
Last edited by Jim in Tucson; Aug 16, 2009 at 09:09 PM.
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Aug 20, 2009, 12:07 AM
#9
Very interesting thread indeed. I have a 255lph fuel pump along with a MBC, APS twin vent BOV, GSC 264s, and Injen CAI, UICP, LICP. I've already been tuned for pump already and I, too, believe that running E85 would result in more power even with a lower boost level than what I'm making on pump.
Sep 2, 2009, 06:27 AM
#10
I am planning to run E85 with my stock VIII turbo. I would like to only purchase injectors once regardless of the power levels I achieve. I am looking at the FIC 1250cc injectors both for my present as well as my future goals. Would they work fine with the stock VIII turbo? Thanks.
Sep 2, 2009, 09:46 AM
#11
I am planning to run E85 with my stock VIII turbo. I would like to only purchase injectors once regardless of the power levels I achieve. I am looking at the FIC 1250cc injectors both for my present as well as my future goals. Would they work fine with the stock VIII turbo? Thanks.
Sep 3, 2009, 04:40 AM
#15
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Man Thank you for your service. I can't believe you've been 4 times. Be safe and make it home in one piece. I don't want to say you're lucky but you are def. blessed with the craziness going on over there.
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