E85 in 2004 G35x

[expo5.0]

was thinking about doing some basic modifications to the car (intake, spacer, full exhaust) and dyno tunes for 92 octane and E85. I would imagine that with the amount of heatsoak issues complained about around here that running E85 might alleviate that a bit. More importantly i just think it would be cool to be running E85 (plus it would save a few bucks and it gives me something to do). I'm sure i will see some performance gains as well, but even with all that stuff it will be relatively minimal- which is fine as it's really the girlfriend's daily (i don't think she ever gets into the powerband to be honest) and to me it's still going to be pretty slow.

thoughts?

anyone running e85?

what real world dyno gains can be expected from just real basic bolt-ons- any unique things to this vehicle that i need to upgrade (bottleneck type situation).

-drew

[Slider4105]

You can't run E85 in the G for an extended amount of time. Ethanol is very corrosive and will eat away at normal engine internals. G's are only capable of taking up to 15% ethanol blend (per user manual).

Using E85 in a gasoline engine achieves lower fuel economy as more fuel is needed per unit air (stoichiometric fuel ratio) to run the engine in comparison with gasoline. The number I have seen is something like E85 being 30% less efficient.

The engine has to be designed to handle the extra ethanol, if planning to run it as a DD fuel. That's why manufacturers have designed the flex-fuel vehicles and badge the crap out of them and sell them at a premium.
Modified by Slider4105 at 1:21 PM 8/5/2008

[expo5.0]

You can't run E85 in the G for an extended amount of time. Ethanol is very corrosive and will eat away at normal engine internals. G's are only capable of taking up to 15% ethanol blend (per user manual).

Using E85 in a gasoline engine achieves lower fuel economy as more fuel is needed per unit air (stoichiometric fuel ratio) to run the engine in comparison with gasoline. The number I have seen is something like E85 being 30% less efficient.

The engine has to be designed to handle the extra ethanol, if planning to run it as a DD fuel. That's why manufacturers have designed the flex-fuel vehicles and badge the crap out of them and sell them at a premium.

Modified by Slider4105 at 1:21 PM 8/5/2008

there is an additive available that can fix the corrosion problem that has been widely tested on other forums and used in the car communities here in MN.

E85 is absolutely about 25-30% less efficient- you have to counter this by adding that much more fuel to the mix (increasing injector pulsewidth and upgrading fuel pump). I understand this and would still come out a bit ahead $ wise.

I guess this is something that really hasn't come up on this forum much (or that you haven't seen).

it is commonly done by various aspects of the tuning community here in MN. My old bugeye had an E85 file, 92 octane file and a high altitude file all made custom on a dyno and it worked very well on the E85 until my brother totalled it. It can save a bit of $, it runs cooler and most importantly (but not so much for my current application with the G) it can allow you to run much more boost without pulling timing (basically like having about 106 octane).

I

[smockers83]

Nope, no one has ran E85 here. I don't even think someone has thought about it here--this is the first time I can recall someone seriously considering E85.

[TeflonG35]

Nope, no one has ran E85 here. I don't even think someone has thought about it here--this is the first time I can recall someone seriously considering E85.

I've never seen a post about it either.

I'm also curious about what additive is applied so the E85 wont corrode the engine.

[Slider4105]

Well not only would you need to make the block more corrosion resistant, but you would also need to redo the entire fuel system. You would need to get rid of the plastic tank / lining, the rubber hoses would have to be switched to stainless hardlines, the fuel pump would need to be altered. There's a lot more work than just dumping in additive. I'm not saying it wouldn't run, I'm saying it wouldn't run for 100k miles without major modification to the engine and fuel system.

I was trying to point out that you cannot run E85 without altering the engine/ fuel system, and also adding an ecu tune or new fuel map. You can't just go to the pump and pump in E85 and call it a day.

[expo5.0]

the E85 isn't quite as corrosive as you seem to think- the flex fuel cars don't have all the changes you are outlining either.

I've seen it run much through stock vehicles where it was never considered without issues.

The additive stuff does some- but probably just makes one feel better about it. I'm sure on some level E85 does reduce part life though.

i'm not sure what in the original post made you think i thought i could just pour it in and go?

[TeflonG35]

I'm not going to be the guinea pig on this one.

[Slider4105]

I don't know I guess the fact that the manufacturer says DO NOT USE ANYTHING OVER 15% BLEND would mean, it's not safe on an unmodified engine.

My guess that you wanted to just pump it in and go was that you wanted to do basic bolts ons and asked if you needed to do any special mods. And yes you need to change out the fuel system to get rid of any rubber / silicone, and a new ecu tune.

This is just from what Chrysler did to starting in 93' on their flex fuel vehicles

# Piston rings were chrome-plated since methanol attacks the molybdenum-based material more commonly used for piston rings.# Valve stem oil seals were methanol resistant.#The fuel tank was two gallons larger and used high-density polyethylene (instead of steel), fluorinated to minimize evaporation through the tank.# Fuel level sending unit with external resistor element# Stainless steel fuel lines.# Teflon fuel line connectors with braided stainless steel protective covers# Stainless steel fuel filter housing

yep I bet my car has all that stainless and teflon in it. Again I'm not saying it can't be done, and you can't run it for a short amount of time. I'm saying that over an extended amount of time, it's no es beuno.

[expo5.0]

"My guess that you wanted to just pump it in and go was that you wanted to do basic bolts ons and asked if you needed to do any special mods. And yes you need to change out the fuel system to get rid of any rubber / silicone, and a new ecu tune"

the basic bolt-ons and questions about the basic bolt-ons were an aside to the E85 conversion... Due to the fact that I knew i would need a dyno tune to switch to E85 I figured i may as well do all the basic bolt-ons at the same time as well so as to make the tuning time more cost effective... Maybe that wasn't clear. I was wondering if this particular car had any bottlenecks in the system (maybe the throttle body or something similar) which are uniquely beneficial to change out.

That may be true what you posted about the Chryslers but it's hard to argue with the vehicles i see driving around with stock internals and mostly stock fuel systems running E85 owned by many friends and myself in the past. It may hurt long-term longevity, but thus far don't know anyone who has had a problem directly related. I've seen everything from a Weiand SCd 502 chevy (with normal type internals) to 2.7t audi motors running it seemingly reliably.

[expo5.0]

also-

what do you think AMG would say about me custom fabricrating a blower off of a chevy (with a side-mount none the less) and a air-water intercooler set-up using mostly Ford parts in order to boost the whp of their car by over 35%?

They'd say absolutely not!

OEMs are very very careful with what they tell you

doesn't mean the car can't handle it

i realize that's not the same situation as the E85 question (and that there are valid E85 drawbacks) but it's somewhat along the same lines

[Slider4105]

Yeah I didn't mean that you CAN'T do it, but just that most info I have seen has shown that it effects long term reliability of the car. Plus you're right about the whole manu's say not to do something when it's okay, but in this case it's something I would abide by.

More power to you if you can do it, I think it would be pretty darn cool.

[smockers83]

Just a heads up, the G only likes up to 10% oxygenates, aka ethanol, as per the manual, not 15%.

[tollboothwilley]

I talked to Cobb tuning in person back in march and they said the biggest bottleneck on the G35 were the cats. Replacing with HFC's they said made the biggest difference in the vehicle after a good tune.

just an FYI

They have no reason to state anything other than truth since they don't make many aftermarket parts for our cars, just a tuner and some sways.

[Slider4105]

My user manual says MTBE up to 15%.

[smockers83]

My user manual says MTBE up to 15%.

The manual also says up to 10% oxygenates. Not the same as additives like MTBE, plus MTBE has been phased out anyway (I think) with ethanol.