I've been trying to find more info on this E85 that most GM (flex fuel) vehicles can run on. Mainly since I've found that E85 is rate at a higher octane than. Here's a good site for more about E85 http://www.agriculture.state.ia.us/e85q&a.html.

But my question is basically, can you setup or fix a LT1 to run on E85 and Gas. Or would you have to convert PCM and Engine for this? I'm pretty much just curious if this is possible.

 

E85 has higher octane but lower energy content. You would probably need higher flow injectors as well as retuning of the pcm to adjust the spark curve and the A/F ratio. I THINK you also need to replace the fuel lines and pump to insure the E85 won't damage them, though the fuel rails should be good to go, and I have no idea whether or not the fuel pressure regulator can handle it. The other problem is your computer does not contain separate tables for E85 and has no way of knowing whether you put E85 or regular gas in. So you would have to swap out the tune every time you switched fuels, on a 93 this isn't so bad, you swap the prom out (I think 93s you don't need to swap the whole memcal out), on a 94+ you'd have to either swap pcms or reflash every time you switch.

 

There are a couple guys on the b-body board doing it.
You have to understand though that octane IS NOT power and that E85 contains LESS energy than gasoline so you burn a lot more.
The guys playing with it have found that it has to be at least $.60 cheaper per gallon just to break even money wise running it. If the engine is setup to take advantage of higher octane it can help make more power BUT you will have to burn very large amounts.

Basically this is just the latest feelgood fad with a good public relations campaign, REALITY is that it is not that good an idea once you start to understand the science.

 

Can you provide any information on what the b-body guys had to do? new FPR? new Lines? new pump? new injectors?
You shouldn't need to change compression to just use E85 adding a few degrees of timing should be enough to use it.

 

Well all I'm pretty much looking at, mainly with the price of gas now and the fact it's not going to get any better. I just want to be prepared if E85 does start taking a part of the market, that I'll still be able to run my '94 Z28 down the street making noise and leaving rubber.

 

The guys playing with it changed little to no hardware and I guess timing stayed about the same, requires a lot of fueling work and will basically cause a stock engine to max out stock injectors once you get it tuned.
As I said needs to be $.60 per gallon cheaper just to break even on cost to operate, start spending money to make the vehicle compatible and you are going to spend more money rather than less. This is besides the fact ethanol is heavily subsidized by your tax dollars. I know everyone likes a handout but when it is the government taking from you to give back to you you lose a lot along the way.

 

At the moment its a farely cheap way to supercharge your vehicle.

 

People get way too hung up on octane. Been conversing with one of the pump gas drags invitees for the last two years 434ci "LT1"(donovan aluminum block modded for mechanical WP/reverse flow and opti) running 15psi(and an intercooling 75hp of nitrous) pushing a 4400lbs Impala to 9.6 at 146 and he has since found more power in the tuning. He went thru a few pistons along the way but always runs it on pump gas yet most here would think 100+octane necessary for half his power. I am not saying everyone could pull off what he has just that it is laughable that people with really very mild setups think they need lots of octane.

 

You always give these comparisons that are completely irrational. High octane is required for high compression. Swapping out to a 434 donavan aluminum block and modifying it to have a cam driven water pump reverse flow and optispark then supercharging it is nothing like taking a stock engine and supercharging it cheaply by using higher octane fuel. Octane has nothing to do with power and everything to do with compression.

 

Octane has to do with detonation resistance, which is affected by compression.

My point was if a motor making 1200+hp out of just 434cubes can be tuned to work on 93 octane the overwhelming majority here can too. What kind of heat and cylinder pressures do you think that motor is generating, those are detonation resistance concerns too.

I know of a couple other boosted b-bodies running higher than conventional compression on pump gas, they are using much less timing than typical too but it is working for them. One is 10.0:1 17psi 385 timing pulled all the way back to 23degrees but it ran 10.9 at 134 with a 2.0 60ft. and is over 4300lbs. That is a low 10 second mph with a good launch.

There are often differences between "conventional wisdom" and reality, I spend a little more time focusing on reality than most others. It is amazing what people accomplish when they may listen but don't always believe everything they are told and go out on a limb and try new things.