I've owned this 740 turbo for about five years now, it's been modified with a decent exhaust, performance chips and more boost on the stock turbo.
The engine has always needed the highest octane I could feed it, and that was getting expensive! So E85 started to interest me.
Here in Australia, E85 has been slow to roll out, so I had been waiting for some sort of infrastructure to appear locally. Finally two service stations in my city started carrying it, one about three minutes from home, which is great!
In Australia, our ethanol is produced from cellulose and sugar cane waste, so it's a byproduct and that makes me happy to use it, it's not a crop grown specifically for fuel.
So, I knew I was right at the limit of my stock injectors with the performance chips and running 16psi of boost, plus the cost of premium unleaded fuel. After talking to the manufacturer of my chips ( a great Swedish guy who had been running his own car on E85 for a long time), I decided to go for it.
I purchased some 440cc injectors, dropped them in and the car has been running really well ever since. 440cc injectors were chosen as being 45% larger than stock. Given the car was right at the limits of the stock injectors, I erred on the larger side.
The Bosch EFI system in the 740 (LH2.4) is an excellent system, very adaptive and modern for it's day. It has no issues running E85 and adapting things like idle, cold warm up etc to the E85, which as you know needs special attention with high alcohol fuels. On a really cold morning, the car will start, run for a second then stall. Second start is perfect.
The chips I have in the car were originally developed for premium unleaded, but work really well with E85. They feature a much more aggressive spark advance map and have had some of the "safeguards" removed pertaining to overfuelling and underfuelling, both of which can set off the stock ECU and prevent it from storing any data for these conditions. Bosch LH 2.4 is quite adaptive as I mentioned earlier and will move quite a way from the standard baseline chasing the right tune for the engine, using the lambda sensor to do so. The only issue with this learning is it takes several days of driving for it to fully fine tune things, but I can live with that.
I've been running E85 for around four months now and the entire fuel system has held up, no leaks or damage anywhere. The engine is really happy on E85 and it "feels" like a really good tune, no flat spots, great improvements in midrange torque on E85. I have the boost wound back to 13 psi at the moment, when I get a chance I am going to a dyno to ensure A/F ratios are good, then I'll wind boost back up.
I also feel the engine runs a little cooler on E85 and is definitely smoother and torquier in the midrange.
The best part of it is, when I changed to the larger injectors and still had a quarter of a tank of 98 unleaded, the car still ran just fine, the ECU seemed to manage with the big injectors on the unleaded. So I have the ability to run a tank or 98 if I need to (although it would be a last resort due to the learning I mentioned earlier, would "ruin" the E85 fine tuning the ECU has done).
If I could mention a few things I feel are necessary to get a good swap over to E85:
Ensure the EFI system is in good order beforehand. No codes, all sensors working well. The lambda sensor is VERY important. Make sure it's good or new, it makes learning easier on the ECU.
Just buy new injectors. They're cheap enough now to make it worthwhile on an older engine. And it's one variable (used injectors) you don't have to worry about.
If you can buy performance chips for your car, do so. Optimising the tune for E85 frees up so much useable power.
As it is now, the car is using, at worst, 15% more fuel than on 98 unleaded around town. I'm really happy with the conversion. I intend to convert my Alfa over soon, however, it uses an older style injector that is hard to find in larger flow rates. However, it runs a conventional electronic distributor, so tuning spark advance is easy.
Oh yeah, I LOVE the smell of E85 cars!
I'm not going to respond to any of the internet BS brought up about instant engine failure, super corrosion of parts etc, it just doesn't happen in the real world of real cars. E85 is an excellent fuel and it's ready for you to use RIGHT NOW!
If you want to post E85 hate stuff, go find a foil hat forum somewhere. If you want to know more, ask me!