Anyone looking down the road at putting together an engine optimized for E85- which, to me, means high compression? Say 12.5-13:1. This would give back virtually all the efficiency that's lost by switching to E85.

This shouldn't be as hard as everyone is thinking. Think about it- with all the iterations of variable valve timing, and systems that take this to the logical extreme (BMW's Valvetronic), it ought not be that hard. The concern, of course, would be what if there's no E85 available? Then, you'd have to run a 13:1 motor on pump gas. With variable timing, though, a program could be built in to hold the intake open really long, a la Toyota's Atkinson cycle on the Prius. This ought to keep the engine out of detonation, at the cost of some power. After all, the Prius engine is 13:1, and it runs on 87.

Didn't either Smokey or Hot Rod put together a 15:1 350 back in the '80s that got nearly 30mpg, but had only 190hp?

I got to thinking about this when taking my brother's new Prius for a drive last week. When cold, it has a noticeable misfire at idle, that almost feels like pre-ignition. My uncle's Prius does the same, but only for a minute or two on startup.

Todd

 

That seems doubtful to me, seeing that there is simply less energy in e85 than pump gas. The bump in compression will help recoup some of the mpg losses, but the engine is still going to be drinking more e85.

I doubt we will see any factory engines built for specific e85 consumption in mind, simply because of the lack of available e85. I still have yet to see any e85 for sale anywhere in all of eastern Pa, southern Jersey, any of Delaware, or northeastern Maryland. I could see some enthusiasts building engines for e85 to take advantage of it's high octane rating.

 

The SAAB AeroX concept was E100 capable, a DOHC Turbo V6 pushing out 400 hp.

 

Yeah, but it seems to me he was referring to realistic production engines.

 

That would be a realistic production engine if E100 were readily available. It is based on the Turbo 2.8 HF found in the SAAB 9-3 and Caddy BLS.

So if we mean production engines that are E85 only then NO because the infrastucture isn't around for that.

 

Yes, I am aware. That was the problem for an all ethanol engine that I stated earlier in this thread. The engine can be built for it, but if the ethanol is not there, than what is the point?