[Cliff R]

"Would blocked heat riser ports amplify the cold bloodedness of an engine on E85?"

Yes, blocking them does the same thing for gasoline as well. My KRE heads don't have a crossover and my engine needs to be fully warmed up and heat soaked before I make a pass at the track or it will "lay down" or not pull nearly as hard on the run. I could do like a lot of others do and "flood" the engine with a super rich mixture to compensate, but that sort of defeats the purpose and makes repeating the scenario over and over again very difficult at any track outing.

For decades now I've whipped up on folks scores of times who try to do this when drag racing. I see them pushing their cars in staging, hood open, bug sprayers to cool down the radiator, etc, etc. They often do OK in early rounds when you have hours between runs, but if you make it to final rounds and the officials start "hot lapping" you back to staging for another pass, you are going to find it difficult if not near impossible to get things cooled down enough to repeat the last run you made 10-15 minutes ago....FWIW.

Not a big deal really, just pointing out a big problem I've seen with drag racing these cars over the years.

My own set up is raced at full operating temperature and well heat-soaked. Since the engine has no tendencies to run hot or overheat in any weather I can sit in staging with it idling right at 180 degrees in later rounds when we are making them pretty close together.

Anyhow......I also use an electric choke for cold starts. It takes 3-4 minutes before the engine will settle down and idle on it's own in cold weather, and a solid 10-15 minutes before the intake heats up enough so it runs like it should. It still starts instantly and drives fine until this happens, but if I had an exhaust crossover it would all happen much quicker.

Another thing folks don't realize is the cooling effect of the incoming air. Even in the summer months after 2-3 minutes of run time you can put your hand on the bottom portion of my carburetor and top of the intake and they are nearly ice cold! What happens at this point is that the cold incoming mixture of air and fuel hit the cold intake runners and the fuel comes out of suspension cause a lean condition. This is why a choke is needed until things warm up enough that the fuel stays in suspension and makes to the cylinders.

It's nothing but basic laws of physics, it REQUIRES heat to effectively burn a lean mixture. 12, 13, 14 to 1 or higher A/F ratios are well below the LEL at ambient temperature. They need to be heated up significantly to burn efficiently, hence why compression is required and a spark to ignite it. Nothing but basic stuff with reciprocating internal combustion engines, but for some reason folks seem to think keeping everything colder will improve this scenario. That's mostly propaganda from "hot rodding" stuff and nothing could be further from the truth. If you want maximum efficiency heat is your friend here, and I'm talking about engine temps, oil temps and temperatures of the associated parts, etc........

As it relates to this topic we are introducing a fuel that is harder to burn, contains less energy, etc. So steps are needed to effectively use it. I still see folks doing pretty good with it once they get thru the learning curve and nail down the tune, so it is a viable option for those that have it available. For myself it isn't on the table simply because it's not readily available here, and I've tuned my high compression engine for flawless performance on currently available pump gas.......Cliff

[Tom Vaught]

Originally Posted by Cliff R

It's nothing but basic laws of physics, it REQUIRES heat to effectively burn a lean mixture. 12, 13, 14 to 1 or higher A/F ratios are well below the LEL at ambient temperature. They need to be heated up significantly to burn efficiently, hence why compression is required and a spark to ignite it. Nothing but basic stuff with reciprocating internal combustion engines, but for some reason folks seem to think keeping everything colder will improve this scenario. That's mostly propaganda from "hot rodding" stuff and nothing could be further from the truth. If you want maximum efficiency heat is your friend here, and I'm talking about engine temps, oil temps and temperatures of the associated parts, etc........

As it relates to this topic we are introducing a fuel that is harder to burn, contains less energy, etc. So steps are needed to effectively use it. I still see folks doing pretty good with it once they get thru the learning curve and nail down the tune, so it is a viable option for those that have it available. For myself it isn't on the table simply because it's not readily available here, and I've tuned my high compression engine for flawless performance on currently available pump gas.......Cliff

I realize that Twooldgoats (Jim) is "Old School", runs Methanol, and is just plain "OLD",
but you are not exactly young either Cliff.
Maybe you can explain the Physics to him sometime so that he understands that for maximum efficiency (Best Power) you DO NEED some heat in the combustion process.

Tom V.

ps Great post by the way.