rotarygod

I figured this new section needs more threads that ask questions about auxiliary types of injection so what better way than to ask a differet type of setup question to get feedback and questions answered.



Since ethanol, methanol, and other types of alternative fuels have higher octane ratings and hence knock resistance, why couldn't one run without an intercooler on a street car? To be more specific, how about setting up a standalone ecu with a dual table map so that the secondaries only come online only when in boost. I know this is done by many already but how about running a separate fuel pump and fuel system for the secondaries so they only spray ethanol, methanol, etc...? This way when you are cruising around and not under boost, you run on ordinary low octane gasoline but when yo get under boost you are running on the other fuel. You would be using the auxiliary tank nearly as much as the primary fuel tank as even under acceleration you'll be using it but just do some custom work and split the fuel tank down the middle into 2 parts with their own separate fuel pump and lines. It's a bit of work and may not be practical for street use due to availability of whatever alternate fuel you want to use. It could potentially be a way to not use an intercooler and still get some pretty decent power numbers. Obviously above a certain point you still want one but for most people the power level should be sufficient without an intercooler and all of it's associated piping. Although I'm not going to do this, it has been a setup that has run through my head that has had me curious.



How/why would/wouldn't this work? Discuss...

z-beater

Ok, I am no expert but I thought that I would comment. I was going to let the people more knowledgeable than myself discuss but they are not talking. Maybe my response will spark something.



First off there drag cars that run off alternative fuels. More so there are rotary drag cars that run without an intercooler. I have heard stories of cars that make ONE run down the track with meth and their UIM can’t be touched after the run due to the fact that they are so cold. So from this I would gather that one could run without an interecooler. I think that the main downside would be price. For a strret car it can’t be economical to run alternative fuels all the time. Even though I just recently read a thread dedicated to E85 in an Rx7.



As far as the secondaries injecting that is an interesting idea. Currently as you know we have water meth injection. Essentially we are creating a second fuel system. So complexity does not really make this impossible because we are already doing something similar. The main thing that concerns me is that what if we run the alternative fuel tank empty? The second you start boosting…POP. There goes your engine. People inject for the sake of reliability. It has been said countless times water/meth systems are not a Band-Aid.

1Revvin7

We've been doing that for a while, running no intercooler and just methanol injection. We haven't run a setup with injectors tied into the ecu, but we do use an adjustable hob(pressure switch) so the methanol is only injected when you are really on it. As long as you're not road racing, autoX or on the boost for a real long time it works just fine. We've done up to 38psi with no intercooler, however thats a drag race application. And you use a low tank sensor so you know when you are low..

ikari89

i was looking at the air intake temp when my friend was using meth injection on a 15 lb nozzel and it went from 120 deg to 60 deg f, and that was only aprox a 2 sec burst of it. and if you are thinking of using the secondaries to inject meth why not just run pure meth and kick the gasoline alltogether, wouldnt be so great for a street car though. and the only reason people dont run without a intercooler is why not? its really not all that expensive or hard doesnt require any extra tunning doesnt run out and you can stack it with alcohol injection.