I find 24* works well.

 

The one thing I question is if running full advance at cruising RPM/load will hurt fuel economy. I notice the stock rom is running 19.2 advance in this area which may have been all for fuel economy and drivability's sake.

 

I think its a great idea to limit MIVEC uptop if you have meth injection.
You dont want that incoming methonal igniting by having the intake valve open to early.

 

What?

So you're saying the injector fuel will magically not ignite, but the much higher flash point, 120 octane methanol would?

 

Isn't it possible to open up the intake valve to early that the exhuast escaping out the intake valve igniting the methonal. I always thought Air enters before the fuel does.

 

Lemminghead you need to do a little more learning and a lot less posting of your "theories" as they are confusing to other people and perpetuating incorrect assumptions.

 

I am holding 23 to 7600 with a MBC, verified by both my dyno and my JDM 3 bar Also please remember I have switched back to a stock turbo as well for the time being.

I will go get the log and the dyno screen print shortly as well as my S2 MIVEC.

 

 

Hi John, great post! What octane are you running, what BCS and how much power do you think you can make on 91 oct?

 

its a fact that more valve overlap means air enters as the exhuast is finishing leaving. NO theory its a FACT.

So if you start your combustion point to long, retard ignition timing, and the "flame is still burning" then this Heat can escape through the intake valve and that is where you meth is coming in.

 

https://www.evolutionm.net/forums/ev...ck-ix-e85.html

On 91 I think my car would be down around 350 tops. I havent ever tried mixing 91 up to see what I can get it to do.

 

What you are saying about overlap is 100% correct.

I am not quite following how the intake valve is opening before the exhaust valve on the exhaust stroke (how it reads to me anyway)? Positive pressure will still be pushing any flame front out the exhaust valve (not intake) and this is one cause of the increase in EGTs.

The other thing to keep in mind with MIVEC is where we are in comparison to an VIII on the table with a stock camshaft. If you compared the 2 the intake cam would open in the VIII roughly 19.2* advanced on the MIVEC table (this maybe subject to the 30* range of motion having a negative in the table value). It is for certain no less than 17* on the table as far as equivalent overlap however.

 

that is what I am saying the flame front can somewhat be pressed out the intake valve since this pressure will be Higher than the intake pressure. At any rate say even this was not happening you still have methonal being pushed into the flame front and seems to me this can ignite causing another flame front.

 

I must be missing something in your phrasing. What you are describing would mean anytime the intake valve opens it would turn into a blow torch. This doesnt happen obviously as long as the intake pressure exceeds backpressure and flow stays positive through the cylinder.

When it is not all sorts of things can happen, but not quite as it appears you are envisioning it. It take a significant backpressure ratio for reversion to happen and generally most people have stopped trying to add boost at that point.

 

Bradley, that is why MIVEC needs to be zero out at high RPM because the exhuast pressure is higher than the intake and that reversion will take place. That is all the point I was making was take a precaution with to low of ignition timing and to much MIVEC or you will have a blow torch affect