Tesco 99 versus Vpower

[sdminus]

More timing will be just as good !!!

You can learn lots from people that have been there and done it years ago


I used to get 22 deg adv in my twin turbo as apposed to 15 deg it would normally take

[Ross]

That sound bang on as a rule of thumb for a 10% blend. 7-8* more than your petrol map.
I have to agree on the timing before boost, and is my preferred first choice. However with enough sensors you can work out the most efficient boost level for you turbo and time the spark accordingly.

[duncan]

More timing will be just as good !!!

You can learn lots from people that have been there and done it years ago

I used to get 22 deg adv in my twin turbo as apposed to 15 deg it would normally take

I guess we have all learned a lot from others :thumb: and long may it continue.

There is no way mine would have taken 7 degrees extra timing on the meth mix - thats a scarey increase in advance, if it dets then - it is detting big style and would probably be the last time.

Assuming that you are within the turbo efficiency/compressor map (or just outside if using meth) then more boost would surely be more productive but then that depends on whether you map rich or lean as a whole.

[Ross]

On my scoob Sti with Meth + NF. I could get 7* over base map @ 1.6bar on a TD05/06,
My Evo will take a bit more on a similar blend which is strange because it has MUCH higher static compression.

I think the deal with meth weather it be injected in the TB or in tank, when it is injected it turns from a liquid to a gas (endothermically) hence you can run more boost and higher IT's more safely. So in theory it allows you to run the turbo at the far right of its CMap.

[ScoobieWRX]

I always thought that injecting a fluid (i.e. petrol/ethanol under pressure) into the cylinder creates the colling effect, as opposed to when a gas is introduced even though it combusts more quickly it doesn't cool as well (i.e. LPG). I thought even meth would still be liquid even when it reaches the cylinder when introduced in a mix.

Or have i got that wrong??

[sdminus]

Why would you be outside of the compressor efficeny with meth :?

This mapping rich or lean whats that all about. I never map rich or lean neither should you. If you understand the combustion process and wat you are doing you would realise that......

methanol is slowing the burn process down. Therefore you need more ign advance to get the correct burn phase. if you dint do this you are running way out of phase.

now if you run it rich you are slowing the burn further still by leaving excess fuel in the combustion chamber.

If its lean you will speed up the procees and send the ignition closer to Peak pressure and closer to danger.

The afr at which you set up makes peak power should be used not lean or rich as this is not ideal and pointless. Same thing if you run water injection and not tune for it. think of it as adjusting the tune for the new mixture. If you tune it well there will be no danger.

Scott

[duncan]

Why would you be outside of the compressor efficeny with meth :?

Because the methanol as you have always stated cools down the charge, therefore you can step outside of the normal efficiency realm for additional boost without worrying about the normal excessive heat generated by doing this. This does not mean running a TD04 at 30psi because that is just a waste of time, but taking a small step beyond the boundary on one element can be offset by the cooling effect of the methanol.

This mapping rich or lean whats that all about. I never map rich or lean neither should you. If you understand the combustion process and wat you are doing you would realise that......

Please dont patronise me.

methanol is slowing the burn process down. Therefore you need more ign advance to get the correct burn phase. if you dint do this you are running way out of phase.

now if you run it rich you are slowing the burn further still by leaving excess fuel in the combustion chamber.

If its lean you will speed up the procees and send the ignition closer to Peak pressure and closer to danger.

The afr at which you set up makes peak power should be used not lean or rich as this is not ideal and pointless. Same thing if you run water injection and not tune for it. think of it as adjusting the tune for the new mixture. If you tune it well there will be no danger.

Scott

So there is one ideal AFR then is there Scott?

Some mappers in the Subaru market will tune to 11.7:1 some will tune to 11.3:1 some 11:1 or in the 10's. Each has it advantages and each will suit the use the vehicle owner wants (or should do).

I map mine to 11:1 - yes this is on the richer side of the accepted band of achievable AFR. This leaves some fuel in there to help cool down the cylinders for track work. Mapping it to 11.7:1 and reducing the timing would give a similar performance and would be closer to the ideal of 12.5:1 but on track work it wont have the same margin for safety and I need mine to last for more than 12 seconds.

Therefore some map rich some map lean. I like to err on the side of caution because mine gets use on track for prolonged periods.

I still get 26 degrees of timing at redline - what is your ignition advance profile like now?

[Ross]

Why would you be outside of the compressor efficeny with meth :?

You would not be outside the CM with meth.
The point that is being made is that the turbo can effectively be run in a zone that would other wise create IT's that would not be efficient. Methanol is a high octane fuel that is extremely resistant to detonation Its high latent heat of vaporization (1008Joules/g) also makes it an excellent air charge cooler which means a denser mixture at a given pressure and therefore more horsepower.

This mapping rich or lean whats that all about. I never map rich or lean neither should you. If you understand the combustion process and wat you are doing you would realise that......

Safe limits for fueling are defined by EGT & Det IMO. There are well known *safe* boundaries in NA & Turbo charged applications respectively. They are widely accepted afaik.

methanol is slowing the burn process down. Therefore you need more ign advance to get the correct burn phase. if you dint do this you are running way out of phase.

One of the functions of any high octane fuel is to resist/prevent pre-ignition. But there are much better compounds that can be used to back the flame front off, this is not the only function of meth injection.

[sdminus]

Duncan.. for you info we used to load test my engines. buy this i mean long periods at WOT with added resistance from brakes and long slopes.

I ran a digital egt that logged. There is lots for you too learn. There is a big curtain that surrounds tuning engines as i have told you.

I was taught by a guy in the USA who is a tuning god. I also paid for this experiance. I was taught all about meth and nitro by the people that mix and tune top fuel drag cars.

Those that have followed my methods have all gained.

I wont share my ign profile or how i taper my fuel maps and ign cells. this is stuff i spent many many hours and days testing.

[duncan]

I agree there is a lot to learn about EFI.

I am quite happy to share any of my findings, facts, ecu dawdles, fuel maps or whatever - if people want to play secret squirrel games with me, fine, I will find out the answer soon enough myself. Hopefully before destroying this engine I wasnt asking your advice on how to map my car though.

But you are forgetting that I have been tuning cars since before you were at primary school.