Mapping for Methanol in tank

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sdminus
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Post by sdminus »

morrisons at river side keep it

Scott
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duncan
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Post by duncan »

I hope they do delivery cos it would take me half a tank to get up there and back to get it :D

sdminus
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Post by sdminus »

Dunc. Do you have any 3 rd gear full pulls you can post up.

showing

rpm
knock
afr
boost showing atmospheric ( ie - )
time base.

Thats the only real way you can see any gains (if they were done back to back) You should then over lay them to pick out the referance points. You need to see if the tune is altering other areas of the tune therefore reducing or creating a negative effect overall.

Scott
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duncan
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Post by duncan »

will sort one out after cadwell tomorrow :thumb:

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duncan
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Post by duncan »

ok - have found a curious issue:

Because it is running leaner with the methanol in the tank it is 'learning' to add more fuel to get to what it think the AFR should be. This is making it overly rich for the methanol to work its magic to the full.

I will be experimenting with ways to trim this learning whilst on the methanol map to keep it at the targetted AFR's.

1 - alter the ECU's O2 Sensor calibration

or

2 - limiting the long term learning so that this is applied only in closed loop rather than open loop.

sdminus
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Post by sdminus »

Dunc.

It will depend on how the auto tune feature works and how it takes the data from the 02 sensor.


You need to understand what afr is and how it equates ! not being funny but it seems like you are way out of your depth here.



Scott
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duncan
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Post by duncan »

Not taken as funny scott and no offense taken.

I hoping that my experiences help others and am documenting as much as I can about my learning process so as to help me learn/remember and to help others understand.

The auto tune is a simple process on the whole but it does seem to be working on AFR rather than lambda.

James Breadvan
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Post by James Breadvan »

dynamix wrote:

2 - limiting the long term learning so that this is applied only in closed loop rather than open loop.
That sound like a pain in the ass. Can't you just set the ECU to not learn/change in open loop and just read the tables?
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duncan
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Post by duncan »

it is the easiest of the options - 2 figures to change in the map and a very easy switch back. That would stop it applying changes in open loop.

edit to say I am going to change the injector scaling to add the extra fuel that it wants to remove the learning then trim the fuel to ideal targets in the fuel maps rather than switching off the learning capabilities. That is there for a reason and I wouldnt really want to remove the ability of the ecu to cope with mechanical 'issues' altering the flow of fuel.

sdminus
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Post by sdminus »

Duncan.

All wideband sensors measure Lambda. AFR is a calculation made by the electronics using the fuel factor. So the ecu should have no problems on a petrol scale.

The problem you will have is consistancy in the mix. This will greatly influence the amount of fuel the engine requires. Meth cars require approx 2.2 times the amount of fuel. This will apply to all parts of the combustion.

The point i always try to make to people that run things "a bit safe" by adding a touch more fuel "running a bit rich" is pushing your tune further away from the peak pressure point in the combustion process. Doing this you are not makeing the tune much safer but costing you a lot of power.

My advice to you is to tune it manually using a petrol scale. The more meth you add the more inj m/s you will require. Also requiring more ign advance to cope with the slow burn you create. This will stress you ignition system as the amount of fuel and air is going to rise. A good tell tale sign will be the ignition breakup, this will up on a dyno graph best.
Avoid platinum spark plugs and going either too rich or too lean. Methanol will not detonate but it will ping....with meth the first ping will be the last.

Scott
"You think you have a limit, As soon you touch this limit, something happens to you; suddenly you can go a little bit further. With your mind power, your determination, your instinct and your experience as well, you can fly very high."

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