102 - Advanced Tuning Of A Delco ECM with $12P

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Holden202T
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Re: 102 - Advanced Tuning Of A Delco ECM with $12P

Post by Holden202T »

v6bucket wrote:Compression probably helps as the Torana is 12.5:1, but the std VP the Dato's wife has, uses the drilled std injectors on methanol & starts fine cold, like a std car.
question for you, what cranking bpw tables are in the VP, are they stock for petrol or have you adjusted them for alcohol ?
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Re: 102 - Advanced Tuning Of A Delco ECM with $12P

Post by Holden202T »

well I've just increased the crank base pulse width on the Gemini and it definitely starts a lot quicker than it did in that video, might try giving it a bit more and see :) was about 10 seconds this time in 14.8 degree temp :)
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Re: 102 - Advanced Tuning Of A Delco ECM with $12P

Post by v6bucket »

They have been altered, I remember changing it after discussion on this forum, not 100% sure how I came up the the numbers but are close to 1/2 a std petrol number.
Does the sprintcar that you tune have 60lb Deka injectors?
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Holden202T
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Re: 102 - Advanced Tuning Of A Delco ECM with $12P

Post by Holden202T »

yeah and I have a feeling some of its crank and injector bias tables are out :)

I have been waiting for him to send me a spare memcal so I can update the tune for him, he is 2hrs drive away so after the dyno most changes are mail :) I sometimes see them when I help my mate race at Parramatta speedway.
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Re: 102 - Advanced Tuning Of A Delco ECM with $12P

Post by Holden202T »

so I've been playing a bit more with cranking pulse widths to see if methanol will start quicker than the 20 odd seconds it was in that video I posted the other week. I got it to about 5 seconds with the below map, now you might think that its not a huge change but the difference in the -28 degree cell is approx. 10% increase in fuel and 20degrees is about 30%!!!!
methanol crank bpw1.jpg
methanol crank bpw1.jpg (88.08 KiB) Viewed 25253 times
ambient temps were about 16 degrees and the motor had been cold overnight so that's pretty good for methanol :punk:

its probably also noting that the second stage table is pretty much the same increase.

I have always just changed the original tables proportionally to the stock tables to account for changes in injector size or fuel types, but this obviously shows theres more to it than that, maybe different injectors need more or less at certain temps or even fuels change that too.
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Re: 102 - Advanced Tuning Of A Delco ECM with $12P

Post by delcowizzid »

ive got 2 sets of deka 60's and both require different crank fuel values or you end up with no run and very wet plugs LOL
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The1
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Re: 102 - Advanced Tuning Of A Delco ECM with $12P

Post by The1 »

good job on the writeup, good read.
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Re: 102 - Advanced Tuning Of A Delco ECM with $12P

Post by Holden202T »

yeah originally I used to have the same issues with the 202 on methanol with deka 80's, so I backed them right off so stop flooding it all the time and just haven't put the time into it since, but with winter here its seeming to be more important :P

thanks The1!
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Re: 102 - Advanced Tuning Of A Delco ECM with $12P

Post by v6bucket »

Well it looks like I'll have to play with some settings.
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Re: 102 - Advanced Tuning Of A Delco ECM with $12P

Post by Holden202T »

ok so I added another 10 % to my numbers and it really made no difference, so I guess theres a point where you get better results then after that its purely methanol is a prick to start cold :)

also another thing for you to check, theres a table "A/F Ratio - Initial Run A/F Ratio Offset vs Coolant Temperature" (prefixed with map a and b) these are how much it offsets the AFR when first starting, I got caught with this one not changing the numbers to methanol offsets and this can almost flood the motor after it starts! it might be somewhere to look on the dato too just to check its right.
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