Help with BLM tuning

ninthclowd · Post by **ninthclowd** » Sat Aug 08, 2009 1:04 pm

So I've searched around and I'm having trouble trying to find how much you should adjust your VE table per BLM discrepancy.

i.e. if the ECU shows 125 blm at a given cell, should i decrease the VE for that cell by three points?

I read somewhere that to go from 128 to 120 it would be and increase of 7 VE, if that's the case would it be 7/8 points of VE per BLM that you are off? or is it an non-linear equation?

Thx in advance

ninthclowd · Post by **ninthclowd** » Sat Aug 08, 2009 1:08 pm

Not sure if this is relavent, but I'm working with a 1227747 MAP vs RPM vs VE table

JP86SS · Post by **JP86SS** » Sun Aug 09, 2009 4:04 pm

What I do is to take the percentage difference between the 128 (ideal) and the BLM reading you have and then apply only 75% of the correction.
That way you slowly creep up on the pefrect (closest) value without overshooting due to the possible road conditions on any individual drive.

Another way is to find the correction like above but figure out the average of many drives and then apply it. Don't make the change after just one drive with a log. (Unless it is real bad of course)
That way you take any accelleration or coasting out of the values that can tend to make you overcorrect in the tables.
Jp

ninthclowd · Post by **ninthclowd** » Mon Aug 10, 2009 5:41 am

Using a percentage sounds like a good idea and probably not doing so is what gave me so much trouble when I first started tuning. The reason I ask is that I've pretty much finished a VEMaster style program that works with any table(in this case VE) and CSV ALDL log files (so it should work with FreeScan as well as TunerPro). I wanted to make sure there wasn't a more complicated formula than what I was using.

Thx again for the info

Post by **robertisaar** » Mon Aug 10, 2009 6:31 am

INT is another thing to look at, your BLMs could be around 128(which is fine), but your INT could be anywhere from 96-172(depending on the factory settings), if you stay in that VE cell long enough, the BLM will adjust until the INT is close to 128(usually within 4 in either direction), then you will know exactly how much difference is needed. or you could use the fueltrim application and it will work out all of the math for you, you'll just need to remove the samples that are either in open loop, DFCO, or in PE. it will give you a very simple table to deal with...

dizwiz24 · Post by **dizwiz24** » Wed Aug 19, 2009 7:12 am

robertisaar wrote:INT is another thing to look at, your BLMs could be around 128(which is fine), but your INT could be anywhere from 96-172(depending on the factory settings), if you stay in that VE cell long enough, the BLM will adjust until the INT is close to 128(usually within 4 in either direction), then you will know exactly how much difference is needed. or you could use the fueltrim application and it will work out all of the math for you, you'll just need to remove the samples that are either in open loop, DFCO, or in PE. it will give you a very simple table to deal with...

robertisaar,

what is this fuel trim application you speak of? Ive heard of, on newer OBDII tuning softwares, about programs that auto-tune your VE tables. They read your BLM's and then make adjustments automatically to your VE table to compensate.

Is this fuel trim application a feature of tunerpro RT that Im not aware of?It sounds very helpful. Im tuning DA2 on a supercharged 93 corvette.

Also, how long after your mods and reconnecting your battery should you drive around to get baseline BLM's before attempting to tune your VE's to get BLM's nearest to 128?

Any help is appreciated

Post by **robertisaar** » Wed Aug 19, 2009 7:17 am

send me a PM with your e-mail address, and i'll get it to you.

this goes for anyone else as well. just let me know what mask you are using and i should have something that will help.