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Thread: Ross... Motor still falling on face???

  1. #1
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    Default Ross... Motor still falling on face???

    Well I drove a little today. The good news is that it will go into boost to about 135-145 kpa. Roughly about 3-4 psi. The bad news is that it still will fall on face. The bosot goes higher then it did before you changed the Tun, but it still does it? My timing is staying between 10 to 15 degrees. Not sure why, as I have a commanded 18 degree setting on the high octane table??? I did notice two things. It is capping out at 4000 rpm across the board. That is the highest it revs. Also, if my wideband is correct, I am seeing about 9.0:1 AFR above 105 kpa, 105 kpa and below that, it is about 11.5:1. That AFR is way to rich and from 115 kpa to 145 kpa, AFR drops from 9.3 to 9.0. I am thinking it is just falling on its face from being too rich. Would this cause it to suddenly stop revving above 4000 rpm though? This is pretty wierd.

    Unfortunatly I only get about 10 minutes per day to tune. Every time I fire up the laptop, I have to make it count. My next step will be drastically leaning it out. Have any ideas about the 4000 rpm cap? It will accelerate like a bat out of hell untill it falls on its face. Feels like hitting the rev limiter. Someday I will figure this out! :?
    '71 chevelle
    Twin turbo ls1
    1000 HP 93 octane street car!
    96 lb injectors

  2. #2
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    Default Re: Ross... Motor still falling on face???

    It is probably blowing out the spark. The rich condition is probably most of it but you may also need to gap the plugs down.

    You need to work your way up slowly with the tune, try to get your boost VE dialed in (in stages). Start with 105-135kpa. You need to adjust the VE table until your commanded and actual AF ratios are pretty close. The Autotune procedure will really help with this. http://www.efilive.com/doc/Tutorials...20Tutorial.pdf

    You can then use the #s from the columns you have covered to make an educated guess on the next few columns over. You have to keep repeating this process and refining the tune (it can take a long time). Get the fuel close before you mess much with the spark. Adding spark will lean it out some, so you may then need to go back and tweak the VE some more.

  3. #3
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    I have the actual AFR matching the commanded almost perfect. I have been surfing around on my tune for a whil and just noticed a couple things. First, the Main ve map I am using was a tuned map from speed inc from when it did not have turbos. I noticed at 4400 rpm they had the ve going from about 85 to a 105 jump!! That seems like a huge instant jump in ve. I wonder why they would tune this way? I would think it would be more gradual like the smooth transition og the stock table.
    I loaded a stock year 2000 ve table in and also used that to remake the Boost VE table. My tables now have a much smoother transition. I will have to see if this helps, being that it should'nt instantly become so rich, hopefully.

    Another thing I noticed was that the Trans abuse torque reduction was NOT disabled. I don't know if this could affect anything, but I disabled it anyway. Hopefully, one of these two adjustments will solve my goofy problem. I will keep you posted as I find more out after I go for another drive in the next couple days.
    '71 chevelle
    Twin turbo ls1
    1000 HP 93 octane street car!
    96 lb injectors

  4. #4
    Lifetime Member SS2win's Avatar
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    is your timing still dropping considerably? how about AFR?
    2001 Camaro SS
    EFILive Custom OS3

  5. #5
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    I have not had it out yet since I turned off the abuse protection. I think that might have been the problem. Maybe tomorrow. I will let you know!
    '71 chevelle
    Twin turbo ls1
    1000 HP 93 octane street car!
    96 lb injectors

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