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Thread: Open Loop EE Advice

  1. #16
    LT1 specialist steveo's Avatar
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    Quote Originally Posted by spfautsch View Post
    So I switched back to speed density last night in anticipation of doing some logging today and my idle went back to garbage.
    so, your VE table is out to lunch.

    as enabling the MAF takes all the bark away after 4000 rpm when the cam really starts to wake up.
    at high rpm where airflow is much more linear, maf and speed density should be fairly equal. so your MAF table is out to lunch

    Steveo - do you think there would be any value in installing widebands in the narrowband bungs in the collectors? If not I would have to yank the cats.
    yeah, that's a great place, go for it

    honestly, the more i listen to you the more I think you're tuning by these feedback numbers instead of by feeling what the engine needs. if it's limp add more fuel. if that makes it worse take fuel away instead.

  2. #17
    Fuel Injected! spfautsch's Avatar
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    Quote Originally Posted by steveo View Post
    so, your VE table is out to lunch.

    at high rpm where airflow is much more linear, maf and speed density should be fairly equal. so your MAF table is out to lunch
    I guess I missed adding a qualifier to that sentence - the idle goes to $* when it switches to closed loop SD. Before it's up to temp in SD or with the MAF in OL or CL, idle is awesome. You can barely tell it's a 230 degree cam. Not sure if you caught the post where I stated I'd switched CL back on. Whatever the case, yes, VE needs to be addressed.

    Drove it yesterday with almost all non-PE KR disabled. Found some interesting stuff out. See below.

    Quote Originally Posted by steveo View Post
    honestly, the more i listen to you the more I think you're tuning by these feedback numbers instead of by feeling what the engine needs. if it's limp add more fuel. if that makes it worse take fuel away instead.
    I agree, you've converted me. But I think I need to resolve item #1 (VE table out to lunch) first? My first attempt earlier this month at getting VE close wasn't good as I'm still learning, but I think this approach will be better. Here's what I started on yesterday.

    ve-tuning.jpg

    This should be relatively close and a lot smoother than what I ended up with tuning the table directly (and a little haphazardly) with trimalyzer. I still need to smooth some of the edges manually - this was aiming at -4% (slighly rich). Unfortunately my clutch slave has gotten to leaking worse and I'm afraid that's going to have to get fixed before I can log with this change.

    A few things I observed yesterday.

    1) When I switched off the MAF the other night I forgot to increase the PE Enable TPS vs RPM table so I get a broader range of feedback for logging. When I did this for the drive home the mid-throttle power was noticeably much better. Much, as in accidentally smoking the tires at 2800 rpm where it's never really displayed that much torque with this cam. I'm wondering if the narrowbands aren't as inaccurate as I began to suspect, and my VE table is just way too rich.

    2) Without KR at cruise I started to notice knock counts at the oddest place. I had assumed this was primarily happening while lugging up a hill in 6th @ 75mph, ~1700 rpm. But I noticed none of this yesterday. More often than not the knock counts seem to happen after cresting the hill when TPS starts to decrease. I'm kind of baffled with this - wonder if it could be going a little rich and popping when the unburned fuel hits the cats (it's not plainly audible).

    3) Lugging up a hill in 6th in that load range is not generating much along the lines of knock counts, but the engine is definitely not smooth. Almost feels like a cylinder is dead or way out of balance, but when you rap it to 6800 it's as smooth as glass. Now that I'm sure the knock isn't real I'm hoping I can play with timing in this range and see if it can get better.

  3. #18
    Fuel Injected! spfautsch's Avatar
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    Quote Originally Posted by steveo View Post
    so, your VE table is out to lunch.
    You had it pegged. Applying some changes that added fuel in the 400-1200 rpm ranges that were lean by 8% or so has smoothed idle down considerably.

    I think I've realized what's been causing my problems - tuning with too little data. After gathering logs for several days and setting a target of -3% in trimalyzer I was just applying all changes. What helped immensely was setting the minimum record count to a fairly high number. For me 750 really helped weed out the cells that haven't gotten enough "law of averages" applied to them.

    This has brought me to the realization that I'll be logging data all summer to get enough to correct the areas outside of normal cruising. Calibrating my MAF will have to wait until at least next summer. Will probably need new tires by then as well. :)

  4. #19
    Fuel Injected! Terminal_Crazy's Avatar
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    Hi
    I've just pent the last few weeks using trimalyzer to get the ve tables all smoothed out.
    After spending 2 evenings swapping the shifter (springs gone soft) for the hurst the wideband went to shit.
    I'd trapped the 02 sensor cable.
    In the process the ve tables are now screwed.
    Went OL. It was idling at 22:1.(quite happily)

    Ve tables were maxed so dropping injector size 2 points (5%) it was idling at about 12:1. Pe is about 9:1

    F***me does the car like that. It howls now.

    Obviously explains why o2's and wideband didn't quite match but was never that far out when using CL

    It definitely does like the fuel.


    After The run (a really good one I might add ��) Idle had dropped
    '95 Z28 M6 -Just the odd mod.
    '80 350 A3 C3 Corvette - recent addition.

  5. #20
    Fuel Injected! spfautsch's Avatar
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    Quote Originally Posted by Terminal_Crazy View Post
    I'd trapped the 02 sensor cable.

    edited for brevity...

    Obviously explains why o2's and wideband didn't quite match but was never that far out when using CL
    I'm not sure I follow, but I'm intrigued. Care to explain better - I can be a bit slow on the uptake.

    Idling at 12:1 must smell pretty raunchy - are you parking in a garage? Woof!

    I just spent some time fine-tuning the A/C and did a bit of test driving. When I initially charged the system last sunday (before applying VE corrections at idle) it died twice on me. With the "better" VE corrections it actually idles a little more steadily with A/C on, likely from the additional load causing more IAC opening / airflow. I can't imagine running a cam like this with an aluminum flywheel. The way it's running currently I can back into my driveway without instantly killing it, but backing uphill into the garage is still a little dicey.

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