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Thread: My Modified '82

  1. #16
    Moderator KANE's Avatar
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    1982 Dark Blue Corvette
    Crossfire Injection | .496"/.495" Cam | AFR Eliminator Heads | EBL | 3.73
    0-60mph in four and a half seconds



    1995 Trans Am
    1 of 1 Trans Am | 100% documented | RPOs 48U, MN6, and GU6
    1982 Chevrolet Corvette , 350 2k RPM Stall Converter + Updgraded Transmission + Governor Set For 5,450rpm Shifts 3.73 Code 42 Dark Mettalic Blue with a twist

  2. #17
    Moderator KANE's Avatar
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    I kinda needed the gauges "updated" to reflect the new red line. I also thought while I was there I'd update the speedometer too.

    The picture below is in another thread- but thought I would share the before & after here.



    EDIT: LED replacement bulbs are the way to go! They are a lot whiter (and brighter) than OE bulbs in terms of the color. So, I've upgraded all of the bulbs inside the car to LEDs.
    Attached Thumbnails Attached Thumbnails gaugues-before-after-jpg  
    1982 Dark Blue Corvette
    Crossfire Injection | .496"/.495" Cam | AFR Eliminator Heads | EBL | 3.73
    0-60mph in four and a half seconds



    1995 Trans Am
    1 of 1 Trans Am | 100% documented | RPOs 48U, MN6, and GU6
    1982 Chevrolet Corvette , 350 2k RPM Stall Converter + Updgraded Transmission + Governor Set For 5,450rpm Shifts 3.73 Code 42 Dark Mettalic Blue with a twist

  3. #18
    Moderator KANE's Avatar
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    Key highlights for modifications and the calibrations settings...

    Thought I would share these as well.


    The major pieces of the tune are pretty much set now as far as I am concerned- VE, SA, O2 Mv, etc- since I haven't had any big swings in % on VE learns in a couple of months.


    Again, all of these are set for the .465" IN / .488" EX cam, 20lb VAFPR, 90lb injectors, Renegade intake, 85 fuel pump, and production iron heads.
    Attached Thumbnails Attached Thumbnails slide1-jpg   slide2-jpg   slide3-jpg   slide4-jpg   slide5-jpg  

    slide6-jpg   slide7-jpg  
    1982 Dark Blue Corvette
    Crossfire Injection | .496"/.495" Cam | AFR Eliminator Heads | EBL | 3.73
    0-60mph in four and a half seconds



    1995 Trans Am
    1 of 1 Trans Am | 100% documented | RPOs 48U, MN6, and GU6
    1982 Chevrolet Corvette , 350 2k RPM Stall Converter + Updgraded Transmission + Governor Set For 5,450rpm Shifts 3.73 Code 42 Dark Mettalic Blue with a twist

  4. #19
    Moderator KANE's Avatar
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    More on IAT placement...

    In a speed density system, the IAT plays a critical role in calculating the density of the air coming in and how much fuel is needed.

    A challenge I was running into a few months ago was with getting the IAT/CTS blend just right and compensating for using the fresh air chamber as the source of air coming in. In fact, I was getting heat soak that was throwing the mixture calculation off by locating the IAT in the airbox. That meant it would run lean (cooler air temps & denser air) in the morning and rich in the afternoon (warmer air temps / longer running & less dense air).

    At idle, low RPMs, and low speeds I founded I needed to be a little more biased to the CTS than the IAT. However, at wide open throttle and pulling in more air (GMsec), I found I needed to be more biased to the IAT. This is important because the IAT is involved in the calculation of the air density... which is critical to getting the mixture right.

    I also found that as the oil temp warmed up, I needed to adjust the multipliers for increasing the % added to the overall fueling calculation between 100* F and 180* F for the coolant. 180* F is when my thermostat opens up and is about when the oil is fully warm. I mention the oil temp because that's when the block is fully warm- and I think that plays into the density of the air charge, fuel lining the intake walls, and potentially atomization of the mixture itself. My sense is that on a crossfire intake the lack of an air gap (insulation from heat) and the large plenum (surface area) creates conditions where it needs higher %s in the multipliers until it is fully warm.

    As an aside, without an IAT GM was using the CTS exclusively in the chain to determine the air density. That leads me back to the idea the water passage under the intake was critical to getting a steady state for calculating mixture consistently.

    I tried a couple of places before settling on mounting it by the vacuum reserve canister. I've already mentioned the air box as a place that didn't work due to heat soak.

    Here are a few more:
    • Hood / opening for the fresh air chamber: While this would seem like a logical and ideal place to mount the sensor, it too was prone to heat soak as the bracket would warm up and then warm the sensor. It wouldn't cool off fast enough and react to the changes in temperature as the higher volume of air was denser and cooler.
    • Headlight actuator supports: I found that it would get heat soak from mounting by the headlight actuators themselves as they would get warm and transfer heat to the sensor. Same problem as above... not quite as much heat transfer, but still enough to throw things off and not react fast enough.


    By positioning the IAT under the headlight actuators by the vacuum reserve canister, it is measuring the ambient air temperature that is getting sucked into the fresh air chamber without heat soak.

    Had I been using the snorkel under the hood without the chamber or running open elements, I would have likely keyed off the CTS more heavily as it would be sucking hot air in.

    The fresh air chamber really works!
    I can see that by the bias needed between the CTS and the IAT.

    Summary: I am biased to the CTS at lower speeds by about only 35% idle (low demand; low Gm/Secs) and then at about 11% at wide open throttle (at max Gm/Secs).
    1982 Dark Blue Corvette
    Crossfire Injection | .496"/.495" Cam | AFR Eliminator Heads | EBL | 3.73
    0-60mph in four and a half seconds



    1995 Trans Am
    1 of 1 Trans Am | 100% documented | RPOs 48U, MN6, and GU6
    1982 Chevrolet Corvette , 350 2k RPM Stall Converter + Updgraded Transmission + Governor Set For 5,450rpm Shifts 3.73 Code 42 Dark Mettalic Blue with a twist

  5. #20
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    Kane
    I believe you'll enjoy this:
    If it rolls, floats, flies or shoots, runs on gasoline or gunpowder, goes fast, shoots a big bullet, and makes lots of noise, thus producing torque and recoil, it's cool.
    But if it's a ball, made out of leather or inflated with air, that's hit with a bat, racquet, or club, used in a game played on a course, green, or court by yuppies, Democrats, or liberals - forget it.

    If you ever get over this way let us know.


    Whoosh, and blur
    Likes KANE, Mac liked this post

  6. #21
    Moderator KANE's Avatar
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    I posted this image in another place on the CAC, but thought I would reference it here as well.

    Ambient air temperature and air charge makes a difference. Cold days in winter (20*-40*) and I will run faster times 0-60 and hot days ( (90*+) in the summer I will run slower 0-60 times. So, there is a range and a lot of that has to do with the air density. Cooler air is more dense- hot air is not. Yes, that is a no brainier... but it is one thing to understand the principle at work and then to actually see it in the data logs for a couple of years now.

    Anyway, that is the segue into this post: acceleration.

    I swapped out the 2.87 for 3.73 gears.

    I have 5.2 to 5.4 seconds for the 0-60mph with a 3.73 rear end on a 90* temperature day with the engine/transmission fully warm. This is recorded through an actual datalog where the ECM is connected to a laptop with data recording software- not the seat of the pants dyno.

    This is on 255/60/15 tires and a mostly OE suspension with the exception of poly bushings.
    Attached Thumbnails Attached Thumbnails 3_73-governor-purple-green-springs-jpg  
    1982 Dark Blue Corvette
    Crossfire Injection | .496"/.495" Cam | AFR Eliminator Heads | EBL | 3.73
    0-60mph in four and a half seconds



    1995 Trans Am
    1 of 1 Trans Am | 100% documented | RPOs 48U, MN6, and GU6
    1982 Chevrolet Corvette , 350 2k RPM Stall Converter + Updgraded Transmission + Governor Set For 5,450rpm Shifts 3.73 Code 42 Dark Mettalic Blue with a twist

  7. #22
    Moderator KANE's Avatar
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    Here's a comparison graph between where I started in May 2014 and August 2016. I've since tweaked the tune and replaced the worn out plugs and wires.

    As a reminder, the car lost its OE camshaft a decade or more ago when a lobe on the cam wore out. So, I never had the chance to datalog it with the OE cam- just the Comp Cams Compu Cam. The best Road and Track got out of the OE crossfire was 7.9 seconds to 60 while GM eeked out 8.1 seconds.

    With 5.2 - 5.4 for my mods versus GM's 7.9 - 8.1 ... that's 2.5 - 2.9 second improvement on 0-60mph and a 2.4 - 2.6 second improvement over just a cam change.

    compare-jpg
    1982 Dark Blue Corvette
    Crossfire Injection | .496"/.495" Cam | AFR Eliminator Heads | EBL | 3.73
    0-60mph in four and a half seconds



    1995 Trans Am
    1 of 1 Trans Am | 100% documented | RPOs 48U, MN6, and GU6
    Likes Tom Bryant, 82ColEd liked this post
    1982 Chevrolet Corvette , 350 2k RPM Stall Converter + Updgraded Transmission + Governor Set For 5,450rpm Shifts 3.73 Code 42 Dark Mettalic Blue with a twist

  8. #23
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    So would the renegade intake manifold out perform the ported stock intake or a X-ram intake I have read about?

  9. #24
    Moderator KANE's Avatar
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    Quote Originally Posted by Bendeco View Post
    So would the renegade intake manifold out perform the ported stock intake or a X-ram intake I have read about?
    I'm not really sure which one would outflow the others.

    If I had to guess... Xram and Renegade would be more comparable (not sure which is over which) and ported factory would come in third.

    That's a wild guess though. I haven't seen conclusive data with all three head to head.
    1982 Dark Blue Corvette
    Crossfire Injection | .496"/.495" Cam | AFR Eliminator Heads | EBL | 3.73
    0-60mph in four and a half seconds



    1995 Trans Am
    1 of 1 Trans Am | 100% documented | RPOs 48U, MN6, and GU6
    1982 Chevrolet Corvette , 350 2k RPM Stall Converter + Updgraded Transmission + Governor Set For 5,450rpm Shifts 3.73 Code 42 Dark Mettalic Blue with a twist

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