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Thread: performance analysis

  1. #1

    performance analysis

    Ok guys, time to get your thinking caps on!

    First, some data from Mid Ohio:
    SI lap record 1:38.0 (Dean Martin) but that is with 3.73 rear gear, not the 3.31 they're required to run now
    CMC lap record 1:39.1 (Derek Wright)

    Top lap times from Champs weekend qual race:
    SI: 1:38.8, 1:39.3, 1:39.5, 1:39.4, 1:38.7
    CMC: 1:39.6, 1:39.3, 1:39.3, 1:39.1, 1:39.4
    AI: 1:34.1 (which ended up being a new lap record by Hartman...most AI cars were in the low 1:35s)

    FYI the SI cars are all fat, choosing to run at the 4.6 3V power limit of ~300hp/305ft lbs and corresponding 3550lbs or so. In other words, they're running at about 12.0/1 lbs/hp compared to CMC LS cars which are more like 12.7/1

    So an AI car is 4.5 seconds faster than CMC but an SI car is only 4 tenths faster? When looking at SI and CMC rules, I would've expected a fairly decent times gap between SI and CMC...but the difference is in fact quite small. I'd like to hear if you guys think it makes sense and I'm being unreasonable in my mind.
    Al Fernandez
    CMC National Director

  2. #2
    My street S197 4.6 3V dyno'd at 300/300 a few years back. I had it at the track at MSR-H a few months ago while the race car was down. Running my CMC wheels with Falken Azenis 615K+ I was running almost identical lap times to the CMC car, maybe a touch faster. It used to be my primary track car while I was learning so I'm comfortable with it on the track.

    That's a full street car, no cage, no belts, some basic Koni SAs, Eibach prokit springs, stock sway bars. It does have 3.73s. I've weight it at 3600# and change with me in it at the drag strip. It's a little light for a V8 car because it was originally a six cylinder car swapped to a 3V (after I used up the six banger with too much boost).

    Hopefully that's helpful data. This S197 would be an excellent SI car - I wish we had a class for it in TX. I've had it for 13 years now (first car ever) so it's not going anywhere.

    - Josh
    Last edited by Sook; 10-04-2019 at 03:59 PM. Reason: Added 3.73 gear ratio
    CMC #50

  3. #3
    Senior Member Carroll Shelby ShadowBolt's Avatar
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    Quote Originally Posted by Al Fernandez View Post
    Ok guys, time to get your thinking caps on!

    First, some data from Mid Ohio:
    SI lap record 1:38.0 (Dean Martin) but that is with 3.73 rear gear, not the 3.31 they're required to run now
    CMC lap record 1:39.1 (Derek Wright)

    Top lap times from Champs weekend qual race:
    SI: 1:38.8, 1:39.3, 1:39.5, 1:39.4, 1:38.7
    CMC: 1:39.6, 1:39.3, 1:39.3, 1:39.1, 1:39.4
    AI: 1:34.1 (which ended up being a new lap record by Hartman...most AI cars were in the low 1:35s)

    FYI the SI cars are all fat, choosing to run at the 4.6 3V power limit of ~300hp/305ft lbs and corresponding 3550lbs or so. In other words, they're running at about 12.0/1 lbs/hp compared to CMC LS cars which are more like 12.7/1

    So an AI car is 4.5 seconds faster than CMC but an SI car is only 4 tenths faster? When looking at SI and CMC rules, I would've expected a fairly decent times gap between SI and CMC...but the difference is in fact quite small. I'd like to hear if you guys think it makes sense and I'm being unreasonable in my mind.
    I think CMC should have to run 3:31's.

    LOL since that is what I run.

    JJ

  4. #4
    Senior Member Grass-Passer Suck fumes's Avatar
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    depends on whos driving the SI car haha. When me and Corey ran SI they were usually over a second faster.

    The tq is about the same on both classes but 40hp difference is kind of washed out due to cmc cars being able to run 300pds lighter.
    Last edited by Suck fumes; 10-04-2019 at 06:23 PM.
    A man with no enemies is a man with no character.
    ― Paul Newman

  5. #5
    SI cars used to never run at VIR (at least compared to my CMC car). I had spent 4 weekends a year there for 3-4 years before they started showing up once a year if that. When they first started coming they ran about the same times we did. Now that some of the drivers have been there alot they're about 1.5 seconds faster on a longer 3.3 mile track.

    At Mid-O, how many of the SI drivers are regulars at that track? (I don't know) I know the CMC drivers have raced there many, many times. It's possible the answer to my first question could explain the difference.

    Another way to look at it........
    The top 5 cars in SI all ran within 0.7 seconds of one another.
    The top 5 cars in CMC all ran within 0.5 seconds of one another.

    If someone was cheating in either class it's likely they all were! LOL



    I know cheating was found in AI. Anytime a car is pulling away in the straights they are either getting out the corner better.......or laying down more HP. AJ's video shows he was better in the corners yet loosing ground in the straight. That alone supports the other data you and the team found IMO. So, any such evidence in SI or CMC?
    Last edited by t500hps; 10-04-2019 at 07:50 PM.

  6. #6
    This isn’t about potential cheating. We didn’t see anything at the champs weekend that would lead to suspicions in either SI or CMC, quite the opposite actually.

    Aaron, was that before or after SI changed to 3.31 gears?
    Al Fernandez
    CMC National Director

  7. #7
    Senior Member Grass-Passer Suck fumes's Avatar
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    i ran 3:31’s since day one on the SI car. Think corey switched to them mid year. I always enjoyed driving that car it was just so dang heavy with the rules ratio that it would out heat cycle the tires in one day or less depending on track. Not sure why that class never took off? I’m glad i sold mine when I did though cause it appears only the east coast guys still own them.
    Last edited by Suck fumes; 10-06-2019 at 01:21 PM.
    A man with no enemies is a man with no character.
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  8. #8
    Senior Member Carroll Shelby
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    Quote Originally Posted by Suck fumes View Post
    i ran 3:31’s since day one on the SI car. Think corey switched to them mid year. I always enjoyed driving that car it was just so dang heavy with the rules ratio that it would out heat cycle the tires in one day or less depending on track. Not sure why that class never took off? I’m glad i sold mine when I did though cause it appears only the east coast guys still own them.
    I think you answered your own question about why it never took off if tires last a day or less. I thought it was the up front build cost that hurt it when compared to the lap time comparison to CMC/AI. But then I look at SE46 the same way.

    Al-what does your track data show instead of just talking top lap times.
    Bryan Leinart
    CMC #24

  9. #9
    I didn't keep the data so I cannot use it now to compare SI and CMC cars. We used it to compare between SI and between CMC cars and everyone was right on top of each other in terms of acceleration (never looked at cornering lol).
    Al Fernandez
    CMC National Director

  10. #10
    Senior Member Carroll Shelby
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    So now you want to bring the 197's back into CMC?
    Bryan Leinart
    CMC #24

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