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Thread: The Turbo problem in STU

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    Default The Turbo problem in STU

    <snipped>

    -=eh
    Last edited by JS154; 06-04-2013 at 08:09 AM.

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    Eric, didn't you have the pole, led flag-to-flag, and then the win on Saturday before you got wrecked out on Sunday...? In your non-turbo BMW E30?

    - GA

    Saturday Results

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    Last edited by Greg Amy; 06-03-2013 at 10:28 PM.
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    Sorry Greg,

    I don't understand how SRF results are pertinent....

    Eric was T-boned on the pace lap of Sunday's race and was DNS.

    I think his point is that even with the tire and TIR changes we're looking at a repeat of last years Runoffs results.

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    Greg fat fingered the link - times looked comparable...

    That so blows- wrecked on the pace lap??? How
    BenSpeed
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    According to his Facebook post, the pace car bunched the field up, to slow the start down. He says it cracked the welds on the x-bar, and maxed his g-meter out at 5.6g latteral.

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    Quote Originally Posted by Z3_GoCar View Post
    I don't understand how SRF results are pertinent....
    Corrected.

    Quote Originally Posted by benspeed View Post
    Greg fat fingered the link - times looked comparable...
    0.7s fast lap difference across the weekend.
    Not my circus...not my monkeys...

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    Quote Originally Posted by Greg Amy View Post
    Eric, didn't you have the pole, led flag-to-flag, and then the win on Saturday before you got wrecked out on Sunday...? In your non-turbo BMW E30?

    Eric I don't see the data behind your argument... it seems as if you are saying
    that the turbo Solstices should be slowed down because they have some possibility of catching you?



    Is there some way you can build a bridge for me from Saturday's race data
    to your conclusion? Because I don't see it.

    .

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    As a committee member nI should have put more thought into it before posting the letter I sent to the CRB to a public forum, so i am taking it down.

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    Eric - no worries about the letter. While the data from the Ohio race didn't back up your argument I tend to agree that STU is going to be a turbo class. The turbos walked the field at the Runoffs and I think will smoke the field at any big fast tracks like WGI.

    I know I'd put. 944 2.5 turbo in the 968 if I was capable of funding an STU car.
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    FI's still smoking the field... any plans to address this for next year? Laguna Seca may be a smaller track, but all the major straights are up hill, and some are pretty steep, so power to weight imballances will show up in a big way.

    Maybe I should be asking, if STU is even going to be around next season. With only seven cars at the run-offs it seems doomed just like STO was two years ago.
    Last edited by Z3_GoCar; 09-22-2013 at 11:43 PM.

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    Quote Originally Posted by Z3_GoCar View Post
    FI's still smoking the field... any plans to address this for next year? Laguna Seca may be a smaller track, but all the major straights are up hill, and some are pretty steep, so power to weight imballances will show up in a big way.

    Maybe I should be asking, if STU is even going to be around next season. With only seven cars at the run-offs it seems doomed just like STO was two years ago.
    FWIW, a slightly informed opinion having watched pretty carefully - and participated - for a season...

    STU's challenge is NOT the turbos. It's the fact that it's STU, with all that the rule set proposes in terms of budget required to run a pointy-end effort.

    I know the effort we've put into this year and have some idea what would be required to do it right - particularly in terms of braking and getting down to weight. An NA car COULD be competitive but it would take cubic dollars to make it happen. Right now, given the state-of-art and spending in the class, the returns on a forced induction engine are better at, say, 90% of an "all in" budget than for an unblown engine at the same level of spending...

    ...and at some point, diminishing returns means that (1) $1000 improves lap times less than it did earlier in the R&D process, and (2) the gains are made in areas other than the engine - gear ratios, for example - because those low-hanging turbo fruit have been picked. What kind of gear clusters are those uncompetitive NA cars running? Have they taken full advantage of brake system allowances? Etc.

    The rules for ST - much like IT - have got to be made presuming that eventually someone will do a 100% version of every option, and "equity" among those options has to be estimated at that build level. Right now, a less-than-full-tilt build can make more horsepower, so a BIGGER DIFFERENCE, with a turbo than can be made with an atmospheric engine for the same dough.

    I'd argue that accounts for a lot of the "overdog" anecdotal observations.

    K

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    Quote Originally Posted by Knestis View Post
    FWIW, a slightly informed opinion having watched pretty carefully - and participated - for a season...

    STU's challenge is NOT the turbos. It's the fact that it's STU, with all that the rule set proposes in terms of budget required to run a pointy-end effort.

    I know the effort we've put into this year and have some idea what would be required to do it right - particularly in terms of braking and getting down to weight. An NA car COULD be competitive but it would take cubic dollars to make it happen. Right now, given the state-of-art and spending in the class, the returns on a forced induction engine are better at, say, 90% of an "all in" budget than for an unblown engine at the same level of spending...

    ...and at some point, diminishing returns means that (1) $1000 improves lap times less than it did earlier in the R&D process, and (2) the gains are made in areas other than the engine - gear ratios, for example - because those low-hanging turbo fruit have been picked. What kind of gear clusters are those uncompetitive NA cars running? Have they taken full advantage of brake system allowances? Etc.

    The rules for ST - much like IT - have got to be made presuming that eventually someone will do a 100% version of every option, and "equity" among those options has to be estimated at that build level. Right now, a less-than-full-tilt build can make more horsepower, so a BIGGER DIFFERENCE, with a turbo than can be made with an atmospheric engine for the same dough.

    I'd argue that accounts for a lot of the "overdog" anecdotal observations.

    K
    Sorry Kirrk, it's a matter of can't make a 2750lb/310 flywheel hp car compete with a 2500lb/300whp turbo/FI car. The power to weight numbers still just don't work out for N/A at this point even with a total wheel men behind the wheel. Eric's 4th and Andrew Cadell's 7th are the best we can do at this point, and Andrew's ride was prepared by VAC, then there's Irish Mike's World Challenge e-46. All were multi seconds behind any of the first three.

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    Are you making the argument based on power/weight or on Runoffs results...?

    The difference between 8.87 lb/hp and 8.33 lb/hp simply doesn't guarantee a win irrespective of other variables that influence lap times. No way.

    K

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    Quote Originally Posted by Knestis View Post
    Are you making the argument based on power/weight or on Runoffs results...?

    The difference between 8.87 lb/hp and 8.33 lb/hp simply doesn't guarantee a win irrespective of other variables that influence lap times. No way.

    K
    Ah, but my arguement is that there's no way that a 2750lb/310 flywheel hp -> 2750lb/256 whp -> 10.7 lbs/hp has a chance aginst a 8.33 lb/hp car... unless the driver in the 8.33 lb/hp car is suffering from CO poisining.

    I'm saying the finshing order at the run offs is direcly predicted by the hp/weight of the cars. 1st/2nd were in the 8.3 range 3rd was at the 9.7 range and 7th was in the 10.5 range. That is a disparity that's not being addressed to date, and will only be made worse at Mazda Raceway Laguna Seca by all the up-hill straights.
    Last edited by Z3_GoCar; 09-26-2013 at 01:13 AM.

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    At which point you're making comparisons between examples using a mix of "flywheel hp" and "whp," using what I presume are "known" values - and I tune out as quickly as I do when people start playing math games with driveline loss and dyno rumors in IT.

    K

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    I am building an all out engine, and so have several others. I know that the VAC car that finished 7th was with an all out built motor and chassis. Irish Mike was using his acutal World Challenge car. So, your insinuation that there are no fully built N/A cars is patently false. It's also false that a turbo car would be any less expensive build than a N/A build, it requires an additonal highly engineered part that stresses all other parts around it.

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    My observations of the Result of the RunOfFs are that the only car that really needs an adjustment is the Lotus. There wasn't a single Turbo car there other than the one found to be non compliant that went any faster than the NA cars.
    Last edited by Rabbit07; 09-27-2013 at 08:36 AM.
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    Quote Originally Posted by Z3_GoCar View Post
    I am building an all out engine, and so have several others. I know that the VAC car that finished 7th was with an all out built motor and chassis. Irish Mike was using his acutal World Challenge car. So, your insinuation that there are no fully built N/A cars is patently false. It's also false that a turbo car would be any less expensive build than a N/A build, it requires an additonal highly engineered part that stresses all other parts around it.
    I didn't say either of those things.

    I said that it's easier to get more bang for the first 90% of spending (against a theoretical all-in build) with a turbo than it is with an NA engine, and I stand by that assertion.

    As to particular examples, I have exactly ZERO knowledge of what Flynn or anyone else spent on their engines. Whether it's his "actual" WC car (or not) has no bearing.

    My general complaint is that this argument focuses on only one factor - and a binary one at that. Whether a car has a turbo (so code that"1" in the data) or no turbo (code it "0") simply is NOT a good predictor of lap times, in and of itself without considering other variables.

    How about roof height for starters...? My PERSONAL druthers are that "Touring" cars should be defined by interior volume, before other factors get dealt with, to make sure that they are all starting on a more even platform. Lots of other variables (e.g., weight reduction potential, frontal area, parasitic drag, add-on wing efficiency, CoG, etc., etc.) are built on that foundation and "Lotus" and "Miata" don't seem consistent with first-principle understandings of what a Touring Car is (see also, "Grand Touring").

    K
    Last edited by Knestis; 09-27-2013 at 10:46 AM.

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    K, I am with you brother. Cars such as the Miata, Solstice, Lotus really have no place in touring car racing. I noticed this when I first became aware of the class. I even had mentioned it to rules makers, but was dismissed. No surprise to me that cars such as this have an advantage regardless of them being boosted or not.
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    Amen.
    Not my circus...not my monkeys...

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