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Thread: Race built engine - what improvement could be expected?

  1. #21
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    IF cars get moved between classes, (A to , I would submit that it makes more scientific sense to move them with a line item allowing the continued use of 7" rims.

    I assume some cars will need a weight adjustment. OK, thats fine, as it can be done apples to apples....I'll use my car as an example. Lets say my times are top dog at most tracks when I compare them with ITB times. (OK, I'm dreaming, but bear with me!) So the rulesmakers might want to add a little weight. Fine. But if you also change the wheels at the same time, how can you confidently predict performance? And how do you decide what to add for weight?

    And for a lot of guys, it is a serious budget item. The standard quiver is 3 sets of wheels, and a set of rains mounted.

    In the end, I agree that the big picture is important, and that a signifcant "trickle down" needs to occur. But I think that the bottom line is the on track performance, regardless of wheel width. Throwing away known performance is, in my mind, a questionable action, especially in light of the bugetary concerns.

    That said, if you asked me whether I wanted to stay in A, at my current weight, and race against the big 4 at their current weight, or be moved to B on 6" wheels, I would, begrudingly, put B stickers on my car. I say that assuming that the CRB will be making significant moves of cars from S to A, such as the Neon, the NX-2000, The SE-r, and so on. But ask me tomorrow, and my answer might change!

    ------------------
    Jake Gulick
    CarriageHouse Motorsports
    ITA 57 RX-7
    New England Region
    [email protected]

  2. #22
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    Just to add a little pragmatism into the mix: My 14x7 wheels (FWD 4x100) can be easily sold as they will fit many ITA/S cars. However, if the RX7 migrates to B (as it should) a large investment in RX7 13x7 RX7 wheels will much more difficult to recoup.

  3. #23
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    So why not class the car with both widths and put a premium on the 7" stuff say an extra 10 lbs per wheel ? or some thing like that. Aren't the Pro7 and Spec7 cars already on 6" wide wheels?


  4. #24
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    Now we are talking about two different things here - a true reclassification request and a competition adjustment. Similar, but I do think there is a difference. What I ('87 prelude si) and Jake ('87 MR2) are looking for is a reclassification. Same weight (no adjustments), follow ITB rules (6" wide rims) ectera. There are some cars out there that should simply be reclassified and others that could be reclassified but at the same time would require an adjustment in the min. weight allowed. The first is a bit easier than the second. Not saying that both shouldn't be addressed in the future.

    Darin definately brought up a very valid point about wheel changes due to the smaller width. At the same time it would be difficult / probably unfair to change the rules in ITB to allow 7" rims. Why should the cars that are staying in a class / not receiving a benefit be penalized by another car getting reclassified (or a comp adjustment)? While the move is valid and very necessary in several circumstances, the existing ITB cars shouldn't bear the cost of the change. (And I'm not saying that's what you were getting at, but a related conversation)

    My sincere hope is that if the SCCA decides to utilize competition adjustments, it still really looks at the classification and doesn't over utilize the weight reduction / addition. As an example, we have done a lot to try and get Jake's MR2 down to its min. weight. From stripping the car to draining all windshield washer fluid. With his MR2 year (different MR2 years can reach the min. weight), it simply isn't very feasable to obtain the min. weight. In that particular car's case, it would be pointless to simply keep the car in ITA and reduce the min. weight from what it currently is. There are many other situtations like this one.

    ------------------
    Dave Gran
    NER #13 ITA
    '87 Honda Prelude

  5. #25
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    Darin, 20% gain for an rx7 although possible is not feasable unless you only race for 5 laps. I was at 117 RWHP all last year and was getting killed on the straights by other 7's, so I tried a setup that leaned out the top end and got 125-128 RWHP (unpredictable), and promptly blew the motor on the second lap. from here out im running on the safe side of the tuning gains ratio, one side housing was all I saved from that last mistake.

    [This message has been edited by 7'sRracing (edited February 19, 2004).]

  6. #26
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    Originally posted by 7'sRracing:
    [B]Darin, 20% gain for an rx7 although possible is not ... I was at 117 RWHP all last year .... so I tried a setup that leaned out the top end and got 125-128 RWHP (unpredictable), and promptly blew the motor on the second lap[.../B]

    Well, you just contradicted yourself...

    117RWHP + 18% for parasitic losses = 138hp which is EXACTLY what I stated. If this is on the safe side, then I was wrong... maybe 25% is more accurate.

    Then you tell me that the other RXs were faster... did they run for the whole race?

    There is more to getting power out of a rotary than leaning it out... There's more power there than can be achieved with your typical Racing Beat header... There is more power there than can be achieved with your typical exhaust system... than your typical Mazda ignition... etc...

    Also, at a track like Portland, where I usually race, there's the biggest factor of all... In a drag race, my car was faster than it's sister car, but in a race, even if we were side-by-side at some point in the corner, he would pull me by a couple of car lengths down the straight... No offense, but the you may not be getting all you can out of what you have...

    All that being said, I completely agree that the RX-7s need some help...



    ------------------
    Darin E. Jordan
    SCCA #273080, OR/NW Regions
    Renton, WA
    ITS '97 240SX

  7. #27
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    Originally posted by gran racing:
    My sincere hope is that if the SCCA decides to utilize competition adjustments
    Let me clarify something. I have NOT heard ANYONE on the ITAC suggest that we do ANYTHING in the way of "Competition Adjustments", beyond using weight and/or reclassifications. I do not expect that wheel width allowances are going to be changed, and I am pretty certain that there are NOT going to be any cars moved to ITB with a 7" wheel width allowance.

    I think it is safe for me to say that the goal is to keep the integrity of the IT rules, both in spirit and intent. We are discussing minor, strategic adjustments to help revitalize/modernize the class and increase it's popularity, but on whole, the class philosophy, intent, and traditions should continue.

    Basically, we are doing our best to not screw things up!

    Stay tuned...

    ------------------
    Darin E. Jordan
    SCCA #273080, OR/NW Regions
    Renton, WA
    ITS '97 240SX

  8. #28
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    ok, points taken, I was never a math major
    and yes there were some other motors puking and some going the distance and yes I guess I could build a set of headers on the dyno. But, then again im just a average schmuck trying to race on a budget. I tweaked the motor to see if I could even get a glimps of their tail lights at the end of the straight.
    I never got a chance to find out, was still in traffic when it let go.

  9. #29
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    Since you guys talked about power to weight ratio..

    Is there a good rule of thumb or a number that is concidered acceptable(competitive)?

    20? 21? 22? 23? 24? 25?



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    Stacey_B AOL IM: SCCAStaceyIB 1990PGL SCCA STSL "Girls Do It Better" Cal Club T&S, BWRP,WS,Lag,Hallett www.scpoc.com : www.probetalk.com Racing is my life. Winner One Lap of America 2003- SSGT2 class 1996 Ford Probe GT.

  10. #30
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    10 would be a good number!

    At the PRI show in December I saw a slick new sports racer that works the power-to-weight ratio very hard. With a 180hp motor it tipped the scales at 750#.

    Let's see...carry the 2...times pi...raised to the 2/3 power... Yikes! 4.17#/hp!

    Of course, you would need a second mortgage to pay for all the CF...

    Gregg

  11. #31
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    The YZ 250 (actually 330 cc) I last raced in 99 with me on it had a 6.1 P/W ratio. I really miss it.

  12. #32
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    "...to pay for all the CF..."

    CF?

    Ty

  13. #33
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    CF = Carbon Fiber = empty wallet

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    Nico
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  14. #34
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    Originally posted by Racy-Stacey:
    Since you guys talked about power to weight ratio..

    Is there a good rule of thumb or a number that is concidered acceptable(competitive)?

    20? 21? 22? 23? 24? 25?

    Well, it depends on the class. If you're considering racing a car that hasn't seen much action in a certain class, figuring out it's P/W ratio is one data point that can indicate it's potential performance.

    For example, in ITA we all know that the CRX is a top dog, and it races with about 125 hp at the wheels. At it's racing weight of 2140, the result is 17.12 . Compare that with my RX-7, which has (theoretically!) 118 hp at the wheels, and races at 2380, for a P/W ratio of 20.17, and you can see that the RX-7 will need distinctly better handling (uh-oh), better brakes, (oh jeeez..) or better torque (what was I thinking!?) or some other combination of characteristics to run at the front.

    Just a wag here, but in ITA, 17 or 18 is a good number with solid handling and braking, and in ITS, the number looks to be in the 13?-14 to 15 range. I say "13?" because getting folks to admit actual numbers is tough, but I bet the faster E-36s are in the 13s.



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    Jake Gulick
    CarriageHouse Motorsports
    ITA 57 RX-7
    New England Region
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  15. #35
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    I liked my 6.1:1 better but my $7000 racer cost my insurance company a $30000 surgery.

  16. #36
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    I was thinking for ITB. : )

    Thanks....


  17. #37
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    Not sure what this means (maybe the Hondas aren't as developed as they should be) but we have one 12A RX-7 here in the SEDiv who is faster than any ITA car.


  18. #38
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    Originally posted by lateapex911:

    ... but I bet the faster E-36s are in the 13s.


    From what I've heard, try "under 12" for size.




    [This message has been edited by oanglade (edited February 24, 2004).]

  19. #39
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    Originally posted by oanglade:

    From what I've heard, try "under 12" for size.
    Are you talking crank or wheel horsepower? To get under 12 you would need ~240hp in a 2850lbs car. I can beleave they are getting 240hp crank but not 240hp to the wheels.

  20. #40
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    No, there is no way an E-36 is putting 238 down at the wheels! What did they come with stock? 190? At the crank! I think the rumoured 217 is pretty respectable....

    IF they did, it would be obvious, as the 7s are putting down what, 180? And THAT'S being optimistic. No way they could even SEE the bimmers after 4 laps if the bimmers were putting down 238!

    As for ITB, anybody care to toss out some numbers? How about you RST guys....you're being unusually quiet!

    I would GUESS that a good ITB number might be 21- 22?

    ------------------
    Jake Gulick
    CarriageHouse Motorsports
    ITA 57 RX-7
    New England Region
    [email protected]

    [This message has been edited by lateapex911 (edited February 25, 2004).]

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