Landracing Forum
Bonneville Salt Flats Discussion => SCTA Rule Questions => Topic started by: fj1289 on April 07, 2014, 12:12:35 AM
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If the carbs are not visible - can they be replaced? If so, could they also be replaced with throttle bodies as long as the modification cannot be seen?
For P-PB class, can the turbo be replaced if it remains hidden from view and mounts to the stock exhaust and air box?
Thanks
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Back in the day, venturies had to be the same size but they dropped that requirement years ago. As long as the airbox and exhaust are unmodified from stock you should be good. Stock replacement Turbo fits and is hidden from view should be OK as well....
But I don't get a vote... contact the scta motorcycle chair for a final written ruling..
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fj here is the rule
7.J ENGINE CLASSES
7.J.1 Production:
Production engines shall be the same model as the model of the frame being used and shall have
STOCK EXTERNAL APPEARANCE. Production motorcycles shall use OEM cylinders, heads and
crankcases to comply with this class. OEM engine displacement determines the displacement class for
competition. Displacement may not be increased beyond that class limit. Starting mechanism shall be
retained and operable. Carburetors or throttle bodies shall be OEM for that model production engine. All
production engines run in gas class. See Section 7.D.3
So it it is pretty clear. You can't change them.
What sort of internal changes you can make to the Carbs, I'd usually clarify things like that with the Tech People.
Just remember, Production is just that, pretty much Maxing out what the Factory gives you. That is what makes the Class the challenge it is. 8-)
Pete :cheers:
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Opps, yep what he said of the carbs... I thought that used to be in the production description.... guess it is back with engine classes...
Been over 10 years since we ran production.
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DOH! Thanks. I got stuck in the chassis section and didn't remember the engine section...
Turns out it was an oddball engine displacement too -- 3 cc's over its "badged" displacement.
Thanks for pointing out the obvious and where to find it
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fj I got caught out at my first Speedweek over here trying to Run Production. Ended up in M-G :-)
Pete :cheers:
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The rule regarding the turbocharger is that "but an original brand factory installed turbocharger or supercharger is required". I don't know if this leaves much for interpretation, no matter if the turbo is visible or not. My take is if it came with a Hitachi, or IHI turbo, then you can't put a Garrett on there. Since production requires that you be able to provide documentation for standard parts, this seems pretty clear. Obviously an e-mail to someone at SCTA is going to be the final authority on this, not us rule book lawyers.
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Turns out it was an oddball engine displacement too -- 3 cc's over its "badged" displacement.
So if it is 653cc, then you are over the limit for 650 and have to run in the 750 class with the Kawasaki 750, 167mph record. :-o
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Mostly "what-if'ing" the rule book - looking for future projects.
Yep - the Kawi 750 loks to be the best weapon for the job...and there are a lot of folks out there that know them a lot better than I do.
One more bunch of "out there" questions concerning production engines -
What types of mods are acceptable to the OEM carbs or throttle bodies? Can they be bored to a larger ID? Can they be bored to the extent they need to be epoxied? Could a set of CV carbs be modified to function as slide valve carbs and the butterflies be removed? Or could a set of carbs be modified to accept fuel injectors and remove the slides? Just curious how much creativity is allowed? Or where does it violate the "spirit" of the class? Especially in a niche class that hasn't had a qualifying model produced in nearly 20 years.
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Rule book lawyer advice again, it says it has to be a stock carb or throttle body, so unless the originals came with epoxy on the exterior, it sounds shaky to me. I am sure the guy who's record you just beat will point out the epoxy too. As far as internal mods, I think that is wide open. If you can disguise a fuel injector to look like a carb without additional hoses, wires, pumps, or regulators, I can't see what is wrong. Again, before you start an expensive project, be sure to send a quick email to one of the rules guys, as their decision counts more than 100 opinions on the forum.
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If you are looking at a Honda CX650 Turbo would that be in P-PPB and be running against a 133.625 Record?
Pete :cheers:
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We ran a Turbo Seca and it went into 750 class because of it's displacement. The kawi is best as it is not saddled with a shaft drive! And it actually made decent power.