Prep Differences Between SM and ITx

[gran racing]

I get where you're going with this Jerry and agree we don't want to turn away entries. At the same time, how a person gets to said HP does matter at least to the current GCR. Otherwise build a car much less expensively to achieve X HP than doing a full-on motor and other development work.

This is interesting and would love to see the document once done.

[ner88]

I get where you're going with this Jerry and agree we don't want to turn away entries. At the same time, how a person gets to said HP does matter at least to the current GCR. Otherwise build a car much less expensively to achieve X HP than doing a full-on motor and other development work.

This is interesting and would love to see the document once done.

That wasn't the direction I was going...
My concern is "how do we keep it simple for tech"
Because its a SM running in IT one can't assume the head was done to SM specs, in stock form it meets all the rules...

I would also suggest it costs more to build a front running SM motor (with less HP)than an IT motor.

[gran racing]

Alright, my bad.

[Andy Bettencourt]

I would also suggest it costs more to build a front running SM motor (with less HP)than an IT motor.

No way. Balancing, blueprinting, overbore, port matching, intake and exhaust design and testing, crank scraper, oil pan baffling...

Remember, lots of the little things SM's do to maximize factory specs can also be done in IT.

[ShelbyRacer]

No way. Balancing, blueprinting, overbore, port matching, intake and exhaust design and testing, crank scraper, oil pan baffling...

Remember, lots of the little things SM's do to maximize factory specs can also be done in IT.

Except that all that work allows you to recon things that aren't perfect. The SM ruleset has allowances for similar levels of precision, but the process by which you get there is completely different. I consider SM to be a LOT like Showroom Stock was when there were factory teams involved. Sure, you can't "modify" the factory parts (though standard recon is allowed within limits), so you go looking for the most perfect factory parts you can find. That said, I'm making some assumptions, and I'd think that Andy would probably know the exact cost of either build better than me...

Still, that valve pocket machining allowance is a sticking point for me. I realize that one of the reasons it was done was to "allow for core shift" so that you can build a "spec" motor wiithout having to go through 50 or 500 castings looking for the best one. However, having done significant amounts of headwork in my time, that allowance, even with the "sharp edge must remain" and the "no aluminum in the bowl area or the ports may be..." clauses, there's still quite a bit of allowance beyond IT. There's certainly enough difference to make a big dent in the difference between a "stock" motor and an IT build.

Also, Andy, the way I read the SM rules, there is more than ample allowance for rudimentary balancing and blueprinting. While it may not offer all the latitude of the IT ruleset for that, I can see how it can be done to a degree that would allow for the performance that's been reported so far from SM motors on the dyno, if not even a few hp beyond that.

Oh, and I believe the 100 lb. weight difference on the 94-97 1.8L to be very significant, though I would hope that at least that would be picked up on in impound.

[Andy Bettencourt]

I think for some the SM rules may actually define some of the details of what some of these ragged-edge, tech shed-legal IT motors are doing.

Think about the valve allowance. It's possible you are right on the money for the reasoning behind the allowance. So if the spec is set so that you don't have to go after 100 heads and find the perfect one, you could surmise that the spec is a 'perfect stock' unit.

Guess what? You got to do that in IT to be at 100%. Right? (All based on the accuracy of your assumption in the hypothetical).

[Knestis]

Late to the show but I think the original question has gotten spun around some here...

I think, Greg, that your original problem stems from people being sloppy and/or playing fast and loose in failing to 'declare' what they are running and under what rules. Right?

I'm reminded of when we used to run IT cars in Street Prepared solo classes. We technically couldn't pick and choose allowances from between the two rule sets but people quickly started coming up with all manor of wackdoodle hybrid things.

K

[Greg Amy]

Right. Some mistakenly, some intentionally.

I've submitted a request to the CRB to require competitors to declare their prep level on the side of the car (e.g., "ITA/STL"). We'll see if they go for it. From there I continue to work on my knowledge articles so everyone's clear about the regs.

- GA, who forgot about the SP allowances in Solo II...used to run my ITB Scirocco in CSP, was it?