136 replies to this topic

[Caveman-kwebb99]

OK, then if you are certain about the differences between bone stock please provide more information so we can all have better informed opinions. For example, for a given generation engine, quantify the difference between average (or median if that makes more sense) and the 90th percentile in terms of power and torque, based strictly on differences in stock heads.

Now do the plunge and repeat, comparing the average to the 90th percentile. And, how do those now compare to the stock range?

Now do whatever you propose as the spec "blend" and repeat.

Only with those kind of numbers can we hope to judge the best solution. You all sound so certain that I assume you must have a pretty good sense of them at least, so convince us.

 

I suspect its to damn late to do any convincing!

[john mueller]

Much higher than what we have now, shame we can't just fix enforcement rather than change the rules. 

 

I agree Alex and that was NASA's solution.  However several things changed that as an option.

 

• The heads found non compliant at Runoffs were expected to be tore-down. (they were believed to be legal or at least 'tech-shed legal')
• The 'blending' of the STR on these heads was very obvious.
• Most of these heads came from builders who are in leadership positions for the class.
• Measuring or quantifying 'a deburr' -vs- 'a blend' is virtually impossible to do (agreed upon by the three engine experts who attended our mtg)

 

That last point was a surprise to me, but we gave a fair amount of time to discussing all options for taking repeatable accurate measurements on head-to-head and it was arrived at that it basically can't be done.  In most cases blending is visible noticeable but in order to write a rule making it illegal we have to be able to measure it.

 

We're getting close on releasing a joint announcement.  Short term this may be rough but I really do believe over time it's the best thing for the class.

[Caveman-kwebb99]

I agree Alex and that was NASA's solution.  However several things changed that as an option.

 

• The heads found non compliant at Runoffs were expected to be tore-down - they were believed to be legal or at least 'tech-shed legal'.
• The 'blending' of the STR on these heads was very obvious.
• Most of these heads came from builders who are in leadership positions for the class.
• Measuring or quantifying 'a deburr' -vs- 'a blend' is virtually impossible to do (agreed upon by the three engine experts who attended our mtg)

 

That last point was a surprise to me, but we gave a fair amount of time to discussing all options for taking repeatable accurate measurements on head-to-head and it was arrived at that it basically can't be done.

 

We're getting close on releasing a joint announcement.  Short term this may be rough but I really do believe over time it's the best thing for the class.

 

If deburing and blending is that easy to see, we could just flat leave rules as they are and explicity make deburing or blending of any kind illegal... 

 

just my .02

[john mueller]

If deburing and blending is that easy to see, we could just flat leave rules as they are and explicity make deburing or blending of any kind illegal... 

 

just my .02

 

I'll have to edit my post because that's not what I meant...

 

It's not easy to MEASURE the difference between the two.  So if deburring was 'allowed' it would not possible to measure if it morphed into a blend.  In most cases blending is visibly noticeable, however to write a rule making it illegal we'd have to be able to measure it.

[Ron Alan]

I agree Alex and that was NASA's solution.  However several things changed that as an option.

 

• The heads found non compliant at Runoffs were expected to be tore-down - they were believed to be legal or at least 'tech-shed legal'.
• The 'blending' of the STR on these heads was very obvious.
• Most of these heads came from builders who are in leadership positions for the class.
• Measuring or quantifying 'a deburr' -vs- 'a blend' is virtually impossible to do (agreed upon by the three engine experts who attended our mtg)

 

That last point was a surprise to me, but we gave a fair amount of time to discussing all options for taking repeatable accurate measurements on head-to-head and it was arrived at that it basically can't be done.

 

We're getting close on releasing a joint announcement.  Short term this may be rough but I really do believe over time it's the best thing for the class.

Thanks John...somewhat answers my post in the other thread! Godspeed!

[Caveman-kwebb99]

I understand your point, so just make deburring and blending of nay kind explicilty illegal!  That seems easy peasy Japaneezy to me...

 

what am I missing here John?

 

What is stopping deburing of even a stock head if it cannot be measured? 

[Steve Scheifler]

Check your last sentence John, may be a typo.

[john mueller]

I understand your point, so just make deburring and blending of nay kind explicilty illegal!  That seems easy peasy Japaneezy to me...

 

what am I missing here John?

 

What is stopping deburing of even a stock head if it cannot be measured? 

 

No need to deburr a stock head, it's a common practice post plunge cut.

[Jim Drago]

Maybe we should wait for the announcement? 

[mmcspecracer]

Much higher than what we have now, shame we can't just fix enforcement rather than change the rules. 

Couldnt agree more. Tiley posted that for ARRC, his VVT heads were plunge cut and he left sharp edges -so its obviously not a problem to do that. Danny says it was the best race of his career and everyone seems to have had a great time. Consequently, everyone now understands the rule going forward and we dont need to change the rules. More and better enforcement will catch any future misinterpretations at an early stage of the racing season so we dont FUBAR the Runoffs. The guys who have illegal heads need to resolve the issue of getting legal heads with their engine builder. End of story - lets race.

[Johnny D]

Has there been discussion on Tech, etc.

 

This is kind of how we got here.

 

This will also be disclosed later?

J~

[wheel]

Maybe we should wait for the announcement.

wheel

[chris haldeman]

The proof is in the puddin. All the work that has been allowed in the past has brought the cars closer than ever before. All cars built by me of the same rule set dyno within 2-2
This work is being done so we builders can deliver a good consistent product. Current plunge cut, de shroud cut numbers have been pulled from the largest dimensions found on a stock un touched head. If rules change too not allow this the great flowing head search will be endless for those with money.

[MPR22]

Maybe we should wait for the announcement.

wheel

If the announcement is, leave the burr and move on.  Then the SCCA has done the right thing.  If the announcement is, all you hundreds, maybe thousands, of participants who have, shaved your heads to the letter of the rules and who have plunge cut your heads to the letter of the rules need to go buy unmodified stock heads heads.....

 

then the SCCA/NASA  are doing the equivalent of cutting off the arm to cure a hang nail. 

[Steve Scheifler]

Although vague on that point, I'm pretty sure this was not intended to impact shaving for trueing the surface or achieving specified CR. Clarification will be simple.

[Steve Scheifler]

BTW, I think you are allowed to change your vote above. Taking screen shot of how it looks now.

[Bench Racer]

No need to deburr a stock head, it's a common practice post plunge cut.

Are you saying OEM heads are deburred? ^ No, from my research there is zero removal of anything after the OEM plunge cut or head machining other than a high pressure wash. Also there are two large names in the auto mfg. world that machine the short turn radius. My info source is the OEM manager of a cutting tool company that operates in the US and around the world.