207 replies to this topic

[LarryKing]

 

Really? Dude.

https://www.youtube....h?v=RL1Vcn8yX1g

 

Noncompliance now compliant - more rules creep. Ms. Noble's vow to return the class to its original intent sweeped under the rug and stomped on.

[Bad Rusty]

Previously compliant is still compliant in 2015, and non compliant in 2014 is non compliant in 2015.

Here's a real hero for you

Www.chriskylefrogfoundation.com

Merry Christmas!

[LarryKing]

That's Hiro with an "i", not hero.

[FTodaro]

https://www.youtube....h?v=RL1Vcn8yX1g

 

Noncompliance now compliant - more rules creep. Ms. Noble's vow to return the class to its original intent sweeped under the rug and stomped on.

Lets take a closer look.

the change making sure the plunge cut is centered= taking some gray out of the old rule so you cannot take advantage with an angled cut.

adding 1.5 mm deburr, yes that is creep of 1.5 mm but that sadly will not save any of the runoff heads and likely a good number of heads out there. the only reason IMO they did that was to allow for heads that were done at the local machine shops that followed standard practices and not aware of how sensitive our spec head rules are.

There is not allowance for non complaint heads so no wt to be added, If you call that rule creep so be it, but you can argue it creeped both ways.

So depending on your point of view the rule could be said to be more restrictive. .

 

Some testing that i heard about showed that a stock head with a plunge cut and sharp edge was actually worse that some(not all) stock heads. a plunge cut with a slight deburr got back to the stock head.

 

So if the original purpose of the plunge cut was to get the biggest number of heads to be consistent, then this clarification was consistent with that original goal IMO. 

[LarryKing]

Depends on what your definition of "is" is.

[Andy Mitchell]

Don't know if it would help or not, but maybe the folks who are upset about the 1.5 mm thing should pull out a ruler and see just how small that actually is. I know it surprised me, probably because I'm accustomed to thinking in terms or inches. It actually is plausibly within the realm of a routine 'deburr', instead of of full-on porting.  

[James York]

Ms. Noble's vow to return the class to its original intent sweeped under the rug and stomped on.

 

While I don't agree with your description of how the decision progressed,...... I am glad that one persons personal opinion and knee jerk reaction was not supported by the MAJORITY of SM racers and the club chose the best path for its membership.

[wheel]

1.5 mm is .059", slightly less than 1/16" - .062".  It was specified to allow a little slop over someone doing a 1.0 mm scrape with a blade or abrasive device.  It will be interesting to see what the dyno shows.  My bet is that whatever it shows will be within the static of the system.  

wheel

[Jim Drago]

 

 

more rules creep. Ms. Noble's vow to return the class to its original intent sweeped under the rug and stomped on.

 

Ironically, Ms. Noble and the committee added the 1.5 MM deburr. The deburr was NOT in the SMAC recommendation at all. It was added at the request of the committee.  

[Bench Racer]

Ironically, Ms. Noble and the committee added the 1.5 MM deburr.  It was added at the request of the committee.  

This is not aimed at Jim or Wheel, only an observation.

 

Would it not have been sensible to specify the de-burr as .062 inches maximum. It's all most a joke reading only the plunge cut and STR specifications. Some specs are in mm and some specs are in inches. Many SCCA members have the metrics to inches conversion number on the tip of our tong, me included. BUT, a conversion is required leaving room for error and my machinists tool cabinet or my mechanics tool boxes have zero measuring tools for metrics.

[Cnj]

While I don't agree with your description of how the decision progressed,...... I am glad that one persons personal opinion and knee jerk reaction was not supported by the MAJORITY of SM racers and the club chose the best path for its membership.

To add to this, ms Noble is not a rules decision maker - but the club administrator (which in our club is a significant job). The BOD defines the rules.

So I see King Hiros complaint as fallacious.

Cnj

[Danny Steyn]

I believe that there is still some testing going on, or about to go on, behind the scenes to establish just what a 1.5mm debur gives on a dyno. I have heard from some who have done it already and as Wheel states above I suspect that we will see that it might be in the region of 1-2HP, within the noise of sequential dyno pulls. 

[FTodaro]

1 to 2 hp is more than noise IMO, if the question is 1.5mm vs. sharp edge.

Edit: I should retract this statement above after reading Daves post below, I am not really sure how they are testing. IMO if we are discussing the comparison of a sharp edge plunge cut to a cut with a 1.5mm deburr, I would be surprised to see a 1 to 2 hp gain. That was repeatable.

[ChrisA]

I would suspect that they are using something more accurate than a chassis/wheel dyno. I would hope, bench flow testing the heads in the various configurations and then engine dynos of those configs (with and w/out RPs).

[Dave D.]

While I have not dyno'ed many Spec Miatas, I have either for personal cars or cars through my shop dyno tuned larger V6 and V8 cars( both full race and street rod types) and feel that 1% error would be acceptable/expected and the 1 to 2 HP differences between pulls to be "noise". Maybe Drago or Kessler can say that in their experience,if they did see repeatable 1 to 2hp differences that translated into repeatable results on the track that may help others to get their head around this, but at the regional level,would the majority of SM drivers  feel the difference?  I feel, and a few well known race engine builders(albeit circle track)  feel that a chassis dyno just isn't as "scientific" as an engine dyno. There are just too many variables(noise) that can affect repeatability/accuracy to worry about 1 to 2HP. I may be out of line here, but are we maybe getting crazy over numbers that may or may not mean anything?   

[Bench Racer]

 I may be out of line here, but are we maybe getting crazy over numbers that may or may not mean anything?   

David D. in my humble judgment all the illegal head talk/de-burr/STR/dynos and all is more about cheating the rules than any thing else, no doughtthere are gains from massaging the bowl and runner. The lates issue was HeadGate at the 2014 Runoffs while previous to the Runoffs there was WhistlerGate issue in Florida. It was found the Whistler blew a lower compression ratio number with the valve cover on then cover off. Being compression most timers untill then was blown with cover on, folks stated cheating the Whistler. 

 

 

David Dewhurst

and #14

[Dave D.]

David, I wasn't playing down the blatantly cheated up heads. I am referring to the what I feel extreme nit picking over a machine shop breaking a sharp edge after the plunge cut. It seems me some are splitting hairs with worrying over allowing 1 or 1.5 mm of deburring and it's effect on performance. I am totally against the blatant bowl,radius and port work.  

[Bad Rusty]

That's Hiro with an "i", not hero.

Yep, and you're still no hero.

[Bad Rusty]

And post your name you pansie

[Bad Rusty]

Or whatever your friends call you in Daesh