New Tool For Tech

[Dave Zaslow]

NNJR has a new tool.

Simplified:

Take cylinder temperature

Measure bore

Measure stroke

Attach Whistler

Read compression ratio

[quadzjr]

Still with analog gauges when you can get down to the hundredths place for pass/fail. I still would prefer a digital meter, that can be calibrated. However, it is still better then the current pratice.

[Greg Amy]

Note we also have tools for measuring bore and stroke without pulling the head. As I understand it, these tools were purchased, and are wholly owned, by the region using Spec Miata compliance funds. So, they get first dibs, of course. But these tools are valuable for non-destructive tech checks. Especially given our recent discussions on wanting to keep everyone honest, I suggest we use it often, if nothing else to see how it works and keep Tech on its toes.

How about each class get together and agree to use it post-race on one random competitor each day? Everyone's name goes into a hat and a random name is pulled, and they get a full Whistler check. I'm sure Scott would be OK with this, as long as they're not incredibly busy. Absent a formal protest someone could certainly refuse the test, but that would simply draw attention to them, inviting a future protest.

We've got it. Let's use it.

GA

[Andy Bettencourt]

+1. How about top 3?

[quadzjr]

+1. How about top 3?

I like that idea. Would it have to be done during the 30 minute impound? If so it woudl make it a very busy 30 minutes to get to the top three in each class per run group.

[Russ Jones]

It's a good idea and I'm for it, one thing, we have mostly
RX-7's in ITS can we do some sort of check with a rotary engine too?

[Greg Amy]

Would it have to be done during the 30 minute impound?
Only if you want a Steward to have the ability to bounce the car post-race.

I'm personally thinking more inline with a self-policing "gentleman's agreement" type thing, more of a peer pressure to "encourage" competitors to show up with a clean car. If done by Tech but outside the formal 30-minute system, we have the flexibility of time and space (and I'm not worried about someone running back to their pits and hurriedly changing their compression ratio back to 1/2 point over... ;))

Russ, we do need some way to check rotaries. But, unfortunately, I think we only have the finger method, and not too many objective proctologists that know what they're looking for (i.e., the guys that know are the ones that are doing the checks, so it's a moot point).

GA

[gran racing]

I'd be all for it.

[Andy Bettencourt]

How about after qual but before the race? Good 3 hours there. Assuming there was no damage repair to be done, I would have no problem leaving my car in an 'impound' garage at NHMS while it was checked out.

On the RX-7's, I don't know much about the ARRC tests but it would certainly be possible to provide a template of stock-shaped exhaust ports. Maybe a few of us could get together and have something that slipped over the header bolts and lined right up to the posts ala a gasket made for NER. It should be easy to see if the shaping was out of spec.

[Chip42]

keep in mind also that only center-plug heads (a'la miata, toyota 4A-G, etc...) allow bore + stroke measurement with the head on the car. as these measurements are needed for the wistler, only those cars can be checked. otherwise, the head comes off or book value have to be entered and results will not be fool proof.

generally, I like the idea, but specifics of use make it less appealing in mixed-engine classes.

[MMiskoe]

Might want to establish a plan for how accurate you expect it to be. Websites list it being +/-.1 point. So if you have a car that is .59 higher than OE do you do a teardown or not?

It also lists it needing the motor to be between 30 and 200deg F. On a hot day there will be some waiting for the motors to cool down. To be more accurate it would better to measure after the motor has been shut down for a couple of hours so it is at (or near) ambient temp so its not cooling as you go.

Does anyone know how it really works? No details turned up on a quick search. I assume it measures the 'springy-ness' of the air pocked in the cylinder and from that it can extrapolate the volume? But it has to do this w/o pressurizing the air pocket very much.

I'm curious to see how it works (but hope it doesn't stir up a bunch of teardowns that turn out to be un-necessary).

[dickita15]

The 30 minute is the minimum impound for a national race. There is no maximum.