10 replies to this topic

[ner88]

One of our cars was tech'd at Homestead, I was told our restrictor was one of the smallest they have measured.

What does the 38MM usually measure?

Back at the shop I see 37.8 mm

[Jim Drago]

One of our cars was tech'd at Homestead, I was told our restrictor was one of the smallest they have measured.
What does the 38MM usually measure?
Back at the shop I see 37.8 mm

All the restrictors measure the same... the tool was probably off. All the plates are stamped with same stamp, none are cut to avoid just this and all are under the specified size similar to your measurement above. You are not allowed to modify or open to exactly 38.00 in SCCA, Nasa I believe you can, but not worth the hassle IMO.

[Parity]

I was told they're intentionally made smaller to allow for thermal growth assuming they're inspected hot. If they measure over by any amount even if hot you fail. Measure it at room temperature, then run it under hot and try again. You'll definitely see growth.

[ner88]

I totally understand the reason for being undersized.

But, my question is how much under??  .20 or.05mm

This was a new plate and also had a very bad/rough lip left from the press/cut

[James York]

Mine measured 0.20 mm under when i had mine teched.  Seems to be the norm for them to run a tiny bit small.

[chris haldeman]

.25mm small on every plate I have checked, and I've seen quite a few

[davew]

The measurement on Voyteks was over 1 mm small. I plan on checking myself when we prep the car next week.

 

dave

[Jim Drago]

.25mm small on every plate I have checked, and I've seen quite a few

That is exactly what I see, on EVERY one

[ner88]

Thanks everyone, I never paid much attention, it was always just handed back after a check.

[Jim Creighton]

NER 88, if you are at another race when I am there, bring me your plate. I'll measure it with my tool. Bill E measured it and I saw what looked to be .050 under. The plate also had a lip on one side, something I had not seen for quite a while. Bill measured a lot of plates and only one other at Sebring was off, also another new one and it was .050 under. It was a silver plate. I believe yours was one of the weird color 38mm if I remember right.

 

The norm is .020 to .025 under on all the plates from Enterprise.

[Diller]

0.25mm small on a 47mm plate here. Guess it's normal for every plate.