restrictor throat testing device...

[mason]

does any one know what the restrictor throat testing device looks like? Ball? flat plate on a rod?

-john mason
chief engineer engine team
Cal State Northridge
www.ecs.csun.edu/sae (http://www.ecs.csun.edu/sae)

[mason]

does any one know what the restrictor throat testing device looks like? Ball? flat plate on a rod?

-john mason
chief engineer engine team
Cal State Northridge
www.ecs.csun.edu/sae (http://www.ecs.csun.edu/sae)

[Alfonso Ochoa]

Jajajajaja....it just make me laugh thet I think we all have thought about that dude. I'm pretty sure it's a flat pad and they turn it plenty of times....

Alfonso Ochoa Vega
cabezota311@hotmail.com
F-SAE USB Team, Venezuela

[Nigel Lavers]

From what I remember it's a ball with a rod on it that they kinda jam in there (forcefully)!

As for tolerances... I would make sure to make 2 venturi's if you are doubting it (one small and one on size). We sure are.

Nigel

[Richard Lewis]

Our final restrictor orofice is 19.99mm and made from aluminum. I missed seeing them test it on our car last year, but how forcefully are we talking about here? (ie: BFH?) http://fsae.com/groupee_common/emoticons/icon_eek.gif

-------------------------
UVIC Formula SAE Team
http://members.shaw.ca/drax77/UVICFSAEcar.jpg
http://uvic.fsae.ca

[Charlie]

It is not a ball, it is a bar with a rounded end. They attempt to slide it through at several different angles to make sure the hole is not oval. The particular judge that tested ours the last 3 years was not in the least forceful.

-Charlie Ping
Auburn University FSAE 1999-present

[Frank]

if it was 19.9mm

you'd lose what? 1%?

notice 1% on a dyno, a flowbench repetitively?

perhaps, but i doubt you'd see the same result next month!

why risk anything in the manufacture of your restrictor (regardless of design)?

0.1mm is a pretty big diametral interference

so what about 19.92-19.94mm, more reasonable for plastics..

19.95-19.97mm, yeah id do that with metals..

why on earth would you try and approach 19.99mm?
you'd have to WANT damage to occur to the device

$0.02

[Kevin Hall]

I'm sure that the judges are reasonable when measuring the restrictor. When is the last time you took a micrometer, set it to size, and then forced it onto a part to make sure it was the right size?? If you want to make one that is bang on at 20.000mm, go right ahead. It will probably pass, as I would believe that the measuring device they have is 20.001mm to check for OVERsizing!! If you are going to make it that close, temperature is going to make a difference, so having that spare at 19.900mm may not be a bad idea. Afterall, what does it cost to bore out a second one - $5 for material, and another hour on the lathe. If your budget is that tight, you won't survive testing, and remember, spares aren't cost, so it won't matter there either. Good luck http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Frank]

why do i bother?

[Richard Lewis]

20mm is 20mm, and that is what is stated in the rules. 19.99mm is 19.99mm. I've made mine exact, and I don't see why the judges cannot do the same. In which case, there is not a problem.

However, the point of making a spare is a good one. Doing it now sure beats running around at the competition trying to do it.

-------------------------
UVIC Formula SAE Team
http://members.shaw.ca/drax77/UVICFSAEcar.jpg
http://uvic.fsae.ca