Anyone have one or know someone who does???
Raymond
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Anyone have one or know someone who does???
Raymond
SCCA has one, it gets used just a "little" at the runoffs.
SCCA has two and, yes, they get used a bit at the runoffs.
Club Racing bought the second one used from Pro, when Trans-Am went down...
Raymond
We have one here at our shop. What would you like to know.
Dave Parker
For those that don't know what it is....
Static engine compression ratio meter
The WHISTLER is an electronic device that instantly determines the compression ratio of virtually any engine.
Using the WHISTLER is easy, just remove a spark plug and screw the WHISTLER adapter in its place. Enter the number of cylinders, CID, and temperature of the engine into the WHISTLER. Then, bring the engine to TDC and the unit will display the compression ratio to the nearest tenth of a point.
http://www.katechengines.com/corpora...s/whistler.php
http://www.katechengines.com/corpora.../whistler1.jpg
Dave-
I would like to get one to an event next season... If it is sooo easy to use I don't know why we wouldn't use one next season at a random event in tech for a spot check.
Raymond "The Steward in me" Blethen
Well, for one thing they cost over $2,000, which is a chunk of change for Tech.Quote:
If it is sooo easy to use I don't know why we wouldn't use one next season at a random event in tech for a spot check.
My original thought was some local roundy round but maybe we can find a reasonably priced rental for the weekend??? hummm
Raymond "That is if SCCA wouldn't let the region use it..." Blethen
First a quick disclaimer that I don't have a ton of experience with engine building. Now, that being said, I've been told by some engine builders that although the Whistler works for Spec engine type classes, it won't work too well for IT where you can overbore. Part of the Whistler algorithm is based on the engine displacement... which changes with an overbore. No way to insure displacement so your compression # doesn't mean a whole lot. GIGO.
You are correct, the overbore of the engine does have to be known in order to get a good reading with the whistler. The displacement, in cubic inches, is put into the machine along with the temperature in the cylinder and the number of cylinders. The whistler was used at the Runoffs this year in several classes.Quote:
Originally Posted by Xian
Ray, Steve, are you just trying to determine the the compression ratio of the Audi's?
Bill-
I think it would be more interesting to watch you use it while I watch as a tech steward... Just about everyone would be fine, and it would cut back a lot of rumors.
Raymond
So if you were "smart" with all this stuff, couldn't you get a factory bore high compression engine to "whistle" the same tune as an overbored, legal compression engine? There are many (most??) engines that'll make more power on compression than they will on overbore.Quote:
Originally Posted by wdether
How does $2,000 for a region compare to all the other costs of running a race season? I certainly would be willing to pay an extra $10/race for the region to get one.
Or am I being way too simplistic?? (says Jeff after reading Greg's discussion on the FWD adder/subtractor!! :blink:)
Ray,Quote:
Originally Posted by RSTPerformance
Whistlers are available on loan from SCCA. If the SM compliance program continues in 2009 there might be training sessions held during one or more races in the NE. If the SM compliance does not continue in 2009 it still might be a good idea do some compliance checks with the whistler at one or two events. Checks would not be just on Spec Miatas. I could let you know. By the way, DC Region has a whistler.
Xian,
Some head configurations do allow for measurement of the bore through the sparkplug hole.
"So if you were "smart" with all this stuff, couldn't you get a factory bore high compression engine to "whistle" the same tune as an overbored, legal compression engine? There are many (most??) engines that'll make more power on compression than they will on overbore."
If the whistler only determines the unswept volume, then the C/R it determines would be a function of the swept volume value that the operator entered into the device-if a stock bore was assumed rather than the up to +.040" allowed overbore-then the C/R calculated would be lower than one with a larger bore.
Two points come to mind:
The operator could make calculations of C/R with standard and +.040" values.
A 040" overbore doesn't raise C/R profoundly. What we're looking for isn't a motor that is 9.7/1 when the limit is 9.5. We're looking for much higher deviations, the kind that return major changes in torque, the kind that are properly illegal and reprehensible. Kinda like the difference between a car that's 2lbs underweight and one thats 150.
It's an interesting idea, but for general use/checking I see some issues as have been pointed out above. And, If I build my engine to be 10.4999:1, when my starting point is 10:1, and this reads within it's stated range of "nearest tenth of a point, does that mean if the CID were incorrect, it could round me into illegal land? In other words, if it isn't 100% accurate, can it make a cheater out of a legal guy?Quote:
Enter the number of cylinders, CID, and temperature of the engine into the WHISTLER. Then, bring the engine to TDC and the unit will display the compression ratio to the nearest tenth of a point.
I understand it's great at doing the same engine again and again, like Chevy 350s, but I'd want assurances that it had the accuracy not to err and cause MORE questions than it sets out to answer when it does many varied examples.
First, it IS NOT 100% accurate. Its stated accuracy is within 0.1 C/R, and that's derived from large capacity engines such as 'Merican V8s.Quote:
Originally Posted by lateapex911
Second, it needs official documentation and calibration from the supplier to ensure its accuracy. That documentation should include statements of accuracy with percentages of either displacement or compression ratio.
Third, a Whistler reading should NEVER be used as a go/no go for tossing someone, but ONLY as a baseline indication for if an engine needs to be torn down.
If we choose to break out a Whistler for compliance checks - and I'm not opposed to the idea - we need to be prepared to break down engines for actual compression ratio checks were one to "fail" a Whistler test. That means the regions that use these devices need to be prepared for engine disassembly and be equipped with the tools, equipment, and skills for actual measurement of compression ratio.
I can assure you that if I were tossed for illegal compression as measured by a Whistler (assuming within a tenth or two), there will be an immediate appeal. The Chief Steward will be forced to have the engine disassembled and Tech will monitor our removal of the head and then will have to accurately measure all the volumes of the engine. And, per GCR 5.12.2.c.5:If the car is found to be eligible for the competition in which it is entered, the race organizers shall stand the expense of the disassembly, inspection, and reassembly.Again, I'm not against the use of the tool to detect macro deviations from the regulations; it's a great tool for checking to see if someone is running a 12:1 engine in their first-gen ITA Acura Integra, and that's what it was designed for. But, if you think this tool is good for checking for someone tickling up against the limits of prep, you're fooling yourselves...
Just sayin'.
GA
Greg- good points...
How about a CR check after qualifying with the results posted for competitors to make a decision on protesting or not? Obviosly we would need a disclaimer about the accuracy of the results that are posted. I do think that we should be self policing, but I think we need some help/guidence on a good decision or not.
Raymond "We all know that it is very expensive to pay for a teardown, but we all wanted to see one at one point or another." Blethen
Can anyone calculate what the range of C/R would be on a, for example, 2.2l engine at stock bore and .040 over? That would give us an idea how accurate the Whistler is in our arena.
Calculate the volume of a std cylinder, and one that is +.040" oversized.
Got to GCR and find the formulas for C/R calculation.
Using the (known) desired C/R, solve for unswept volume using std cyl.
Calculate new C/R using 40 over swept volume.
The math is simple; the measurement's the problem, esp if piston isn't flat-topped.
Raymond:
Get your hands on one this winter, I'll help you round up a few people willing to have a car checked to see how it really does report. If it does what it says, you should be able to run around and do street cars to see how it behaves. Should be in low demand for the next couple of months.
I do not see that it has the accuracy to back itself up. Like Greg said, once you throw the hockey gloves down on the ice & point at some & say "cheater", you best be ready for the 5 minute misconduct & game ejection.
Its a great idea to try out, but you might be better off doing it on the side so you can learn what to expect before bringing it to a race. Once you do it in the tech shed you're committed to doing tear downs.
Matt
really fun if the piston has a dome........but I agree the math is simple.Quote:
Originally Posted by pfcs
Heck I wrote a program for it on a Apple IIe in high school :)
Bora scope is better spent $, You could CC most of these engines, and do the math for size and compression,pretty easy. IMHO.