"Diaphragm" or "Piston" Diverter?
12-03-2004, 12:08 AM
#1
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"Diaphragm" or "Piston" Diverter?
Hey All,
I was looking at forge's website.
http://www.forgemotorsport.com/vehic...product=FMDVRA
I was just curious which is better and why? The race ones they sell only come in Diaphragm...is there a reason for this? Thanks
I was looking at forge's website.
http://www.forgemotorsport.com/vehic...product=FMDVRA
I was just curious which is better and why? The race ones they sell only come in Diaphragm...is there a reason for this? Thanks
12-03-2004, 05:48 PM
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Just curious, but why so many posts about how a diverter/BOV sounds? Is that really part of the buying criteria? Sorry to hijack your thread, Derek. Don't take it wrong. Your thread just gives me the opportunity to ask the question.
I read the Japanese tuner mags ever now and then and these guys have the BOV's with what look like fog horns on 'em. Guess I never thought the sound coming from under the hood is very important. But I do have to admit that hearing a fully race prepped 935 go whistling by at full boost is awfully wicked.
OK. You can have your thread back Derek ;-)
I read the Japanese tuner mags ever now and then and these guys have the BOV's with what look like fog horns on 'em. Guess I never thought the sound coming from under the hood is very important. But I do have to admit that hearing a fully race prepped 935 go whistling by at full boost is awfully wicked.
OK. You can have your thread back Derek ;-)
12-04-2004, 12:14 AM
#6
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diaphrams can tear...just like our stock deverter valves...the ones without a diaphram will never tear. One less thing to go wrong. Lindsey sells a billet deverter valve replacement(no diaphram) its 125 bucks. I just ordered one because I tore my stock deverter valves diaphram from running 20psi.
12-04-2004, 03:43 AM
#7
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"my understanding is that the diaphram valves have a limit on how much boost they can handle."
It's not so much the boost, but rather the action that wears them out. Open-close-open-close in rapid succession wears out the rubber diaphrams. If you draw a picture of the valve, you'll see that boost is equalized on both the top and bottom of the diaphram when it's closed, so there's no net force on the diaphragm regardless of the boost-level. It's only when you let off the throttle, then you have vacuum on top that opens the valve against the spring. FWIW, I've worn out the 'better' 993 unit with the brass center instead of the stock 951 plastic center. But they both broke in less than 2-years when the rubber diaphram part ripped.
It's not so much the boost, but rather the action that wears them out. Open-close-open-close in rapid succession wears out the rubber diaphrams. If you draw a picture of the valve, you'll see that boost is equalized on both the top and bottom of the diaphram when it's closed, so there's no net force on the diaphragm regardless of the boost-level. It's only when you let off the throttle, then you have vacuum on top that opens the valve against the spring. FWIW, I've worn out the 'better' 993 unit with the brass center instead of the stock 951 plastic center. But they both broke in less than 2-years when the rubber diaphram part ripped.
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12-04-2004, 02:23 PM
#8
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Originally Posted by alexands
Just curious, but why so many posts about how a diverter/BOV sounds? Is that really part of the buying criteria? Sorry to hijack your thread, Derek. Don't take it wrong. Your thread just gives me the opportunity to ask the question.
I read the Japanese tuner mags ever now and then and these guys have the BOV's with what look like fog horns on 'em. Guess I never thought the sound coming from under the hood is very important. But I do have to admit that hearing a fully race prepped 935 go whistling by at full boost is awfully wicked.
OK. You can have your thread back Derek ;-)
I read the Japanese tuner mags ever now and then and these guys have the BOV's with what look like fog horns on 'em. Guess I never thought the sound coming from under the hood is very important. But I do have to admit that hearing a fully race prepped 935 go whistling by at full boost is awfully wicked.
OK. You can have your thread back Derek ;-)
Ok but why would forge have both the racing valves in diaphragm only?? No piston racing valves available...im i just looking into this too much?Thanks