SC Pulleys for $85...
06-12-2002, 08:34 AM
#41
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Oh Yes,
Grant it, it is fun has heck getting beat out of the hole by mustangs and then
catching them at the 1/8 mark and passing them at the finish. The win is very
sweet.
But, I just rather beat them all the way.
Grant it, it is fun has heck getting beat out of the hole by mustangs and then
catching them at the 1/8 mark and passing them at the finish. The win is very
sweet.
But, I just rather beat them all the way.
06-12-2002, 08:59 AM
#42
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Diddy,
from what i can follow, our SC boost will not level off, as long as RPM's rise, boost will rise in a linear fashion since it is belt driven, constant speed. i think that turbo's "level off" because they have a blowoff valve that will open at a set boost. not sure if anything similar is available for SC's.
hecash
paxton people were skittish when i asked them output of unit, would only go as far as saying 11-12 expected. i guess the whole variance could be in dealing with the size of the piping/throttle body/manifold etc.
i think our problem so far is that not enough people with SC's are doing dyno's with boost being monitored for us to adjust our spreadsheets based on real info. when i did my run, they were able to plot the boost, but could not get me the actual datapoints, so i figure i am off a little on each one, only used major cross points where i had the RPM listed on the gridline and traced it over to the boost headings.
i think the progression of the boost should be linear minus small losses since the impeller gets a specific scoop of air on the input side and then compress it to push it out the other pipe. i am sure that at different speeds, external temp/air pressure, etc that the input will vary a little, but the output should be approximately the same throughout the RPM band. could also be something with airflow dynamics where at a low impeller speed, some of the air is remaining in the impeller area, at high speeds, more of the air is "thrown" out, making for smaller boost pressure being seen at low RPM and then increasing at higher speeds outside our linear expectations.
maybe if randy gives me his old pulley i can do another dyno run and get figures for that....
keith
from what i can follow, our SC boost will not level off, as long as RPM's rise, boost will rise in a linear fashion since it is belt driven, constant speed. i think that turbo's "level off" because they have a blowoff valve that will open at a set boost. not sure if anything similar is available for SC's.
hecash
paxton people were skittish when i asked them output of unit, would only go as far as saying 11-12 expected. i guess the whole variance could be in dealing with the size of the piping/throttle body/manifold etc.
i think our problem so far is that not enough people with SC's are doing dyno's with boost being monitored for us to adjust our spreadsheets based on real info. when i did my run, they were able to plot the boost, but could not get me the actual datapoints, so i figure i am off a little on each one, only used major cross points where i had the RPM listed on the gridline and traced it over to the boost headings.
i think the progression of the boost should be linear minus small losses since the impeller gets a specific scoop of air on the input side and then compress it to push it out the other pipe. i am sure that at different speeds, external temp/air pressure, etc that the input will vary a little, but the output should be approximately the same throughout the RPM band. could also be something with airflow dynamics where at a low impeller speed, some of the air is remaining in the impeller area, at high speeds, more of the air is "thrown" out, making for smaller boost pressure being seen at low RPM and then increasing at higher speeds outside our linear expectations.
maybe if randy gives me his old pulley i can do another dyno run and get figures for that....
keith
06-12-2002, 09:27 AM
#43
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Why don't you just put a turbo wastegate in your intake tract? They open when they see a set pressure, and open just enough to hold that presure. You can get a Delta Gate for $250 or so new, a lot less used. Another option is that old Audi 5000 Turbo cars used an external wastegate, and can be had very cheaply. I don't think you are going to find a valve that can vent that much air otherwise. I plan on trying this when I buy my vortech S/C. I am going to stick with 8 psi pulley for a while until I can get this working by limiting boost to 6 pis. Then I will get another pulley for say 14 and do the same while limiting it to 8 psi. I hope to be putting almost 8 psi into my engine at like 5.5k rpms.
What I am trying to get is whipple behavior fo the centrifigual cost and ease of install. We will see if I can get it to work. I just wish someone would get off their lazy ass and make a whipple S/C system for the S2000, but it isn't gonna happen.
What I am trying to get is whipple behavior fo the centrifigual cost and ease of install. We will see if I can get it to work. I just wish someone would get off their lazy ass and make a whipple S/C system for the S2000, but it isn't gonna happen.
06-12-2002, 10:26 AM
#44
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smaller pulley at lower speeds = more boost/torque/hp in low/mid range. higher speed pulley expands, limiting boost. it is a centrifigal pulley, use its spin rate to force the out the radius, sure sounds great!
but then the tensioner has to adjust for the difference in belt width, might slip when worn.
but on a serious note, a smaller pulley with a wastegate to blow off boost at higher end to keep engine safe might work, but i doubt that i will be the one to expreiment with that. will be happy to learn from other's mistakes....
no way could i police myself to putting in a very small pulley and limit my boost by limiting my RPM's..... i like seeing the tach display arc its way to the right!
keith
but then the tensioner has to adjust for the difference in belt width, might slip when worn.
but on a serious note, a smaller pulley with a wastegate to blow off boost at higher end to keep engine safe might work, but i doubt that i will be the one to expreiment with that. will be happy to learn from other's mistakes....
no way could i police myself to putting in a very small pulley and limit my boost by limiting my RPM's..... i like seeing the tach display arc its way to the right!
keith
06-12-2002, 02:04 PM
#45
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[QUOTE]Originally posted by KAMcDonald
[B]but on a serious note, a smaller pulley with a wastegate to blow off boost at higher end to keep engine safe might work, but i doubt that i will be the one to expreiment with that.
[B]but on a serious note, a smaller pulley with a wastegate to blow off boost at higher end to keep engine safe might work, but i doubt that i will be the one to expreiment with that.
06-12-2002, 02:53 PM
#46
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when i said limit RPM i meant never go above XXX rpm's by not putting my foot into it, if i had to do that, then where is the fun? i wind it out just to hear it sing and hear the harmonics as i shift to higher gears while slowing down to only 15 mph over the limit.... only had the SC for a few weeks, wonder now why i did not get it sooner.
keith
keith
06-12-2002, 02:55 PM
#47
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[QUOTE]Originally posted by KAMcDonald
[B]when i said limit RPM i meant never go above XXX rpm's by not putting my foot into it, if i had to do that, then where is the fun? i wind it out just to hear it sing and hear the harmonics as i shift to higher gears while slowing down to only 15 mph over the limit....
[B]when i said limit RPM i meant never go above XXX rpm's by not putting my foot into it, if i had to do that, then where is the fun? i wind it out just to hear it sing and hear the harmonics as i shift to higher gears while slowing down to only 15 mph over the limit....
06-12-2002, 03:08 PM
#48
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yeah, been doing that all along...
had a passenger one time trying to explain to him what VTEC was, he said he never paid that much attention. so i let the car in front get a little ahead, then hit rev limiter and brakes in 1st (damn bumper-bumper, red light ahead traffic!!!) and asked him if he heard/felt the change in engine at 6k.
funny thing was, he said he was not paying attention to the sound over his screams....
i offered to to it again, but he said no, never mind.
keith
had a passenger one time trying to explain to him what VTEC was, he said he never paid that much attention. so i let the car in front get a little ahead, then hit rev limiter and brakes in 1st (damn bumper-bumper, red light ahead traffic!!!) and asked him if he heard/felt the change in engine at 6k.
funny thing was, he said he was not paying attention to the sound over his screams....
i offered to to it again, but he said no, never mind.
keith
