Roots Type SC
Joined: Oct 2003
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From: MAHT-O-MEDI
Originally Posted by s2000Junky,Jan 22 2008, 02:01 PM
He was running 10psi as a daily driver, with the servo boost control he could have it dialed down to just a few psi in the lower rpms, but it was still not the most reliable, water injection helped stabilize further to prevent detonating. I think front wheel drive cars are gay but my Friend was into them at the time, he and a group of his friends founded club SI and were doing stuff like this before anyone. I think the automatic servo boost control was patented.
Sounds like they are starting to come out with some refined versions that can actually work for us. I would be currious to see more. I might have to get in on it.
Sounds like they are starting to come out with some refined versions that can actually work for us. I would be currious to see more. I might have to get in on it.
If you run higher boost and get the related heat, you need an intercooler or other solution.
Sure you will run into problems if you want 15psi out of this thing, but I'd be very happy with 7 psi out of it. This is not like the a CF blower that makes 7 psi at the end of the rpm range for a quarter of a second before a shift. Full boost almost in an instant and fat torque curve all the way.
The downsides for me are the battery thing, and figuring out what you want to do to your hood to let out some heat and get cool air to the blower.
Joined: Aug 2006
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From: Huntsville, AL
Originally Posted by s2000Junky,Jan 22 2008, 03:28 PM
My concern with the roots is that 5-7 psi at 3000rpms is a problem.
Hope that your bad experience with another company
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[QUOTE=MugenRioS2k,Jan 22 2008, 01:57 PM] after 15K miles on one kit out in hot Arizona and approx 7000 miles on one here in AL both AP1's (My AP2 to go on very soon) there has been no problems with detonation due to a very solid tuning and the Air to water IC.
Hope that your bad experience with another company
Hope that your bad experience with another company
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its not like tour going to be pulling away from a light and BAM! 7psi! you have to give it full throttle to make the full 7psi(or whatever your pulleys rated at)
usually on my civic it wouldnt give me the full 7.5psi untill around 4k or so, so it wasnt like i had to go easy on my launches so i didnt over boost the engine at low rpms
usually on my civic it wouldnt give me the full 7.5psi untill around 4k or so, so it wasnt like i had to go easy on my launches so i didnt over boost the engine at low rpms
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Originally Posted by s2000Junky,Jan 22 2008, 02:25 PM
So what are the psi levels at for a succesful experience at 3-4k? I know our engine is well capable at high rpm's. I just don't see how a roots type blower can work without some kind of automatic variable boost control to be efective at all rpms of a F20-22 without running meager boost of say 3psi for fear of destroying the motor. Its typicaly a v8 blower, what has changed that has made it adaptable to run with our engine at low rpms without detonation? How can our high strung 4 banger consume what this thing puts out at such low rpm? Tuning isn't the aswer. You can only have so much timing retardation, or is that it? A wide sweep of timing for maximum retard at low rpm and then advance as the the engine can consume what the blower is putting out, is that enough?? I don't know. But if someone can asnwer my question of what has changed to allow a roots to work for our application now, that would be great. The centerfuge blower works great because its natural tendancy is to build boost as the engine makes revs, which is much later where the engine can safly handle it. My understanding is the roots comes on all at once at such a low rpm, that it would destroy our engine without allot of safguards to then limit most of the bennifit the roots would otherwise offer. Help me out here...
you can see the bypass in the picture of my blower, its that orange hose near where the throttle body bolts too, when the boost is high in the manifold it will recirculate it back into the intake..i dont really know how it all works but it works...
if you look the pics of that s2k blower, u can see the black diaphragm on the top of the unit(its black with a little silver rod sticking out) thats the bypass valve, connected to it will whatever relieves the pressure...
Joined: Apr 2007
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From: Long Beach, MS
The bypass valve is not there to relieve excess boost. At part throttle without such a bypass system you would still have a partial vacuum in the intake manifold. You would just have a little less of a partial vacuum at a given throttle opening. But you would compensate by opening the throttle a little less to maintain your desired cruising speed.
The bypass valve opens at part throttle cruise to avoid pumping losses that would otherwise develop under those conditions. The result is better gas mileage under cruise. Allowing air to recirculate from the charger's output back to its input lets the compressor screws inside the supercharger "free wheel".
Otherwise at part throttle the supercharger would still be doing work...compressing the available air flow. At part throttle you don't need any the supercharger to perform any work. And since the supercharger is driven by a belt that is powered by the crank, any work done by the supercharger is using engine power that otherwise could be used to move the car forward.
The supercharger still saps a little power from the engine...power needed to keep the screws turning. But you aren't using engine power to pull air into the intake manifold. Of course the engine is doing the pumping, pulling air in when the pistons go through their intake stroke. And it has to pump a little harder to draw in fresh air if the supercharger isn't providing more dense air. But I guess the engine is a more efficient pump than the supercharger is.
The bypass valve opens at part throttle cruise to avoid pumping losses that would otherwise develop under those conditions. The result is better gas mileage under cruise. Allowing air to recirculate from the charger's output back to its input lets the compressor screws inside the supercharger "free wheel".
Otherwise at part throttle the supercharger would still be doing work...compressing the available air flow. At part throttle you don't need any the supercharger to perform any work. And since the supercharger is driven by a belt that is powered by the crank, any work done by the supercharger is using engine power that otherwise could be used to move the car forward.
The supercharger still saps a little power from the engine...power needed to keep the screws turning. But you aren't using engine power to pull air into the intake manifold. Of course the engine is doing the pumping, pulling air in when the pistons go through their intake stroke. And it has to pump a little harder to draw in fresh air if the supercharger isn't providing more dense air. But I guess the engine is a more efficient pump than the supercharger is.
Joined: Jul 2004
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From: lost angeles
you're bring up a problem that just has not been noticed w/ the SOT/BPR blower.
Wlaurent had his up and running w/ BPRs ELF management (which didn't work well - hence the beta designation) but I read no-where that he was having problems w/ detonation...
MugenRioS2k would know as he is in the beta program and therefore able to access the beta forum on SOTs site...
Wlaurent even ran the thing w/out an IC for a bit -- although his underhood temps (along w/ living in AZ) made the IC a necessity.
before you spread rumors maybe you should read the threads at both S2ki and SOT ----
Wlaurent had his up and running w/ BPRs ELF management (which didn't work well - hence the beta designation) but I read no-where that he was having problems w/ detonation...
MugenRioS2k would know as he is in the beta program and therefore able to access the beta forum on SOTs site...
Wlaurent even ran the thing w/out an IC for a bit -- although his underhood temps (along w/ living in AZ) made the IC a necessity.
before you spread rumors maybe you should read the threads at both S2ki and SOT ----