Re: My oppinion, YMMV, is recirc. The boost pressure dumpe - Saab Performance Bulletin Board - Saabnet.com
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Re: My oppinion, YMMV, is recirc. The boost pressure dumpe
Posted by Dean (more from Dean) on Fri, 6 Sep 2002 11:05:22
In Reply to: My oppinion, YMMV, is recirc. The boost pressure dumpe, Talladega900, Thu, 5 Sep 2002 16:05:47
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The whole point is to preserve the rotational inertial of the turbo wheels. Assuming that there is an advantage to having the air introduced to the turbocompressor, to preserver the inertia of the air as it goes through the turbo, through the IC and pipes, through the BPV and back again is silly. All of energy of significance was the energy of the air in the system compressed to perhaps 15 PSI. That PxV energy is lost in any case. The energy in the recirculating gas will be vicous damped very quickly and that amount of energy is very small, being porportions to the mass of that amount of air which is trivial.
The amount of energy in the turbo wheels is quite large, and if lost, will show up as turbo lag. So one needs a BPV or dump valve to vent the air when the throttle is closed as the back flow surge will take a lot of spin out if the turbo wheels, and can create shock waves that can destroy the turbo. I expect that a dump valve and a BPV in recirc used together would have some advantages, but only when shifting agressively. A dump valve will discharge faster and sooner, but will close before the job is done. A BPV will finish the job and stay open. But if shifts are very quick, the advantage of the BPV might be negated.
posted by 207.43.195...
Posts in this Thread:
- Atmospheric v. Recirculating Which is better?, Traffic Shark , Thu, 5 Sep 2002 13:34:09
- just switched from Forge to TurboXS, nickR, Thu, 5 Sep 2002 17:09:29
- I got my Forge to "hoot" too. Reversed the mounting, Talladega900, Fri, 6 Sep 2002 00:06:17
- Re: just switched from Forge to TurboXS, Roger Wilco, Thu, 5 Sep 2002 17:13:38
- not too loud, nickR, Thu, 5 Sep 2002 17:28:18
- Re: not too loud, Dean, Fri, 6 Sep 2002 11:44:43
- I want one! so no CEL? nm, Chris., Thu, 5 Sep 2002 19:15:28
- Re: not too loud, Roger Wilco, Thu, 5 Sep 2002 17:45:42
- hahahaha, nickR, Thu, 5 Sep 2002 19:04:18
- My oppinion, YMMV, is recirc. The boost pressure dumpe, Talladega900, Thu, 5 Sep 2002 16:05:47
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