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Someone needs to implement this idea. The ever-present lack of low end tq is still the only thing holding me back from putting a SC on my S.
yeah, brought this up about 6 months ago. I was even beginning to implement it using a bypass valve from a turbo. But, I decided to not get a SC for the S...so i lost interest. It would be very cool though.
i've got the 4.375 and 3.875 on order, was going to post results of boost/hp/tq here from dyno runs. given hecash's 10.5 lb boost at 8500, i might not put the 3.875 on since i am not running with an intercooler. guess i better run the 4.375 first, and maybe try the 3.875 at 500 rpm increments so i do not blow the engine.
i was looking at the SC limits before, cannot find the exact number but the spreadsheet i was playing around with went to 16800 engine rpm and 70196 sc rpm, so i think 70k is a better number than 60k. the ratio is 3.54 to 1 (engine/sc rpms) for the novi-1000
Hey guys, I think that the max impeller speed is 55,000 rpms ,but I would imagine the impeller would have a factor of safety attached to it as well. It seems like the blower is good for up to 1100 cfm and 14psi of boost. Seems like I can't post the image that I have of the paxton manual spec page , but I can email the pic to whomever would like the info.
went ahead and tried out the 4.375 pulley, at max it ended up giving 1 lb boost over stock, actually it stayed about lb greater than stock pulley from about 6600 all the way up. on the low end it went from .6 to .96 @ 3200 rpm.
had to add 1.5 turns on the FMU since trying to go above +1 on the VAFC always trashed the run, and go to 2 step colder plugs (had 1 step already) to solve a small pinging issue. since the intent was to try out the 3.875 pulley as well, was not planning on doing a lot of tuning. i had calculated that the boost at 9k should go from 5.79 with stock pulley to 6.37 with 4.375, ended up with a max boost of 6.78 at 8700, where i was calculating 6.08. we were not sure if this meant i would be off about 2.1 lbs for the 3.875 (.7 with 2/10 smaller diameter, 2.1 with 6/10 smaller diameter) or if more variables would come into play. my charts showed it would be 7.17, but Hecash posted he had 10.5 lbs with a 3.875... too many things pointing at over 8 lbs boost, and with no aftercooler we decided to play it safe.
max difference was at 6200 rpm 15.72 hp and 13.28 tq. i think that if we had played awhile longer we could have gotten it a little stronger above 7600 rpm. max with stock pulley was 255.25/157.76@8500, now we got 260.43/158.14@8700. generically HP numbers arrive about 3-4k earlier, i think that is why the new run starts registering on the dyno at 26k instead of 31k, and it hangs onto the power for a couple k's on the high end as well.
10-16-2002, 12:54 PM
