I measured my crank pulley at 6", but people seem to be calc impeller speed with 5.75?

What is the actual part you are measuring? At the ribs? top of ribs, in the channel?

1/4" difference is alot, esp when calc impeller speeds!

Thanks

 

5.75

 

well thats good to know. so basically with my blower/pulley combo, my redline rpm is down to 6400 rpms.

man i hope that SI spec upgrade is for real. 65000 impeller speed would be nice.

 

the Si's max impeller speed is 55k rpms, the E-trim's is 65k

you can still rev to 6600 rpms though. It's not like the blower is suddenly going to explode or anything. You're just pushing it slightly beyond what vortech says it'll take - kinda like how you're pushing the stock block beyond what nissan says it should do. Besides, it's probably pretty brief that you're doing 6400-6600 rpms anyway

 

what is the reason that the bearings are failing on the vortech's?

I thought it was contributed directly to overspinning the blower.

my blower is in the serial # range for bad bearings, so there is a VERY high chance than it could suddenly explode


either way, good to know. Thanks Sentry!

 

well in your case, maybe I'd be careful then, because your blower probably will go bad at some point. Normally the normal bearings can handle being overspun. Vortech's max rpms that they rate each blower for are slightly conservative

 

I'm pretty excited about the Si trim impeller. I know it's not a big difference from what we have now but that extra 2000k rpms will allow me to safely go to 7000 rpm's and take full advantage of my RevUp. I'll definitely be monitoring Jet Mech's thread to see how the upgrade goes for him.