timucin

using 8-71 weiand ; need to know the psi's
what size pulleys do i have to use to receive 6 and 8 psi?
top?
bottom?

any www showing charts about pulley size?
8mm
bb

thnx

timucin

man;
i memorised these stuff long time ago but completely forgot everything, plus i also lost my documents.
509 cid engine

timucin

thnx too old
but what is -3.7% is equal to?
psi?

timucin

Too old; excellent web page ,you have
cool!
will call you for sure when i trun back to boating in near future

timucin

509 cu.in
8-71 blower
-3.7 % under drive
6000rpm max

boost?

Reed Jensen

-3.7% under drive means the blower pulley is turning 3.7 percent slower than the crankshaft pulley.

Regardless of the RPM... if the throttle is wide open ... the boost remains the same all through the RPM range.

Reed Jensen

Somewhere in my huge stack of catalogs ... I have a BDS catalog... and there is a chart that shows approximate compression ratios and boost figures with a chart showing cubic inches and size of blower and ratios... My guess is with a 8-71 being underdriven on a 502 cubic inch engine... you are going to get about 3 lbs of boost. I can't find the catalog and the BDS site doesn't show it... sorry... that is the best I can do is guess at what boost you will have... I had a 10-71 blower on 540 cubic inches ... driving the blower 1to1 and I had 5 lbs of boost.

KNOT-RIGHT

If your running a intercooler depending on which one
you have to add approx 2lbs for the restriction.

Heads, cam duration and compression play a major role.

For instance I run 540 Merlin cast Iron Fully ported heads crane 741 cams
10-71 Richard lee intercooler. I am 10.6% overdriven and get 7lbs. at
5000rpm.

timucin

-3.7% under drive means the blower pulley is turning 3.7 percent slower than the crankshaft pulley.

yep i know this

there has to be a chart showing the boost levels according to pulley ratios
like 8.71 makes X psi of boost on top of 509.

i had this cart but i lost..

duunoit

iTrader: (1)

Tim,

Is this what you're looking for? The pdf version of the catalog is available here. This came off page 206 (p.44 in the pdf).

Chris