Tuesday, July 25, 2006 - 12:32 pm, by: Luke Bartlett(Ss_torry)
Just wondering, has anyone here ever changed their crank pulley on a 1UZ for something larger?
Otherwise, can anyone recommend where I would be able to get a larger pulley from/made?
Reason i ask is I want to increase the boost on my supercharger, but there is 3/10ths of stuff all room up top between the radiator hose and the belt already.
Tuesday, July 25, 2006 - 06:01 pm, by: Tai Johnsen(Privatejohnsen)
Hey luke, i saw in the Raptor setup that a separate pulley had been mounted onto the harmonic balancer to drive the SC..
Any chance you could use that and extend the pulley on the blower out a little to suit? Then you could get any ratio you want and it'd pretty much run straight down and not have to straddle the radiator hose too..
Wednesday, July 26, 2006 - 11:37 am, by: Anish Varsani(Yomama)
How much boost are you after? You might be able to change the blower pully instead. I've got a pully giving 7psi. I've been told thats the limit with stock compression.
Wednesday, July 26, 2006 - 01:20 pm, by: Luke Bartlett(Ss_torry)
Yeah, I'm running a 75mm pulley at the moment, only making about 3-4 psi. Smallest I can find is 65mm, which will make it around 6.5 psi if my calcs serve correctly based on current boost. Problem is that's a tiny pulley, and clearances are already poor around the area with the radiator hose.
Wednesday, July 26, 2006 - 02:09 pm, by: Brett Moloney(Lxsv8)
Luke on my blower (the one you saw at Lews a couple of Saturdays back) I currently have a 68mm pulley and this is providing 9.5psi at the blower. I have been told that by putting on a 65mm pulley my boost will be around 12psi. This is only a 3mm difference and you are talking 10mm. As you know mine is centrifigal and yours is an m90 from memory so I don't know if the results would be similar or not. My point is that with a 10mm smaller pulley surely you will achieve more than 3psi extra. Something to be careful of is the smaller the pulley the increased likelyhood of the belt slipping.
Thursday, July 27, 2006 - 08:51 am, by: Luke Bartlett(Ss_torry)
I'm not sure which kit it is sorry, came with the car and to date havent been able to identify who made it. All i know is the blower mod was done in '03.
The equation I'm basing this on, as from planet soarer is
Boost = (14.7 x blower volume / half of engine volume x pulley ratio) - 14.7 - loss due to valve overlap.
An eaton M90 is supposed to move 1475 cc's of air for every rotation. Currently with a 75mm pulley on the blower, and a 140mm main pulley, and assuming overlap loss to be max 0.25 psi, i should get about 5.3 psi. I'm only getting 3.5, which to me is indicating wear in the blower, or possibly a leak somewhere, more likely the first though.
so re-entering 3.5 as the boost with a 75mm top pulley will give me an effective lower pulley diameter that covers the wear in the blower. this comes out to be 127mm.
Reversing this again, but with the 65mm pulley, gives a final boost of 6.34 psi, inclusive of whatever fault my engine has.
But as you were saying about belt slip, that's true, as is the chance of belt breakage due to a tighter radius, hence why i was wanting to increase the bottom pulley size. make sense?
Thursday, July 27, 2006 - 09:07 am, by: Tai Johnsen(Privatejohnsen)
I saw a pic of a blower on ebay with teflon flaking off the rotor blades.. Whats to stop that crap going through your intake into the engine? Can it hurt anything?
Yeah, tested at redline, made 3.5 under acceleration, wound up to 4 at redline.
Come to think of it I can hear a whining coming from under the dash at idle, or closed throttle when vacuum is highest. Are the air con controls in soarers electrically or vacuum operated?
Saturday, July 29, 2006 - 07:02 pm, by: Tim Staier(Tradewind)
Teflon going through is unlikely to damage engine. The extra clearance between the rotors will lower efficiency and boost a bit though.
Brett, the centrifugal increases pressure very quickly with just a small speed increase as pressure is a function of tip speed whereas the positive displacement blowers have to be given quite an increase in RPM to get some extra pressure happening.
Previous
He was running 8 PSI..
