Pulley Swap, Sizes, and Info...

[Sp00ner]

Originally Posted by BlueMonster

I thought awhile ago WOP clarified this pulley size saftey ordeal.. Didn't he say we can run like a 2.7" safely? I'll have to see if I can find that thread he posted in, but it was pertaining to the pulley size and s/c rpm's.

Well, Wop never really gave a concrete limit, he's actually been on the "No one said the blower can't go faster" bandwagon, he also found us the newest Eaton charts that say 16,000 RPMs, and remember that it's 16,000 continuous RPMS, not peak...

[BlueMonster]

Yea, I just remember everyone getting excited about the news that the s/c can aparently hold up past 16,000 rpm's according to WOP. At any rate, I plan on switching my 2.9 with a 2.7 here soon for that little extra umph

[djt81185]

yo whats a 2.4 @ 7200rpm?

[NoRemorse]

Originally Posted by djt81185

yo whats a 2.4 @ 7200rpm?

one trillion RPM.

You scare me dan.

[06redline..I miss my Vw]

i currently have the gm stage 2.. i want to go to the 2.8 pully and on here it says its good for 16psi or so. but also it says engine management recomended. with me already haveing the flash and shit done i should be ok swaping this pulley on correct.....please bare with me forced induction is still very new to me. I am learning as I go

[sheek360]

Originally Posted by djt81185

yo whats a 2.4 @ 7200rpm?

wtf!?! u got brass ones dude

[Boosted_Ion]

Originally Posted by NoRemorse

You scare me dan.

He also scares little children on the side of the road as he goes by. I wonder how much louder a 2.4" pulley would be?

[mgm1979]

Originally Posted by ptparker

I inferred all of these numbers from alpha's two figures like so:

A 2.8 pulley spins 15657 at 7000 engine rpm. Its multipler is 2.23. So the circumfrence of the 2.8 pulley is 8.796. So using that multipler and the circumfrence of the s/c pulley, the crank pulley is 19.68. So that makes the crank pulley a 6.262.

By doing all of the same calculations above for the 2.6 pulley, the crank pulley comes to a 6.37. I think that .1 inches is perfectaly acceptable margin of error, so I split the difference and called the crank a 6.3 inch pulley. These are geometric calculations based on the two facts alpha stated.

Crank S/C Multiplier ([crank]*PI)/([SC]*PI)
6.3 3.5 1.8
6.3 3.4 1.852941176
6.3 3.3 1.909090909
6.3 3.2 1.96875
6.3 3.1 2.032258065
6.3 3 2.1
6.3 2.9 2.172413793
6.3 2.8 2.25
6.3 2.7 2.333333333
6.3 2.6 2.423076923

Are these #s still holding true? Can we update the chart/graph with the 2.5 and 2.4?
And, are we still saying the blower "safe" RPM limits are 16,000 and below?

-- Just curious.

[fullthrottle]

Originally Posted by 06redline..I miss my Vw

i currently have the gm stage 2.. i want to go to the 2.8 pully and on here it says its good for 16psi or so. but also it says engine management recomended. with me already haveing the flash and shit done i should be ok swaping this pulley on correct.....please bare with me forced induction is still very new to me. I am learning as I go

you can go to a 2.8 youll be oik shit you can go to a 2.7 if you want.

[Blown 4-banger]

A 2.4" pulley @ 7200 rpm would spin the blower to around 18,750 rpm!!!

Also, I though the continuous peak was 14,000 and the short burst peak was 16,000???