Tuning 30 Series Driven Pulley

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REDB30

New Member
#1
#1
I've been reading everything I can find online about tuning these driven pulleys. I've read that using a stiffer (yellow) spring will hold the driven pulley closed longer and keep the rpms up, but I can't find anyone stating how high of rpms can be gained by doing this. I've already tightened my stock spring to the tightest hole.

I recently finished my ending build which consist of predator 212 hemi with:

+0.020 rod (put me at almost zero deck)
Arc billet flywheel
26mm chinkuni
Arch mini bike header
Stainless valves 27mm & 25mm
Ported head (not shaved yet)
22lb valve springs
Billet valve retainer kit
Stock head gasket
CM grind cam

My goal is to tune my driven pulley to allow me to reach around 6000 rpm and hold around there all the way through overdrive.

Right now it will get up to around 4200 rpm initially and then begin to shift to over drive too quick and pushing my rpms down to around 3900 rpm. Its steadily picking up speed rapidly, but I know it would do better if I could keep the rpms up in the powerband throughout the shift.

Does anyone have any experience tuning these for higher rpm?

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TheDullCarbide

TheDullCarbide

Active Member
#3
#3
I would focus more on the driver pulley than the driven. You can swap driver weights and garter springs to adjust your stall rpm, to adjust your shifting rpm. The only reason I would see to modify the driven is if your belt is slipping. Stock configuration is zinc weights with blue garters. Mod aluminum weights are not available but all other parts are:

 
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TheDullCarbide

TheDullCarbide

Active Member
#5
#5
REDB30 said:
What if I drill the weights?

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Click to expand...
You can. I would drill from the insides of the weights and be sure to weigh them. Drill in the same spots on both weights. They need to be equal or hell may break loose. If you can't weigh them, don't try it.
 
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R

REDB30

New Member
#6
#6
Are the ones that I have made of steel? I saw some comet ones that are aluminum for $19 when searching google.

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ole4

ole4

#10
#10
Tire size. I run 12:72 for street use 8:1 drag race. These are on 10” rims. I’ll have to measure diam. A tav when in high is 10% overdrive so your like 4.5 to 1 final high gear ratio. That is a big load.
 
R

REDB30

New Member
#11
#11
ole4 said:
Tire size. I run 12:72 for street use 8:1 drag race. These are on 10” rims. I’ll have to measure diam. A tav when in high is 10% overdrive so your like 4.5 to 1 final high gear ratio. That is a big load.
Click to expand...
I'm running 15" tire on 6" wheel.

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R

REDB30

New Member
#13
#13
I'm going to buy a 10 tooth sprocket for my TC and see how that changes things. Before I mess with the springs and weights. Here's where that should put me. Screenshot_20180920-102254_Chrome.jpeg

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R

REDB30

New Member
#20
#20
Ok. This weekend I swapped out my front sprocket to the 10 tooth but the TC was still shifting way too quit pulling the bike down out of its powerband. So I threw in the aluminum weights in the driver and the yellow spring in the driven in the third hole. Made a huge difference. Driver engagement is around 3400rpm and the rpms stay around 5500 through it the shifting of the TC. The bike is so dangerous now. I can crack the throttle wide open at about a 25mph roll and I stand wheelie on dirt road. Here's some pics too.


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