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Discussion Starter · #1 ·
Hi guys,

Current spring is a 250-350. Pulling @ 8100, click 5. How much do I need to increase my fininsh rate to get 8500 ? 410 ? 440? 460? 286 ramp

KJC
 

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If I remember rite from My experimenting 30 pounds is good for 200 rpm's and 1 gram is good for about 100 rpm's. what is Your pin weight at?
 

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Discussion Starter · #7 ·
What ramp are you using ?
286, pulls wicked hard........but not enough RPM..........I used 286's because out of my handful of goodies, thats what was the closest. It also should be said, that I kinda have a "10 tooth driver" situation going on. The sled is a 9700. It has 13 tooth, 1.97 pitch drivers. They are very close to the diameter of the 10 tooth internal drivers. Also, it is the old triple chain, so changing sprockets is a bit more challenging. At 60 MPH it pulls every bit as hard as my 670. I'm looking for a set of PX,DX, 228, CF1 ramps. I made a calculator in Excel.....With the TRA in this chassis, it is currently geared for 121.......I'm not sayin that I'll see it but man......it pulls H A R D top end.

KJC
 

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228, 281, or 145 will get the rpm you need, px will load the motor too much. Cf1 may do the trick too. Wind up your secondary or lower the finish angle on the helix
 

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228, 281, or 145 will get the rpm you need, px will load the motor too much. Cf1 may do the trick too. Wind up your secondary or lower the finish angle on the helix
I have 145's and they work so-so..... they shift too fast first 100 feet. motor flashes to 7000, then climbs to 8100. RPM is also 8100 with 145's.

secondary is straight 44 @ 18 lbs. Thanks for responding :)

***New question, for comparison***

When you switch from 9 to 10 tooth drivers in a Mach Z, and leave the chaincase alone.... Is it necessary to change primary setup ? Does making this change require clutching changes ?

KJC
 

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What year is the 521? The later ones weren't exactly high revving engines. My '91 topped out at about 7,200RPM. Even with twin pipes, you shouldn't need to be spinning it up to 8,000RPM. You're probably overrevving it?
 

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He's got twin pipes onto er.
Yup, I read that. Still don't see the sled picking up 900-1,300RPM with a set of twins though. Not unless they're really aggressive pipes and the sled has a a healthy port job, with a lot of other intake and exhaust mods. My advice is still for him to start adding weight to the pins until the sled slows down.
 

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286, pulls wicked hard........but not enough RPM..........I used 286's because out of my handful of goodies, thats what was the closest. It also should be said, that I kinda have a "10 tooth driver" situation going on. The sled is a 9700. It has 13 tooth, 1.97 pitch drivers. They are very close to the diameter of the 10 tooth internal drivers. Also, it is the old triple chain, so changing sprockets is a bit more challenging. At 60 MPH it pulls every bit as hard as my 670. I'm looking for a set of PX,DX, 228, CF1 ramps. I made a calculator in Excel.....With the TRA in this chassis, it is currently geared for 121.......I'm not sayin that I'll see it but man......it pulls H A R D top end.

KJC
pulls as hard as a 670, wow that thing must be BUILT!! maybe it can spin 8000+?? or i need a pair of tall boots.
 

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286, pulls wicked hard........but not enough RPM..........I used 286's because out of my handful of goodies, thats what was the closest. It also should be said, that I kinda have a "10 tooth driver" situation going on. The sled is a 9700. It has 13 tooth, 1.97 pitch drivers. They are very close to the diameter of the 10 tooth internal drivers. Also, it is the old triple chain, so changing sprockets is a bit more challenging. At 60 MPH it pulls every bit as hard as my 670. I'm looking for a set of PX,DX, 228, CF1 ramps. I made a calculator in Excel.....With the TRA in this chassis, it is currently geared for 121.......I'm not sayin that I'll see it but man......it pulls H A R D top end.

KJC

pulls as hard as a 670, wow that thing must be BUILT!! maybe it can spin 8000+?? or i need a pair of tall boots.
Don't underestimate those old 521s. They were serious runners.

Sent from my ADR6425LVW using Tapatalk
 

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Factory twin pipes, designed to work @8500. No boots required. Come to PA and I'll loan you my flip flops & a helmet. :)

KJC
lol nah im good. My mach pulls pretty hard for an old beater. Im not saying i dont believe you.My old blizzard 503 pulled pretty hard for just a 500 fanner. But nowhere near a 670. Thanks for the invite tho :)
 
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