thunder shift kit

viper700t

viper700t

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I have a buddy who had a thunder shift kit just laying around so he gave it to me..however i never heard much of these or seen any so my question is, am i wasting my time or not...it just comes with the weight arms and all the rivets and shims however dosnt come with any springs or anything..so im not sure what works with these..can i just put them in and see an improvement or will i need to add a different primary spring aswell..i have a 53/43 helix ands green sec spring in my viper now..let me know what you know of these kits or if you know any setups that will work with them

:sled2:
 

I am a big fan of the Thunder shift adjustable weight kits, I run them in my SXs and I run Heavy Hitters in my SRX.

Here's the setup I used back from about 2000 right up to now in my 99 ported/piped 700SX[8700 RPM] it should get you close.

base weight: 38.8 grams
tip 8.6 grams
middle 2.6 grams
----------------------------
total 50 grams

Primary spring y/s/y [tall cover] 35/118
if it over revs in your Viper try w/s/w
if it under revs try g/s/g

Helix Dalton 53/47
secondary spring green @ 70
 
I also use the heavy hitters. they are my go to weight. I've tried a lot of set-ups and at the end of the day when I need a little more I always end up back at my heavy hitters and always gain a little. different weight I know but same company so I say try out Bobs setup.
 
alright thanks..ill have to give them a try..bob, do you just keep the heel empty btw? because i havnt looked at them yet but i believe they have 3 holes..(tip, middle, and heel)?
 
viper700t said:
do you just keep the heel empty btw? because i havnt looked at them yet but i believe they have 3 holes..(tip, middle, and heel)?
Click to expand...

On my SX I leave the heel empty.Weight in the heel primarily effects the engagement rpm, middle mid range, and tip top end. I have found that most tripples like the weight biased to the tip for good top end and acceleration. The Viper with its power valves may also need a bit more weight in the middle.
 
sideshowBob said:
On my SX I leave the heel empty.Weight in the heel primarily effects the engagement rpm, middle mid range, and tip top end. I have found that most tripples like the weight biased to the tip for good top end and acceleration. The Viper with its power valves may also need a bit more weight in the middle.
Click to expand...
Same here......always run the heel empty and weight in the middle and tip locations. Usually i have more in the tip than the middle, but there have been instances where i had the middle and tip the same.
 
i have used these weights to replace an 8ab yamaha weight in one of the user clutching chart set-ups. worked awsome.
 
so when u say i may need more in the middle..does that mean i should still shoot for 50 g overall or just add some more to the middle and not worry about overall weight of 50??
 
You really wont be able to shoot for any particular weight/ total or otherwise. It will all depend on your sled/riding style/etc.. try his setup and post your results (rpm's throughout the shift) and guys can help you dial in from there. As a side note I only use the fett bros 150/300 spring with my heavy hitters but they are 53.3g base.
 
Do any of you guys run heavy hitter, thundershift etc... in drag race set ups? Or is 8BU-00 just as effective? just curious...
 
I'll add one more thing, Like Bob stated the heel primarily affects engagement rpm just like the heel position in the heelclickers. With my HH's (like Bob and Mopar) most of the time I leave the heel empty BUT you can find extra traction at the line by adding some heel weight when you're spinning out of the hole if it's your only option. At my last event we rushed to add 48 chisels halfway through the day when the starting area got chewed up. But some added heel weight would would give you some added traction if you dont want to go through the bloody knuckles we went through.
 
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