TRA turbo arm weight

turbo800 · Jan 21, 2014

I'm curious what everyone is running for TOTAL arm weight (grams) and spring rates in their 800 turbo's?

I have Thundershift arms with the adjustable weight points. Looking to dial in my clutching a touch better, I don't think I have the weight spaced correctly...

I'm running almost 70g arms and a (160/350) spring.

winter brew · Jan 21, 2014

I havnt done a lot with turbo clutching, but I am curious why (it seems) most guys are running the big springs and then have to run big arm/pin weight? Why not dial down the finish on the spring to run less weight? It seems this would make for a quicker responding setup as well. Maybe there is a good reason I am missing?

What are you running in the secondary? That will effect how the primary is setup.

turbo800 · Jan 21, 2014

I'm running a Team straight 48*/44* helix.

I think I have a little too much weight mid shift and not quite enough at full shift. It's under revving in the mid and over revving on top.

Kinda trying to get an idea where I stand compared to everyone else...

Bacon · Jan 21, 2014

winter brew said:
I havnt done a lot with turbo clutching, but I am curious why (it seems) most guys are running the big springs and then have to run big arm/pin weight? Why not dial down the finish on the spring to run less weight? It seems this would make for a quicker responding setup as well. Maybe there is a good reason I am missing?

What are you running in the secondary? That will effect how the primary is setup.

Then you can't brag in the bar how much weight your setup can pull. I agree, run lighter springs and lighter weights. It's also easier on the clutches with a lightweight setup. My turbo setup is probably completely different what most run, but it works.

swrev · Jan 21, 2014

I don't know the spring rates in my turbo XP. I'm running stock arms and rollers w/ the pins only 3/4 full. Helix is 43/47. The ramps are 441's that I ground down on the first part of the ramp. My setup works very well. Give Dynamoe Joe a call or email, he has some ramps that work very well w/ the turbo doo's. My engagement is about 3800 rpm. I originally had a straight 48 in my sled, I like the progressive much better.

turbo800 · Jan 21, 2014

swrev said:
I don't know the spring rates in my turbo XP. I'm running stock arms and rollers w/ the pins only 3/4 full. Helix is 43/47. The ramps are 441's that I ground down on the first part of the ramp. My setup works very well. Give Dynamoe Joe a call or email, he has some ramps that work very well w/ the turbo doo's. My engagement is about 3800 rpm. I originally had a straight 48 in my sled, I like the progressive much better.

I'd like to know your total arm weight if you could scale it???

I've always wondered how a reverse angle would work in a turbo application.

I'm using an old TRA II with 300 ramps, they are pretty flat on the top end. Might need to try something more aggressive for better backshift.

Backcountrypro · Jan 21, 2014

I am running Tom's Arms. Sorry but I am unsure of the exact weight but it is heavy. Tom's sent the arms to me with the weights installed. I will look for a pic of how it is set up later. I am also running a unknown set of ramps that came with the arms from Tom's.

Ok....I know I haven't been much help so far but all I can say is the "stuff" from Tom's works! Here is what I do know....with the hardware from Tom's I am running a 160-290 primary spring. For the secondary I am running a straight 44 degree helix with the heavier XP spring. I am running on clicker two and I can possibly add more weight to the arms and click up one or two more to give me more adjustment range incase I decide to turn the boost up. Speaking of boost this is on a Turbo Performance Etec running around 8 lbs of boost with a stock 163 track. We ride at 8k feet and up.

I am at the point with clutching this thing that I can almost call it perfect. It is working the best it ever has. The sled is so responsive in and out of the throttle.

swrev · Jan 21, 2014

I don't want to derail this thread, but how do you guys feel like your sleds do in a straight type of race? That is where I feel my setup lacks. Uphill or boondocking is great w/ up shift and back shift. On the flat, it just doesn't have the pull I would like regardless of where I turn the boost level. Sled is 163, 8 tooth drivers 21/49 gearing. I don't like it when my buddies turbo Pro gets me on the top end on the flat. In the trees or uphill, he's not even close. I would estimate my turn out speed (right before burying it) is in the mid to upper 50's when climbing in deep snow.

I'll try and way an arm the next time I have the clutch apart.

turbo800 · Jan 21, 2014

Backcountrypro said:
I am running Tom's Arms. Sorry but I am unsure of the exact weight but it is heavy. Tom's sent the arms to me with the weights installed. I will look for a pic of how it is set up later. I am also running a unknown set of ramps that came with the arms from Tom's.

Ok....I know I haven't been much help so far but all I can say is the "stuff" from Tom's works! Here is what I do know....with the hardware from Tom's I am running a 160-290 primary spring. For the secondary I am running a straight 44 degree helix with the heavier XP spring. I am running on clicker two and I can possibly add more weight to the arms and click up one or two more to give me more adjustment range incase I decide to turn the boost up. Speaking of boost this is on a Turbo Performance Etec running around 8 lbs of boost with a stock 163 track. We ride at 8k feet and up.

I am at the point with clutching this thing that I can almost call it perfect. It is working the best it ever has. The sled is so responsive in and out of the throttle.

Thanks for the great feedback guys!

My buddy is running the same setup on his '13 XM. It runs really well, but needs some fine tuning on the clutching. He claims he's added all the weight that came with the Tom's arms kit and he's still down to clicker 1 and over-revving. He claims they have aluminum pins, I haven't verified, but I told him to get some steel threaded pins for more tip weight!

I would also be curious to know your total arm weight too!

Backcountrypro · Jan 21, 2014

I have a 160-260 spring that I tried one time, it felt a little soft on the low end but it really did a nice job of loading the motor. I switched back to the 160-290 when I went to the 44 helix and heavier XP secondary spring. I guess I could throw the 160-260 in and see how it does with the 44 helix and heavier spring. I am guessing this would get me to clicker 3 or 4.

One more note, I geared up two teeth to a 21:51.

turbo800 · Jan 21, 2014

Backcountrypro said:
I have a 160-260 spring that I tried one time, it felt a little soft on the low end but it really did a nice job of loading the motor. I switched back to the 160-290 when I went to the 44 helix and heavier XP secondary spring. I guess I could throw the 160-260 in and see how it does with the 44 helix and heavier spring. I am guessing this would get me to clicker 3 or 4.

One more note, I geared up two teeth to a 21:51.

Isn't that technically gearing DOWN ratio wise???

I think I'm gonna eye up what I have on the shelf for springs and ramps tonight...

Backcountrypro · Jan 21, 2014

Nope....stock is 19:51 and I went to 21:51.

turbo800 · Jan 21, 2014

Oh, my XP came with 21/49 gearing...

nuttyn01 · Jan 21, 2014

Its all about the balancing act between the two clutches. We used to throw 21-23 grams just in the pin but the resolution between throttle and clutching was a bit lazy. Guys are getting some things figured out on their boosted clutching. General consensus is around 14-18grams in the pin, plus whatever the arm weighs. I don't weigh the arm due to I never change it. I weigh the I items I change. I believe most of the guys that really have anything completely different that are working completely different/better will not be posting their set-ups. Clutching is no different now than it was in the NA days. Ten people=Ten ways.

Spaarky · Jan 21, 2014

swrev said:
I don't want to derail this thread, but how do you guys feel like your sleds do in a straight type of race? That is where I feel my setup lacks. Uphill or boondocking is great w/ up shift and back shift. On the flat, it just doesn't have the pull I would like regardless of where I turn the boost level. Sled is 163, 8 tooth drivers 21/49 gearing. I don't like it when my buddies turbo Pro gets me on the top end on the flat. In the trees or uphill, he's not even close. I would estimate my turn out speed (right before burying it) is in the mid to upper 50's when climbing in deep snow.

I'll try and way an arm the next time I have the clutch apart.

Swrev ...,. Are you saying your beating a pro in the trees and on the hill? But on the trail your getting beat?

No offense it's a mountain sled not a lake racer. Who cares??? Grip it and rip it.

If I had a guess, if you are running the 13 or newer Pro's, the belt drive gearing might be getting you on the top. They have fairly tall gearing. Your getting in the trees and hill because your makin some more hp or set up difference.

As far as set up goes. I agree with Bacon and Brew, lighter is better. We have always tried to end up with about the same weight as a stock sled. Why? You already are fighting the turbo, then throw bigger weight in, then your fighting that too. Lighter weight is quicker spool IMO.

For me the proof was in the pudding. We faught the bottom end. Added fuel took fuel away. Wouldn't clean up. Then started to drop weight. Whammooo it came alive and took more fuel.

gus bohne · Jan 22, 2014

What the skidoo guy LACk is the knowledge to adjust start point on the ramp .
flyweight guys have spider shims to adjust this OH SO important start ratio of the shift PATH on the ramp.

How many of you even know that ski doo has 4 different lenght POSTS ?
do any of you know WHY ?

When we tune the doo tra 2 or 3 we machine the post , the we can use shim washers INSIDE the govenor cup spline pocket to set our start position. Its the same process as tucking mass.

Back in the early 2000's I was met with resistance from the race shop on working this way. in 004 they followed suite themselves. When Bellman made the billet tra 2 . he used the same pricipal. that is one hell of a clutch.

Paul, you should be selling shim packs to these guys and trimming their posts for them. you have no idea how much your leaving on the table when you only work with 1/3 of the tuning components you have.. helixs are not the cure all but a good reverse sure does help with backshift and up shift..

Of course the old guys hate this they would rather custom grind taller ramps or thicker ramps and charge you 300 $ ..come on ,, we can tune this in seconds trailside, quicker than you can turn the clickers you can pull the bolt, slide off the sheave and juggle the shim pack..

good post guys

Gus

swrev · Jan 22, 2014

Outlaw Addict said:
Swrev ...,. Are you saying your beating a pro in the trees and on the hill? But on the trail your getting beat?

Exactly, I want it all! haha

Turbo Pro's I've seen are not even in the same ballpark in the trees or hill. It's between 60 to 70 they will catch me and keep pulling and mine goes a little flat on acceleration. Even when I was running more weight, it still didn't keep shifting the way I would like. My top speed should be good for much more mph than that. I may try one of DJ's helix. I think I am actually loosing belt squeeze and slipping the belt in the upper mph. Only belt I've ever blown wasbetween 70 and 80 mph. RPM all of a sudden spiked and belt blew before I could get 'er shut down.

Gus, would shimming be able to help w/ my type of issue. My up and back shift is great up till the 60 plus range. I can keep up w/ big bores out of the hole easily enough, so bottom end is great. I would think tucking weight would work great for drag racing, but would it work also for tree riding w/ out loosing the snappy feel? There must be a point when tucking the weight must go away and you get to use it. Is it possible to adjust the "tucked weight" out to the point where it would only show up in the upper mph?

tukernater · Jan 22, 2014

We have been using those shim packs for a while now really make a different in your gearing to.

turbo800 · Jan 22, 2014

nuttyn01 said:
Its all about the balancing act between the two clutches. We used to throw 21-23 grams just in the pin but the resolution between throttle and clutching was a bit lazy. Guys are getting some things figured out on their boosted clutching. General consensus is around 14-18grams in the pin, plus whatever the arm weighs. I don't weigh the arm due to I never change it. I weigh the I items I change. I believe most of the guys that really have anything completely different that are working completely different/better will not be posting their set-ups. Clutching is no different now than it was in the NA days. Ten people=Ten ways.

I realize most people don't talk total arm weight, but I didn't know how much weight difference there was between the TS arms and stock arms, that why I was asking for TOTAL weight. I measured the stock arms this morning at 60 grams. That means I'm only running 10g more than stock, but I know it needs more pin weight!

I have a brand new GTX2863 turbo for this year. It'll be interesting to see if it needs even more weight.

turbo800 · Jan 22, 2014

Backcountrypro said:
I have a 160-260 spring that I tried one time, it felt a little soft on the low end but it really did a nice job of loading the motor. I switched back to the 160-290 when I went to the 44 helix and heavier XP secondary spring. I guess I could throw the 160-260 in and see how it does with the 44 helix and heavier spring. I am guessing this would get me to clicker 3 or 4.

One more note, I geared up two teeth to a 21:51.

I checked last night, I have a couple of springs to choose from with the same engagement, but lower finish rate.

Pur/Pur (160-320)
Pur/Blu (160-290) same as your running

I also found some 228 ramps that are very close to a 441's, I think they are worth a try!

TRA turbo arm weight

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