TRA turbo arm weight

[swrev]

The other thing about 441 is the fairly flat start. Etec turbo sleds may need that so they don't rev too quickly, you can grind more of a slope to it to make the bottom end rev more quickly w/ the carb turbo w/out causing electronic engine control issues.

Compare the ramp pics on ibackshift.com. I ground my 441 ramps down to a more progressive ramp than what DJ' ramp looks like in the comparison pics of his against 441. Works great for response, but like I mentioned early, lacks top but I am pretty sure that is mostly in my secondary. Not sure at what point, when grinding ramps, you could take away to much. If I get my arms out, I'll mark on the ramps where my rollers make contact.

 

[gus bohne]

there comes a point where the lever is swung out past its usefull range of shift force, this is where more energy is pushing out than forward.

Now If your driven is to tightly sprung or to shallow a cut they will go flat. but to me thats an indicator of gearing to LOW. Once we get close to 1 to 1 we loose load on the engine. work makes heat, heat makes boost and burns fuel.

those of us who had succes in hillcross learned early on about gearing, shift LIMITERS and the resultant change in the entire personality of the sled.
swrev I wonder if your just running out of workable gear ratio and that is what you feel as flat..??

moving the govenor cup in or out has no effect on gearing or speed it only effects the area of the shift path USED. allows you to PUT the shift curves strong points and weak points where they best suite YOUR needs your riding and your personality.
someitmes I see ramp changes that would not have been needed had the person been able to move the ramp IN or OUT .020 !! just that little has an effect. mostly this was used to make the 440s snappy , the fixed ramp design is tip heavy and slower to respond than the fixed roller type of clutch.

total lever mass is a tool as well, mass distribution is very very strong tool as well as ( in the toms case ) curve of lever vs mass location in reference to center of gravity of said lever. the curved lever of the tra 3 is done for JUST that purpose, to hide mass under center and act Lighter early in the swing. it helps to raise eng rpm without changing spring rates.

there is lots more,, lots more.. joey has a wealth of knowledge for reading about HIS approach and why it works for him. we all have our merits and yes many will make the tach do the same thing.. just make yourself happy and have fun.

I also love the thundershift levers almost as much as the stm levers. both allow placment above or below the lever allowing you to further tune the amount in play at anytime in the swing. arms tha place mass ONLY thru the sides do not allow this very wide range of tuning. for the money the thundershifts are good. STM is very pricey but has over 50 grams of range and can be placed to or bottom or ends of pin !!!

 

[nuttyn01]

The difference between the fly weight style clutch and the TRA is in the ways the apply the weight to do the work. The TRA has always been better at applying more push to the belt lower in the shift curve. Then the fly weight styles are better at application in the upper part of the shift. Not saying you cant make both do very well through out the shift curve. It just takes more discipline and dedication to the clutching to get it accomplished.

 

[Spaarky]

First off... if this post starts to derail this thread, just tell me to STFU. I can take it...

swrev... if you are eating the Pro's lunch, that is really depressing. I was all jacked to move to a Pro. My old carbed 700 will run dead heats with a well set up XP. Sure doesn't make me want to step up to the next chassis.

Since the Polaris section is full of "my Boost @ 6lbs. is the same as a BD @ 10lbs" and my this or that doesn't run because a sensor is going off. or my favorite, mounting my muff pot to a turbo. Thought I would post over here to learn something. Imagine that. Seems like I learn more in the Doo turbo section.

Gus hit on gearing, real lightly. I have never had anyone be able to give me a straight answer. Please forgive me, I am not a clutching/gearing genius. A lot of the old school turbo guys like tall gearing... 1.85-1.95:1 or taller. Now the trend in the mountain segment is to shorter gearing with the turbos. Polaris for example 19/43 or a 2.25-2.3 range. Why? I completely understand it on the N/A platform.

If you gear that low on a turbo platform, aren't you missing out on some track speed? I run pretty tall gears, it still goes to full shift out fairly quickly and holds it. I have watched it with my hood off. My experience is the harder you work the turbo, the better it runs....

Are the kit builders covering up fueling issues on the efi's? to get better bottom end? Then you throw in the reverse helixs and all the other trick stuff. Is it a personal preference thing of give and take. Give up some top end to gain bottom end. Frankly, I don't think it hurts my bottom end. Someone have some kind of answer to it?????

 

[gus bohne]

guys, christopher continues to LOCK my INBOX FULL. I empty it and next time I log in it reads 100% full and I have an advertisement from him peddling some gimmick for sale ??
HE and BRYCE can message me anytime they want but NO ONE else can !! LMAO

gus.bohne@comcast.net anytime ..I will reply that day or the next morning.

sorry for the inconvenience it is what it is..

Gearing is a tool addict. ask yourself this 1 question.
I gained 50 % more torque at the SAME operating rpm, HOW do make use of it ?
In that scenario ( turbo ) if you DONT gear for the NEW torque gain youve WASTED quite a bit of that new energy .
WHY?

Because did not WORK it to its potential. I dont advocate gearing a mountain sled for 150 mph, no. from real world riding testing and proving,,, you create much too much belt heat with low gearing and high shaft speeds.

1.78 is not tall gear for any turbo but thats MY method and as we know there are so many ways to skin this apple

 

[tukernater]

guys, christopher continues to LOCK my INBOX FULL. I empty it and next time I log in it reads 100% full and I have an advertisement from him peddling some gimmick for sale ??
HE and BRYCE can message me anytime they want but NO ONE else can !! LMAO

gus.bohne@comcast.net anytime ..I will reply that day or the next morning.

sorry for the inconvenience it is what it is..

Gearing is a tool addict. ask yourself this 1 question.
I gained 50 % more torque at the SAME operating rpm, HOW do make use of it ?
In that scenario ( turbo ) if you DONT gear for the NEW torque gain youve WASTED quite a bit of that new energy .
WHY?

Because did not WORK it to its potential. I dont advocate gearing a mountain sled for 150 mph, no. from real world riding testing and proving,,, you create much too much belt heat with low gearing and high shaft speeds.

1.78 is not tall gear for any turbo but thats MY method and as we know there are so many ways to skin this apple

Yep just tried TO PM you ,but you just answered and confirmed my thought on gearing to low .Thanks

 

[swrev]

Dang it, now I have to regear before I ride again. I have a 45 bottom I'll put in and see what it does. That'll put at 2.14 vs 2.33. I have tried a 19 on top before w/ the 49 bottom (2.57), it completely killed the turbo benifits and lost about 5 mph in a climb.

Outlaw addict, just basing a decision off my experience w/ turbo Pro's probably wouldn't be fair. There has to be some good running ones out there. I just haven't seen one that would make me want to turbo a Pro. Big bore is the only way I would go on a Polaris. They seem to have to many electrical issues that get compounded when putting a turbo on them.

 

[turbo800]

Gus is right. Turbo's are load based to build boost. Lift the tail of your sled in the air and see how much boost you can make, not much. Giving the sled too much mechanical advantage (gearing down) is counter productive.

IMO, the smaller the track, the more you need to gear UP to take advantage of the new HP/TQ. I typically gear UP two teeth on the drive gear (ex. 19 to 21) and leave the driven gear alone on a 159/163 track setup. With good traction, its not uncommon to see 75+mph uphill track speeds.

 

[Backcountrypro]

Here is a pic of how I have my arms set up. I am not sure what it all weighs.

 

[turbo800]

Thanks. I assume the big roller is aluminum, not coated steel correct?

This is the pocket scale I use to weigh my arms:
http://www.harborfreight.com/digital-pocket-scale-93543.html

 

[Backcountrypro]

Yes it is aluminum, I believe it alone weighs something like 12 grams and the weight below it is around 6 grams. I am going to add four grams to the next position down because with this set up I am on clicker 2 and adding more weigh will get me to a higher clicker number. This will give me more range of adjustment for when I turn the boost up. I have a grains scales here that I use for reloading, I will weigh the arms this weekend.

 

[turbo800]

That would be great to know. I've never used my grain scale for clutch parts. This pocket scale seems repeatable to .1 grams, good enough for this setup.

Side note, I find it interesting measuring stock pistons vs aftermarket pistons. You wouldn't think there would be much weight difference, but there is!

 

[Backcountrypro]

Here you go I got the arms weighed up.....

 

[Backcountrypro]

Assembled arm

 

[turbo800]

Anybody know how many grams the solid pins the roller rides on weigh?

 

[Backcountrypro]

Short solid pins (sit flush on the outsides of the arm) are 16.0 grams and the solid long pins (sit about a 1/8 inch outside of the arm) are 18.8 grams.

 

[fredw]

So what advantages is there with toms arms over stock arms, don't seam to have any issues with stock arms

 

[turbo800]

So what advantages is there with toms arms over stock arms, don't seam to have any issues with stock arms

It just gives you places to spread the weight out over the entire arm instead of just on the end. This can help load the motor in right places of the shift curve along with your primary spring rates.

 

[turbo800]

Short solid pins (sit flush on the outsides of the arm) are 16.0 grams and the solid long pins (sit about a 1/8 inch outside of the arm) are 18.8 grams.

Thanks, I wasn't aware they made the long "outside" solid pins.

Got to ride it around the house with the new clutch setup and new turbo. Very impressed with the throttle response!

I also picked up a Team reverse angle helix to try. One side is a 44-48 and the other is 42-46. I'm running a straight 44* right now.

 

[Backcountrypro]

I needed more wieght on my set up. Added another 6.1 grams, this should put me at 84 grams.