TRA settups...attn clutch guru's

[tollen77]

on a trip through the factory were the sleds are assembled , i was left with the impression that a mistake in the assembley process was nearly impossable .
to get past that check point with it out of align is hard to see happen .
pdi at the dealer ship does have this as a check on the assembly list but on this chassi i cant see it .hay but crazier things can and do happen, not a perfect world , have read on here about some issue so who can say it doesnt . i havent found one yet but i sure wouldnt say it isnt so , even after seeing what i have seen i have also seen how fork lift drivers can oporate LOL's

Well that's comforting to hear re: the BRP factory. Al, you mentioned you've had good results changing the QRS spring... which direction down the spring scale did you move?

My own guess would be something a little stronger to create more pinch, but please, enlighten me. By the way, absolutely love 'The Thing'... not only does it work but it sounds amazing!

 

[turboal]

the epi spring i use has the same start rate as the stock spring but has a 50 lb higher finish . seemed to match the needed squeeze were the other was letting it spin hard , over the 30 mph mark . made the largest gain in track speed of all we tried out.
same responce when we used the team secondery , had to use the same approach with the same angles .identical results .
epi part number is SRER-3 is all yellow for those who have been asking.

 

[ak]

Thanks Al.

 

[Throttle Junkie]

have mine on the work bench ready to put in along with new primary setup

 

[tollen77]

Thanks Al!

Any loss of backshift with such a stiff spring? From everything I've heard, the QRS backshifts like a demon compared with most other secondaries. Is there anything req'd on the primary to compensate for this, say a spring that also has more finish??


Thanks again.

 

[winter brew]

More secondary spring= stronger backshift.

 

[Teth-Air]

More secondary spring= stronger backshift.

I agree so how does turboal explain the increased backshift equating to higher track speed? This sounds backwards to me? I expect higher track speed to come from the belt moving higher in the secondary not lower, after all isn't a stiffer spring going to slow the belt from climbing the secondary?

 

[Original Tetonice]

It's all about how well you sqweeze the belt and everyone has there own way of getting there..... Not to get off topic here but the secondary spring can also effect your RPM since the secondary is torque sensing...Not enough spring will allow for a faster upshift but will result in a slower backshift which can cause lower rpm & belt slippage in condition such as deep powder, hillclimbing......That could be a reason for AL liking a higher finish.

Sqweezing the belt just right is more of an art than a science.


OT

 

[DaveB]

The spring changes the rate of upshift and increases the backshift sensitivity.....it will not change the amount of upshift. Al's logic stands.....

 

[winter brew]

No matter what springs (or any other clutch component) are used, the engine can only accelerate a sled or hold climbing track speed as its amount of power will allow. There are an infinite number of ways to achieve an efficient clutching settup that will harness as much of this power as possible, the main differences being the "feel" and consistancy. The key is always a "balance" between primary and secondary so both clutches can respond quickly to changing loads, one clutch overpowering the other will always make more heat, be less efficient and allow the engine to vary RPM which will decrease power to the track. A quick heat check after a pull can tell you alot about what your clutches are doing and where to look to make improvement.

 

[Sneddonrider]

Just put the epi secondary spring on my 800 154 and ran it hard for 5 kms in the field (we have 3" of snow ) pulling from stop to 120 km repeatedly stopped and put mu hand on the primary clutch and it was cool to the touch. last year tried lots of different pin weights and springs and never could I touch the clutches after running it hard. RPM holding steady at 8300 every time i hit the throttle, was all over the place before the secondary spring was changed. Finally feels like a roller secondary.

 

[Throttle Junkie]

Thanks Al!

Any loss of backshift with such a stiff spring? From everything I've heard, the QRS backshifts like a demon compared with most other secondaries. Is there anything req'd on the primary to compensate for this, say a spring that also has more finish??


Thanks again.

More primary finish rate would slow upshift/increase backshift also. The main reason for the stiffer spring the in the secondary is to stop slippage of the belt.

 

[turboal]

you can drop the clicker number 1 and see if it still back shifts for ya . using the movement of the clickers allows one to see a balance on the higher squeeze . it is eliminating the slip due to high load factors over 30mph .
these slipages are occuring with the added heat from the primary when it is not running flush contact due to tower cap bushing clearances allowing enough movement .

i always head out on clicker one and see were the days snow asks for it to be at.any changes it allows a base line for you to see how different changes to clutching make.

up shift is gained back if the extra squeeze that you apply is holding it up by lower the clicker number .
remmember the start rate of the epi spring is the same as stock and the extra squeeze happens at a point in the upshift that needs more squeeze were the load factor is not diminishing as a softer track would .now with out the slip you will see a track speed gain.

if the slip factor gets to much then the heat gets past the adhesion point and spin begins . just as in a car tire it isnt accelorating when it is spinning .stopping the spin gets the track moving .

it is a balance as mentiioned . if the clicker number is now on 1 at your playing elevatiion, then two things can be done . put the higher top gear back in on the 154 and 146 but not the 163 as it is pretty decent stock.
or add 2 grs to the pin to drive the clicker number back to 3 at your playing elevation.

clicker 3 is the best number at elevation . any more a number and you have rpm , but lack track speed . 5 and 6 are the same and show even lower track speeds .

2 and 1 are a bit slow as a rule on back shift at elevation for the weaker engines needed responce times . is why we seem to find 3 as the most happy number .

primary is pretty basic . it is the secondery that one can time the situatioin best from as a rule .
the 43/47 depends on how long it is a 43 for before iot becomes a 47
if it is progressive in degree developement then it is a wild motor we have driving it. the 08 's set up is the quickest i have run so far in our playing . always room for more and ever year we learn more it seems .
was up today and the snow is growing. need more .

 

[Throttle Junkie]

sorry for bringing this up again but is the issue with the spring cap bushing that it's too loose causing it to bind?? I have mine apart right now and it definatly not too tight. Do you buy a 09 cap or just the bushing?

 

[Original Tetonice]

I've been running a 42/46 in our Team secondary with great results. The degree steeper multi angle for 09 should work well.....And i agree once your belt has started to heat soaked the tune of the TRA begins to change and the rpm can and will drop of the power curve. This wwekend we should be on the snow comparing a mod 08XP 163 vs a stock 09 XP 163 and 154

OT

 

[Original Tetonice]

sorry for bringing this up again but is the issue with the spring cap bushing that it's too loose causing it to bind?? I have mine apart right now and it definatly not too tight. Do you buy a 09 cap or just the bushing?

The TRA hisortically have had biinding issues which resut in heat.

OT

 

[AK-Rider]

I've been running a 42/46 in our Team secondary with great results.

OT - Nice to hear you like the 42/46. I put one in my QRS, but I haven't had a chance to run it yet. Have you made any other changes from stock... ramps, springs, etc.?

 

[tollen77]

The spring changes the rate of upshift and increases the backshift sensitivity.....it will not change the amount of upshift. Al's logic stands.....

You're assuming there is no belt slip with a softer spring.

 

[tollen77]

More primary finish rate would slow upshift/increase backshift also. The main reason for the stiffer spring the in the secondary is to stop slippage of the belt.

Yeah, I had my head on backwards there, My bad!

 

[DaveB]

You're assuming there is no belt slip with a softer spring.

I was responding to the statement in post #87....