All UTV's CVT clutch performance

[badassmav]

I would like to preface this thread by saying that the ones who know me know that I am all about total disclosure, so everyone can achieve better results for their efforts without taking unnecessary time and money away from their family unit. Some appreciate that, and some despise it. If you are a hoarder of information, don't weasel in on the 2 way street that I am attempting to pave here. If you do, and you don't share what you have learned, you are a PANZY! If this is you, get off of this thread and back to not letting people in line while in traffic, you PANZY!

What we all do here in our tiny world of racing is either rewarding, exhilarating, aggravating, emasculating, and at times, even humbling. I know that testing via the trial and error method takes time and money. Valuable time and money that can be better applied elsewhere other than racing. Therefore many take the stance that it is some how "proprietary" or "privedged" information when they find a new set up that works well, so they hoard it. Like they are the one who originally created it. Most all of what we do here has been done before. It's nothing secret. Nothing proprietary. Most of it is common sense when you see the whole picture laid out in front of you. With that being said, lets get down to the business at hand.

It is time to open up a dialogue without restraint. How many of you out there have heard of, are running, or have experience with the Ski-doo TRA primary clutch? I just came across this technology this morning here in the underground. In response to a recent post, UTVUG member Baxter said,

"What sled are you referring too?We twisted the triple pro stock drag sled 9250 at 265hp all day long.What is it you worried about?We personally never had a clutch failure.Maybe I missed something.I'm not sure if the clutches are the same.Do they run a TRA in the Maverick?"

If it is so reliable for the snowmobile racers, why cant it work well in our world, or has it been a dark secret? Of all the times people talk about clutch performance, I just heard about it now, so I'm diving in to learn and to share, so if you are keeping a secret, your secrets not good with me!

Attached is the beginning of total disclosure, so all you Panzies close your greedy eyes!

 

[BiggJim]

LOL

 

[badassmav]

LOL

Have you, or are you guys running a TRV type clutch? C'mon Jim, in between giggles, cough up a few words. Your mind has a plethora of knowledge. I know you at least heard of this type of primary clutch before.

 

[BiggJim]

Have you, or are you guys running a TRV type clutch? C'mon Jim, in between giggles, cough up a few words. Your mind has a plethora of knowledge. I know you at least heard of this type of primary clutch before.

Never heard of it! You have a link? We run OEM clutchs...we learned the hard way last year.

 

[the stripping shop]

I have the cvtech on 1 can am its like the old bronco clutch for the rhino. I finallys got the team industries from dirty dawg. Its just like the the Polaris 3 finger. both can am have stm secondary hook up ten times better and belt temps dropped a crap load. probably because got rid of that steel inner sheeve that can am uses. plus both units are 4-5 lbs lighter free hp. now they back shift and run about 8000rpms up hill.

 

[the stripping shop]

is the TRV type the rhino style with wet clutch I believe. old technology. you can't compare a sled to a utv totally differenet way to clutch.

 

[megadesertdiesel]

i dont know sheet about TRA, QRS or ????? but i found some videos here.

http://www.goodwinperformance.com/faqnews.htm

 

[badassmav]

Never heard of it! You have a link? We run OEM clutchs...we learned the hard way last year.

It's all new to me. Here's what I saw this morning:

http://www.thumpertalk.com/topic/764543-snowmobile-clutching-theory/

 

[Blue Coyote]

BAM will like all this tech stuff:
http://www.sledgear.com/TRAtech.htm


NorthWestOffroad.net
Racing- Adventure - Fun
Maverick XRS

 

[NIKAL]

Look at the CTV on the Predator X18 buggy's. Its a modified version of the Arctic Cat snowmobile CVT. I think it used parts from Team Ind, and from someone else? I know Write Gearbox was or is a dealer for the transmission in these cars. The engine in the Predator X18 is the Chevy 2.4 Ecotec, which is about 170 hp. The CVT is matted with a VW type 2 R&P dif and turns 33 inch tires. Years ago I had talked & helped Eamon the owner of Predator when they were looking to adapt this car to be able to race in Baja. Typicaly this car ran with no CVT cover, just a belt guard. But when racing in Baja or Dakar a cover was needed. Belt temps were a concern a slight issue until a simple Parker Pumper style system was plumbed to the cover blowing air on both the primary & secondary units.

 

[badassmav]

is the TRV type the rhino style with wet clutch I believe. old technology. you can't compare a sled to a utv totally differenet way to clutch.

I have not yet come across anything saying that it is a wet clutch. I need to keep in mind GVW as well. Baxter said they drag race their 265 h.p. "sled" @9,200 +rpm all day w/out problems, and never had a clutch failure. His racer is probably 3 times lighter than ours, and in a drag racing environment, the heat build up in the CVT can not be too much, so there's our grain of salt to keep in mind.

 

[the stripping shop]

I have not yet come across anything saying that it is a wet clutch. I need to keep in mind GVW as well. Baxter said they drag race their 265 h.p. "sled" @9,200 +rpm all day w/out problems, and never had a clutch failure. His racer is probably 3 times lighter than ours, and in a drag racing environment, the heat build up in the CVT can not be too much, so there's our grain of salt to keep in mind.

sorry was thinking the arcticcat style TRV that runs rollers and wet clutch. TRA is what is in ski doo 800 2 stroke. and your right cant compare drag sled to desert race not even in same class. I have worked on some of those sleds but totally different animal. I have 2 of them in stock what info do you need on them.

 

[Bajaxp]

I have not yet come across anything saying that it is a wet clutch. I need to keep in mind GVW as well. Baxter said they drag race their 265 h.p. "sled" @9,200 +rpm all day w/out problems, and never had a clutch failure. His racer is probably 3 times lighter than ours, and in a drag racing environment, the heat build up in the CVT can not be too much, so there's our grain of salt to keep in mind.

You are spot on! Definitely apples and oranges. And be careful of dyno testing CVT's. What works on the dyno doesn't necessarily work in the dez. My 2 pesos!

 

[badassmav]

You are spot on! Definitely apples and oranges. And be careful of dyno testing CVT's. What works on the dyno doesn't necessarily work in the dez. My 2 pesos!

Can you elaborate on what is different about the performance of the clutch on the dyno compared to how it works in the desert?

 

[Freeezen]

Mechanically smarter people than me will surely answer, but some will say the dyno cannot accurately simulate a real world load on the motor. Now others will say that through experience the dyno is useful to tune for what works in the real world. There are pages and pages of posts on another forum arguing the usefulness of a chassis dyno vs a crank dyno, fun reading.

 

[the stripping shop]

you cant put clutch/trans in a 1to1 ratio.its always changing

 

[Bajaxp]

Can you elaborate on what is different about the performance of the clutch on the dyno compared to how it works in the desert?

I think it must be total drag thing (wind, weight and 2wd on the dyno versus 4wd in the dez), but I am not 100% certain. All I know is we have had great numbers and correct upshifting and back shifting on the dyno, only to have it run like a pig in the desert. But I think you could successfully tune your EFI system on the dyno if your ECU has open architecture or if you have the special software to program the 3D map with the hexadecimal code. My 2 pesos for what it is worth.

 

[badassmav]

I think it must be total drag thing (wind, weight and 2wd on the dyno versus 4wd in the dez), but I am not 100% certain. All I know is we have had great numbers and correct upshifting and back shifting on the dyno, only to have it run like a pig in the desert. But I think you could successfully tune your EFI system on the dyno if your ECU has open architecture or if you have the special software to program the 3D map with the hexadecimal code. My 2 pesos for what it is worth.

Makes sense.

 

[warlock]

you cant put clutch/trans in a 1to1 ratio.its always changing

John Dyer at Racers Edge in Tucson took a Clutch and Welded it together after measuring it all out to get close to the 1 to 1 Ratio if I remember correctly.
Tim Kelly in Tempe has a Dyno that attaches to the rear wheel hub on vehicles so you don't have tire slip issues to deal with and his Dyno can manipulate load control and really test the car fully .

 

[NIKAL]

One of the things you dont realize or think about is shock load & wheel spin. Shock load through the drivetrain was greater then I realized. I only learned about this when XTrac was working & developing a TT gearbox for Jimco.

I will be the first to tell you I know little about the CVT clutch. But one area I see where shock load could be a huge factor in a UTV or CVT trans is due to the fact the CTV shifts are base on clutch weights & RPM. As your suspension is compressing & rebounding you are constanlty losing traction & then as the tire compresses on the ground you are gaining full traction, which is constantly sending shock through the drivetrain & CVT. I would guess you could see a bit of belt slippage too, which I would expect to cause more heat & belt failure. I dont know of a dyno that can duplicate any of this.

Also years ago while prerunning I learned about how much wheel spin you are getting. My Baja Bug prerunner had one of those CV magnet speedo senders. Coming across the San Felipe dry lake bed my speedo & GPS were almost 8 mph off, vs when being on the pavement. My Baja Bug has just about 100 hp and runs the Yokohama Super Digger 3 tire on the rear. So as you increase your hp I would expect you would see even more wheel spin in the dirt. When I asked Simon with Xtrac about wheel spin, he said they see 15-20% on the Class 1's & TT's with the BFG Project tire. Simon said the only way to test shock loads & wheel spin was in real life testing. They could not duplicate what they saw on the track in a lab. He said this was a huge surprise to them as Xtrac builds Indy car, F1, La Mans and even Dakar gearboxes. Every type of vehicle they have worked with they had been able to duplicate or R&D in a lab setting. American Off-Road Racing was a huge eye opener for them.