Clutch kits - real world results?!?

[Mighty]

Mike, does John want some real world results? Have him send me a kit to try I'll be in Muni for the TY ride in a few weeks and I'm sure there will be many Ulmer and Simmons clutched sleds up there to compare with his setup

 

[welterracer]

Am i correct as to say you didnt do your testing from a DEAD STOP??

20mph roll on drag races do not really take full benifit from the clutch kits!

 

[RoyT]

Excellent post SRXracer! Nice to see someone acutally do a somewhat controlled test like that against a baseline sled. IMO, THAT is the way it should be done! And as far as telling a seat-of-the-pants difference? LOL... well, unless you're talking 15-20hp difference, forget about it. It's all too easy to fool the seat in your pants into THINKING it feels faster, into THINKING it sounds faster. "I just spent $$$$$ on these mods, it must be faster... right???" We did a test a few years ago with our F7s just like you described above. We left mine stock, and tried different kits in my bud's, tried higher RPM, lower RPM, and you know what? When all was said and done, everything we tried still left them damn near even! Thanks again for sharing the results of your test on those sleds, on those conditions, on that particular day. – Roy

 

[BADSLED]

TRACTION!!
With sleds making so much torque throughout the powerband it comes down to traction. You need to be putting the extra power you're making to the ground.

For those of you who have gone to NHRA events and seen top fuel cars know what i mean. 7,000hp is amazing but it comes down to proper clutch setup so the tires stay hooked up to the finish line.

 

[dirkdiggler]

The point most of you are missing is if you put more power to the ground you have to adjust your chassis to accommodate the extra power. Simply bolting on parts isn't going to do it.

I'd be willing to bet if the traction was increased you'd see gains with the clutching. It only stands to reason that if you put 10 more hp to the track that you have to increase the traction or your going to loose Lengths "period".

 

[Mighty]

I agree Dirk, but how many guys actually do the other things needed? That's why they buy kits, they want to bolt on those 10 sled lengths without having to do the other things needed :ORC

 

[SRXracer]

Welter, the "20 - 1000' runs" were all from a dead stop. We went out on the road and did roll-ons to test the top end. The 1000' runs were on good harpack with about a 6" or so base. We run down a field access road that gets plowed with a tractor on occasion to knock the drifts down. The result is a great hard pack real world surface to test on.

Mike.. keep us up to date on jon's testing, and let us know if he will be releasing anything to the public. I am really impressed if you are seeing 10 lengths in the real world on trail sleds- ie. not on the ice with chisels and chassis set up for straight line. That was one of the main things i wanted to verify - with (almost) unlimited traction as chisels or picks will provide it is easy to see the big gains of putting the extra power to the track, but i am more interested in making these sleds run in trail form - regular studs (144 or 192), and chassis set up that is realatively trail friendly. You make good points about 4 stroke RPM's and it taking a while for them to break in. I'm not sure where my sled is in the break in process, but i can say both setups ran in the prescribed window of 10200 to 10500.

 

[snowmaaan]

Great post - I too have been wondering if the kits will really make a difference. I understand clutching and have many parts in my "supply" - however the time location and reference piece is always missing. I am planning to do some checking on a set of weights that I just picked up - I am sure that there are gains that are hard to detect - midrange acceleration gains and such. However, as you stated SRXracer and Knappy, real riding conditions (all over improvements including backshifting and traction loss) are what the average consumer really want. I have clutched many SRX's that are very fast top end - however trail riding/ditch riding is less than desireable due to the setup.

KnappAttack - Mike, do keep us informed of what is being done on the kit! Also, isnt there an ECM or fuel mapping change (essentially a chip) change that could improve hp like a car or truck?


Again, great post. If the frikin snow doesnt melt here by Sat I will have some results of a stock RTX vs RTX and than one with a clutch kit.

More later.

 

[yamadoo]

This makes sense the OEM people are getting closer every year. I think it is harder and harder to make a real world difference, not alot on the table like before.

I think this every time I go to a race and see you can hardly tell who won it is so close. But win by a thousandth is a WIN.

Congrats to Yamaha engineers and great post


Merry CHristmas

RIde safe, I will be on the north shore trails til after new years

Yamadoo

 

[helix]

I can tell you that John Wheelock has been testing for some time. He is a good track dyno operator,..he has snow..and he has been back and forth between the two . He tests alongside his Ski Doo 3 cyl that is piped,ported etc for consistant testing out on the snow...and is still adjusting for breakin on his new Attack. He claims he is seeing awsome results,and I expect he is.

SRX racer and Mike make some very good points...people often get thrown wayy off by what feels good,or by their power impressions this time of year when they haven't been riding for a while...they are "sure its better than before"...You gotta spend the time side by side before and after...and conduct thorough testing like srxracer did.

Good post

 

[fourload]

I must say I agree with alot of this argument, especially the traction issue.Alot of the time clutch kits raise the engagement too much or go a little too agressive with the weights or helix on the low end and you end up behind the guy that is stock in the trail application.All I can say is my friend has an identically setup GT to mine 144 goldiggers and all suspension settings right down to the shock setting.We raced when I was stock and we were pretty even. We both weigh about 235 +- 5lbs, and we also have over 400 miles on our sleds. Now I have an ulmer stage 2 kit, (figured I would try someone different)he is stock. His rpm's have come up alot since his was new and so have mine.We are both running about 10500 on a good long hardpack trail.Every time we race I beat him by at least 4 or more sled lengths in about 1000ft .This kit has a low 3500 engagement and seems to make all of its gains in the low to midrange area.Top end will be tested next weekend on our 30 mile long lake.I have had 2 machz's, 2srx's, 2rx1's and now the apex in the last 9 years and have used clutch kits from goodwin,maximum,hauck,bender,heelclicker,speedshop,pioneer and have tinkered on my own.Most of them(without going into specifically which one)did run slower in the trail application and did run slower on the top end than stock.

 

[Yama-Crazy]

keep us posted with the results

 

[RoyT]

Another good post on this topic by fourload – thanks! – Roy

 

[helix]

Good report fourload

 

[SRXracer]

Fourload, that is good to hear. Keep us informed if that distance changes as both of the sleds break in further. Were you both running the 10500 before, and then also after you installed the kit? I will say that the kit i beat when stock that was mentioned in the first post was a ulmer stage 2 kit.

Diggler, Mighty, and others that keep saying TRACTION!! I hear ya, and i don't disagree one bit. BUT, then everyone that is making the huge claims better start releasing chassis setups, and including 244 chisels in their kits too! I have to think that by far the extreme majority of people are buying clutch kits are running them on the trail, and those should be the results that should be advertised - not "12 length gains!! P.S. - 3 lengths in the real world, you need 300 studs and have to set up your chassis for absolute maximum transfer to realize full 12 length gain." The intention of our tests were to try and compare apples to apples using a basically stock chassis, although we did adjust transfer up slightly. While there certainly may be room for improvement in our chassis, i think it was pretty good compromise for a trail sled. The sled was carrying the skis slightly, and without excessive ski lift which i think wastes energy.

It should be interesting to see what people find as these sleds start to get 800 to 1000 miles on them, that is for sure!

Thanks to everyone for keeping this discussion positive!