Stepping up

[odypilots]

After getting waxed by the ProtoDie buggies on the track last year, something had to be done. I thought about buying one of their cars, but $17,000 was too much for me, so AtvNut said "Why don't we build a couple of Pilots with sled engines in them?". So we are. The buggy is at the pipe builder's now, but here are a few pictures of it before it left.

[LiveWire]

Looks good.

[atvnut]

THANK YOU

[odypilots]

More pictures

[atvnut]

This is a long over due pos and I want to thank Dave and all involved for making this project move along smoothly. There is more dedication in this project then you can imagine such as 56hrs worth of drive time just to get 2 pipes made. I am now going to ask Dave to step up and give ya a report on the machines performance in the past 2 yrs or so.

As we never put my machine together as of today for medical reasons but i am going to attempt to slide back into the drivers seat this summer and see how things feel.

Thanks again Dave for making this one of the most memorable experiences of my life

[odypilots]

Welcome back, Jeff! I hope your return to the driver's seat goes smoothly.

As for the machine's performance, it did what was asked of it, to be competitive with the cars that were too much for a modded Pilot to be able to race with. It was amazingly trouble free for the amount of modification that was done to it.

[odypilots]

A bit of an update. Last summer the 600 started eating drive belts. I didn't think to much of it because some old belts were being used up. Well, it wasn't old belts. Dirt, built up in the TRA drive clutch, had GREATLY BOUND UP the pivoting arms inside. It appears that this binding was causing the clutch to stress the belt. The big mistake on my part was to power wash the clutch, driving the dirt where it wouldn't get on it's own, because I didn't do that until this past year.

I was hoping to get some time on ice to play with clutching, but that doesn't seem likely to happen, so testing may wait until spring.

[baz]

Any more updates Dave? Keen to know the current status,and what you've learned?
Cheers Baz

[odypilots]

I've been clutch tuning. Looking for higher engagement, I decided to change the spring on the drive clutch,a TRA II. I had a 160 230 spring in it, 281 ramps, and ramp adjusters set at 5. Pin weights weren't checked.

The driven clutch, a Arctic Cat tall tower roller, had a yellow spring and a 62/56 helix wound to the tightest spring adjuster hole.

Actually, since the trying of 3 different drive springs and 3 helixs in the driven, the original set up was pretty close.

So as to make a noticeable change, the drive spring was swapped for the stiffest spring available, a 240 430 I believe. No change to the driven. The engine went from only hitting maximum revs 10% of the time to 70% of the time.

Jeff really wanted to see what a 49 helix would do for it, so in it went. Now it's hitting max revs 85% of the time. Sounds great, huh? But it wasn't. Top speed was affected, lower. The engine seemed labored, too. An  inspection showed a great deal of belt smear on both clutches. I wish I would have played with spring tension on the driven to get a feel for what those changes would have made, but didn't think of it.


Next time out, I tried a lighter spring, a 230 350, ramp adjusters on 5. I didn't like the 49 helix, and my 62 56 helix was showing signs of wear, so I put in a 64 56 helix, still with the yellow spring. The too immediate rise to high revs, which I put down to the 49 helix, was gone, with the 64 56 helix behaving
much like the 62 56. The clutches still seemed to be fighting themselves, though less than with the 240 430 drive spring. Everything was good at low speeds, but at high speeds, the clutches didn't seem happy. Than a belt started coming apart during a high speed run. This same belt was on with the stiffer spring last test. I think the damage was done with the 240 430 spring and the 49 helix in the driven. Again, embarrassingly, no adjustment was made to the driven clutch's spring tension.

So now I have a 200 290 in the TRA, and no changes to the driven, ready for it's next test.

[odypilots]

I'm liking the 200 290 spring in the TRA. Testing was in a smaller area, so top speed was not reached. Still, there was 100 yards or so, so it did get to picking them up and putting them down pretty good. The clutches felt much more in sync than with the stronger springs in the drive.

One correction to the driven clutch set up is that in all above posts is that the Arctic Cat driven's yellow spring was adjusted to the softest position. Dohh! I had got it in my mind it was in the tightest position, and only when I (finally) went to adjust it, saw I was wrong.

A cheap temp gun was used to check how hot each clutch was getting. There was about a one minute drive from the track to the pits, so that readings may be affected to some degree. Hehe, I made a funny. Also the time it took to climb out of the buggy.

The drive was 155 degrees, and the driven was 120 degrees. From my limited knowledge, these temps indicate the belt is being held more tightly by the driven. Since the driven spring is in the softest hole, it seems a softer spring is called for?

So I think I'll run it like this and check belt life.