Turbo Proclimb clutching thread, 10k + elevation

I'm sick of digging through old threads regarding clutching info and not finding what I'm looking for. I present the following trial and error info regarding high elevation clutching on a Proclimb M8 with turbo.

162 x 3" track. 20/49 gearing.

I have the Rapid Response primary and Team Tied secondary, which were set up by RacinStation for an N/A sled.
Primary using MDS weights at 78 grams with white spring. I believe it is a Team 120-310.
The Tied has helix: 71-55-.36---71-57-.36 ER TIED HELIX (AC960049), and I'm not sure what spring is in it.

I rode the sled for a week with this clutching, and it held a consistent 8280 RPMs. Snappy engagement and nice warm, but not remotely hot clutches. I was more than happy with the setup.

Then... I got an inclination to put a Boondocker PG turbo on the sled. Base kit, and I had it set to run 7 psi boost on a 30% Racegas/91 mix.

I put the Lime Green spring from Boondocker in the primary, and their best guess was to run 80 grams in the primary, so I added 2 grams to the heel of my MDS weights. I'm not 100% certain which spring comes in the BD kit, but I have reason to believe it's a Team 150-340 primary spring.

I did not make any changes to the secondary, because there isn't **** for useful info on the Tied secondary with a turbo at 10k+ elevation. Boondocker said they had no testing with that setup.

Test ride was conducted in perfect turbo sled conditions. Over the hood fresh/falling powder at Rabbit Ears. I did not expect everything to be perfect, and I found the following:

Engagement is harsh as sh*t, IMO. I could rarely see my gauges because of snow coming over the hood right away, but it seems to engage between 4500-5000 RPMs, and when it does, it causes an immediate track spin that I only dig out of because turbo.

Max RPM is 8500 RPMs... about 300 more than I would prefer.

I cleaned the clutches up before the test ride, and it looks like the bottom half of the clutch sheaves have belt slip marks. Not black or excessive, but not clean like they used to run.

Clutches do not get hot.

This was a relatively new, but broken in belt. There seems to be wear on face of the belt cogs, maybe pulling too much into the secondary?

Backshift seemed to be pretty good, but I felt like it was revving slowly on the bottom end, and the bottom end has no "snap" to it. It actually kinda sucks. Edit* By "snap" I mean the throttle response. It has lots of "snap" on engagement. It's stupid.

Sled pulled hard on the top end, but I didn't want to get too crazy since it was over-revving. It's completely ride-able, but not nearly optimal.

Max boost shown on the BD box was 5.8 psi and I don't really understand why, since I had it set for 7. New to turbos.

I did the BD install myself. I was greatly impressed with the quality and fitment. The only "bug" I had with the turbo was the TPS sensor bogging me out. This was due to the throttle cable being overly tight. Loosened the throttle cable and the issue was 100% resolved. I ran the base BD #'s and found them to be suitable. No throttle dead spots or bogginess once I cured the throttle cable issue.

I cracked my TCL after about 20 miles of riding. The dudes at VOHK didn't have one in stock, but one of the techs had a spare at his house. Reps to those guys for helping a guy out.

Long post, but maybe will help guys out who are just setting up a turbo sled for elevation and I can tell you that this particular setup works, but it's a little bit sh*tty. Would not recommend it.

I'm going to call RacinStation tomorrow and see what they have to say, and hopefully some guys can chime in with a setup that works better.

What RPMs are guys shooting for with a turbo setup? It seems like with a turbo and the elevation, it would be better to rev a little higher than HP peak, which people claim to be 8000-8100 RPMs.

Thanks in advance.
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Well-known member
Lifetime Membership
Nov 27, 2007
Red Lodge MT to North, CO
The mds weights run heavier than other springs but work well with NA Secondary setup.

80g isn't enough, they also engage higher.

Put the 120/310 spring back in and load the mds weights to about 84g with more of the weight in the middle.

Try it and adjust as needed, you shouldn't have to mess with the secondary.

Mds 73g is about equal to 66g cat weights.
Wyo - You're one of the dudes I can count on in this forum to write intelligent things.

Another member hit me via text and suggested pretty much the same thing... dropping the lighter primary spring back in.

I'm not a clutching genius by any means. I know the lighter spring will help the harsh engagement, but I thought it would make the over-revving worse.

He suggested it would actually allow the clutch to shift out more easily, instead of keeping the sled in a lower gear and running the RPMs up. That makes sense with what I'm seeing with the belt marks on the primary.

Perhaps why I'm not seeing 7 psi of boost is because the clutch wasn't loading the engine/turbo enough?

Thanks for the info.


Well-known member
Lifetime Membership
Nov 27, 2007
Red Lodge MT to North, CO
Think of this

If the sled hits 7800rpm you can put in lighter weights, about 2g lighter give or take
Or if 7800 you can go from a 285lb finish rate spring to a 310lb finish and get the same effect to h hit rpm.

Either will hit rpm but there is a slight difference in response.

Take a 120/285 vs 120/310. 165lb vs 190lb worth of total change in shift. Now take and go from 0 to 100% shift, for every 1% of shift it takes 1.65lbs of force from the weights to shift. For the 310 spring it takes 1.9lbs of force per 1% of shift. So it acts different.

Depending on your secondary things can vary. But you had a setup you liked so base it on that setup.
Now think if you you will have the same thing but the clutches will shift out farther with more power.
Basically you need to start with the same but change the finish.
I don't know the team clutch at all but in the past it is almost like running a starting setup like you would a under powered high elevation but then finish with a low elevation setup.
Little higher engagement and loaded on top.
Very good, bro.
I had to read that twice, but I see what you're saying with the spring vs. weight correlation.
I will swap back to the Team white spring and add a few grams to the MDS weights.

There are three storms heading through CO this week, and should result in some decent fresh for this weekend. I'll head to Kebler and put it in the trees and see what it does.

Will post back with the outcome and hopefully give some idea of a working setup with the turbo/Team clutch combo.

I'm gonna shoot for 8250-8300 RPMs.

This time I won't get all excited and forget to mark the clutches.
I did a full day of tree riding today with the Team white spring back in, and 84 grams on the MDS weights. There were some good and bad things with these changes.

The snow was very much settled as opposed to over the hood powder like last time.

Still over-revving. It's actually worse. I hit a max of 8590 RPMs with this setup. Holy h*ll.

Clutch engagement was about 100 X better than it was with the BD supplied green spring. Even riding it into the trailer was better. I didn't leave black track marks all over my garage floor like the green spring did. That f*cker would straight up do burnouts.

I marked the primary, and the belt is riding about 1/2" from the top of the sheaves. Much further up than it was with the BD spring. No evidence of belt slippage at all. Clutch sheaves are nice and clean.

Both the primary and secondary are running cool enough that you can hold your hand on them, and they're warm, but not burning a$$ hot. We pulled the panels on a stock '14 M8, and his were much hotter after running the same lines through the trees. I have vented panels and he does not. I think that has to help quite a bit, but the stock Cat clutches are bullsh*t anyway.

Once again, I had boost on the EBC set for 7 psi, and this time I only hit a max of 4.2 psi --- what the actual f*ck?!

Either I'm retarded... or I have a problem somewhere. I came up with multiple theories on the 4 hour drive home:

I'm going to start with tearing the turbo plumbing down and checking for a leak somewhere, but if I had a significant leak I think I would get some bogging or hesitation? Sled ran top notch all day. Started first pull every time, good throttle response, ran fine, but not hitting the boost I want to see.

Am I still not loading the engine/turbo enough?

For example - If a guy just threw a sled up on a stand and revved the sh*t out of it, you would not expect to see 7 psi. With the clutch weights being too light, with 20/49 gears, and 7 tooth drivers... maybe not enough load?

I dunno. Like I said - I'm new to the boosted sled world. I built a Vortech supercharged Mustang (centrifugal supercharger) several years ago, and I know you had to have some load on the engine for that f*cker to spool up, otherwise you'd run in vaccuum if you just cruised it. But if there was a vaccuum leak, you'd know all about it.

Either way, I'm going to check the plumbing for leaks and load the MDS weights to 90 grams for the next ride and see what happens. The sled is completely ride-able and enjoyable. I had a blast and my *** is kicked because I ate sh*t three times today. I just want the boost to hit where I set it... so I can do out of control wheelies up hills and look cool on GoPro.

Rabbit Ears is melting quick. Muddy Creek lot will be a mud pit by tomorrow with this weather.


* Edit... 8590 RPMs is not "cruising"... F*cking sled is pissing me off and not knowing the answers to fix problems immediately sucks.
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Sep 22, 2002
Eastern Wa
The helix you are using has a steep initial angle which loads the motor and turbo HARD, maybe too soon. Most turbo guys run a reverse helix like a 36/40 to slow the shift down to give spool time for the turbo. Also if you are still running the mds N/A weights they might not have enough arch in them to load the turbo on the top end. I know that mds has a turbo specific weight. You are on the right track, load it till it quits pulling the weight. Just remember the heavier the weight the laggier its gonna feel too, you have to swing those heavy things. Like Wyo was saying, lighter spring weight the less weight you need to swing. So the 100-330 spring will let you swing more weight to overcome the spring than a 100-285. So if your heavy weights make it laggy, try a softer finish spring and leave those weights alone.
Hope this helps you out.
Thanks for the feedback. I appreciate it.
I expected some tweaking would be required, and honestly, the sled runs and rides even better than I initially expected it would.

It's crazy how the clutching affects the boost the turbo makes. It's complicated but I'm learning a lot by sorting this out. Eff it.

I'm going to try a little more weight in the primary, and see what happens if I do that. If that doesn't get closer to the desired result, then I'm out of options... except for throwing some more $$$ and parts at it.

I need more friends who ride N/A Cats so I can sell off my take-off parts.

Thanks again for the info.


Well-known member
Nov 13, 2009
So are you using the Turbo C1ts weights or the standard C1s weights ? There is a reason we make the different profiles. Have a ton of boost guys out there using the C1ts most using 100 start rate 120 max give me a call and I'll help you out if you want.
So are you using the Turbo C1ts weights or the standard C1s weights ? There is a reason we make the different profiles. Have a ton of boost guys out there using the C1ts most using 100 start rate 120 max give me a call and I'll help you out if you want.

I have the N/A weights. I was on your website last night looking at the turbo-specific weights, and deciding on whether to experiment with what I have or just toss out a bit more $$$ and use weights that are designed for the turbo. It does seem ridiculous to invest in the turbo and then use clutch components that don't optimize performance.

Boondocker should make the clutching components optional when purchasing the kit. They could shave a few bucks off the initial cost since the weight spring combo they offer isn't going to work for a number of customers. I didn't use the weights at all, and the spring came out after the first test run.

Anyone need some lightly used C1s weights?
This mother f*cker

I've made all kinds of tweaks lately trying to get the sled to hit the boost the way I want it to.

58-62.36 helix in Tied Secondary
Black/Silver 160-280 spring

MDS Turbo weights loaded at 76.5 grams with more weight in the heel.
Polaris Black spring in primary 100/340

I went back to 21/49 gearing, but still have 7 tooth drivers. This seems to have helped the top end more than the 20/49 gears.

I adjusted the wastegate in the turbo, it wasn't seating all the way.

I'm turning between 8200-8300 RPMs in bumper deep powder.

I have checked all the plumbing multiple times. I'm about sick of doing it... but the max boost I ever see in the Stats on the BD box is 5.8 psi. WTF. What am I missing? I have it set for 7psi.

Sled runs like a champ. I'm happy with the clutching and the way it shifts and sh*t. Occasionally I'll get a little bogginess if it's sitting and idling for a minute, like it's loading up, but feathering the throttle clears it up. It isn't terrible and isn't my main concern at this pooint. It flat rips on top end.

It has twice bogged in a wheelie, but my fuel was low when that occurred.

Anyway... what would you guys check out? Is the integrated EBC not calibrated or something? I feel like this is something stupid that I'm just not clued-in on. I'd like to get the sled to hit 8 psi if I want it to.

I'm gonna tear into it again tomorrow, but I'm more or less stumped at what to look for at this point. I can live with 5.8 psi, it's fun as hell. But if I can turn it to 8 way up here in the mountains, then I'm damn well gonna do it.
I was having a problem with the boost actuator.

Currently running Polaris black 100/340 primary spring.
78.1 grams (4.9 in heel, 3.2 in toe of MDS weights)
Team black/purple 160/240 secondary spring
58-62.36 helix in Tied secondary

21/49 gears

This gets me 8330 RPM at 9 psi @ 10k+ feet

I'm not super stoked about the engagement with the 100/340 spring. I'll likely try a stiffer spring.


Well-known member
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Jan 14, 2003
Speedwerx white or Dalton Aqua Black primary will give you higher engagement and the same finish rate. A bit more turbo friendly than the Polaris black.
This setup is better:

Running 7-9 psi @ 10.5k - 12k ft elevation

MDS weights @ 85.2 grams
Team white/bronze primary spring - 105/280

The Team spring is measured differently than the Polaris spring and is actually a stiffer spring.
(Thanks to RacinStation for that info)
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