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OCD Sledhead
Mach Z 900R
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Discussion Starter · #101 ·
I see people complaining about missing RPM on mach z. Stock primary spring is 417224165 (170-300). Cheapest and easiest fix might be to go with 417224166 spring (170-350). I would definately try that first.
You are correct. However my situation is abit more unique. PM me if you want more on the direction I am headed dont want to derail.

Dan
 

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OCD Sledhead
Mach Z 900R
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Discussion Starter · #102 ·
2022 XRS Renegade 900 Turbo R, first ride today, approximately 250kms on the sled after today. Quick adjustment, 1 1/4" Ice Ripper. First tank of gas, rode relatively easy. 2nd tank, rode a bit harder, anywhere from 7700rpm to 8000rpm. Very very consistent in that range. Stock Doo belt. Loving the new 900 Turbo R... Cochrane area today, Hearst tomorrow..
Great to hear.....yes it seems like the 880 ramp sleds are much more likely to REV higher and closer to where they should. I assume that is a single ply track?

Dan
 

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OCD Sledhead
Mach Z 900R
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Discussion Starter · #103 ·
While the belt deflection does not directly relate to peak rpm issue some are attributing the Mach's sluggish performance down low to the ramp. That reported sluggish perfromance can be directly related to belt deflection. Do your homework Contigo!
Yes agree....was first thing I fixed after first couple runs, was VERY loose from factory.

For those that are not sure why, the deflection is mostly felt on "drive-off". When the belt has too much deflection or LOOSE, this put the belt higher into the primary on drive-off, so in essence you are in a higher gear. What many dont understand it, that once you are riding the springs take over. So once you let off and get back on the throttle, the belt will then be tensioned only by spring pressure.

So a loose deflection can hurt bigtime on a drag race for instance, as the belt will remain in that higher gear until you let off throttle. In the end it does seem to always gain a small amt of RPM on top, but helps moreso with drive-off.

Take into account with mechanical reverse the actuator can get hung up and cause an error.

Dan
 

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And at 8000 how much actual speed did you pick up. Any sled reving 8000 is still not that much faster than 7700. Still seem slow.
 

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Or maybe clutch calibration isnt on point. Not the first time when new model comes out. Not enough testing on different conditions/altitudes.
Not when some are revving 8000 and some revving 7500. One here is at 8000 and one at 7400, both mach's.
 

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Disagree....MUCH of this is the Mach ramps. Driving these two sleds back to back its instantly felt. I do not like the Mach ramps at all.

Now that being said, the top end RPMS are still lower on one sled then the other(with same ramps installed) but are much closer within 150rpms or so. That is a lot closer than 400+ rpms difference and may be attributed to the single ply track vs 2 ply. As a matter of fact, In my conversations last spring with rep at shows, all the test mule Machs had single ply tracks, could that be why the rpms are off? Did those test mules rev correctly due to having single ply LIGHTER tracks? Dont know but it certainly is plausible.

I'm actually a lot less concerned that their is a boost leak/issue now. Yesterday I was running my lake and seeing much better speeds even while under revving. And I think once I have this thing clutched with my setup it will be right where it should be.

IMO the Mach Z ramps are a total miss. Guys may disagree but you have likely not slapped another set of ramps in you Mach yet to compare the hard hit of the NON FLAT SPOT ramp. I will take a hard bottom pulling sled every time over the Launch control which is simply a gimmick that I really do not need.

Daltons arriving today with Chris's super fast shipping from his place in NE USA to me in Muskoka Ontario exactly 1 week. Thanks again Chris for getting them out to me.

Dan
I'm saying that the low rpm across the board is not isolated to a specific ramp.Mach or other.
The issue maybe exaggerated with your profile.
Your Mach is definitely on the low end compared to others.
Not enough hp, too much weight, wrong springs, ECU.

It's early but at this point it's looking like a primary spring or both may need to changed.
 
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And at 8000 how much actual speed did you pick up. Any sled reving 8000 is still not that much faster than 7700. Still seem slow.
This.

I know people are chasing RPMs, but what are they seeing for speed comparisons? Are the 8000 RPM sleds crazy faster than the 7700 RPM sleds?

Mine is just a 900T, stocker. I have on a new XS821 and yes, I'm only seeing 7700-7800. Today in decent conditions it was 7,700 @ 108 speedo.
I will say my arms hurt from holding on and my face hurts from smiling, and that's what's most important to me. 👍
 

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Anyone ever think BRP clutched these sleds for drag racing! Max torque is actually 7700rpm
Who‘s put a Mach on timers? Is it quicker at 7700 or 8000? Max MPH will be at 8000 that’s basic math, but what’s actually quicker?
 

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Second ride of mine today. In standard it ran up to 8000 and drop back to 7900. On sport I also saw that but did see it go up to 8100 and drop back to 8000. The first ride didn’t see this. It in the 30s that day and the trails were soft. I’m guessing that played into it.
 

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Russj, that's the question I've been asking!

Forget the tach, what do the actual numbers say??? Speed & ET mean way more than a number on a tach.
 

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Mine runs 8000 and settles in at 7900 with the stock belt. Haven't tried my Gboost belt yet but I will eventually. Currently at 700 miles and I haven't seen a +/- 100 rpm difference since it was new.
 

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Buddy and I raced maybe 30 x today on groomed lakes,I consistently saw 118 -120 on speedo running at 7700 with the 571,put on the xs 821 and was still running 118-120 but at 7400-7500
I have put on a rip2 2ply 1" and it sucks out of the hole but top ends well
My buddy had the stock 1.25" and would wipe me at lower speeds but I could usually top end him but only by 1 or 2 mph
The new sleds are fine everybody is just comparing them to the tuned 900T which is roughly the same
Try racing a stock 900T, not even close :love:
 

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2022 Renegade Adrenaline 900R
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The new sleds are fine
I respectfully disagree. They are slow on top. Maybe you have a good one.
I like this sled A LOT & if this is all it's got i'm cool with that.
It pulls hard & is VERY fun.
BUT, and a huge BUT, it has more somewhere. We just need to find it.
I'm barely above an 850 or Apex.
Doo also claimed "First Across lake". Must be a small lake. Maybe they meant pond.

I firmly believe there is something small like a clutch spring or Crack Pressure or maybe boost leak.
When my sled runs at 8000 then i'll live with whatever it's got on top cuz like i said i'm VERY happy with it.

MOST guys are seeing 107ish. That is NOT something to brag about with 200 hp!
 

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But I will say, the low section of cogs even with top of driven sheave is a crock, that is super loose overall and will have terrible drive-off.

Dan
[/QUOTE]
So how do you adjust your belt? Thanks
 

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if the engineers would give us the sxs pdrive we could run a very tight belt and still have reverse
the beancounters should see the logic of only one pdrive

I adjust mine as tight as possible and still have reverse
 
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I respectfully disagree. They are slow on top. Maybe you have a good one.
I like this sled A LOT & if this is all it's got i'm cool with that.
It pulls hard & is VERY fun.
BUT, and a huge BUT, it has more somewhere. We just need to find it.
I'm barely above an 850 or Apex.
Doo also claimed "First Across lake". Must be a small lake. Maybe they meant pond.

I firmly believe there is something small like a clutch spring or Crack Pressure or maybe boost leak.
When my sled runs at 8000 then i'll live with whatever it's got on top cuz like i said i'm VERY happy with it.

MOST guys are seeing 107ish. That is NOT something to brag about with 200 hp!
Yeah 107 wouldn't be good enough considering my stock 900T was showing 108 yesterday just riding, and has done as much as 115 when the conditions were better.
 
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