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2019 Defender XT cab 30" Cryptid tires and EPI Mudder WE437427 clutch kit


Andystoy19
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This machine has the Monster FI reflash so the base line may be different on a stock machine with the same tires and clutch kit. The tires are labelled 30" but are 29" diameter but have increased the rotating mass of the tires on the machine by 80 lbs.

Rolling at 3000 RPM in high to WOT with stock clutching RPM 5900-6000 very quickly holding steady until top speed of 80kph/50 mph.The MFI reflash removes some of the torque limitations (belt saver) so that the engine can get RPM more quickly providing more torque and HP and acceleration to the machine. The reason I used 3000 RPM and rolling for the tests is to try and reduce belt slippage which would be greater starting from a stop.

EPI kit installed with yellow primary spring and green secondary spring and EPI helix, (note I had to use heat to release the 4 secondary helix bolts the first time). Follow the EPI video for install but the kit does come with a good instruction sheet. I removed the passenger side rear wheel to provide more access and bought the Can am clutch holder and clutch puller bolt. The kit comes with the yellow primary spring two secondary springs an almond color and a green(stiffer) spring and helix. Clean the clutch surfaces with brake clean and blow any belt dust off both clutches. I use a scotch brite pad to lightly buff the primary and secondary clutch surfaces to remove any belt smear usually down low on the primary clutch from slippage during engagement and initial start.

Rolling at 3000 RPM in high to WOT (with EPI installed) RPM goes to 6200 and seconds later (mid shift) starts to increase and tops out at 6600 RPM and 88kph/55 mph not corrected for tire size. The kit allows the engine to get RPM much quicker than stock clutching and allows it to reach more power sooner with a better top end and a much stronger pull right from 3000 RPM to 6600 RPM. I want to try and get at least 7000 RPM (max power) at WOT so I have ordered a couple more primary springs (with a higher finish rate) that are stiffer than the one I installed, I will update in a couple of weeks once the springs arrive and I get a chance to install them. Right now the engagement RPM is very similar to stock. The clutch may be slightly more aggressive at engagement than stock so the machine may be very slightly more jumpy which would be the only downside so far.

This is a definite improvement from stock and one that I would do again.đŸ˜‰Â The picture of the kit is upside down???

 

20200908_150755.jpg

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  • 2 weeks later...
  • 2 weeks later...

I replaced the yellow spring with the CAPS2 black (stiffer finish) and going from a 3000 RPM rolling start I go very quickly to 6700 RPM (+100 RPM) but the feel of the pull seemed more "revy" and not as strong as with the yellow in the original kit. Changed back to yellow and that will be the end of changing things on the EPI clutch kit.

In summary, its a good kit for making the machine more responsive right from engagement (2000 RPM) all the way up the shift range(6600 RPM). Its a good idea to baseline your machine before installing the kit and after including when trying different spring rates. Without the baseline you have to rely on memory which tends to be very subjective. My machine with stock clutching was much slower responding to throttle input and lost more top end because the clutching wouldn't allow the engine to get into its max power range. The info I have is that peak torque is at 5700 RPM and peak hp is 1000 to 1500 RPM above that so at 6600 RPM I am very close if not at maximum Hp.

Non of us drive our machines like a dragster but in order to get a baseline (without another machine to test against) I used 3000 RPM to max engine RPM resulting in an increase in engine RPM vs vehicle speed throughout the shift range. Hope this info helps if you are looking to make similar changes.đŸ˜‰

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  • 9 months later...

Dalton Industries have a kit DBHD10 that they list for 2016-2019 stock machines. Looks like 3 pieces: primary spring, secondary spring and new helix (parts appear to be similar to the EPI kit I installed) that does not mean they are similar or will perform the same.

"Designed to recover bottom end performance without hurting top end" and the application is HD10 and HD10 Maxx with 28-30" or larger tires.đŸ¤”

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