825i Build Thread

[flyin6]

That 1000cc Chery engine would be the ticket if it is dimensionally about the same, but then again, where?
Have thought about bigger diameter tires as well, but in my build mission statement, spare parts readily available is a mandate, so I'm staying stock 27" tire size.
RPM'ing the engine would certainly get more speed, but the thought of cruising around at 7,000 doesn't appeal to me much. Having the engine grenade beneath my two passengers would be undesireable to say the least.
The gator definately needs a lift. Just to get things farther off the ground. I have Fox shocks as well, single springs and have my collars cranked all the way out in the front which is only yielding an inch over stock...

[gatorman30]

Here is the link to Chery motors (https://www.cheryacteco.com/en/Link) you need to click on the powertrain manual in the lower left for the specs. I have also seen this manifold (Link)

This place sells buggies with the Chery engines maybe they would sell one have to look at all the diminsions sometime... (Link) but 86 hp would be nice.

I was not saying increase the RPM's it just does not like being below 3000 RPM with the CVT even cars with a CVT will run higher.

You have a lot of weight without four more people your best bet would prob be getting new springs then you could get 1 1/2" to 2". Eibach or King both sell replacement springs.

[ratrod]

The primary and secondary clutches on the gator are a lot like those of a snowmobile. With springs, weights, and helix you can tune the clutches for maximum performance depending on the condition. You can also change the gearing on a sled to match conditions, and track length. I would assume that you could do the same with the gator's clutches. A good starting point would be to cross reference the part numbers on the gator clutches with those of a snowmobile. Once you know what sleds that clutch is used on you can find all sorts of spring and weight kits for cheaper on the internet than Team Clutch charges for the gator application. I'm not sure of the gearing in the gator, but I would assume it could handle the extra speed.

[flyin6]

The primary and secondary clutches on the gator are a lot like those of a snowmobile. With springs, weights, and helix you can tune the clutches for maximum performance depending on the condition. You can also change the gearing on a sled to match conditions, and track length. I would assume that you could do the same with the gator's clutches. A good starting point would be to cross reference the part numbers on the gator clutches with those of a snowmobile. Once you know what sleds that clutch is used on you can find all sorts of spring and weight kits for cheaper on the internet than Team Clutch charges for the gator application. I'm not sure of the gearing in the gator, but I would assume it could handle the extra speed.

...Good info
I've looked at the diesel clutch and the gas clutch of several models and yup, they are different.
I actually own a 2007 850D as well. Was thinking about swapping some parts at one point. THing is I don't understand the science of this CV clutch deal vs a standard transmission and rear gears (which I understand very well)
Given time, I will be able to figure it all out, but for now, it's learning time.

[Gator Joe]

That is Bad A*s I got some great ideas after seeing your Gator. I am getting mine set up, but time and money is slowing me down. Nice set up Bro. Gator Joe

[gatorman30]

Here a write up on how the CVT works... It is long but clears up a lot. The Polaris Ranger weights are supposed to work with the John Deere but do not know for sure... Your biggest issue is going to be weight combined with added power. I am trying to lower the weight of mine as much as I can, not a possibilty for you. I would carry spare belts they are not much and easy to change I think I paid $65 from the dealer...

The CVT is designed to start in the lowest gearing, and then gear up until top speed is reached for the given engine output. At a stop, the primary sheaves are spaced at the maximum distance, causing the belt to go to the lowest point on the sheaves. The secondary sheaves are together except for the distance the belt doesn't allow them to move. This causes the belt to be towards the outer edge of the secondary sheaves. This creates the greatest mechanical advantage. It's much the same as starting off in 1st gear in a conventional transmission. Once you start moving, the transmission will automatically adjust that gearing ratio to balance the engine torque output with the resistance of the wheels.

The ratio changes because of the physics of the clutch.

The primary consists of the two sheaves I mentioned before. One is fixed, and the other moves in and out on a collar. When it moves inward, the V gets tighter between the sheaves. This causes the belt to rise in the primary. The higher in the primary it moves up, the further the belt travels per rotation, increasing the speed of the belt.

The secondary responds to the primary belt height. The secondary also has a fixed and movable sheave as well. The difference is that the secondary also has a spring in it to force the plates together. The belt doesn't stretch much, so as the belt rises in the primary, it wedges the the secondary sheaves apart and moves close to the center of the sheaves. This causes the secondary to increase rpms. This means the ATV goes faster.

When working together. The Primary squeezes increasing the belt speed, and the secondary spreads, increasing the output speed.

What causes the primary to squeeze the belt and gear up is centrifugal force. At the end of the primary movable sheave is a fix plate. It's bolted securely to the end of the shaft. The Moveable sheave slides on the fixed plate and collar, with 8 weights between the plate and sheave. The weights act like wedges. As the RPM of the primary increases, the weights are forced outward and slide inside the channels on the primary sheave. This causes the weights to wedge against the sheave, forcing it inward towards the fixed sheave. Greater RPM's = Greater squeezing force.

Now you're probably wondering why the transmission wouldn't just gear all the way up when the engine increases RPM right?

The magic happens in the secondary. Although the spring keeps tension on the movable sheave, pushing it towards the fixed sheave, there is also extra force created by shaft resistance. This resistance is transferred from the wheels through the final drive gears, and then onto the secondary. On the secondary, the movable sheave is also mounted with pins that move inside corkscrew like channels. When a load is applied to the wheels from acceleration, a hill, or mud, that load utilizes the corkscrew action to increase the pressure on the secondary movable sheave. When this pressure exceeds the force the weights create on the primary, it will hold the lower gearing until the weights overcome this resistance.

So to summarize it for you. The weights cause the primary to squeeze harder as the RPM's increase. The secondary resists this gearing up based on spring pressure and resistance created by the corkscrew affect due to resistance on the tires do to acceleration, hills, or mud. It always finds that perfect balance.

Now that you know how it works, lets mess with it to make it do what we want. Since the CVT is tuned for stock everything, it needs to be tuned when tires, weight, or engine torques is changed. If you don't, you're not getting the most from your machine, or your mods.

Lets start with the primary:
You can modify the primary by changing weights, machining sheaves, adding shims and modifying the cam plate.

The weights determine the shift up of the primary. Lighter weight hold lower gearing longer, and heavier weights cause it to gear up sooner. Your goal is to weight the machine to hold your gearing under full throttle just below peak torque on a flat road. This way, when resistance is created by a hill, extra weight, or mud, the machine will hold the gearing longer, putting you in the peak torque of the engine under full throttle. Hell ya!

Shims and machining. By adding shims or machining, you can increase the lowest gearing substantially by spacing the primary sheaves apart, allowing for the belt to drop lower in the primary, and rise higher in the secondary. Shims will lower the gearing range entirely, so top speed will be lost. Machining can be done to lower gearing to increase the gearing range without losing top end speed. This is done by only machining the inner part of the sheave, and leaving the out sheave the same. Other machining removes the from the whole face, lowering the entire gearing range like the shim mod. The benefits are that it keeps the sheave angle stock for decreased belt wear. (Mad Mike's mod #2)

Here's a guide on installing shims.
How to do the shim mod.

Fixed plate mod. If you've taken some meat off your sheave and lowered the gearing range, the fixed plate mod can restore your top speed. The tips of the fixed plate where the weights ride are bent in slightly at the ends. This allows the weights to push the movable sheave more in the top end, restoring your top speed gearing. (Mad Mike's mod #3)

Take a breather if your eyes are seeing double.

Secondary.
The only thing you really need to modify in the secondary is the spring. The spring assists the secondary with holding gearing, and downshifting. Since it takes pressure off the pins reducing the wheel resistance force needed to return the secondary to lower gearing, it will increase the downshift rate as the spring pressure increases. As a side affect, it does increase the primary force needed to overcome the heavier spring, so weights will need to be heavier for a heavier spring to maintain the up-shifting profile the weights create. The stronger spring also increases the pinching force on the belt reducing slippage and thus heat.

Now if you're deciding on tuning your clutch, you should follow these steps.

First, start with engine mods, cause what you want from your transmission will change with power output. Then I'd do the machining, shims, and fixed plate mod. This will determine the gearing range you're working with. Change it later, and you'll have to change everything else. Next would be your secondary spring. This will affect your weighting, but your weights won't effect your spring choice. Then finally, get your weights and tune your machine in to get the gearing set to the RPM peak that you prefer.

Remember, no gearing set up is perfect for all. Rider weight, cargo weight, pulling weight, and riding conditions all have their affects on what RPM the transmission will shift best at.

Wet clutch springs can also be changed to increase wet clutch engagement RPMs. Gets you into the power a little sooner. The wet clutch is just 5-6 shoes or blocks that are pushed outward be centrifugal force. When RPMs overcome the springs holding the shoes in, they connect with the clutch housing and engage the crank with the primary. Stiffer springs will increase this RPM engagement, and are found in 500+ and 1000+ RPM. 1000's are more for racing.

[ratrod]

If you think about it, older snowmobiles from the late 70's early 80's were in the 340cc to 545cc range and they were putting out 40-60 horse power and they could reach speeds of 85 to 100mph. My Mountain Cat 1000 the secondary clutch spring is adjustable for different shift points, and you can buy different angled helix's to tune it further. Has anyone investigated the gators secondary to see if its adjustable?
I would think the ideal situation would be to leave the gators engine as stock as possible in the event something happens. Getting parts for a stock motor would be easier then having to modify parts or waiting for special order items to arrive. Any motor work would be time consuming, where as clutch work is made to be done on the trail. A spare clutch and belt(s) might set you back a few hundred bucks, but could be changed in a matter of minutes.

[flyin6]

Well, after reading that short little summary about clutch mechanics...
I think I'm sticking with the plan to build the engine first.
It sounds like I am going to have to get smart on all things clutch to get the thing to run in it's new power band and produce sprint speeds consistient with what I think I might need.

So on that point, I spent a couple hours reading about the Chery 372 engine we have and am impressed with the fact that no one hot rods this engine. There are turbo charged 1100cc 4 cyl versions of the Chery engine out there and even available for sale from China. So at the moment I am not committed in any one direction, however my sense is that I should bolt on a Garrett T-15 turbo and spend some time figuring that out to give me something around a 100% horsepower increase. then figure out how to get the clutch to work with those characteristics.

[gatorman30]

The rods are forged so it should handle at least 10psi.

Nice build up on the Duramax, I have a 6.4 Ford it's amazing how much power the new diesels can make last run on the dyno was 632hp. Did you get a built trans? If not how does the Allison hold up? And your suspension install made me even more grateful for a solid axle.

Another question why a piston M4 over a SCAR 16 or 17. I personally love mine and they are accurate.

[flyin6]

The rods are forged so it should handle at least 10psi.

Nice build up on the Duramax, I have a 6.4 Ford it's amazing how much power the new diesels can make last run on the dyno was 632hp. Did you get a built trans? If not how does the Allison hold up? And your suspension install made me even more grateful for a solid axle.

Another question why a piston M4 over a SCAR 16 or 17. I personally love mine and they are accurate.

10psi, how about 14 or more?? It will hold. It's in the timing, mixture, and H20 injection. I have years of experience with grand nationals. Stock blocks at 25psi in the 650HP range.
I read about those forged rods, however couldn't find any info on those pistons. I looked at them but couldn't tell much. From what I know GM stood up Chery and put some money in that engine to make it bulletproof in the chinese market. That means it is likely over engineered. I think a painted interior of the block and forged rods hint at that. So I think I will be fine. I will monitor A/F ratio with a gage and program in a safety retard should it go lean.

My LML D-max is a great truck to be sure. It was pushing 507 at the rear wheels with 4.56 and just under 1000 ft lbs. Needless to say, it's plenty quick. I am keeping it there for now pending a trans. The 2011 and newer Allisons are uber strong, but not up to much more than I am pushing, so a fully build 6K trans is in the future. I plan to add twins at that time and call it a day. It's not a drag truck, but I want it to be spirited while carrying the extra heft.
I have read plenty about our injection pumps. For some reason they are failing in the powerstroke application but not in the D-Max. Strange... I do know you NEED to run Opti-lube or something very much like it (and not diesel kleen) to get some luge to the pump or it will fail in time. Check out the technicals on the optilube. You'll be surprised.

I have a lot of years "down range" and that's where I developed my opinion from. First you only need to shoot the most common ammo. So when you jump from 5.56 up to some of the military calipers, that's all well and fine until things turn south. Then you won't be able to get ammo.
In my view only buy weapins in the calipers of: .22LR, 5.56NATO, 9mm, .45auto, 7.62 X 39, 7.62 X 51, and 12 gage.
Considering that as an assumption, the AK is so much better of a weapon that our tiny .22's that I only have my M4's because there is ammo, and the setimental attachment. But the bad guys shot at me all the time with that AK, and I can tell you it is very destructive. Ammo is cheaper and does much. much more damage as well. On top of all that, they are cheap...end of story.
For bench racing, sure SCAR and gas piston M4 guns are cool, but give me my AK.