I finally got it done! Was a job to fit a turbocharger in the tiny space of an ATV! The intercooler was a piece of cake. Tomorrow I will put ARP head bolts in and turn up the Bosch fuel injection timing to 20 degrees BTDC. Factory is 0 degrees, I had it set at 5 degrees BTDC. Fuel is maxed, no black smoke! EGT after running WOT for 2 miles is only 800F. It hits the governor at 4300 rpm which is only around 45 mph. The only modification that Kohler (Kohler 702 SD motor) offers is a 4,500 rpm governor spring, which might give me a 50 mph top speed. Here is a picture before the turbo. I plan to do a video of a drag race between the diesel and my 700 AC TRV gas model. I think the gasser might beat it in a quarter mile, or maybe not! Second pic is some of my gauges: EGT on top , oil pressure and boost on bottom. Oil pressure runs 85-90 and 35 psi hot idle. Boost reads between 15 and 20 psi.

 

Congratulations and well done. What a project! You now know that drivetrain inside and out. How much more power do you think the turbo boost added to the engine? I would think 25% or more. I'm glad the fueling worked out good and you don't have a lot of smoke. I enjoy diesels but don't like excessive black smoke. Seems like such a waste of fuel, and can give the efficient diesel engine a bad name.

David

 

It's hard to say as for power gain. Supposedly they are only 17 hp stock. Also they are quite heavy, like 950 lbs or so. When I got it, it was cold as heck, -5F and it started right up, I took it out on the road and opened her up. First impression was it was very loud and very slow to get to speed, 35 mph took half a mile or so, maybe in a mile you could hit 40. Off road, however it was fine, at least it had lots of torque, once you got it rolling nothing would slow it down. Then, I gutted out the very restrictive exhaust, maxed out the fuel delivery and advanced the fuel timing 5 degrees. Honestly that felt like double the power! Now, if you power brake it and spool up the turbo , it leaps off the line about like my 700 cc TRV gas job. So the Gas AC weighs 100 lbs less, has 44 hp , it's not the fastest, but below 60 mph, it is pretty quick. I think the diesel might pull a hole shot on it and the gas would start pulling on it above 30 mph. Now, the diesel has great throttle response, no smoke at all, in fact, no smell either. Exhaust is much quieter and it has the coolest lope at idle. HP guess might be 40, but with crazy torque! Guess what, probably more than any Honda, or KingQuad 500 or Outlander 450 and a bunch more gas models.

 

It sure sounds like you transformed a slug into a rabbit. It must be quite satisfying. You sure have an unusual Arctic Cat. What is the displacement of that Kohler diesel anyway?

David

 

The diesel models were never designed to be fast. Most people that bought them probably did so to get the extra pulling power. I'd be happy with it the way it is, you've created a quite trail worthy atv with a ton of low end torque. Great throttle response and strong acceleration are nice to have. I'm sure you could put whatever size tires you can possibly fit on it and it would have plenty of power to turn them. I assume the diesel model has beefier driveline components as well to handle the extra weight and torque.

 

The Lombardini/Kohler is a 700cc side by side twin. Yesterday, I advanced the fuel injection timing to 15 degrees BTDC , stock it was 0. I have played around with the super heavy duty CVT clutching. Now I think I need heavier weights and maybe reclock from B4 to B3, not sure. I took it off into some really tough rocky trails that really test the machine. and it's great but not perfect. My 700 cc AC TRV is a bit better, the Diesel acts more like driving a race car with a loose torque converter. You have to rev a bit to get it to move, and when your in a pile of big rocks, you need a bit more finesse with throttle. On the other hand, it lets the turbo spool up really fast, for a good hole shot. I want to drag race my diesel vs the gas 700 AC with 44 hp. Should be interesting for an eighth mile. Diesel gets to 40 mph really quick. Had her up to 47 mph today, so around 49 mph with the big tires. Acceleration above 40, however is painfully slow. The reason that I bought the 700 TRV gas model, because the Diesel is the same model, essentially, and it's rugged as a tank. Almost bought an Outlander for same price. BTW, I had 30" Mudzillas on it before the turbo, it turned em fine, but I'm running 26" ITP Terracross RT's now a better tire for where I drive and I want to maximize performance.

 

Thanks for the diesel engine specifications. I was guessing Kohler built this engine for a generator or some other machine. Sounds like an Italian joint venture or something. I always enjoyed seeing the Kohler six cylinder two stroke D Sports Racer run at Elkhart Lake vintage sports car show. It is a very unique machine.

You are a very good ATV tech, especially with the Arctic Cat components. Adjusting the clutch so it engages when you want it is more than i have learned so far. People talk clutch kits all the time to get the response they want out of there ATV. My Can Am is plenty jerky when the clutch bites. I use brake drag when backing up trying to smooth things out a bit.

My friends ride AC 700 TUVs. Single cylinder I believe. BIG thumpers. They are very durable machines. I think the engine has Suzuki roots. One of my friends is pretty hard on his equipment and the Arctic Cat takes it just fine. We'll see if my Can Am is as good.

Next thing you know you will be talking compound turbos; one is good, two is better.

David

 

obj216, I have a 2014 AC 700 TRV also, it's quite similar to the Diesel, same chassis. The biggest differences, are, the Diesel does not have power steering, and in 2008 the front differential lock was a manual lever, the 2014 has electric engagement. I nearly bought a new Outlander 570, dealer gave me, what I think was a "killer deal" out the door for $5,999 ! The dealer that had the AC 700 had just taken it in on trade for an automobile, they had it marked for $6,999. They only had it for 1 day, I went in with cash and offered $6,000 and they paid all sales tax and fees. So far I'm very happy with both. I still have some tweaking to do with the Diesel, I need to, actually reduce the fuel and retard the fuel injection timing. It is totally maxed out now, so it "clacks" until you give it 1/2 throttle or more, and it smokes quite a bit. Also at idle, it seems overfueled, does a little bit of "diesel roll" (rpm go up and down). I've ridden it enough now, in some really steep and rocky trails, to say, it has plenty of power. Both have very smooth clutch engagement. The Diesel has a really stout looking CVT from CV TEAM, and a really stout looking transmission. Picture of the Diesel. What I thought was no smoke (because I was looking ahead, not back) was actually quite a bit, I wouldn't want to ride behind it until I cut back on the fuel. Even if I loose a bit of power, it has plenty.

 

I know this is a long shot but I am hoping to get a parts list and some help with how you completed this build. I have a 2007 model and it hasn't been run in a few years. I have it at a mechanic right now just to get it up and running but I would like to get him the instructions and parts list to complete your build! Did you happen to document what you did in the build and what parts you bought? I would very much appreciate any information you could share. Thanks in advance, Ed