"REVIEW" SSI Mountain Performance Bolt on Kit

I installed the SSI Mountain Performance kit on a 18 Mtn Cat. The kit I installed consisted of a SSI Billet head with inserts, Boyesen Rage Cage Reeds, SSI stainless steel Y-pipe, SSI titanium can, stock pipe which has the SSI pipe mod done to it and a SSI clutch kit specifically for this setup.


Install: The install was pretty simple as long as you are mechanically inclined and have basic hand tools for working on a sled. I replaced the stock reeds without having to remove the air box which was a big plus and I used a suck tank to evacuate the coolant from the sled to replace the head. I was surprised that almost every drop of coolant that I took out of the sled fit back in before I took it out of the shop and ran it with the front end raised up. I just pushed down on the rear bumper as far as I could and you could hear the air bubbles evacuating the system. Once everything was back together I did run it for a while with the front end elevated and managed to get a little more coolant in.


Now for the important part of how it runs. I was very skeptical of running this many add-ons without a fuel controller and I took it very easy for quite a while and checked the plugs often and even checked the wash a few times to make sure everything was normal. After that it was time to open it up for long pulls and see what it could do.
If you thought the throttle response was impressive on the stock DSI motor it is even better with this kit and the midrange pull is phenomenal!! I have had quite a few big bore motors on previous years sleds and this honestly feels like you are on a big bore sled. I did have an opportunity to ride this sled with a stock 18 for a little bit and it outdid the stock sled with ease everywhere we had the two sleds. There really was not much of a comparison between the two.

This sled at the time was not run below 8000' and up to about 9750' with the majority of the riding being done at 9250'. I set the magnets in the weights to SSI specifications and it was hitting the target rpm or just a little under the peak rpm of the kit. I tried to take a magnet or two out of the arms and gained some more throttle response on the bottom end but the peak rpm didn't go up much at all.
I did add a gallon of race fuel to a tank of premium just for insurance but don't think it will be needed at the elevations I rode at.
If you are on the fence about getting one of these kits don't hesitate. They run super good and the install is fairly easy if you have ever worked on your own motors.

"NOTE" I ordered the BDX ProMax Induction hood when I ordered the rest of the parts but they were waiting on the frog skins to show up and a new combination windshield gauge mount for the hood to be completed so I told them to hold off on that. I did have two 2" bulls eyes mounted on the factory hood behind the hood wings when I did this testing. Last night when I got home there was a box on my front step with the new hood from BDX. That will go on next and I will give a report on it in a few days. This new hood is very lightweight and doesn't feel like anything when you are holding it. It is supposed to be 8 to 9 pounds lighter than the stock hood with the headlight but I think it will be lighter the way it is designed and how lite it feels.

I do know of another guy that has ridden his sled with basically the same setup as mine at 4K and not had a problem. He is adding a gallon or so of race fuel to a tank at that elevation and not adding any race fuel up higher like 6K and up. I still need to do a little more testing before I could tell you 100% though. I might throw a PCV on this setup and add some fuel just to see if it likes it and give another report on it.

Sunvang said:

Thanks. If this setups is reliable without a fuel controller, then its a no brainer. Do you only read the spark plugs, or do you use a a/f gauge also?

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I usually like to put a set of EGT's on a sled when I do stuff like this to make sure that everything will be ok. I was told by a few different people that a fuel controller would not be needed with this setup so I didn't order one at the time. A few days before I left I couldn't take not having a fuel controller or some way of monitoring what was going on in the motor so I tried to find someone that could get me one and nobody had anything and was waiting for them to show up.


I am old school when it comes to tuning and for me it is still a set of EGT's and also monitoring spark plugs and looking at the wash. I have had several AFR gauges and for me the only use I have for one of them is for wide open tuning. For me tying to tune your midrange or anything else with one is about worthless. Seems to me like the numbers are moving so fast I cant tell what they are supposed to be. Other people really like them.

I do have a PCV on a different 18 that I am thinking about taking off that sled for a day or so and just add some fuel here and there in known spots to see if it does help. This setup runs so darn good already but if I can make some improvement with a PCV I would be all for it. There has not been a single hiccup or hesitation anywhere that would make me believe that it would need more fuel at this time. I have heard that the new C tech motor is pretty rich on fuel from the factory and that the ECM has safeguards built into it to take timing away and add fuel if it is needed. This would be off the det sensor and before you would get a det code on the display it would be making adjustments. From what I understand you would have to really hit the det hard to get a code to pop up.
A PCV will get put on this sled after the first of the year and I will do some testing to see what happens.

Had the 18 out for several days of testing with the SSI kit on it. I installed a PCV and made a really good map for it. I pretty much only had a 2 throughout the midrange and a couple 3's in on the very top end. The last day of testing it warmed up considerably and I noticed it didn't pull quite as hard on top end so I made everything a zero in the last two columns and it was back to running the way it was. Ran spot on the rest of the day until I decided to try a different helix and in the midrange it had a slight stumble. I changed everything to a zero in the whole map and it ran flawless again. This puzzled me so I decided to stay another day to test it some more in the morning when it would be cooler but it was still 35 degrees at sunup. I rode it for a while and left the map in it with all zeros and it never missed a beat. So I would say that a fuel controller is not needed with this setup. I was even running the new Pro-Max hood that dropped 9.2 pounds.

SSI pipe mod for stock pipe

Just wanted to follow up on this post a little bit. Dyno Tech finished up a dyno session on the 18 C-TECH 800 a little while ago. With a PCV with timing they were able to get an additional 10 HP with just the pipe mod on the sled.