Has anyone looked into adding a manual boost controller in the wastegate circuit? The PWC with the same motor had a maximum boost of about 2# more than the FST set-up and the motor components must be durable enough to handle the additional loads. Instead of laying out the bucks for the PWC components you could install one of the five manually adjustable boost controllers offered by Boost Controller. Looking for input as to how the various sensors and ECU would respond with a moderate, 1-2#, increase in boost pressure, assuming boost pressure and air fuel ratio gages are in place for monitoring.

www.boostcontroller.com

I am curious about that also. I am looking to buy a 07 FST and would like to know more about bumping the boost up. I wonder if a standard fuel controller would work with a boost controller also. It is only a bosch motronic ignition system. It would all depend on what parameters are in the ECU.

Yes, you can use a manual boost controller. If you look at the Wicked Racin kit, they include a manual boost controller with the exhaust pipe and gauges. I have been doing some of the math on the boost pressure possibilities and have basically just decided to run with my watercraft boost solenoid for the remainder of this year. I know that this setup is OEM safe with this engine, and I do not currently have an aftermarket boost or AFR gauge to keep an eye on things. I will be going for more pressure next year and will go for a manual boost controller then. I am seriously thinking about a two-stage remote activated controller. One setting would be for normal boondocking situations, and then a high boost setting for the occasional hillclimb blast.

As Excursion pointed out to my uninformed self in a previous post, and after "stealing" the shop manual from my dealership to study further, the fuel pressure is boost biased. Baseline is 43-44 psi + boost pressure. So, stock with 17 psig pressure, you have a rail pressure of 60-61 psig. With an increase in boost to 22.5 psig you would have a rail pressure of 65.5-66.5 psig (if you have the AFR at around 12:1 with 100F intake air temp) this should net you around 170 hp.

The only thing that may need to be defeated is the overboost programming in the ECU, or not, I do not know (yet).

I'm not as worried about the boost since I have other things to play with for my next ride. My new Holz EZ-Steer spindles are going on Saturday. I may also be getting some "hand-me-down" Dragon RMK A-arms to go with the spindles as well. And since we've gotten over a foot of fresh snow in the last day, the weekend can't come fast enough!!

After going through the manual, my question is just how much air could you stuff into this Weber MPE750 motor? I'm wondering what a monster turbo (or two stock turbos in a twin setup) with the larger FS throttle bodies (46mm vs. 39mm), some upgraded injectors, and a massive intercooler (or methanol injection?) would do? I'm just a little curious. May need to find a second turbo 'just-in-case'...

I was told by a dealer in New York that POLARIS has a ECU program that pushes the stock FST to 180 HP, and that is at 24lbs. Boost. Also with this program it holds a 8 second time limit on these new figures and returns it to stock 140 hp and 14lbs of boost to protect it from burning up. Also he told me that the factory Intercooler is to small. I should aks him next time I am there about the overboost programming.

This sure would be a handy programming addition!! I had heard through the grapevine that there was a program that some of the 'factory' hillclimbers were playing with out west, but nothing has come of it. That sounds like it could be it. My dealer had talked to the guys at SLP over the summer about such a program, and they said that there was one, but it was not going to be released for the rest of us. Maybe they were also trying to blow me off. Dunno, but an ECU "shot" like that would be neat to have. Kind of like an endless bottle of Nitrous.

I can also easily believe that the intercooler is way to small. If you look at the stuff that JayJay and Hemidude are riding, it is painfully obvious that the rest of us are a little "small." I just don't have the dough to throw at them to get the high output setup. I'll get there, I just have to do it one small piece at a time!

your right, little by little, like I said I will find out more about the ECU and that HOT program, I wonder if anybody has tried to use a stand alone fuel system like they put on the foriegn cars I can't see why they wouldn't work. who knows I don't even own a FST, I am just curious to see about making power on them so next sled can be a FST or switch back

If I was polaris, that would make me nervous. On a warm day, someone runs a lower octane gas then they should, and a the 7th second it starts knocking....I'm not saying it will be a huge issue, but 24lbs of boost is a TON of pressure.

Which is probably why they would let racers run this, as they would be running race fuel anyway. The ordinary Joe ususally doesn't even want to pay for pump premium to dump in their sled. The knock would be much less of an issue. I keep a 55 gallon barrel of 113 octane around at all times for my dirt bike, but it has too much lead in it to dump it into my FST (at least if I don't want to replace the oxygen sensor all the time). I will be switching to an unleaded race fuel when my current barrel is dry so that I can more readily use it in the FST when I begin to go up on the boost pressure.