Kingers BOOSTED garage....

Thankfully I bought a parts skid this past summer and I swapped out the shaft and had a extra bolt. This would have been a trip ender as the ZX2 bolts are not available locally. Heading north with my Daughter and Papa (my Dad) for her first experience on a sled! They will ride the 2 up ski doo that she helped me fix up, and I will continue to tweak and tune the twincharged, I am sure Dad will want to take a pull on the apex LOL.

I am hoping for 14-15 psi of boost on WG spring now with the swapped pullies. If so I will finally get to play with Duty cycle so I can eventually get into closed loop boost control. Still running on OL fuel though, my O2 sensor flaked out and new one isn't here yet. I think it was way to rich and killed it. I took out 12%-18% fuel from the 3500-6500 range where it was pig rich. So this trip will just be all about boost control and if I have it or not.
 
Also testing a cold start issue, seems to really have to crank in the mornings to fire. Going to be -11 tomorrow and I am praying I don't flood the engine. I added more fuel at cold start to see if it helps or hurts.
 
Couple updates:
1. Cold start was brutal, I was adding too much fuel, took some away and it fired up
2. IAT reads 11,000+ degrees when its froze and needs to heat up. I can't find any comps for this so i think I am safe in the motec tune
3. Boost still uncontrollable, takes longer to get to 20 psi but still gets there and hits my cut. So I will have to add a 2nd Wasteagate
4. Lowered SC boost is not as fun, I will want to swap back to 10-11psi for trail snap that I like. It was better then a turbo alone but still had a tiny amount of lag.
5. I need to muffle the WG dump.
6. Closed loop fuel the sled does not like .89 as a aim value, I will take out 4% and go to .85 pretty much everywhere except full boost.
Lambda works on and off and seen a slight correlation to really rich lower rpm in vacuum and .67 flashed a few times before it would just show 1.000 for about 10 mins after that. I may be washing the sensor. I have a new one to try. Wish I could load test it this summer and really dial in the fuel tables in a controlled condition then just comp for lower air temps in winter


Lastly my 11 yr old daughter came on her first trip and had only put 5 miles on the ski doo we fixed up last summer, My dad came out of snowmobile retirement to ride with her on the 07 600 Ski Doo SDI with a 2 up seat, she rode behind him for 50 miles and then they swapped and she drove for 30 miles! She did great and the smile was ear to ear. Next year we will get her the WI permit so she can drive herself and she is already counting the days until we can do so! She is hooked! A chip off the old block with this quote "Dad I like seeing the hills so I can push the gas and get a little air" :oops:
 
I can’t wait till you have this thing dialed in and can stretch its legs. It appears that the speeds are going to be huge. great job so far and to have your daughter joining the sport!
 
Looks like everyone had a good time!
 
Plans for summer in addition to above:
-Send Turbo in for inspection, its leaking grease and would be warranty work, add 2nd gate to the turbine housing when it gets back
-Convert Motec fuel and timing tables to pressure based instead of throttle position based on the Y axis like it is now. This will give me more stable fueling. Looking at the data logs it takes between 25-75% throttle to maintain around 50 mph, meaning I am varying the throttle that much it of course accelerates and decels but in general I am moving the flipper that much. Well in my fuel table that is a 54% delta (change) in cells (sites as Motec calls them) between 25-75%. Meanwhile my MAP is hovering in a 20-25 kpa delta which is a much smaller range and should be easier to control. Any boost system should be pressure based anyway not sure why Precision did all the maps in throttle position, I guess I will find out this summer. I plan to grass test the sled all summer at my land to dial it in, then add compensations in the tables for winter use.
-Going to add a meth system, currently looking at tanks, pumps, nozzles to try and figure this out and make it look clean. I will do a 4 nozzle direct port injection kit with the nozzles aimed right at each TB. Probably only spraying above 20 psi to save meth and give me the protection at high boost. I plan to still mix torco as insurance but may try to ween off of that over time once I can see the data logs
-Try to get to a Dyno

So I am leaning towards abandoning the chassis/cosmetic redo for another year. I actually don't hate how it looks and I really want this dialed in before I invest in that time to swap the tunnel, custom cooling system, etc. I may go through the ZX2 after all the grass testing and replace all bearings (this has never been done) and possibly try to adapt an air shock with on board compressor, it would be nice to know if that will work the way I want before I create a new tunnel anyway. So use the old swiss cheese tunnel as an experiment to learn what I need to incorporate into a custom tunnel. A good example is I found a sweet 7 qt meth tank that I want to embed in the rear of the tunnel, I can use this old one to validate it works back there before designing a new tunnel around building it in.

Lots to do!
 
Was that wet weight? With such a rearward bias you will be relying on snowtrackers to get you through corners? Do you have the rest of the numbers for the doo you mentioned, would be interested to know the individual weight for the rear shocks of the doo.
 
Yes full wet and fully loaded even had a can of Torco in the back along with tools. The learning here is that as long as you maintain that 120-130lbs in the front skis the sled will handle and turn. Now if your sled was 400lbs and then you need a more 50/50 again only to get the 120lb of ski pressure.

With the 4 strokes having more weight in the rear is a good thing for stability. I have 850 Doo XRS friends that don't like running over 100 mph because the rear gets loose, this helps explain why mine is very stable up to 130+ mph. Also explains why the 4 strokes get a good hole shot. Mine not studded can hold my own with purpose set up grass drag sleds I have raced. They have chisels and traction like crazy yet mine holds the same, so in this case more weight equals more traction.

I will get the Doo weights, I also want to know.
 
On paper (my spreadsheet) you are 57lbs heavier than a winder but that's on paper and given what you have there I think you are doing about as good as can be expected. Less is always more in this case though. I have no actually had a chance to weigh mine yet, that's for later in the summer. I am reverse engineering the sidewinder as an exercise in understanding some of the engineering aspects. No real objective other than brain stimulation, trying to get my head around the chassis dynamics. My approach is bottom up, figure out what the numbers are and work backwards to geometry and chassis dynamics, handling, etc. One of my main concerns currently is that the balance of the sled is very good stock, but I know that the track is insufficient for the trails around here. Also, I want to compare the SRX to what info I can get for other machines to see if there is something to learn from them. If nothing else its a great way to look like you are diligently working on something techy while banging away on a spreadsheet that has nothing to do with the board meeting you are stuck in. I even had one of the marketing execs look over my shoulder and ask me if the tables I was working on (gearing at the time) were part of the Q1 sales figures, I answered "yes, its not looking good, see all of these red cells, that is underperformance of individual salesman by region and sku" and he glanced at the VP of sales, did one of those uh oh whistles and walked away.
 
I will update my spreadsheet, I have my Winder BTX in there but dang it was only half a tank of fuel. Your numbers are about spot on with the 57lbs heavier though. I can drop that much and I will, I want it to be lighter then winder but being a apex twincharged, no one will believe me HAHA. When you say "One of my main concerns currently is that the balance of the sled is very good stock" what is your reference or baseline to make that statement? On my sheet my BTX is very rear biased sitting there, then when you add a rider it goes front biased, then when that rider stands it gets really close to 50/50 at 46/54 something like that. I went down a road thinking like a car guy and that 50/50 but I am now convinced you only want that during off trail. On a hard packed trail you want 30/70 unless your ski weight drops below 120lbs then it wont steer so that is also the key, get that dialed in and go ride. Back in the lightweight apex mtx era they kept taking off easy weight in the rear, the seat and exhaust were 50lbs for cry eye, suspension another 30lbs off. Well that changed the handling and they would trench, then drop and roll chain cases came out, well what did that do move more weight to the front ski, now they didn't trench but instead plowed and wore ya out. Finally had to add a turbo and moved the weight rear and combined with the power finally handled decent but were still a handful.

Have you watched the skinz shock therapy vids? This is the one that got me to purchase 4 scales and start my analysis:
 
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