Hey Guys,
Thanks for the replies and sorry I have not got around to responding for so long... been way too busy not getting enough done on my build....
Might be easier and get more out of a boost bottle.
I do see the value of a boost bottle if tuned correctly. I like the idea but I think it would only give me gains if I had a twin carb. With a single carb, I think the boost bottle effect is already happening, because each cylinders' cage set is effectively open to the same volume post-carb, but pre-reed. I think each side of this volume (Cyl 1, Cyl 2) would take turns acting as a boost bottle.
I htink your better off spending time/efford to get the intake air as cool as possible because the little time its actually in the cases i doubt the lake water cooling the aluminum will do much. In the summer the water temps were I ride in WI are only 15* or so different from the ambient temp. Sometimes the water is warmer when I ride. Then in that case you might even be warming up the air in the cases with the warm lake water..... Therefor your best bet is get ambient temp air feeding to the carb and keep plenty of airflow into the engine bay since it doest get warm in there.
I for sure agree that cooling the pre-carb would be more effective, but I do not think the water would ever heat up the cases... after an engine is warm I do not think the cases could ever get colder than the water. Any water going through the cases will for sure leave warmer than when it went in. That aside I cooling the intake is on my list of things to get to..
Rig up some kind of battery powered freon pump?
That would be pretty damn cool if some type of light weight refrigeration cycle could used, kinda like the ford lightning. I think they used A/C cooled air in the intake for short bursts and gained like 10% HP... pretty neat.
Add a stroker plate to the bottom and put a couple NPT fittings in it.
That looks like it would work quite well, but not sure it would be worth the crazy cost for cool billet stuff...
It's interesting that the cases have cavities around the intake area already. It makes sense to remove mass to shed excess weight in these areas but is it possible there was also thought given to cooling these areas?
Case porting requires the filling of these voids so you would have to choose which mod would net the most gains. I'm guessing that case porting wins every time.
I tried to look into the mod on snowmobiles but never did find anything on it. No mention of cooling the intake air in the Gordon Jennings 2-stroke handbook either. As mentioned above, the mod might be far more effective on a skidoo given the naturally cooler difference in ambient air flow.
Ya I thought is was kinda weird how they did not utilize those voids... it is not like Yamaha to miss details like that nowadays, but looking at the port matching of this engine.. I am not suprised,
Case porting is for sure above case cooling on the mod list, but I was primarily looking into cooling the exhaust side, as it is the main source of heat and also has the biggest voids. The exhaust side does not need to be filled for porting, and also I have 61x cases which do not really need to be filled like the 62T cases.
I did not mean to imply it was a mod for snowmobiles, it is used to some degree on the most of the stock liquid cooled engines for all the 2 stroke brands at the moment.
Cooling the intake air with a cooling device may not be expressed directly in many engine books, but it is just implied with theory. More oxygen, more fuel, more power, and colder air has more oxygen. Every body always wants more oxygen to throw fuel at.
Skidoo actually did cooled cases on there line of 800's. It was scraped after a year because the cooling caused too much of a difference in temp between the bearings and case clearances. That coupled with guys not knowing how to warm up a sled the right way, resulted it many many blown cranks. On somewhat newer sleds, cooling intake air isnt a concern, but actually can turn into. A problem. That's why some sleds have Coolant lines the run through the intakes and/or the carbs. Not to cool them, but to warm them so they don't freeze up.
Unless the water is 110 degrees, it's almost always going to be cooler than the air the engine is taking in. Not the ambient air, but the air under the hood
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I am not sure about the older sleds but I think the current etec still cools the the cases, actually I think they are the only one of the 3 two stroke brands that have a coolant loop right under the crank, the other two just have a small jacket that dips into the cases, more like what I am suggesting for a 701. People not knowing to properly warm up always is messing stuff up... seems like it should be obvious to not pull it over and pin it... but somehow it still happens.
For sure throttle bodies and carbs can freeze up in the right conditions, and that is why coolant is sometimes run through them, but colder snow free air is always desirable. Safely getting cold air to the engine is still a problem on modern snowmobiles.
If you wanted the coldest air you can get, quickest and easiest I think would be to run a small radiator type cooling exchanger right above the carbs and plumb lines and a small pump to a box holding a block of dry ice and circulate a closed loop of coolant through the circuit. Biggest obstacle would be making the cooling exchanger breathe enough air to keep the engine happy. It would be a limited use set up but am Confident it would work. Can't forget to rejet as well since you'll need to be a lot richer
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This has been on my mind for sure, minus the dry ice, I do not want something I need to replace every few minutes... or something that will burn me when I mess up handling it.
But a water cooled exchanger... that is what I am thinking. I started off thinking I would use a liquid to air intercooler, but then I realized that without forced air... or a crazy big one, I would never flow enough air, not to mention they are quite pricey... Then a friend at work suggested using a heater core from a car... genius. Costs 20 bucks, flows a butt ton of air and doesn't need a lot of water flow. I am now wanting to make an airbox with a cooled heater core in it. Basically a funnel that seals straight to the carb/carbs at the bottom and has an exchanger at the top... I need some temp data for under hood conditions, but I think a few HP could be had... obviously the results with differ... ambient temp, water temp, under hood temp, water flow and core efficiency will alter your potential gains, but on a hot day with cold water... might be quite noticeable.
As for the seadoo cases, they look like they could help, but same problem.. how much.
There is this stuff call Nitros........... It cools the Fuel Charge....................... KABOOM
It definitely cools the air charge... and adds a lot more oxygen
I have read around on the X but haven't found too many detailed threads with people using a nitrous system on a superjet, I very badly want to put together a nitrous system... 15-30hp gain would be nuts at the push of a button.
