Billet water pump, who's interested?

Man that is super cool. One day I would love for you to explain how you made that. As a machinist myself it just blows my mind how a chunk of aluminum can look so good. Nice work!!

Colo moto that impeller is absolutely beautiful. I'm sure it will work as well as it looks and when it dose I'll be in line to get one!

Switching to an "acorn" type nut should help improve the pump efficiency somewhat, too.

Better yet, some sort of bullet nose type cap that totally covers the nut flats and smooths the transition to the center hub would be even better.

PS note for all that the 250 and 450/510 impellers are different pitch/size (check P/N). I have seen both next to each other at GP motos when we were chasing one down for me.

there are a number of people who have 250's that are running the 450 impellers.....

In a hydro analysis the (n) value would be much better (lower) for the billet impeller would have less flow restriction, and therefore the water would move quicker across them, where as the cast one would have (higher) (n) value unless it was polished. Or do I have that backwards? To late to think, must sleep now. Of course the pitch of the blades will also have a role to play. Nice part Colo moto. How about the impeller and housing as a larger unit to change the flow rate? Just a thought.

Gary

Im sure people would be more curious if these were for the 450/510. Not saying they are not BA (BadA**) but I havent seen to many 250's overheat. When i have, they were pretty much almost standing still.

7602 always makes awesome stuff. tweek them to really drop some temp numbers and make them for the 450/510 and you will probably sell tons of them. There is always a thread about a 450/510 overheating.

Mike

Very nice impeller indeed. Forgive me tho- but what value is increasing the through put of just the water pump if you are going 5 MPH? Are you expecting the radiators to passively radiate additional energy due to the increased flow?

My 07 450EXC would boil when speeds got slow and the engine work got heavy, like slow technical rock sections etc. Ive never boiled my Husky- even in the same sections of the same trail in similar conditions that would gurgle the pumpkin into submission.

Seems to me the hot ticket would be adding a thermo set point activated fan in addition to the impeller. BMW 318i from the 80s came with 4 different thermo switches 82, 86, 91 and 99 C. They are shoulder sealing 10 x 1.25 thread pitch and quite small. At X temp the switch closes, then opens again below X- 5C (ish). I used one of them and a 80 CFM 100 mm computer fan on the backside of the radiator. I never boiled the KTM again- not even in Moab in the middle of summer on some gnar gnar trails.

ColoMoto:

I dont know how far away LaJara is from COS- but I have a dyno and datalogging equipment and I like to mess around with all my bikes. Lets get together at my shop and get some numbers down and see what makes sense for a solution?

http://64.25.14.42/DRZ_bluepickle/KTM Rad Fan.html

Hows this project coming? Any idea of a release date?

Heat Exchange

Hey boys & girls, here's a Poindexter thought... Heat exchange in the coolant has 2 places it happens. One is in the radiator and the other is in the motor (we usually forget about this and only concentrate on the radiator). If you slow flow down or speed it up it affects how heat is either picked up (in the cylinder) or dumped off (in the radiator). Resident coolant time in BOTH places affects cooling efficiency. For each particular application there will be an optimum flow rate (maybe slower, maybe faster). Engineers get close on paper, but real world temp readings should be most accurate.

Colo Motos impeller appears to have a more 'cupped' design than stock which looks like it will move more coolant (more flow). Polishing would be good for orfices that the coolant goes through to increase flow but not necessarily the impeller. The shape and clearances will be most important. It may be difficult to improve on the factory design as they take alot of things into account. Although adding the 'Y' pipe certainly helps and makes you wonder what those guys (designers) were thinking.