Does a M7 have enough cooling??

[CATSLEDMAN1]

Sno huck'n

A20 in the HILL CLIMB? position may well be worse than stock.......why, drive along side the sled you are evaluating in loose snow at the speed where you are the most concerned and see where it's kicking the snow and at what speed, if I recall the attach 20 with stock paddles turned backwards hucks snow back and up and about none will hit up under neath your sled and into the heat exchanger, and about 20 mph the worst. With an attack20 backwards and stock m snow flap, a blizzard of chit and no under tunnel cooling.

The best position I found for the stock attack 20 was in someone else's pickup headed away from my house.

 

[Mjunkie]

A20 in the HILL CLIMB? position may well be worse than stock.......why, drive along side the sled you are evaluating in loose snow at the speed where you are the most concerned and see where it's kicking the snow and at what speed, if I recall the attach 20 with stock paddles turned backwards hucks snow back and up and about none will hit up under neath your sled and into the heat exchanger, and about 20 mph the worst. With an attack20 backwards and stock m snow flap, a blizzard of chit and no under tunnel cooling.

The best position I found for the stock attack 20 was in someone else's pickup headed away from my house.

It was worse in HC, and like you said I think it was throwing the snow out of the tunnel, also I only ran it in that position in spring conditions, so it would run warmer anyways, but putting the bigger exchanger on solved my heating problems. I still run a little warmer than I'd like from time to time but I'm not where I have to stop and let things cool off like I was before. As for the track itself, I love my a20, in the deep fluffy stuff it works awesome, and in the spring, it's easy to climb anyways because of the conditions. The claw may be better but I bought a brand new a20 for $125 delivered to me, and I doubt the claw is THAT much better in the same fluffy stuff. Just my .02

 

[Vorman]

I'm running the 2.5 extreme

and I just used the scratchers on the road and can watch the water temps drop x 20 deg. Also sometimes have to go a little faster when everyone else is creeping up some of the rough entry trails to keep it cool even with the scratchers. Beats me up sometimes but keeps them under control.

That's not my problem though. It is climbing in the deep heavy with multiple stair step climbs that you just creep over and don't really give them sled a rest. Probably 2000 to 2500 foot climb. Mid-climb it will be losing power and dropping RPMs and getting warm. I never really let it get hot which means I have to turn around and sit on a bench for a few minutes. Blows the point of the BB when you have you drop down to stock M1000 power and are hot and have to sit.

I use the stock intake but I also have a a 2.5 flo-rite directly mounted in the hood above the air box (fine until it is covered with snow). I can't think that having 400 degree air for a few seconds before it clears it out would affect the actual climbing intake charge's overall temp or the ability of the EFI to correct for it as air temp changes. And I don't think blazing hot twins heat something that has that much air flow in it. Seems like you could heat the entire intake and run a lot of 25 degree air through it and you wouldn't have much difference in air charge temperature. I also might be talking out my butt on this one but...

 

[CATSLEDMAN1]

For sure nothing is certain

I hear what you saying about trying to pin point the problem. what I have experienced is far more consistant running in marginal conditions when I have eliminated the m sleds sucking underhood hot air, and the M7 and its issues seemed to respond the best and run better and more consistantly when you at lease plug the plenum hot air intake port. Same motor in our firecats would pull and climb without issues, then 05 we all bought m7's, same motor, worse clutch's, different air intake.......different majic box???, smaller cooling system and we had issues in hot weather and high altitiude with the m's, while two of our riding group on their firecats with trimmed long tracks on the same days were smiling ? Ok......what was the difference, the M's combination of factors were running way hotter and giving us problems.
track/snowflap/air intake/cooling capacity/gearing/dinky secondary clutch......took a year or so to get the m's up to operating par with the old firecats. A KOSO water temp gauge on my m7 was the first good tuning tool that told me I needed to keep the engine cooler. Next was when we sealed up the speedo pods so we could ride in 4' of powder and eliminated the hot air intake issue, then geared the sleds down...........whole lot of running issues diappeared after just those changes.

 

[bigjb]

Thanks for all the info and your past experience, it give me a good idea for what I have to do for next year.

 

[bigjb]

Ok tried a little test yesterday in spring conditions. I used my fuel map for road riding (fat so I can keep the egt temps under controll) while riding in t shirt weather yesterday. I could pound a hill repeat times and would have the same results, same mark on the hill no more no less. On the same hill I changed the map to leaner settings (found the power) and it would flat rip! But it would only do it for 2 good pulls and start to bog on the third and then it was cool off time. The dragon and xp I was riding with had no issues at all but they both seem to have much larger heat exchangers and both sit in the tunnel versus just at the rear bumper. I think I will try a different cooler next year.

 

[M7SLEDHEAD]

Crossfire Cooler

What year Crossfire are you guys taking the coolers out of?

 

[McustoM]

I did not have any coolant available but had some royal purple ice laying around when my coolant was a little low after a tuff roll and actually noticed a little difference when going down a icy trail with another a stock m7 mine took probably 75 yards longer to have the overheat light come on. Dont know if this would help or not but I ride washington so the temperature doesnt get too extreme where the decreased freeze point from adding the royal purple would make a difference.

 

[mrquick68]

Ok tried a little test yesterday in spring conditions. I used my fuel map for road riding (fat so I can keep the egt temps under controll) while riding in t shirt weather yesterday. I could pound a hill repeat times and would have the same results, same mark on the hill no more no less. On the same hill I changed the map to leaner settings (found the power) and it would flat rip! But it would only do it for 2 good pulls and start to bog on the third and then it was cool off time. The dragon and xp I was riding with had no issues at all but they both seem to have much larger heat exchangers and both sit in the tunnel versus just at the rear bumper. I think I will try a different cooler next year.

we'll - at least you pin pointed the problem to be HEAT. Twins make much more HEAT. Plus the twins you have are uncoated, which i believe make more power BUT they put more heat into the engine compartment, which means you are injesting more heat into the motor PLUS your running the motor harder, which also produces more heat. You fattened the motor up and things got better, right? You were dealing with less heat and things got more consistant. the problem with the M7 was it didn't get enough flow through the motor to properly cool it when things got HOT. Then BOG. i believe its a heat soak issue, and i believe the combo of the RKT stock cut head and SLP pipes make this problem worse. If you can get more cooling and more specific cooling on the head, then i think you'll fix this issue.

 

[Mjunkie]

What year Crossfire are you guys taking the coolers out of?

I can't remember off hand right now for sure, but I think it was off an '07 I took mine from.

 

[bigjb]

we'll - at least you pin pointed the problem to be HEAT. Twins make much more HEAT. Plus the twins you have are uncoated, which i believe make more power BUT they put more heat into the engine compartment, which means you are injesting more heat into the motor PLUS your running the motor harder, which also produces more heat. You fattened the motor up and things got better, right? You were dealing with less heat and things got more consistant. the problem with the M7 was it didn't get enough flow through the motor to properly cool it when things got HOT. Then BOG. i believe its a heat soak issue, and i believe the combo of the RKT stock cut head and SLP pipes make this problem worse. If you can get more cooling and more specific cooling on the head, then i think you'll fix this issue.

This is what I believe to be true. Next year will be a different set up (different cylinders, pistons, and head) but same principals will apply. For the remaining rides of the year I'll go hoodless and see if that helps.
Which coolers do you guys think work better, a U cooler type that sits up against the tunnel and has alot of surface area or the style like stock that rests at the rear bumper?? Seems to me the tunnel cooler would work better as long as the track dosn't hit it.

 

[Mjunkie]

I can't remember off hand right now for sure, but I think it was off an '07 I took mine from.

It was an '07. It didn't take any modification except for cutting the stock lines a little shorter because the crossfire cooler had longer tubes coming off it. Was very clean and is about 3 times bigger than the stock one I took off. It hangs down in front of the snow flap the same as the stock, but extends up the tunnel a lot farther to give more capacity and a lot more cooling surface.

 

[Vorman]

I talked with Jeff at Dakota and he said...

That coated twins heat sink the motor because they hold the heat too much, though I suppose underhood temps would be better. I don't think more head cooling would help my cutler as I think that flows quite a bit already. I think better coolers is the big thing. Think I will be cheap and get the crossfire coolers from '07 then think about the mesh hood after that if it doesn't cut it. Probably melt the mesh with the super sized twins though.

we'll - at least you pin pointed the problem to be HEAT. Twins make much more HEAT. Plus the twins you have are uncoated, which i believe make more power BUT they put more heat into the engine compartment, which means you are injesting more heat into the motor PLUS your running the motor harder, which also produces more heat. You fattened the motor up and things got better, right? You were dealing with less heat and things got more consistant. the problem with the M7 was it didn't get enough flow through the motor to properly cool it when things got HOT. Then BOG. i believe its a heat soak issue, and i believe the combo of the RKT stock cut head and SLP pipes make this problem worse. If you can get more cooling and more specific cooling on the head, then i think you'll fix this issue.

 

[mrquick68]

This is what I believe to be true. Next year will be a different set up (different cylinders, pistons, and head) but same principals will apply. For the remaining rides of the year I'll go hoodless and see if that helps.
Which coolers do you guys think work better, a U cooler type that sits up against the tunnel and has alot of surface area or the style like stock that rests at the rear bumper?? Seems to me the tunnel cooler would work better as long as the track dosn't hit it.

you can't go hoodless with an M7 without resistors!

 

[Mjunkie]

That coated twins heat sink the motor because they hold the heat too much, though I suppose underhood temps would be better. I don't think more head cooling would help my cutler as I think that flows quite a bit already. I think better coolers is the big thing. Think I will be cheap and get the crossfire coolers from '07 then think about the mesh hood after that if it doesn't cut it. Probably melt the mesh with the super sized twins though.

I had to make one small heat shield on the clutch side where the pipes come real close on my diamond s, the only other thing I did is put a bunch of heat tape on the intake plenum down by the nose where the pipe gets close also. Haven't melted anything after 2 seasons, the plenum is a little bit mishaped from the heat, but still just fine.

 

[CATSLEDMAN1]

M7 mod

Some one on here may have done the reroute ? you may be able to have better 700 engine cooling by routing the cooling into your m7 the same as an M8 ? Don't know if it can be easily done, but one leg up the 800 has over the 700 on cooling is that the cool water flowing back to the engine cools the heads first on the 800 and later laydowns, the 700's cool the head last. Its that hot combustion chamber that starts all the laydown engine systems retarding timing etc that can produce sub par performance just when you need it most.

 

[Mjunkie]

Actually the water on the 700's go from the head down also.

 

[Team Pigeon]

Plumb in a water temp gauge.
Until you know what your water temp actually is, you guys can just keep on typing.

 

[Norway]

Plumb in a water temp gauge.
Until you know what your water temp actually is, you guys can just keep on typing.

This is good advice, BUT! What has been a major selling point on mountain sleds for years? Weight! And it is starting to become difficult to find easy pounds to loose.

Very tempting to take away some water...

Just had my engine dynoed and we went from 225 to 215 with 30deg F hotter temps. I'm running a CMX based cooler in the rear but will be changing to a tubular cooler over the summer with a thermostat at 110 deg F.

As for IF people have enough cooling, no way on the modded M7's. The CPC 1000 kits being the worst off.

Get a CF cooler for stock an lightly modded M7's, 1000cc kits get all you can afford and put Redlines Water-Wetter in.

RS

 

[mrquick68]

Actually the water on the 700's go from the head down also.

i believe they reversed the flow on the M8 versus the M7, so while it looks the same its actually backwards flowing.