what happened to the rear heat exchanger?

[onrof]

The 07 Apex featured a radiator w/ electric fan and a rear heat exchanger... now it looks like someone deleted the exchanger off the yamaha site!

(from the apex features page)
"Radiator/Heat Exchanger
In order to generate consistently-strong engine performance in any condition, all Genesis 150FI sleds feature a small radiator and electric fan assembly on the right hand side of the engine cab."

I wanted this for my supercharged GT since the coolant runs high in anything but loose dry snow. The RTX also trips the overheat light (184 degrees) on 40+ degree days.

http://www.yamaha-motor.com/sport/produ ... tures.aspx

 

[SledFreak]

I heard the Rear Heat exchanger is only for the Mountain guys, but we still need to get this confirmed.

 

[welterracer]

they probobly figured out that they cannot run 100% strait coolant!

 

[Mighty]

Right on Brian, after reading our posts here on TY they properly mixed the coolant and found they didn't need the rear exchanger 8)

I just combed Yamaha's specs on the 07's and SledFreak appears to be correct. They only list the rear exchanger on the Mountain's.

 

[waldo1]

Yamaha has not hear of any issues with there sleds - handwarmers are fine - wheels - chaincase - steering bushings - they never over heat - we must be the only ones with these issues.

 

[ReX]

The sleds in group I ride with (3 Apex, 1 05 RX-1, Poo's, Doo's) didn't have any overheating issues at all with a 60/40 mix of coolant on our shorties (121" track). None of them have rear coolers (other than the exposed aluminum pipe) and we rode on some extremely hard packed ice trails (overheating our sliders) as well as in very warm temperatures.

Based on that I would have to say it probably isn't required and saving the weight/cost is probably the right decision...

 

[actionjack]

I had the light come on twice on the GT. Once briefly riding slow on a snowcovered trail in Alama, QC went into fluff along the trail and it went out. The other time was 2 weekends ago in St-Michel-des-Saints, QC in much less than ideal conditions - read warm, rocks, mud, snirt. I know its 100% anitfreeze and I'm gonna fix that.

Funny thing is the manual clearly states a 60/40 mix!

I doubt the rear exchanger is needed with the right mix.

 

[waldo1]

point is - they run on the high end of what "too hot" for loosing hp and gas milage. there always at 180 ish - they run better at a cooler temp - period.

 

[SledFreak]

At a 60/40 mix, when you test the antifreeze, what should it read. -50? Mine came on at the end of the season and it was -4 degree celcius and conditions were snow/ice conditions, so I had to stop a couple of times to cool it down. I want to advoid this next season. It pisses me off that my buddies F7 had no issues when running in the same condition and my new Apex, four stroke/supposed to be cooler running sled over heats. Not good.

 

[bjniceguy]

The fan switch can't be more than a curcuit that closes at 205 & opens back up at 195. Find an automotive one that closes at 175 & replace it.

When I had my RX-1 Supercharger I was paranoid about water temp & put on radiator & fan and used a 165 on/ 150 Off automotive switch in hose by secondary clutch. It only ran when sled was idleing or we were very short on snow. As soon as sled got going again, it shut right off. I did have 60/40 antifreeze in it.

 

[ReX]

If you're borderline overheating at 100% antifreeze you should be fine at 60/40 or 50/50.

Water thermally conducts approximately 2.5 X better than antifreeze. Switching from 100% to 60% antifreeze/40% water would increases the thermal conduction of the coolant by about 50%.

60/40 also has a much lower viscosity (more "liquidy") than 100% and that increases the thermal convection (how well it conducts heat away while flowing) much more than the difference in conductivity alone.

A quick google search found; Tests performed by Red Line Synthetic Oil Corporation showed that it took 21 seconds to cool a 304°F bar to 250°F in 100% antifreeze, but only took 10.2 seconds with a 50/50 mix.

I haven't heard of a properly functioning, stock 121" 4-stroke Yamaha that actually overheats with a 60/40 coolant mix. The 136" Warrior was another story. Some of those did seem to overheat.

Here is a chart and a link to the coolant information:

http://www.redlineoil.com/whitePaper/17.pdf

 

[Candyredrx1]

Point is this, Here its April, NO handle bar warmer fix, No Chain case issue resolved, No center idler wheel fix . No you guys are running to close to the edge with the temperature. No wonder my Vector runs so good with the Apex's. Over 2000 trouble free--plenty warm hand warmers, No chain case problem, Idler wheels in great shape and BTW I run with a couple guys with Apex's and they can't believe that Vector runs that good. OH and lets not forget the over 20 MPG on the Vector. I came off of a ATTAK, best move for this season

 

[waldo1]

Kalvin - your the last one in the pack unless we let you up front - Its totally worth it! Sami dosent even want a vector - come on - your just too cheap to anty up.

 

[maddogjeff]

ReX, great post. That info should be sent to Yamaha and every dealer tech out there.

 

[SledFreak]

Point is this, Here its April, NO handle bar warmer fix, No Chain case issue resolved, No center idler wheel fix . No you guys are running to close to the edge with the temperature. No wonder my Vector runs so good with the Apex's. Over 2000 trouble free--plenty warm hand warmers, No chain case problem, Idler wheels in great shape and BTW I run with a couple guys with Apex's and they can't believe that Vector runs that good. OH and lets not forget the over 20 MPG on the Vector. I came off of a ATTAK, best move for this season

There's no way a Vector can run with an Attack. So either you are BS or your buddies are letting you win.