Yamaha R6 Forum: YZF-R6 Forums banner

1 - 18 of 18 Posts

·
Registered
Joined
·
524 Posts
Discussion Starter #1
I'm thinking of changing the rad cap (stock is 1.1 bar) to an aftermarket high pressure rad cap (2.0 bar).

My goal is to try and reduce my bikes coolant temp now I know increasing the cooling system pressure will increase the boiling point of the coolant but will it actually make my bike run cooler?

Graves and CV4 are 2 reputable brands with rad caps I found.

Has anyone done this mod?

Also what is the difference in temp I can expect?
 

·
Registered
Joined
·
4,979 Posts
I'm thinking of changing the rad cap (stock is 1.1 bar) to an aftermarket high pressure rad cap (2.0 bar).

My goal is to try and reduce my bikes coolant temp now I know increasing the cooling system pressure will increase the boiling point of the coolant but will it actually make my bike run cooler?

Graves and CV4 are 2 reputable brands with rad caps I found.

Has anyone done this mod?

Also what is the difference in temp I can expect?
you dont raise pressure... you dillute the glycol content. Guaranteed its too rich.
 

·
"The Dude abides .. "
Joined
·
4,719 Posts
high psi rad cap does nothing to raise boiling point.. it simply keeps the coolant from overflowing at the 1.1bar (a 1.6bar cap would keep coolant from puking out a the temp the 1.1bar cap would allow it to pass). As you know, Graves sells one. I suppose it's handy when you are on a race grid for a few extra moments waiting for the idiot that didn't write his grid position down and is mucking about getting to the right spot. Engine temps can rise pretty fast in those situations, especially if like on most race bikes, you removed the fans.

I run 1.6bar caps on my crf450r harescramble/enduro dirt bikes (stock is 1.1bar like an R6) to keep em from puking coolant in the occasional tight woods sections, or when stuck behind a slower rider. Again, it does NOTHING for reducing the operating temp. It's just better than losing a little coolant every time you stop for a moment.
I have yet to bother with anything but stock rad cap on either of my race bikes.. even here in FL.

Run Engine Ice, ensure all your radiator fins are straight, make sure your fans are operating.. that's about it.
 

·
Registered
Joined
·
287 Posts
do you have a cat on your bike still? they soak up a lot of heat that in turn gets soaked into the motor, that can help too.

are you running a pc3/5? perhaps your bike is running just a bit rich, depending on your altitude that can make your bike run hotter too. I know with my BMW it helped just throwing map on a stock bike, because form factory they are tuned rich, which in turn also makes the bike run hotter. for instance one person found their AFR as high as 15.5 when optimal A/F Ratio = 13.2 - 13.5 : 1 according to dynojet.

both of these things can add up to a bit of added cooling, but its only food for 20F or so in the same conditions on my BMW. I haven't had the chance to do the same sort of thing on the Yamaha, as I already have a pipe and pc3 on it.
 

·
Registered
Joined
·
4,979 Posts
do you have a cat on your bike still? they soak up a lot of heat that in turn gets soaked into the motor, that can help too.

are you running a pc3/5? perhaps your bike is running just a bit rich, depending on your altitude that can make your bike run hotter too. I know with my BMW it helped just throwing map on a stock bike, because form factory they are tuned rich, which in turn also makes the bike run hotter. for instance one person found their AFR as high as 15.5 when optimal A/F Ratio = 13.2 - 13.5 : 1 according to dynojet.

both of these things can add up to a bit of added cooling, but its only food for 20F or so in the same conditions on my BMW. I haven't had the chance to do the same sort of thing on the Yamaha, as I already have a pipe and pc3 on it.
FYI...15.5 is lean as hell especially under load.
 

·
Registered
Joined
·
524 Posts
Discussion Starter #7
Yeah I am running engine ice and distilled water, and I have a bazzaz with the zafm all tuned to an afr of 13.2 for my entire fuel map. I'm gonna try a new rad cap anyways and see what difference I get with temp. I'll make sure to let everyone know what I find out
 

·
Registered
Joined
·
1,940 Posts
Removing the thermostat, water w/ water wetter, Samco hoses, stock cap = running temp of ~148F highway cruise

Coming off the track temps would be 155-165
 

·
"The Dude abides .. "
Joined
·
4,719 Posts
Removing the thermostat, water w/ water wetter, Samco hoses, stock cap = running temp of ~148F highway cruise

Coming off the track temps would be 155-165
hence the reason you NEED a thermostat. The 3rd gen especially, needs to be running about 180f+-
 

·
Registered
Joined
·
1,940 Posts
I have a t-stat now and back up to normal operating temps. That was just answering the OPs quest for cooler temps.

No glycol.
 

·
Registered
Joined
·
104 Posts
Hi pressure cap WILL increase boiling temp about 2-3 degrees per psi. So a standard cap will bring bp to about 260 degrees. The higher pressure cap will bring bp even higher
 

·
Registered
Joined
·
2,909 Posts
just ignore this guy. he's literally asked this same question in multiple threads. he's afraid of the one he bought that's 1.4. for fu ck sakes. everyone keeps showing him the factory road race team (graves yamaha) runs a 2.0 cap.
he's going to keep asking until someone tells him not to use it. so here, DON'T USE THAT CAP. YOUR BIKE WILL EXPLODE!!
 

·
Registered
Joined
·
27 Posts
I actually never got a solid answer from someone who had actually done it, that was the reason for posting on multiple threads and it's my first super sport I always wanted an R6. I wanted to make sure I wouldn't damage any part of the bike.
My apologies for annoying you by posting and thanks a lot you actually answered my question/concern.
Ride on and Ride Safe ✌
I appreciate all the help.
 

·
Registered
Joined
·
2,110 Posts
My comment was in reference to the pump up cooling system pressure testing kits. Some people will sit there and pump up the system to several times what's on the stock radiator cap, damaging hoses and potentially creating leaks in the system.
 
1 - 18 of 18 Posts
Top