M8 Engine Temps
Road Warrior
Joined: Nov 2022
Posts: 1,541
Likes: 543
From: MN
I have Stage II with custom PV tune.
I went with S&S Grand National slip ons with cats because I can't stand exhaust stink anymore, after being exposed to it for a couple decades prior to cats being invented. I appreciate MoCo moved cats back from the heads for M8's, It's fine riding with legs forward on the Heritage Model. But sitting at stoplights with legs down gets hot - legs much closer to cats. Choice of vice, I guess.
Also thought about 2 into 1, but sort of wrecks the look of the Heritage design more than the flat tipped slip ons. There's also a single cantered crossover pipe between the head pipes, so that's a quasi x pipe connector that helps scavange some.
I went with S&S Grand National slip ons with cats because I can't stand exhaust stink anymore, after being exposed to it for a couple decades prior to cats being invented. I appreciate MoCo moved cats back from the heads for M8's, It's fine riding with legs forward on the Heritage Model. But sitting at stoplights with legs down gets hot - legs much closer to cats. Choice of vice, I guess.
Also thought about 2 into 1, but sort of wrecks the look of the Heritage design more than the flat tipped slip ons. There's also a single cantered crossover pipe between the head pipes, so that's a quasi x pipe connector that helps scavange some.
Advanced
Joined: Jan 2013
Posts: 68
Likes: 13
From: Illinois
Old New Rider, throwing no shade your way.
I will follow and see what you all come up with and admire the fact you want to make it better. I personally have long ago accepted they run very hot and there are millions on the road still running.
I put really good synthetic in her and enjoy the wind.
Best
I will follow and see what you all come up with and admire the fact you want to make it better. I personally have long ago accepted they run very hot and there are millions on the road still running.
I put really good synthetic in her and enjoy the wind.
Best
Road Warrior
Joined: Nov 2022
Posts: 1,541
Likes: 543
From: MN
Old New Rider, throwing no shade your way.
I will follow and see what you all come up with and admire the fact you want to make it better. I personally have long ago accepted they run very hot and there are millions on the road still running.
I put really good synthetic in her and enjoy the wind.
Best
I will follow and see what you all come up with and admire the fact you want to make it better. I personally have long ago accepted they run very hot and there are millions on the road still running.
I put really good synthetic in her and enjoy the wind.
Best
Oil cooling heads with radiator was a great improvement, obviously from data we've seen to date. It also admits that MoCo wanted to extend engine life by less severe thermal cycling of cylinders and heads.
We don't have data that says how long they run versus % of original power. They could have lost 20% power and guys would claim they run forever. Everything's a tradeoff. I wouldn't want the expense of a full up liquid cooling system for a motorcycle engine, but I do want forced air cooling when stopped. Which is often during road construction and traffic jams.
I didn't right this week it wasn't just hot, it was dangerous, heat index got to 117 F in Minnesota. Dewpoint temp near 80 F. We can't take that. It gets to -30 F in winter. I only ride in full body armor. I really should move. Not to Phoenix.
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,922
Likes: 8,027
From: poway
What improvement data to date?
Seasoned HDF Member
Joined: Jan 2008
Posts: 13,672
Likes: 11,459
From: State of Confusion
a long time ago in a galaxy far, far away, Steve Cole did some M8 107 HD fan assisted oil cooler before and after testing using very similar test ride conditions .. for those wanting to review all the deets you can read until your eyeballs get tired but in a nutshell very compelling evidence of improvements .. not sure how the Twin Cooled would have compared
https://www.hdforums.com/forum/milwa...-system-9.html
Before Upgrade Results:
Measured Peak Engine temperature = 340 F
Measured Peak Oil Sump temperature = 267 F
Measured Peak Head Oil Return temperature = 290 F
After Upgrade Results:
Measured Peak Engine temperature = 302 F
Measured Peak Oil Sump temperature = 201 F
Measured Peak Head Oil Return temperature = 240 F
https://www.hdforums.com/forum/milwa...-system-9.html
Before Upgrade Results:
Measured Peak Engine temperature = 340 F
Measured Peak Oil Sump temperature = 267 F
Measured Peak Head Oil Return temperature = 290 F
After Upgrade Results:
Measured Peak Engine temperature = 302 F
Measured Peak Oil Sump temperature = 201 F
Measured Peak Head Oil Return temperature = 240 F
HDF Community Team
Joined: Oct 2018
Posts: 4,347
Likes: 3,392
From: Seattle
a long time ago in a galaxy far, far away, Steve Cole did some M8 107 HD fan assisted oil cooler before and after testing using very similar test ride conditions .. for those wanting to review all the deets you can read until your eyeballs get tired but in a nutshell very compelling evidence of improvements .. not sure how the Twin Cooled would have compared
https://www.hdforums.com/forum/milwa...-system-9.html
Before Upgrade Results:
Measured Peak Engine temperature = 340 F
Measured Peak Oil Sump temperature = 267 F
Measured Peak Head Oil Return temperature = 290 F
After Upgrade Results:
Measured Peak Engine temperature = 302 F
Measured Peak Oil Sump temperature = 201 F
Measured Peak Head Oil Return temperature = 240 F
https://www.hdforums.com/forum/milwa...-system-9.html
Before Upgrade Results:
Measured Peak Engine temperature = 340 F
Measured Peak Oil Sump temperature = 267 F
Measured Peak Head Oil Return temperature = 290 F
After Upgrade Results:
Measured Peak Engine temperature = 302 F
Measured Peak Oil Sump temperature = 201 F
Measured Peak Head Oil Return temperature = 240 F
I spend too much time in traffic where temps skyrocket, and having to deal with lane splitting where I cant get going consistently fast enough to not hit over 320F.
Getting temps down at below 35mph is something I'd really like to have happen.
Seasoned HDF Member
Joined: Jan 2008
Posts: 13,672
Likes: 11,459
From: State of Confusion
This makes me even more wanting of that fan assist that DK is developing for the M8 Softails.
I spend too much time in traffic where temps skyrocket, and having to deal with lane splitting where I cant get going consistently fast enough to not hit over 320F.
Getting temps down at below 35mph is something I'd really like to have happen.
I spend too much time in traffic where temps skyrocket, and having to deal with lane splitting where I cant get going consistently fast enough to not hit over 320F.
Getting temps down at below 35mph is something I'd really like to have happen.
edit: another one of the reasons I chose not to add one to my current bike is because I tour a lot, averaging close to 20K a year and noticed the oil cooler fins took a beating, so installed the oil cooler cover (which isn't supposed to fit over the fan assisted oil cooler but apparently some have made it work) to offer protection and it has worked admirably as it was designed and intended to .. it's been a valuable trade off for my application
Last edited by mjwebb; Aug 24, 2023 at 06:05 PM.
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Road Warrior
Joined: Nov 2022
Posts: 1,541
Likes: 543
From: MN
To quote Wild Bill Hickock: "are you satisfied?"
I read member experiences and data, and mention sometimes. These members were generous enough to repeat their contributions. I don't care about being right, but I do care about trusting members who are nice enough to share their data. Plus, it's just physics that heat conduction from metal to fluid then fluid to air is more efficient than metal to air. I would think most folks know by now, since there have been both air-cooled and antifreeze-cooled engines both for a long time. And the reason engines changed from air-cooled to liquid-cooled was...... (hint: it wasn't because they are cheaper - they're way more expensive).
I read member experiences and data, and mention sometimes. These members were generous enough to repeat their contributions. I don't care about being right, but I do care about trusting members who are nice enough to share their data. Plus, it's just physics that heat conduction from metal to fluid then fluid to air is more efficient than metal to air. I would think most folks know by now, since there have been both air-cooled and antifreeze-cooled engines both for a long time. And the reason engines changed from air-cooled to liquid-cooled was...... (hint: it wasn't because they are cheaper - they're way more expensive).
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,922
Likes: 8,027
From: poway
a long time ago in a galaxy far, far away, Steve Cole did some M8 107 HD fan assisted oil cooler before and after testing using very similar test ride conditions .. for those wanting to review all the deets you can read until your eyeballs get tired but in a nutshell very compelling evidence of improvements .. not sure how the Twin Cooled would have compared
https://www.hdforums.com/forum/milwa...-system-9.html
Before Upgrade Results:
Measured Peak Engine temperature = 340 F
Measured Peak Oil Sump temperature = 267 F
Measured Peak Head Oil Return temperature = 290 F
After Upgrade Results:
Measured Peak Engine temperature = 302 F
Measured Peak Oil Sump temperature = 201 F
Measured Peak Head Oil Return temperature = 240 F
https://www.hdforums.com/forum/milwa...-system-9.html
Before Upgrade Results:
Measured Peak Engine temperature = 340 F
Measured Peak Oil Sump temperature = 267 F
Measured Peak Head Oil Return temperature = 290 F
After Upgrade Results:
Measured Peak Engine temperature = 302 F
Measured Peak Oil Sump temperature = 201 F
Measured Peak Head Oil Return temperature = 240 F
The upgrade was a fan to the oil cooler while putting around..
Conditions:
Ambient temperature during testing upper 70's
In Town riding with little traffic but normal stop lights
Speed limited to posted speed limits (35 - 45 mph)
Results:
Measured Peak Engine temperature = 340 F
Measured Peak Oil Sump temperature = 267 F
Measured Peak Head Oil Return temperature = 290 F
Steve's results with the oil cooler fan:
Conditions:
Ambient temperature during testing low - mid 70's
In Town riding with little traffic but normal stop lights
Speed limited to posted speed limits (35 - 45 mph)
Results:
Measured Peak Engine temperature = 302 F
Measured Peak Oil Sump temperature = 201 F
Measured Peak Head Oil Return temperature = 240 F
Ambient temperature during testing upper 70's
In Town riding with little traffic but normal stop lights
Speed limited to posted speed limits (35 - 45 mph)
Results:
Measured Peak Engine temperature = 340 F
Measured Peak Oil Sump temperature = 267 F
Measured Peak Head Oil Return temperature = 290 F
Steve's results with the oil cooler fan:
Conditions:
Ambient temperature during testing low - mid 70's
In Town riding with little traffic but normal stop lights
Speed limited to posted speed limits (35 - 45 mph)
Results:
Measured Peak Engine temperature = 302 F
Measured Peak Oil Sump temperature = 201 F
Measured Peak Head Oil Return temperature = 240 F