Are cylinder head cooling mods snake oil? First tests may indicate so

[honeybadger]

Alright data from the cylinder head cooling mod test is in. To recap, I have water temp sensors installed in the back of both heads in addition to the OEM one (this one is not exposed to water). I then installed the MMR cooling mod with a ball valve so I could turn off water flow and data log the difference.

I went out and did a few laps with a ball valve closed, simulating the OEM configuration (no water "flow" between heads). Came in hot, turned the ball valve open and went out to see if it made a difference. It did - but not a statistically relevant one and not in the right direction. The delta between my heads actually got worse.

This is a bust, IMHO.

Session in full for transparency



Next, I tested my own cooling mod where I pumped "cool" water from the pump directly to the back of the cylinder heads.

I tested this in the next session. Even though I drove the car harder, got it hotter (check out oil temps), the heads ran cooler. Success! CHTs below 200 in a 25 min session in 80 degree ambient temps? WINNNNN

Full session for transparency. again



Some takeaways -

1. my data logging on Saturday across 4 sessions showed that the cylinder head temps were always within 1-2 degrees of each other. This is a solution to a problem that doesn't exist, IMHO

1. Sharing water between the two heads did not result in an improvement

1. Supplying cooler water from the front to the back of the heads does yield improvements

As always, this is not definitive data. interpret how you want

I'm also attaching my AIM Racestudio data files so you can dive into the data if you want
https://1drv.ms/f/c/8f6ab0808ad3acc2/EptpMgtSOkJJkm-xBzhbLSABfWcWkvQariG46ii2Nfzmuw?e=G8IByf

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[honeybadger]

Baseline session from Saturday with no crossover

 

[pilotgore]

Alright data from the cylinder head cooling mod test is in. To recap, I have water temp sensors installed in the back of both heads in addition to the OEM one (this one is not exposed to water). I then installed the MMR cooling mod with a ball valve so I could turn off water flow and data log the difference.

I went out and did a few laps with a ball valve closed, simulating the OEM configuration (no water "flow" between heads). Came in hot, turned the ball valve open and went out to see if it made a difference. It did - but not a statistically relevant one and not in the right direction. The delta between my heads actually got worse.

This is a bust, IMHO.

Session in full for transparency



Next, I tested my own cooling mod where I pumped "cool" water from the pump directly to the back of the cylinder heads.

I tested this in the next session. Even though I drove the car harder, got it hotter (check out oil temps), the heads ran cooler. Success! CHTs below 200 in a 25 min session in 80 degree ambient temps? WINNNNN

Full session for transparency. again



Some takeaways -

1. my data logging on Saturday across 4 sessions showed that the cylinder head temps were always within 1-2 degrees of each other. This is a solution to a problem that doesn't exist, IMHO
2. Sharing water between the two heads did not result in an improvement
3. Supplying cooler water from the front to the back of the heads does yield improvements

As always, this is not definitive data. interpret how you want

I'm also attaching my AIM Racestudio data files so you can dive into the data if you want
https://1drv.ms/f/c/8f6ab0808ad3acc2/EptpMgtSOkJJkm-xBzhbLSABfWcWkvQariG46ii2Nfzmuw?e=G8IByf

Good info.

I lost touch with your build awhile ago. Holy cow that thing sounds nasty!! Nice work!

 

[robvas]

People have been calling BS on the head cooling mod since the 4V days, at least 25 years ago...

 

[WItoTX]

First, thanks so much for posting all the info on the cooling mod you did. To take the time to put all that together, it's great for folks like me. I was actually going to pick your brain on it next month at COTA.

In my mind, it made no sense to connect the two heads, because it's not like water is actually flowing, just filling the line, at best. If I understand correctly, you mod actually pushes water into the engine from the front AND rear, which makes a ton of sense why it would actually cool the rear of the head. I also understand that all the cooling water comes from the front of the head, and "generally" flows from the front to the rear of the head, and from the top of the head down and out through the bottom and back to the radiator. Is that a correct assumption?

So my next logical question, how long until you start selling the mod you built?

Thanks again for posting all that info. It really does help the community.

 

[Mrhavasu]

Thanks, always good info. Appreciate all the work it takes to provide
all that.

 

[honeybadger]

First, thanks so much for posting all the info on the cooling mod you did. To take the time to put all that together, it's great for folks like me. I was actually going to pick your brain on it next month at COTA.

In my mind, it made no sense to connect the two heads, because it's not like water is actually flowing, just filling the line, at best. If I understand correctly, you mod actually pushes water into the engine from the front AND rear, which makes a ton of sense why it would actually cool the rear of the head. I also understand that all the cooling water comes from the front of the head, and "generally" flows from the front to the rear of the head, and from the top of the head down and out through the bottom and back to the radiator. Is that a correct assumption?

So my next logical question, how long until you start selling the mod you built?

Thanks again for posting all that info. It really does help the community.

Shaun does a great overview of the cooling system and theorized why he believed the original mod would never work. THis is where I got the idea and he was spot on in his assumption.

I still think the heads can benefit from additional cooling. The delta between coolant temps and head temps demonstrate that pretty clearly. but the market available options are just snake oil - the theory isn't there and this data proves it.

@5.2 liters of democracy and I have already been scheming on how we can adapt for stock setups. I'll always advocate for an electric setup, tho. More efficient and more flexibility

 

[Unbridled5.0]

^ same link I was about to post

 

[WItoTX]

Shaun does a great overview of the cooling system and theorized why he believed the original mod would never work. THis is where I got the idea and he was spot on in his assumption.

I still think the heads can benefit from additional cooling. The delta between coolant temps and head temps demonstrate that pretty clearly. but the market available options are just snake oil - the theory isn't there and this data proves it.

@5.2 liters of democracy and I have already been scheming on how we can adapt for stock setups. I'll always advocate for an electric setup, tho. More efficient and more flexibility

I'd be very interested in a setup like that. At least until this motor lets go.

 

[NGOT8R]

@honeybadger great job on this! I have the mod as it comes from MMR on my car, but really like what you’ve done here. I am going to be cutting my jumper hose and connecting it to a coolant block to feed my two turbo wastegates. This has definitely gotten my wheels turning again.

I do have a question. Where’s your water pump? I see the modified delete plate with the piping welded to it that feeds the heads and connects to the lower radiator hose on the driver’s side.

 

[honeybadger]

@honeybadger great job on this! I have the mod as it comes from MMR on my car, but really like what you’ve done here. I am going to be cutting my jumper hose and connecting it to a coolant block to feed my two turbo wastegates. This has definitely gotten my wheels turning again.

I do have a question. Where’s your water pump? I see the modified delete plate with the piping welded to it that feeds the heads and connects to the lower radiator hose on the driver’s side.

Water pump is near the alternator. It's a Pierburg CWA400 (OEM on BWMs and other German cars). It's be awesome so far - absolutely love it. My cooling system runs a 16an out of the driver head and a 12an out of the passenger head and t's them into a 16an inlet into a swirl pot to reduce steam/bubbles, then into radiator, then out of radiator and into the water pump.

Here's a current view of my plumbing

 

[NGOT8R]

Ahh okay! Beautiful job on the install. I see you’re also running a head oiling mod from the looks of the lines at the rear of the engine.

 

[honeybadger]

Ahh okay! Beautiful job on the install. I see you’re also running a head oiling mod from the looks of the lines at the rear of the engine.

yep - I'm running the oil lines to help ensure constant oil pressure in the galleys. Not sure they're technically needed in my engine since it has a dailey engineering pump, but they can't hurt so I've kept them

 

[CobaltFilly]

Shaun does a great overview of the cooling system and theorized why he believed the original mod would never work. THis is where I got the idea and he was spot on in his assumption.

I still think the heads can benefit from additional cooling. The delta between coolant temps and head temps demonstrate that pretty clearly. but the market available options are just snake oil - the theory isn't there and this data proves it.

@5.2 liters of democracy and I have already been scheming on how we can adapt for stock setups. I'll always advocate for an electric setup, tho. More efficient and more flexibility

And please let me know if it would be an adaptable item on the V6 engine! Not sure much on this topic at all, but I like to learn.

then again, maybe the engine is so much smaller and less heating that it only needs bigger radiator, pump, and swirling tank or whatever its called

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