munich55

Hi guys,

is there somebody who has installed the johnson cm 90?
Is it easy to install and are other fittings needed?
Thank you

Forrest Gump 9

It's a big one. If you go with the CM90, one is all you ever need. I have a brand new for cheap if you need.

chawkins2001

Yeah, that is a big daddy, go for it.

OCKlasse

Does it still go in the factory location?

Rafiki

yea am trying to order one today , wondering if i should go with the CM30 or CM 90

munich55

payment sent :-)

reitmeid

If you do go with the CM90, order the one with 3/4 inch (22mm) in/out. Makes installation much easier.

Toadster

wasn't one of the threads saying it flowed too much to cool properly - but I'm assuming you have a better H/E already?

https://mbworld.org/forums/w211-amg/...ses-bosch.html

pearlpower

One of those things where folks get all excited over their purchase and install and start posting about how great it is, but then without any real numbers to substantiate their claims.

munich55

So i received it.
Thank you ForrestGump9 :-)
At the moment i still have the stock h/e and now i am not sure how to install it with the 1.1/2'' (38mm)
Can i get there somewhere an reducer???

munich55

I can't find an reducer 1,5'' to 3/4''
Is it possible to install 2 reducer one after the other
1,5'' to 7/8'' and 7/8'' to 3/4'' ?

Roverron

Yes if you have the room.

wallaka

That's not how physics works. The faster the fluid flow, the faster heat can transfer.

Toadster

the materials that are doing the heat transfer need to be able to transfer the heat efficiently as well, there was a thread in how the faster pumps showed higher IATs because they didn't have enough time to dissipate the heat through the I/C...

so yes, if you have an optimal I/C setup - then pump till your hearts content, otherwise you're pushing/pulling hot water too quickly

munich55

Hmmmm
I never chanced the i/c-pump. I don't know how much room there is.

Rafiki

soo for a stock H/E should i just go with the CM30 and is it a direct fit,

pearlpower

The Bosch '10 pump is direct bolton and was better in my testing vs the CM30 which have been known to have some quality issues-though mine performed well, though not better vs. the '10 unit.

dtohio

+1, correct, you can't flow too fast.

kustom2k1

I think it can flow too fast if the surface of the HE isnt large enough. Im sure there is a gpm thats just right depending on the size of HE.

pearlpower

Wrong! How about you guys show your own testing?? If not, then your wasting typing time and not offering anything helpful to others. Buy the units and provide your own tests as others have. THEN come back and post up.

https://mbworld.org/forums/w211-amg/...-vs-wp136.html

there is another floating some where, search for it.

AKnight55

Yup, this ^^^^^

None

But it is how thermal dynamics works yes you can have to big of a pump if your moving the water/coolant faster then you can shed the heat with your heat exchanger of choice, then the faster you go the hotter it gets!

I had similar results to Pearpower with the 90 on my current car, stepped down to a smaller GPM pump and saw coolant temps drop over 20 degrees over the higher flowing pump.

pearlpower

Some might say it is more an effect of cavitation from such a high velocity pump, either way the results for a few are not positive unless you have a rear trunk tank.

Another thread

https://mbworld.org/forums/w211-amg/...xperience.html

additional discussion
https://mbworld.org/forums/w211-amg/...tory-help.html

Waaaay back when when I worked auto parts, folks would come in and complain that their car/truck would overheat when they removed their thermostat. Put in a new one, all was well.

It's a matter of balance.

wallaka

For any given heat load, a slower fluid flow results in slower heat transfer. The empirical data (which I'm not going to argue with, I'm no Toadster) says to me that the increased flow causes turbulence in the system, pump starvation/cavitation, or other design flaws to surface, not that the water is moving too fast to transfer heat.

The engine coolant is another issue entirely--on most engines, the thermostat acts as a flow restrictor to keep a slight pressure in the water jackets. This mitigates the localized boiling (around exhaust ports, etc) that can happen. An engine with poorly-designed coolant passages, e.g. the SBC, can have a real problem when the thermostat is removed because they will then have boiling and detonation due to the boiling. Never heard of any similar problems when installing a high-performance water pump or radiator, except when the suction would collapse the radiator hose...interesting. I wonder if that's been checked on with these higher flow pumps?

Derail aside, the CM30 that I installed is working fine, though it's only been a month and I've only seen temperatures in the 75-80 degree range. I suspect that my OE pump was malfunctioning, anyway. I also installed a bigger heat exchanger at the same time so I can't make any scientific claims. I do note that I haven't seen any heat soak since installation, and before it would take about two WOT pulls to about 100 mph with the 180 pulley and the supercharger would cut off.

pearlpower

You may very well be correct. A quick Google reveals that this topic has been beaten to death (on motors) with no obvious conclusion. Incidentally, most lower radiator hoses have springs to prevent them from collapsing. Not all-most, I only sold a few thousand of them.

The bottom line however is the MASSIVE and I do mean MASSIVE pump raises the temps unless a rear tank setup is on place or resistor to slow it down. For those with only stock or an upgraded H/E, the Bosch '10 and CM30 work great.