70° Thermostat

[BBRTuning]

Yep as mentioned lower coolant temp and higher oil temp up to a point is ideal from a power perspective. On my last engine build the OE thermostat that was in the car would operate around 70-72C for whatever reason, when I replaced the cooling system on my latest build it runs “correctly” at 80-82C now. Always wish I could get that old (worn?) thermostat back.

I’ve actually started collecting parts to run an electric pump, have The CNC blockoff plate and was going to PWM control a Pierburg EWP in the Emtron ECU. Using closed loop you can easily target 65-70C under load and 85-90c during cruise and idle for efficiency for example. New OE performance cars (Porsche etc) do exactly this using electronic thermostats and EWPs, often running close to 100-105c at light load and dump the coolant temp when being driven hard and/or in Sport/Track mode.

I looked into a custom thermostat as well but looked troublesome. If this happens I may just ditch the EWP project for simplicity!

[sapote]

When I was helping with the drag race cars Mid/upper 4's in the 1/8th mile (not BMW), we would connect the cooling system to refrigerated cooling system which would get the coolant down to near freezing. It would not be uncommon to have the blocks sweating because they were so cold when we would pull them to the starting line.

This activated the fuel enrichment, not because engine is more efficient or higher performance.
oil lubricants is best above 100C,
more friction loss with cool cylinder walls.

[George Hill]

This activated the fuel enrichment, not because engine is more efficient or higher performance.
oil lubricants is best above 100C,
more friction loss with cool cylinder walls.

What? There is no "fuel enrichment" table based on coolant temp on these cars, some are even carbureted.

Yes, we ran the oil higher temp higher than that, we are talking about coolant temp.

[Anri]

Yep as mentioned lower coolant temp and higher oil temp up to a point is ideal from a power perspective. On my last engine build the OE thermostat that was in the car would operate around 70-72C for whatever reason, when I replaced the cooling system on my latest build it runs “correctly” at 80-82C now. Always wish I could get that old (worn?) thermostat back.

I’ve actually started collecting parts to run an electric pump, have The CNC blockoff plate and was going to PWM control a Pierburg EWP in the Emtron ECU. Using closed loop you can easily target 65-70C under load and 85-90c during cruise and idle for efficiency for example. New OE performance cars (Porsche etc) do exactly this using electronic thermostats and EWPs, often running close to 100-105c at light load and dump the coolant temp when being driven hard and/or in Sport/Track mode.

I looked into a custom thermostat as well but looked troublesome. If this happens I may just ditch the EWP project for simplicity!

Beau,

I have exact the same identical case with OEM
t-stat from 1990 E34M5 with 200k+ it does open
at around 68°C and New OEM BTT opens at exact
79°C factory spec. While its kind of cool that is a sign
of going bad and if it gets stuck closed mama-mia. I
have solution also for E34M5 3.6 3.8 70°C.


The S54 70°C is ready. In fact, I tested it earlier this
morning. It works great.



Spec: Opens at exact 70°C fully open is at ~76°C
closes at 62°C which is perfect. This weekend I will
install it on Jonathan's freshly build S54 and I need
to collect data installed in the engine with flow.

In your case with El. fan you can extend the max
speed, don't know were is your temp sensor installed ?
its a win win.


People with fan clutch will work great as well, the engagement
will be earlier and the switch off point on the fan clutch is at around
65°C


Starting from Next weekend give it max 1 week of
daily driving conditions and I will be ready to make
Group Buy for the 70°C.

As much as like EWP and the benefits deep down
keep coming back to simplify and reliability. Sort of
EL power steering..to name Volvo pump everyone is
using etc..but what happens when we go to ButtonWillow
and the massive Caster loads going directly to the to
the electrical motor ? I am sure Motorsport el pumps
are design to take the hi loads but I have better way
to spent $2500 around the track car with more rewarding
benefits.


Regards,
Anri

[bigjae46]

Yep as mentioned lower coolant temp and higher oil temp up to a point is ideal from a power perspective. On my last engine build the OE thermostat that was in the car would operate around 70-72C for whatever reason, when I replaced the cooling system on my latest build it runs “correctly” at 80-82C now. Always wish I could get that old (worn?) thermostat back.

I’ve actually started collecting parts to run an electric pump, have The CNC blockoff plate and was going to PWM control a Pierburg EWP in the Emtron ECU. Using closed loop you can easily target 65-70C under load and 85-90c during cruise and idle for efficiency for example. New OE performance cars (Porsche etc) do exactly this using electronic thermostats and EWPs, often running close to 100-105c at light load and dump the coolant temp when being driven hard and/or in Sport/Track mode.

I looked into a custom thermostat as well but looked troublesome. If this happens I may just ditch the EWP project for simplicity!

Rogue sells a t-stat delete. I wonder if that’s would allow the coolant to run even cooler?

[Anri]

Rogue sells a t-stat delete. I wonder if that’s would allow the coolant to run even cooler?

It's never a good idea to delete thermostat completely.
The warm up time will be forever which is not good.

The coolant will not run cooler because no matter what
ones the engine warms up it will never be able to go
down to say 30-40°C even during winter time.

[digger]

Rogue sells a t-stat delete. I wonder if that’s would allow the coolant to run even cooler?

it would run cooler but you are in effect building a boat engine and should build the engine with that application inmind. There is a very good chance of scuffing the pistons on a race engine as pistons will still get hot and expand at a high rate being Alumnium but the cylinders wont expand much at all with oe cast pistons the clearances are on the tight side of tolerance already. I imagine there are also diminishing returns as there needs to be a delta at all times

[BBRTuning]

Beau,

I have exact the same identical case with OEM
t-stat from 1990 E34M5 with 200k+ it does open
at around 68°C and New OEM BTT opens at exact
79°C factory spec. While its kind of cool that is a sign
of going bad and if it gets stuck closed mama-mia. I
have solution also for E34M5 3.6 3.8 70°C.


The S54 70°C is ready. In fact, I tested it earlier this
morning. It works great.



Spec: Opens at exact 70°C fully open is at ~76°C
closes at 62°C which is perfect. This weekend I will
install it on Jonathan's freshly build S54 and I need
to collect data installed in the engine with flow.

In your case with El. fan you can extend the max
speed, don't know were is your temp sensor installed ?
its a win win.


People with fan clutch will work great as well, the engagement
will be earlier and the switch off point on the fan clutch is at around
65°C


Starting from Next weekend give it max 1 week of
daily driving conditions and I will be ready to make
Group Buy for the 70°C.

As much as like EWP and the benefits deep down
keep coming back to simplify and reliability. Sort of
EL power steering..to name Volvo pump everyone is
using etc..but what happens when we go to ButtonWillow
and the massive Caster loads going directly to the to
the electrical motor ? I am sure Motorsport el pumps
are design to take the hi loads but I have better way
to spent $2500 around the track car with more rewarding
benefits.


Regards,
Anri

This is great! I'll buy a 70C anyway when they're available and just run that at least for now, the EWP was more of a fun project to play around with but simplicity sounds nice..

[oceansize]

Anri

Do you think there is an application for this in a street driven supercharged car? I'm running a conservative 5.5 pounds of boost.

[Anri]

Anri

Do you think there is an application for this in a street driven supercharged car? I'm running a conservative 5.5 pounds of boost.

Hi,

On FI running cooler temp is a must coolant and oil.
Supercharges do create constant drag to the crank
and loads the system means will generate more heat.

Are you running fan clutch or E-fan ?

Regards,
Anri.

[oceansize]

Hi,

On FI running cooler temp is a must coolant and oil.
Supercharges do create constant drag to the crank
and loads the system means will generate more heat.

Are you running fan clutch or E-fan ?

Regards,
Anri.

Thanks Anri. I'm running a fan clutch.

[digger]

This activated the fuel enrichment, not because engine is more efficient or higher performance.
oil lubricants is best above 100C,
more friction loss with cool cylinder walls.

everyone knows lean is mean so enrichment will slow you down....the coolant and oil temp are not the same, nevertheless there is some coupling between the two but you can always drop down the viscoity if the oil temps are too low but this is not normally an issue on endurance type racing engine. Ofcourse on a drag racing engine they will run thin oils due to low oil temp and other reasons

[Anri]

This is great! I'll buy a 70C anyway when they're available and just run that at least for now, the EWP was more of a fun project to play around with but simplicity sounds nice..

Beau,

Years back I read Tech article from I dont
remember from Behr or Wahler that in case
they go bad they will alwasy stuck open, it
has to do something with wax mixture they use
inside and the proportion. This will explain why
your old one and the one I still have is opening
early, its on its way out.


This design thermostat started life on E34M5.
This is hi flow design comopared to the older traditional
style design. Ever since every manufacture started
using this type of thermostat. The E34M5 t-stat is in
S62 engine as well.

Regards,
Anri

[sapote]

When I was helping with the drag race cars Mid/upper 4's in the 1/8th mile (not BMW), we would connect the cooling system to refrigerated cooling system which would get the coolant down to near freezing. It would not be uncommon to have the blocks sweating because they were so cold when we would pull them to the starting line.

I guess for these engines there is no radiator and so this is to make sure the whole block is cold enough for not getting overheated during the race. This is not related to the subject of cooler engine is good for power though.

[sapote]

Yep as mentioned lower coolant temp and higher oil temp up to a point is ideal from a power perspective. On my last engine build the OE thermostat that was in the car would operate around 70-72C for whatever reason, when I replaced the cooling system on my latest build it runs “correctly” at 80-82C now. Always wish I could get that old (worn?) thermostat back.

I’ve actually started collecting parts to run an electric pump, have The CNC blockoff plate and was going to PWM control a Pierburg EWP in the Emtron ECU. Using closed loop you can easily target 65-70C under load and 85-90c during cruise and idle for efficiency for example. New OE performance cars (Porsche etc) do exactly this using electronic thermostats and EWPs, often running close to 100-105c at light load and dump the coolant temp when being driven hard and/or in Sport/Track mode.

I looked into a custom thermostat as well but looked troublesome. If this happens I may just ditch the EWP project for simplicity!

I don't see how a 70C engine helps in giving more power -- cool cylinder walls rob the heat (and power) off the combustion gas as the delta temp is higher. I love to hear the reason for better power with 70C cool engine.

The modern cars with mapped Tstat lower the coolant temp to avoid micro-boiling around the exhaust valves during high load, but they don't operate around 70C most of the time as someone just replace a stock Tstat with a 70C Tstat.