Tested and Ready 70° and 75° Thermostat

[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..

[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

[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.

[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]

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 75°C
closes at 66°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

[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.

[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.

[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!

[George Hill]

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.

[Anri]

The whole running hotter thing makes zero sense. My car feels like trash when the coolant would get over 220f. Feels excellent at 170f. My top speed data backs this up.

Jae,

Same thing here and with every E46M3.

When I do dyno on cammed S54s and let them
cool down at around 70-75°C in-between passes
then hop in the car and do immediate pass the
power is at peak, second run drops 3-4rwhp and
on the 3rd run when the coolant temps is
at 90-92°C they lose ~10rwhp.

Additional cooling tricks and other tricks
are required to be able to run near the peak
ignition, and the internal expansion under control.



Regards,
Anri

[bigjae46]

No on almost everything you said. Those temps are only optimum for fuel efficiency and emmisions at cruise and light load which is the main goal of the OEMs. It is well known that lower coolant temperature makes more WOT power due to better knock resistance and improved VE due to increased charge density. Often you need to make changes to run colder to ensure proper mixtures, ignition timing, running clearances, and control friction losses due to potentially colder oil temps in certain conditions, so ideally you keep oil hot but colder coolant.

Aero on F1 cars trump just about everything so they are choosing to run hot due to running small radiators for aero reasons. It is simply a by product of conflicting requirements and the ultimate goal for lower lap times not more power and aero is king and higher priority

The whole running hotter thing makes zero sense. My car feels like trash when the coolant would get over 220f. Feels excellent at 170f. My top speed data backs this up. My lap times also support the engine runs better at when the coolant and oil temps are lower vs higher.

F1 cars generally trim cooling when they run higher speed tracks like Monza.

[Anri]

No on almost everything you said. Those temps are only optimum for fuel efficiency and emmisions at cruise and light load which is the main goal of the OEMs. It is well known that lower coolant temperature makes more WOT power due to better knock resistance and improved VE due to increased charge density. Often you need to make changes to run colder to ensure proper mixtures, ignition timing, running clearances, and control friction losses due to potentially colder oil temps in certain conditions, so ideally you keep oil hot but colder coolant.

Digger,


Spot on all of it Digger. When I did 55°C t-stat on
our track E46M3 alongside with larger radiator
70% distilled water and 30% coolant it did run
tight very torque and running at near the max
ignition it made big difference between the stock
system and after.

Absolutely yes on fuel economy. My E31 840Ci M62
at summer time in traffic on AC running temp 115°C
it does ping every singe time off traffic light, the T stat is
97°C, let alone the power drops like its 4cylinder....it
so bad..

Updated the T-Stat to 71°C and no
more pinging, soon the S62 is going
in but still felt did not want to destroy
the M62.

Bank-2 on inline-6 runs always hot.

On my S38 I have dual wide band on both
banks separate. Bank-2 always run little hotter
not by much than Bank-1 but my temps are in
the ~75°C

Another $2k and it will get me individual EGT
probes for my upcoming 4.0l S38 to be able
to monitor individually the EGTs and control
the ignition timing on each cylinder.


Regards,
Anri

[digger]

The best opearting temp for internal combustion engine is 90C to 120C due to material fatigue and design clearance. In theory, the higher opearting temp is better as less loss to combustion temp and pressure needed to push the pistons down. Cool air/fuel mixture is desirable but it should be treated separately from coolant temp.

So having a stable coolant temp at 85c or 90c is not bad, but when it continues to rise then it is bad.
Again, I don't think having the Tstat opens early at 70c is good, but a 70c Tstat inherently opens more than the stock Tstat at 90c, and this allows more coolant flow through the radiator - it's what one wants to prevent overheat on the track.

The ideal Tstat should not open until the coolant reached 90c, then continue to open more to keep the temp at 90c as the engine generating more heat. Unfortunately a classical spring loaded wax motor can't do this. Don't know why BMW didn't use an electric heater in the Tstat to control it as an "ideal Tstat" -- propably due to reliability issue.

F1 cars have coolant opearing temp at 120C.

No on almost everything you said. Those temps are only optimum for fuel efficiency and emmisions at cruise and light load which is the main goal of the OEMs. It is well known that lower coolant temperature makes more WOT power due to better knock resistance and improved VE due to increased charge density. Often you need to make changes to run colder to ensure proper mixtures, ignition timing, running clearances, and control friction losses due to potentially colder oil temps in certain conditions, so ideally you keep oil hot but colder coolant.

Aero on F1 cars trump just about everything so they are choosing to run hot due to running small radiators for aero reasons. It is simply a by product of conflicting requirements and the ultimate goal for lower lap times not more power and aero is king and higher priority

[Anri]

The best opearting temp for internal combustion engine is 90C to 120C due to material fatigue and design clearance.

Can you explain yourself in more deep technical details were did you
read this or come up with these numbers ?

If this is truth why all S engines do have T-stat at 79-80°C as opposite
of M54 or say my E31 840Ci M62 at 105°C with thermostat of 97°C?

Why BMW Motorsport made the 55°C on a car without AC condenser and
all nicely ducted up the front ?

F1 cars have coolant opearing temp at 120C.

And how does F1 engine starts from cold ?! with coolant heated
up to temps (I can find out asking Brian who is on F1 world) to be exact.

F1 internal clearance are design to operate in specific conditions and they
are only in hi revs.

Regards
Anri

[sapote]

The early opening and lower operating temp is desirable from a pure perfomance persective though assuing some adjustments. if you arent able to consisently operate at the t-stat temp or thereabouts on track then it's fairly pointless

The best opearting temp for internal combustion engine is 90C to 120C due to material fatigue and design clearance. In theory, the higher opearting temp is better as less loss to combustion temp and pressure needed to push the pistons down. Cool air/fuel mixture is desirable but it should be treated separately from coolant temp.


So having a stable coolant temp at 85c or 90c is not bad, but when it continues to rise then it is bad.
Again, I don't think having the Tstat opens early at 70c is good, but a 70c Tstat inherently opens more than the stock Tstat at 90c, and this allows more coolant flow through the radiator - it's what one wants to prevent overheat on the track.

The ideal Tstat should not open until the coolant reached 90c, then continue to open more to keep the temp at 90c as the engine generating more heat. Unfortunately a classical spring loaded wax motor can't do this. Don't know why BMW didn't use an electric heater in the Tstat to control it as an "ideal Tstat" -- propably due to reliability issue.

F1 cars have coolant opearing temp at 120C.