751 (edited by darkostoj 2019-09-10 07:37 AM)

Re: I bought a Rolls Royce and want to build it.

rlchv70 wrote:
TheEngineer wrote:

So if you pump water through the radiator too fast, it doesn't cool down as much, and then you start to counter your heat removal capacity gain from increased volumetric flow with the decrease that comes from using hotter water. Heat transfer relies on temperature differential after-all. So it's more complicated than saying "the more water you can push the better", because as with most things, there are trade offs.

Some cars do fine with no thermostat, because the radiator is over-sized and the increase in flow rate doesn't really lead to a coolant temp increase that hinders things. Some cars cannot run without a thermostat because it breaks the balance of the system and leads to a thermal runaway. There is no magic one line answer that solves all setups.

Former cooling system engineer here.

Remember that it is a system.  You pump the water through the radiator faster, it doesn't cool off as much in the radiator, but it also doesn't heat up as much going through the engine.  The net difference is that the coolant runs cooler, all things being equal. Q=m * Cp * delta T

Problem is, things aren't equal.  The main problem is pressure.  Without a thermostat, the pressure in the upper hose and radiator are increased.  This can exceed their design pressure and leading to failures.

Increasing the flow rate may lead to hot spots in the engine and radiator, also causing unexpected failures.

Best practice is to keep a functioning thermostat.  Will let the engine warm up quickly and maintain its temp.

I was hoping you could shed some light on how to design a proper cooling system from scratch?

My assumptions are that we use pressure at the radiator inlet & radiator outlet to determine the flow rate correct?

*Assuming we have no thermostat* we can use things like changing water pump flow, thermostat housing restrictor plate, single/double/triple pass radiator to change the flow characteristics.

So if we plumb a pressure gauge at the radiator inlet, and another at the radiator output we can determine the amount of restriction right?

Do you have a step by step process on how to accurately size/design a radiator cooling system from scratch?


-----------------------------------------------

Other updates on the car

1. removed the AEM ecu and went to a factory computer.  Runs much better, much simpler, and using the OEM engine harness.

2. Currently trying to figure out how to pull CAN/Serial data off the OEM ecu to power my dash gauge display.  It's not a super easy thing since the car is PRE-08 so the CAN system isn't standard. Also the ECU doesn't have oil pressure, temp, or fuel level.

3.  Going to add hood vents to help extract some engine heat

4. Adding an accusump

5. Going to add a oil/water exchanger for the oil cooler and remove the air cooler in front of the radiator.

6. Going to dig into the radiator/cooling system on how to cool better.

----------------------------------------------

We are racing the car at the Empire Hill Climb in Michigan this Saturday.

https://empirechamber.com/event/empire- … b-revival/

Team Pacific Motors - 1977 Rolls Royce Silver Wraith

2018 Where the Elite Meet to Cheat - Organizer's Choice Award
2019 Rust Belt GP - Spirit of Entropy Award

Re: I bought a Rolls Royce and want to build it.

darkostoj wrote:

I was hoping you could shed some light on how to design a proper cooling system from scratch?

My assumptions are that we use pressure at the radiator inlet & radiator outlet to determine the flow rate correct?

*Assuming we have no thermostat* we can use things like changing water pump flow, thermostat housing restrictor plate, single/double/triple pass radiator to change the flow characteristics.

So if we plumb a pressure gauge at the radiator inlet, and another at the radiator output we can determine the amount of restriction right?

Do you have a step by step process on how to accurately size/design a radiator cooling system from scratch?

That is a very loaded question with a complicated answer.  The way the OEMs do it correctly is based on experience, CFD, wind tunnel testing, road testing, and a bunch of iterations.


For our purposes, you stuff as much radiator in the car as possible.  Make sure as much air can pass through the radiator as possible and will not recirculate.  Utilize OEM thermostat and water pump.  Plumb the radiator to the engine with short, but not restrictive piping.  Make sure the suction side will not collapse (use hard pipe or hoses with springs inside).  Since we do not do a lot of low speed driving, one electric fan is usually enough to keep it cool when pitting.

To answer your questions regarding measuring restriction and flow rate:

Flow rate is a function of both the pressure drop and the restriction.  To measure the restriction, you would need to know both the flow rate and pressure drop, to measure the flow rate, you need to know the restriction and pressure drop, and so on.  The equations can get complicated and really doesn't gain you a lot of information for our purposes.

As long as you have a thermostat, you don't need to know any of this.  Oversize the radiator and the thermostat will control the flow rate to maintain the proper temperature.

Re: I bought a Rolls Royce and want to build it.

Concur with the above. Biggest radiator you can fit, ducted well so all the air from the front of the car goes through it, not around it, and can then escape the engine bay somehow. Simplify the routing to be just the short loop in and out plus the bypass loop for when the thermostat is closed. Factory style 180°F or lower thermostat. It was discussed earlier that the viper thermostat is a strange 3 position one, but you said you already took care of simplifying that.

Other things you can consider, put in an oil temp gauge. If the oil is getting too hot get a bigger cooler, it will help.

And check tuning, can't recall if you have an AFR gauge already. If the ECU is slow to richen the mixture you'll generate more heat. Been battling that in the saab, stupid thing was sticking in the 14s even as boost built, which makes temps skyrocket. Since you went back to the stock computer that may change things for better or worse.

20+ Time Loser FutilityMotorsport
Turbo Dodge Powered E36 Build
2008 Saab 9-5Aero Wagon
Retired - 1989 Dodge Daytona Shelby 2011-2015 "Lifetime Award for Lack of Achievement" IOE, 3X I got screwed, Organizer's Choice

Re: I bought a Rolls Royce and want to build it.

Our Ford V8 Jegs radiator is way more that we need but it's nice to have to add tape to the grill on the cold days and not have to give it a second thought on hot days. I don't think the car has seen over 190 all year.

Of course we have 8 cylinders less than you.

Apocalyptic Racing - Occupy Pit Lane racing
Racing the "Toylet" Toyota Celica powered by Chevrolet Ecotec.
24x Loser with the Celica. 16x loser in other fine machines
Overall winner Gingerman 2019

755

Re: I bought a Rolls Royce and want to build it.

Brett85p wrote:

Our Ford V8 Jegs radiator is way more that we need but it's nice to have to add tape to the grill on the cold days and not have to give it a second thought on hot days. I don't think the car has seen over 190 all year.

Of course we have 8 cylinders less than you.

So you guys are running that new 2-cylinder Ecotec? wink

Captain
Team Super Westerfield Bros.
'93 Acura Integra - No VTEC Yo!

Re: I bought a Rolls Royce and want to build it.

VKZ24 wrote:
Brett85p wrote:

Our Ford V8 Jegs radiator is way more that we need but it's nice to have to add tape to the grill on the cold days and not have to give it a second thought on hot days. I don't think the car has seen over 190 all year.

Of course we have 8 cylinders less than you.

So you guys are running that new 2-cylinder Ecotec? wink

I hope I didn't just jinx us....make that 6 cylinders less....

Apocalyptic Racing - Occupy Pit Lane racing
Racing the "Toylet" Toyota Celica powered by Chevrolet Ecotec.
24x Loser with the Celica. 16x loser in other fine machines
Overall winner Gingerman 2019

757 (edited by darkostoj 2019-09-11 03:18 PM)

Re: I bought a Rolls Royce and want to build it.

Unfortunately, a thermostat is not possible due to the space constraints right now.  I need to 3d model a new thermostat housing to have it fit, since anything OEM won't work.

So, right now...without a thermostat the car has a triple pass radiator.

It's obvious to "fit the largest radiator possible."  What about single/double/triple pass?  Any ideas on how to select which is best?

Team Pacific Motors - 1977 Rolls Royce Silver Wraith

2018 Where the Elite Meet to Cheat - Organizer's Choice Award
2019 Rust Belt GP - Spirit of Entropy Award

758

Re: I bought a Rolls Royce and want to build it.

what about an inline thermostat housing?
https://www.amazon.com/Meziere-WN0071-I … B003NDFEC0

Re: I bought a Rolls Royce and want to build it.

Caveat, I am not a radiator expert. In theory the more passes, the better. However the more passes the better your water pump needs to be. The more passes the higher the restriction of the radiator since you're trying to push the water through less cross sectional area, but a longer distance. So if the water pump isn't up to the job, a triple pass might work worse than a single or double.

20+ Time Loser FutilityMotorsport
Turbo Dodge Powered E36 Build
2008 Saab 9-5Aero Wagon
Retired - 1989 Dodge Daytona Shelby 2011-2015 "Lifetime Award for Lack of Achievement" IOE, 3X I got screwed, Organizer's Choice

Re: I bought a Rolls Royce and want to build it.

Spank wrote:

what about an inline thermostat housing?
https://www.amazon.com/Meziere-WN0071-I … B003NDFEC0

Use this or make your own.

The Engineer is correct, generally, the more radiator passes, the more efficient, but has a greater restriction, heavier, and maybe thicker.

761 (edited by darkostoj 2019-09-12 07:04 AM)

Re: I bought a Rolls Royce and want to build it.

rlchv70 wrote:
Spank wrote:

what about an inline thermostat housing?
https://www.amazon.com/Meziere-WN0071-I … B003NDFEC0

Use this or make your own.

The Engineer is correct, generally, the more radiator passes, the more efficient, but has a greater restriction, heavier, and maybe thicker.

I don't think i'll be able to fit an inline housing....however I got to thinking and I may try mounting a thermostat housing on the radiator and not the engine.

Team Pacific Motors - 1977 Rolls Royce Silver Wraith

2018 Where the Elite Meet to Cheat - Organizer's Choice Award
2019 Rust Belt GP - Spirit of Entropy Award

Re: I bought a Rolls Royce and want to build it.

darkostoj wrote:
rlchv70 wrote:
Spank wrote:

what about an inline thermostat housing?
https://www.amazon.com/Meziere-WN0071-I … B003NDFEC0

Use this or make your own.

The Engineer is correct, generally, the more radiator passes, the more efficient, but has a greater restriction, heavier, and maybe thicker.

I don't think i'll be able to fit an inline housing....however I got to thinking and I may try mounting a thermostat housing on the radiator and not the engine.

You better make sure there is a decent size hole to bypass some coolant through a rad mounted thermostat or it may never get its initial signal to open.

Are you actually worried this will run too cool?!? I see a racecar thermostat as a cheap absolutely unnecessary device that can randomly fail and blow up my expensive bits. (this has happened to me) (we race in the hot south)

Homestead Chump 5th-Sebring 6th-PBIR Lemons 9th - Charlotte Chump  CrashnBurn 9th
Sebring 6th again -NOLA Chump 1st -PBIR Chump Trans Fail 16th
Daytona 11th - Sebring 6th - Atlanta Motor Speedway 2nd - Road Atlanta Trans Fail 61st-Road Atlanta 5th
Daytona 13th - Charlotte 9th - Sebring 2nd-Charlotte 25th broken brakes - Road Atlanta 14 10th-Daytona 14  58th- Humid TT 19th Judges' Choice!

Re: I bought a Rolls Royce and want to build it.

Team Infinniti wrote:
darkostoj wrote:
rlchv70 wrote:

Use this or make your own.

The Engineer is correct, generally, the more radiator passes, the more efficient, but has a greater restriction, heavier, and maybe thicker.

I don't think i'll be able to fit an inline housing....however I got to thinking and I may try mounting a thermostat housing on the radiator and not the engine.

You better make sure there is a decent size hole to bypass some coolant through a rad mounted thermostat or it may never get its initial signal to open.

Are you actually worried this will run too cool?!? I see a racecar thermostat as a cheap absolutely unnecessary device that can randomly fail and blow up my expensive bits. (this has happened to me) (we race in the hot south)

I have been struggling with keeping the car cool.

Team Pacific Motors - 1977 Rolls Royce Silver Wraith

2018 Where the Elite Meet to Cheat - Organizer's Choice Award
2019 Rust Belt GP - Spirit of Entropy Award

Re: I bought a Rolls Royce and want to build it.

darkostoj wrote:
rlchv70 wrote:
Spank wrote:

what about an inline thermostat housing?
https://www.amazon.com/Meziere-WN0071-I … B003NDFEC0

Use this or make your own.

The Engineer is correct, generally, the more radiator passes, the more efficient, but has a greater restriction, heavier, and maybe thicker.

I don't think i'll be able to fit an inline housing....however I got to thinking and I may try mounting a thermostat housing on the radiator and not the engine.

You could get OLD school cool with this with thermally activated grille bars like an old...Packard, I think.

Shut airflow off to the radiator until engine temp comes up, and then the vents/bars open. Easy to control by hand, easy to control by actuators and maybe an Arduino, harder but hella awesome to actuate with expanding metal like the old school cars did it.

Slap a small restrictor plate on the water pump outlet if over pressurizing with the pump is a concern and you're good to go.

The League of Legitimate Nigerian Businessman - Admiral General Captain
1972 Ford Pinto Wagon

765 (edited by darkostoj Yesterday 07:18 PM)

Re: I bought a Rolls Royce and want to build it.

Hey guys, something strange happened.

We got a trophy for winning something, and not sucking the most like the last 2 trophies.

Ran the Autoweek Empire Hill climb in Michigan. There was a lot left in it, but it was a little hairy running through the woods at 100+mph and I suck at driving. Still won vintage class and was at the top of the pack with street tires where everyone else was running slicks.  Overall a very fun event.

https://youtu.be/omyViByjj5o

https://i.imgur.com/BvVBtsN.jpg

https://i.imgur.com/6sEAC5y.png

https://i.imgur.com/WTlJ6uY.png

https://i.imgur.com/WFBoGYz.jpg

Team Pacific Motors - 1977 Rolls Royce Silver Wraith

2018 Where the Elite Meet to Cheat - Organizer's Choice Award
2019 Rust Belt GP - Spirit of Entropy Award

Re: I bought a Rolls Royce and want to build it.

I love this shot!

https://i.imgur.com/WFBoGYz.jpg

Re: I bought a Rolls Royce and want to build it.

Congrats on the win.


And god damn I need that steering wheel in my life.

20+ Time Loser FutilityMotorsport
Turbo Dodge Powered E36 Build
2008 Saab 9-5Aero Wagon
Retired - 1989 Dodge Daytona Shelby 2011-2015 "Lifetime Award for Lack of Achievement" IOE, 3X I got screwed, Organizer's Choice

Re: I bought a Rolls Royce and want to build it.

Badass

Homestead Chump 5th-Sebring 6th-PBIR Lemons 9th - Charlotte Chump  CrashnBurn 9th
Sebring 6th again -NOLA Chump 1st -PBIR Chump Trans Fail 16th
Daytona 11th - Sebring 6th - Atlanta Motor Speedway 2nd - Road Atlanta Trans Fail 61st-Road Atlanta 5th
Daytona 13th - Charlotte 9th - Sebring 2nd-Charlotte 25th broken brakes - Road Atlanta 14 10th-Daytona 14  58th- Humid TT 19th Judges' Choice!

769

Re: I bought a Rolls Royce and want to build it.

darkostoj wrote:

Hey guys, something strange happened.

We got a trophy for winning something, and not sucking the most like the last 2 trophies.

Ran the Autoweek Empire Hill climb in Michigan. There was a lot left in it, but it was a little hairy running through the woods at 100+mph and I suck at driving. Still won vintage class and was at the top of the pack with street tires where everyone else was running slicks.  Overall a very fun event.

I think the universe is trying to tell you to stick to events that are 25s or shorter in duration. Have you taken it to the drag strip yet? (-;

seriously though, nice work!!!

"THE WONDERMENT CONSORTIUM"
Everything dies baby that's a fact,
But maybe everything that dies someday comes back?