Toms RCR 40 Trackracer

[EGLITOM]

Chuck

took your advice and made it smaller. Not much but about 25 %.
I also set the expansion tank higher.
The bright tape and red line is marking the top of the thermostat housing level. The volume above is app 1,3 liter the volume below this level is 2 liter.
I won´t use a recovery tank so i designed the expansion tank in a way which enable it to fully cover the expansion without overflow.
I calculate a total water volume of around 14 liter ( 3,6 gls) ( including the 2 liters in the expansion tank). If one assume a expansion rate of 8 % ( which is a lot and i think a save assumption) the 1, liter expansion room should be ok.
Pressure cap will be a 21 PSI Stanton race cap ( I have not yet found one with lower pressure rating and the release lever).
Well that´s the theory, If you specialists out there could confirm or deny that this is correct i would very much appreciate.

Thanks
TOM

 

[Chuck]

Wow. 21 pound radiator cap? I used a 13 pound stat with the red release lever. I guess if you have any leaks they will show up pretty quick.

The smaller tank looks better. For comparison, we used a 1.5 quart expansion tank and a 2 quart recovery tank. A one quart recover tank would probably have sufficed, so your 3.3 liter design should be fine. All that space above the level of the thermostat housing is also good.

 

[EGLITOM]

Chuck

Just wondering how the radiator caps are rated.
13 pounds = 13 psi correct ? if so this would be slight vacuum situation. So it is probably 13 psi overpressure and thats a lot.

My cap has a pressure rating of absolut 1,4 bar = 20 psi , therefore i assume it has an overpressure of 0,4 bar = 6 PSI.

So something is strange here. May be one can explain

Thanks
TOM

 

[David Morton]

As far as I know, the number printed on the radiator cap number is the pressure it can withstand in psi before the inbuilt spring compresses and allows steam / water to escape. If it says 21 then it will be approx 21psi when it operates. The merit of such a high pressure as 21 is lost on me and systems that are functional and not blocked can often run without a cap (as a get you home back up). Surely a serviceable system with no leaks or air blockages and a good pump will only need a nominal poundage on a radiator cap ? Does anybody know why high pressure caps can have any merits or benefits?

 

[EGLITOM]

Just talked to the tech guy of my supplier ( dealer for STANT in germany).

He states that the rating on the pressure cap telling the overpressure value.
So in case of a 13 psi cap we talk about absoltu pressure of 27 psi ( which makes sense somehowe because a absolut pressure of 13 psi would be a vacuum)

Nevertheless i totaly agree with David. A system should be designed to achieve a watertemp of 85 to 90°C in every load situation. This is the ideal case, as we all know there are load situations that will raise this temp to a higher level. This higher level requires a higher pressure rated cap to avoid steam building up in the system.

The following table shows the pressure in relation to the temperature.

Temp.(°C) p(bar) Hfl.(kJ/kg) DeltaHV(kJ/kg)
=============================================
0 --------0,0061 --0,00 ----2500,5
5 --------0,0087 --21,05 ---2488,6
10 -------0,0123 --42,03 ---2476,9
15-- -----0,0170-- 62,96--- 2465,1
20 -------0,0234 --83,86 ---2453,4
25 -------0,0317 --104,74--- 2441,7
30 -------0,0424-- 125,61 --2429,9
40 -------0,0737 --167,34 --2406,2
50 -------0,1233 --209,11-- 2382,2
60 -------0,1992 --250,91-- 2357,9
70-- -----0,3116-- 292,78-- 2333,1
80-- -----0,4736-- 334,72 --2307,8
90------- 0,7011 --376,75 --2268,8
100 ------1,0132-- 418,88-- 2255,5
110-------1,4326 --461,13-- 2228,5
120 ------1,9853 --503,5 ---2200,7

it is clearly to see, to have some safety in the system against steam building you would need a pressure cap rated at least to the above mentioned 13 psi ( absolut pressure is 27 psi = 1,9 bar) which gives you a window up to 120° C.

120°C should not be any issue to the euipment in terms of temperature, but one should make shure his system ( radiator , lines, gaskets, tanks ) can withstand at least 2,5 bar (36 psi).

Does this makes sense ?

Also if someone knows anyone at STANT he could call an verify the stated above.

I will order a 13 psi cap for mine for a start. If anyone knows of a lower rated one ( 7 psi)
please tell me

TOM

 

[EGLITOM]

OIL COLLERS MOCK UP

I mocked up my oil coolers setup today.

For the engine i took a 25 row setrab pro line cooler. It will be connected to an external oil filter with AN 12 lines. I have choosen to mount it verticaly. This gives a nice hose routing, no issue with air pockets and gives a nice usage of the rear clip outlet openings.

THe gearbox cooler is a 19 row ( i know it´s plenty) connected to the gearbox via AN 8 lines. THe pump is a MOCAL membran type pump. THis cooler will be mounted vertical as well.

Engine cooler

Trans cooler

Opinions ? Comments ( except " get yourself a new camera, i know this thing KONICA DIMAGE X31 is a POS).

TOM

 

[Jac Mac]

Raising the pressure the system runs at increases the temp at which the coolant will boil, so if you run an inhibitor or anti freeze the boiling point will be higher than just straight water. The bonus in doing this is the safety factor when localised hot-spots due to coolant flow differences or when detonation/pre-ignition occurs ( & it occurs at some point no matter how clever you might think you are ).

If it has a negative its in the possibility that your coolant pipe connections & pump seals have to be in excellent condition.

Most race stuff I have worked with is running 21 lb or 25 lb radiator caps, ----- thats effectively 25 lb plus the 14.7 lb atmospheric that Toms bringing into the discussion to confuse us with!

 

[EGLITOM]

Most race stuff I have worked with is running 21 lb or 25 lb radiator caps, ----- thats effectively 25 lb plus the 14.7 lb atmospheric that Toms bringing into the discussion to confuse us with!

Thanks Jac i love to do that,

I have both caps now 13 lbs and 18- 21 lbs. I will give both a try.
If it works ok with the 13 lbs, i will put one the other cup to have the safety in case i need it. If it already creats issues with the 13 lbs cap , under normal driving conditions, i think there is a need for fixing this first.

Thanks
TOM

 

[EGLITOM]

Expansion Tank

Follwing the mock up of it in cardboard i have a friend of mine cut the aluminium sheets in 3mm strong AlMg3. CHristian the godfather of all welders did a great job on putting it together.
It is mounted on four brackets by the use of elastic elements.

The fuel line will be heat insulated

i think it fits perfect and looks close to the original.

TOM

AWH: 630 h

 

[Jack]

Really nice fab work. Looks super!

 

[Chuck]

Tom:

Very nice. Looks original, but big enough to avoid the need for a recovery tank. I trust you will have no clearance issues with the clip. ( I had to cut a bit to get mine to clear ).

 

[Randy V]

Great fabrication Tom! I hope to be able to weld aluminum like that someday!

 

[jon elliot]

Running a cooling system at a higher temperature means that it becomes more efficient, because the amount of heat that is transferred from the water to the surrounding air is greater when the temperature difference is higher. This becomes particularly important where the engine is working hard, or where the airflow is limited by traffic etc.

 

[Russ Noble]

Hmmmmm..... I don't buy that logic.

Sure HEAT TRANSFER is more efficient at higher temperatures, but you don't want a COOLING SYSTEM running at optimum EFFICIENCY (temperature/flow) under normal conditions as there will be no residual capacity to deal with more arduous situations as in your examples of sustained WOT or slow commuter traffic.

You need cooling system INEFFICIENCY under average conditions. BUT an engine is more efficient at higher temperatures and this is usually controlled by a thermostat. But when the thermostat is restricting the flow the COOLING SYSTEM is LESS efficient because there is a reduced flow passing through it (all be it at a higher temp) and hence the engine itself runs hotter than it would otherwise. When the thermostat opens as in WOT or traffic, the system becomes MORE efficient and can (usually, but not always) cope with the extra demands.

Just because you have a high temperature under normal conditions does not mean that it will cope any better under arduous conditions in fact if there is insufficient residual capacity it will cope less well than if it was running colder initially ie without a thermostat, as that would then give you the extra cushion of getting the whole system up to temp first.

BTW Welcome to the forum Jon.

 

[JimmyMac]

Running a cooling system at a higher temperature means that it becomes more efficient, because the amount of heat that is transferred from the water to the surrounding air is greater when the temperature difference is higher. This becomes particularly important where the engine is working hard, or where the airflow is limited by traffic etc.

:stunned:

 

[Jac Mac]

:stunned:

Mullet or trout??:thumbsup:

 

[EGLITOM]

CHASSIS PAINT

I disassembled my car complety ( after having finished mocking up almost every mechanical part) in order to paint my chassis satin black.

I prepared the chassis by sanding it with a 120 grid scotchpad, than cleaned it with siliconcleaner.

than i used a acidic etchprimer which creates a good adhesion to the aluminium.

As this is live - i have just laid on the first layer of black polyurethane chassis paint ( used in industrial applications) and waiting for it to cure a little, i´m curious if i can manage to post the pics of the finished paint within the posts edit time

Yeah seems that i made it
Chassis painted black " back in black" - at least 50% of it

Won´t have time the next ten days to work on but soon after my return from my business trip i will turn it up side down ( or should i say down side down) and paint the rest of it.

AWH: 650 h

TOM

 

[EGLITOM]

CHASSIS PAINTED

I put in an allnighter yesterday ( started at 9 PM and finished at 2.30 AM) and painted the upper side of my chassis. Now it is completely painted

I´m very pleased with the result. I achieved exact the grade of satin i wished.

TOM

AWH:656 h

 

[Chuck]

Tom:

Excellent approach. Building, drilling, cutting, etc. and then dismanteling and painting is certainly the best way to go. No exposed surfaces. You keep raising the bar higher and higher . . . .

Chuck

 

[Jack]

Looks fantastic Tom, great job! Well worth the effort.