I plan on tracking my e28. Our systems water capacity with a small reservoir is 1.25 gallons. Certainly adequate for the street and dragstrip. Probably OK for driving schools too but I wanted to be sure.

This reservoir is 6" in diameter and 32" long. It's designed to fit between the fender wells in the trunk of an e30 or e28. Capacity is about 6.5 gallons.

TCD Reservoir (http://groups.msn.com/_Secure/0RwAwA1IS12B2zQWd6omgaRfr!rUVlCKoekFDAMy8oBpRJeStB OdH2aqCSdx6lfwUoI!RgdG1sJOgSboNvqkRVaSpIe9VliDaPJC lIy4taJU/P1020115.JPG?dc=4675524984144212363)

Todd

Nice, I wish I had that room. I put in one that is 4" X 11" in my bumper, 2.3 quarts capacity.


I am jealous.

JMC

hawtness! so where does the reservior go on my e34?

How would resevoir capacity help with heat soak in a track situation??

How would resevoir capacity help with heat soak in a track situation??

M, didn't you know bigger is always better? :rolleyes

How would resevoir capacity help with heat soak in a track situation??

It will take 7.5 gallons of water much longer to become heat soaked than 1.25 gallons.
Todd

hawtness! so where does the reservior go on my e34?
Behind the driver's side headlights.

It will take 7.5 gallons of water much longer to become heat soaked than 1.25 gallons.
Todd

http://forums.bimmerforums.com/forum/showpost.php?p=4299501&postcount=15

http://forums.bimmerforums.com/forum/showpost.php?p=4299501&postcount=15

Exactly. You restated the obvious.

"and resevoir capacity at that point does nothing. (well, nothing besides determine how long it takes to get to equilibrium.)"

What part are you not understanding?

Exactly. You restated the obvious.

"and resevoir capacity at that point does nothing. (well, nothing besides determine how long it takes to get to equilibrium.)"

What part are you not understanding?

You have done nothing to prevent heat soak, and nothing to reduce IAT. Though you did find a very pretty way to add a bit of weight. ;)

You have done nothing to prevent heat soak, and nothing to reduce IAT. Though you did find a very pretty way to add a bit of weight. ;)

Dude, you are whacked. :eek:

What takes longer to boil on the stove? 1.25 gallons or 7.5 gallons? Think about it.

Dude, you are whacked. :eek:

What takes longer to boil on the stove? 1.25 gallons or 7.5 gallons? Think about it.


If you read that post, I think hes saying that, for a drag car, that makes a short explosive pass, you dont even need a heat exchanger if you have a big reservoir, because the res will provide all the cool water the system can use in the single pass, before it heats.

And, at the track you have the opposite condition, where a large heat exchanger that is constantly recycling the water via the pump is more than adequate to prevent a general warmup.

A key phrase in that post is, "Any additional volume in stop and go will just be that much more you have to cool off once you start to *go* again. On the track, at some point the temperature of the system will reach equilibrium, and resevoir capacity at that point does nothing. (well, nothing besides determine how long it takes to get to equilibrium.)" .

I dont think you can summarily dismiss this. Certainly, not without some testing. I think there are some interesting points contained therein. ie, adding a big reservoir doesnt necessarily, automatically, assist the ability of the system as a whole, under a given set of driving conditions, to stay cool.

Dude, you are whacked. :eek:

What takes longer to boil on the stove? 1.25 gallons or 7.5 gallons? Think about it.

Analogy time:

This is true as long as you turn down the stove (boost) before the 7 gallon water boils. You can be playing around longer. The water reserve will cool during boost down time, which for a street car is a lot.

This gives more heat absorbing capaity..

just like big brake kits does for rotors

or

1 Farad capacitor for stereo amps....

the point being, you can handle more high load (heat) spikes when it comes and recover when there is low load.

Where do u get one of these?

The point here, which I have made in the past is that the amount of time that a huge reservoir will add until you hit heat soak under heavy load conditions, will be measured in seconds, or at most a minute or so. On the street, that might make a huge difference if your system is poorly engineered and does not have an appropriately sized heat exchanger.

However, on a road course, you will likely get perhaps a single added lap before it heat soaks with a large reservoir vs a small one. So, yes it DOES delay reaching equilibrium, but not by a whole lot, and not at ALL in a properly designed system. In that case, all it does is add weight IMHO...

Hence, I think this will work well on a street driven machine....specially on those hiway speed runs.....

Whay you really need is a bigger heat exchnager....that automatically means more fluid...

That's kinda my point. Rather than spending time and money on a big honkin reservoir, spend your time and money on a big honkin efficient heat exchanger. Kills 2 birds with one stone, and more effectively...

Steve

The point here, which I have made in the past is that the amount of time that a huge reservoir will add until you hit heat soak under heavy load conditions, will be measured in seconds, or at most a minute or so. On the street, that might make a huge difference if your system is poorly engineered and does not have an appropriately sized heat exchanger.

However, on a road course, you will likely get perhaps a single added lap before it heat soaks with a large reservoir vs a small one. So, yes it DOES delay reaching equilibrium, but not by a whole lot, and not at ALL in a properly designed system. In that case, all it does is add weight IMHO...

Not by a whole lot? I just cannot follow your reasoning. How does it not delay reacing equalibrium in a properly designed system? What is a properly designed system.?

I think any conjecture at this point is useless! Actually testing is all that counts. I have a pre intercooler and post intercooler air temp sensor. I'll report actual findings once I hit the track.

FYI, my car uses a 12x12x1.5" heat exchanger mounted behind the kidney and in front of the radiator. I can easily double it's size if necessary.

Todd

That's kinda my point. Rather than spending time and money on a big honkin reservoir, spend your time and money on a big honkin efficient heat exchanger. Kills 2 birds with one stone, and more effectively...

Steve

The heat exchanger adds hardly any fluid capacity to the system.

Analogy time:

This is true as long as you turn down the stove (boost) before the 7 gallon water boils. You can be playing around longer. The water reserve will cool during boost down time, which for a street car is a lot.

This gives more heat absorbing capaity..

just like big brake kits does for rotors

or

1 Farad capacitor for stereo amps....

the point being, you can handle more high load (heat) spikes when it comes and recover when there is low load.

Where do u get one of these?


Shoot me an email at tcd@turbochargingdynamics.com
Todd

Todd,

I drove my twin screwed car around for a year with pre/post intercooler Air AND water temp sensors. I had NO reservoir, and very small water capacity. I never saw any signs of heat sock, temps were always stable once the car had warmed up, and the IATs were simply a function of boost/load and outside air temp.

My system runs with a pump that moves about 5 gpm. So, add a few gallons of capacity, and you get less than a minute of added delay under reasonably steady state loading.

No conjecture, just engineering fact. The calculations are quite simple.

If your front heat exchanger is sized such that it can REJECT more heat than your charge air heat exchanger can ACCEPT, then the reservoir does NOTHING other than add weight...

Steve

If your front heat exchanger is sized such that it can REJECT more heat than your charge air heat exchanger can ACCEPT, then the reservoir does NOTHING other than add weight...

Steve


I agree 100 %

Dude, you are whacked. :eek:

What takes longer to boil on the stove? 1.25 gallons or 7.5 gallons? Think about it.

Did ya year that? Yeah, it just flew right past you... ;)

Lets try again... this way. Lets look at the components of the system and what they do. The *intercooler* side of the heat exchanging system takes heat energy and dumps it into water. What does the water in the resevoir DO? It can't get rid of heat, it can only store it. Now in the heat exhanger, water can get rid of heat. So if the water system has only the capacity of the heat exchangers (IC and radiator), then it will reach equilibrium very quickly. If you add to that capacity, you change the time to equilibrium temperature, but not the equilibrium temperature itself. If you want to lower the equilibrium temperature of the system, you either need to put less heat in, or take more heat out. Resevoir does neither. More efficient radiator does the latter.

Moral of the story? more capacity in the resevoir only delays the inevitable from a cool start. It also prolongs heat soak from a hot stop.
If resevoir capacity was the answer, you probably asked the wrong question.

I think any conjecture at this point is useless! Actually testing is all that counts. I have a pre intercooler and post intercooler air temp sensor. I'll report actual findings once I hit the track.
I have no idea how a water to air system will react on the track... my only experience with the stuff was on a turbocharged LeMans prototype. ;)

I agree 100 %

Hee hee, might have to mark this day on my Calendar!!

:lol

Techno550 also makes a very valid point about the time to "un" soak the system when you are stopped/idling/parked, etc.

Steve

Hee hee, might have to mark this day on my Calendar!!

:lol

Techno550 also makes a very valid point about the time to "un" soak the system when you are stopped/idling/parked, etc.

Steve

LOL, I said that myself.