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Posted: Feb 11, 2006 9:21 PM
by Duke
Believe it or not, had this idea in a dream last night, kind pathetic huh.
I plan in moving my battery to the under the rear seat and was wondering what I would do with the battery box in the engine compartment.
What about this. Mount two heat exchangers in parallel in the battery box. I would have to cut the front of the box out and then the back for air flow. Make some kind on ducting to channel air to the front of the box. To complete it, make a cover with a rubber seal that I can seal the top of the box and thus keep from engine compartment heat. Because I have only one heat exchanger mounted at this time, I would increase my heat exchanger area by 200% with the additional fluid too.
So, what do yall think?
Posted: Feb 11, 2006 9:42 PM
by smackmybutter535i
Anything to run your beast cooler. I think it's pretty trick, won't hurt to try
Posted: Feb 11, 2006 10:38 PM
by russc
That fine, I would run it before the W/A IC. that way your pre-cooling to that device, since it has much higher capacity.
Insulation can help also, so a shrould is in order.
RussC
Posted: Feb 12, 2006 3:41 AM
by Yellow2
I have my IC piped where the 745i air system has it. its the opposite side on the e28. i have a duct piping cold air towards it through the front air dam. I think with the battery hole closed off and insulated, a set of heat exchangers would work very well for cooling anything from an automatic transmission to other oil coolers. good luck
Posted: Feb 12, 2006 4:45 AM
by Merkin
Why not mount the battery in the trunk instead of under the rear seat? It seems like it'd help even more with weight distrobution.
Posted: Feb 12, 2006 6:56 AM
by Rich Euro M5
[QUOTE="Duke M535ti Backup"]Believe it or not, had this idea in a dream last night, kind pathetic huh.
I plan in moving my battery to the under the rear seat and was wondering what I would do with the battery box in the engine compartment.
What about this. Mount two heat exchangers in parallel in the battery box. I would have to cut the front of the box out and then the back for air flow. Make some kind on ducting to channel air to the front of the box. To complete it, make a cover with a rubber seal that I can seal the top of the box and thus keep from engine compartment heat. Because I have only one heat exchanger mounted at this time, I would increase my heat exchanger area by 200% with the additional fluid too.
So, what do yall think?[/QUOTE]
You're close but there's a more elegent solution that you haven't thought of and it doesn't require cutting the radiator support which is a structural member. Cut the floor of the battery box area out and build a custom box with a NACA duct input to channel air from the roof of the brake ducts UP through your heat exchangers and dump it out through new openings in the front sides of the inner fenderwells. I'm sure Shawn D. would help you out with the math on the NACA duct configuration / size and intake/exit sizes to maximize airflow. There's nothing that really prevents you from doing the same on the right side of the car for intake air for the engine with an additional box on the exit side for another heat exchanger. Since you have an aftermarket A/C I don't recall if your A/C receiver/dryer is mounted up front by the the ABS unit. I'd move the A/C dryer and cut the floor out, fabricating bracketry to support the ABS unit, leaving it in place.The engine can only use what it needs for intake air even at full boogey, excess air actually can become a form of DRAG if it doesn't have a way out of a tightly sealed box. If you design the airbox to have excess flow you can mount another heat exchnager in the back / exit side of this box.
Man you're an Aviator and have access to look at how this stufff is done on a Apache. Talk to the crewchiefs I bet they'll let you take a look at how air is ducted through the Apache and any other aircraft you can get up close to. Dont forget to look at the remains of Sadaam's Air Force for ideas.
There's HUGE room inside of the engine bay of the E28 compared to what aIrcraft designers have to work with. USE IT !!!
Rich
P.S. If you want ideas about how to do this without the HUGE expense of fabicating from sheet aluminum let me know. I have made some very complex shapes using composites for my scale R/C Warbirds and it's not hard to do.
[Edit by Euro M88 on [TIME]1139745533[/TIME]]
[Edit by Euro M88 on [TIME]1139746851[/TIME]]
Posted: Feb 12, 2006 10:58 AM
by Steve in No Va
Unfortunately, I too have dreamed about this issue. My idea goes in a different direction. The battery box is water tight isn't it? Why not put a drain plug in it that has a hose going thought the floor of the trunk. Then have an input pipe come in at the top of one side, going into a small heat exchanger and out the other side. Wrap the outside of the box in insulative material like styrofoam. When you need extra power, go to 7-11 an buy an 8 lb bag of ice and dump it in. When it becomes warm water, pull the plub at the bottom of the box and let it drain out. SImple way to super cool the liquid, leaving the original heat exchanger where it is. I would route the intercooler liquid to the front heat exchanger first. Even if you don't have ice in the box, the extra distance would cool the water further. It may help to insulate the return line from the box to the intercooler also.
Posted: Feb 12, 2006 12:25 PM
by Shawn D.
[QUOTE="Merkin"]Why not mount the battery in the trunk instead of under the rear seat? It seems like it'd help even more with weight distrobution.[/QUOTE]
He doesn't want it in the trunk since he's already got stereo equipment and an Alpina auxiliary gas tank in there (see his CarDomain site for details).
[QUOTE="Steve in No Va"]The battery box is water tight isn't it? Why not put a drain plug in it that has a hose going thought the floor of the trunk.[/QUOTE]
Again, he isn't going to be putting one in the trunk. Anyhow, the ice would be no good for sustained running, and "cool cans" are used to cool fuel, not intercooler juice which has much more total heat in it -- the ice would be gone lickety-split.
[QUOTE="Duke M535ti Backup"]I plan in moving my battery to the under the rear seat and was wondering what I would do with the battery box in the engine compartment.
What about this. Mount two heat exchangers in parallel in the battery box. I would have to cut the front of the box out and then the back for air flow. Make some kind on ducting to channel air to the front of the box. To complete it, make a cover with a rubber seal that I can seal the top of the box and thus keep from engine compartment heat. Because I have only one heat exchanger mounted at this time, I would increase my heat exchanger area by 200% with the additional fluid too.[/QUOTE]
[QUOTE="Euro M88"]You're close but there's a more elegent solution that you haven't thought of and it doesn't require cutting the radiator support which is a structural member. Cut the floor of the battery box area out and build a custom box with a NACA duct input to channel air from the roof of the brake ducts UP through your heat exchangers and dump it out through new openings in the front sides of the inner fenderwells. I'm sure Shawn D. would help you out with the math on the NACA duct configuration / size and intake/exit sizes to maximize airflow.[/QUOTE]
The inner fenderwells are structural members as well, and I wouldn't cut them. I also wouldn't put a NACA duct in, as I doubt Duke wants to mount one on his external body panels; a NACA duct is a recessed, ogival-shaped intake -- every other type of duct that's called a "NACA duct" is a misnomer:
I've already thought of this if/when I go to a turbo and want to mount an oil cooler -- I don't want to cut out the slots in my Euro M5 spoiler, so I figured out a different location than in the middle bottom of the valance. Your heat exchangers will work with this concept as well. The inlet will be the hole behind the headlights and the cut out at the bottom of the battery box will be the outlet; you do not need a duct cross-section that equals the frontal area of your heat exchangers -- even 1/2 will do, so there's no need to cut the panel around the headlights. The headlight inlet is in a high-pressure area, and the outlet dumps into the area above the valance and forward of the wheel, which
should be a lower-pressure area.
For cooling when stopped, an electric fan (as used on many aftermarket tranny coolers) would work.
Mounting a single larger heat exchanger at an angle would be a better idea than using two smaller ones; you'd mount it at about a 45-degree angle, leaned back like a Corvette radiator. Not only would this allow a larger exhanger, its placement would help the air turn the corner.
What do you think about this?
Posted: Feb 12, 2006 1:16 PM
by Steve in No Va
Sorry, I thought he already relocated the battery to a box in the truck like an M5. How hot does the liquid get in the system? I was thinking in this direction based on Todd's track tank idea. I figured if your going to the trouble of putting an extra tank in the trunk, why not have the ability to put ice around it by placing it in an insulated box. I never expected it to be a long term solution, although I did expect it would last 20 minutes to 1/2 hour before losing all cooling ability. I gues I based this on the assumption that a track tank in the trunk wouldn't get too hot, or else it may cause you problems in the rear, like unnecessarily warming your fuel tank that is right under the trunk.
Posted: Feb 12, 2006 1:36 PM
by Shawn D.
[QUOTE="Steve in No Va"]How hot does the liquid get in the system? I was thinking in this direction based on Todd's track tank idea. I figured if your going to the trouble of putting an extra tank in the trunk, why not have the ability to put ice around it by placing it in an insulated box. I never expected it to be a long term solution, although I did expect it would last 20 minutes to 1/2 hour before losing all cooling ability. I gues I based this on the assumption that a track tank in the trunk wouldn't get too hot, or else it may cause you problems in the rear, like unnecessarily warming your fuel tank that is right under the trunk.[/QUOTE]
There's no way the ice would last that long, and once it's gone, it's gone. The "track tank" adds reserve capacity to smooth the peaks and valleys of the fluid temperature, caused during high power output and low power output periods. The tank itself doesn't do any cooling.
Think of it this way -- you have a large pot full of water and a small saucepan full of water, both at the same temperature. You turn a burner on below each of them, at the same temperature and the same duration (i.e. you input the same amount of heat). Which one will have the greater increase in temperature? The small saucepan. Now, put an ice pack up against each one for the same amount of time. Which will have the greater drop in temperature? The small saucepan. While the same amount of heating and cooling is done to both, the large pot has a more stable temperature. While both pots will eventually boil if you heat them long enough, the small one will get there much sooner; the large pot can go longer before it's at the boiling point. That's the idea of a "track tank" -- moderating the temperature swings and having a reserve of cool(er) fluid when you need it.
Posted: Feb 13, 2006 12:31 AM
by Duke
Thanks guys for your additions to my idea. I like Shawn's idea on the air entry from the headlight down thru the heat exchanger mounted diagonally in the battery box and out the bottom. Due to the front M-Tech kit, the bottom on the battery box is shielded from the elements so this will work out nicely. Now as Rich suggested, I need to get with my airframe sheet metal guys in order to build ducting from the back of the headlight to the top of the battery box.
I am thinking of maybe a pull thru fan mounted on the bottom side of the HE for low speed air flow.
Now we are cookin!
Posted: Feb 13, 2006 6:32 AM
by Rich Euro M5
The inner fenderwells are structural members as well, and I wouldn't cut them. I also wouldn't put a NACA duct in, as I doubt Duke wants to mount one on his external body panels; a NACA duct is a recessed, ogival-shaped intake -- every other type of duct that's called a "NACA duct" is a misnomer:
I wasn't talking about putting these in the body sheet metal. If you look at how the Brake Ducts route in the M535i, IIRC they are right under the battery box area. There's a lot of air passing through those ducts and I was thinking why not put a NACA duct on the roof of the duct, it would be out of plain view, you'd have to look up inside the duct to see it.
About the fender wells, I wasn't advocating cutting them fully away, just an opening large enough to provide an adequete exit for the heat exchangers. If need be, reinforce the exit and design the cold air box to support some of the load. One problem that did cross my mind. Would the tires rotating in the fenderwells have a negative impact on the flow ?
Your idea about feedng from the front and going out the bottom is simpler and more elegant.
Rich
[Edit by Euro M88 on [TIME]1139830812[/TIME]]
[Edit by Euro M88 on [TIME]1139831004[/TIME]]
Posted: Feb 13, 2006 9:02 AM
by Shawn D.
[QUOTE="Euro M88"]I wasn't talking about putting these in the body sheet metal. If you look at how the Brake Ducts route in the M535i, IIRC they are right under the battery box area. There's a lot of air passing through those ducts and I was thinking why not put a NACA duct on the roof of the duct, it would be out of plain view, you'd have to look up inside the duct to see it.
About the fender wells, I wasn't advocating cutting them fully away, just an opening large enough to provide an adequete exit for the heat exchangers. If need be, reinforce the exit and design the cold air box to support some of the load. One problem that did cross my mind. Would the tires rotating in the fenderwells have a negative impact on the flow ?
Your idea about feedng from the front and going out the bottom is simpler and more elegant.[/QUOTE]
Ah, I gotcha on your NACA duct idea.
As to the exit flow for your fenderwell concept being impeded by the air flow caused by the tires, it might be enhanced if you had downward-facing louvers that would develop vacuum due to being on the lee side of the flow.
Thanks for the compliment on my concept!
Posted: Feb 13, 2006 11:03 AM
by Rich Euro M5
Ah, I gotcha on your NACA duct idea.
As to the exit flow for your fenderwell concept being impeded by the air flow caused by the tires, it might be enhanced if you had downward-facing louvers that would develop vacuum due to being on the lee side of the flow.
Thanks for the compliment on my concept!
I guess I wasn't excatly clear about my thoughts regarding the NACA ducts in the original post. Writing is an art as you well know.
I gave some thought to the wheelwell problem and also thought about Louvers and Augmenters, but the problem is added cost / complexity.
Compliments should come to those, especially engineers, that apply the KISS principle to problem solving.
It's a rare trait in some engineering circles.
I still think Duke should consider learning how to work with composites. But if he did we might have a new monster on our hands. Just think of all the CF Bling he'd end up in the engine bay if he could mold his own stuff. ~0
Rich