Man, I really need to get my GT500 manifolds done............
For the Guys who run a 4L + blower
- Thread starter Fast Willy
- Start date
Yes. The question is "is it worth it". A 15gal tank represents a pretty large heat transfer area. So it will cool the water in it. And obviously you have a much larger body of water so it will take considerably longer to heat that up. But, you're talking about approx 110lb of water/tank. You don't want to haul that around.
This statement is backwards
The surface area-to-volume ratio goes down as the capacity of the reservoir increases (a fat guy will take longer to cool down than a skinny guy). Locating a reservoir in the trunk (especially on a hot day) gets no constant air flow replacing the heated air inside the trunk aggravating the situation further. An HE does the opposite and is designed to maximize the surface area while minimizing the volume to ensure efficient heat transfer. Water soaks-up heat like a sponge but has a hard time getting rid of it. A reservoir only makes sense for drag racing where it can get filled with ice between runs but I would add a switch to turn the pump off so it doesn't melt the ice before launch which will be melted at the end of the 1/4 mile. On a street car I can't think of any justification for a large reservoir all it does is add weigh.
Pretty sure he meant 15 gallons will store more heat than 5 gallons. No need to go more than 5 gallon. That is enough ice storage for the guys using it that way without carrying to much weight.
Do the math. The volume to surface area ratio between a 1gal and 15gal tank are nearly identical. Heat will transfer at the same rate.
No one is putting 1gal tanks in the trunk, they run them under the hood. Underhood temps are a LOT higher than the trunk temps. You will get faster/more heat transfer with a trunk tank. And you need to account for the heat transfer by the lines that travel to the trunk. If rubber lines are used, it won't be much (but more than zero). If someone were smart they would run as much of it as possible with aluminum tubing. Lots of heat transfer. Advantage, trunk tank.
Take a look at the top shelf FR500/BOSS302R and whatever the call the new S550 raodrace cars (I look at them all the time at a shop where a bunch race out of). They run the trans cooler and oil cooler(s) in the trunk. The trunks are not vented at all. These are not the sorts of cars that are set up wrong.
This example holds up if one very important thing is taking place. The heat exchanger has to be able to shed heat as fast as it's getting it. And aside from a few of the combo's I've done, that never happens. In all other situations the water temp coming out of the heat exchanger (post cooling) goes up and up and up. If the heat exchanger can't shed the heat fast enough the only way to improve that is to move the water faster (I know, I know, it doesn't make sense on the surface, but this is a thing) and/or have a larger volume of water to work with. The larger volume of water will delay the time it takes to get to "heat soak".
False
I never said they make sense.
Well I have a currently great running '14 GT500 making 965rwhp with a ported/welded/Bigun cooler with 2 stock Pierburg pumps (one each side of system) and 8G trunk tank.Man, I really need to get my GT500 manifolds done............
It's getting the TVS2650 and a fuel system right now for possibly 1100rwhp.
I'm less than an hour from you if you're seriously able to get one ready to install by April.
-J
I have spent more time reading this thread than watching porn on tumblr. The problem is sqidd, biminilx and weatherman are so intelligent. Me so dumb. Now I know people felt talking to Euclid so many years ago.
I know heat is bad. Planned on bigger heat exchanger with triple pass fans. After that, unsure. Guess I will reread again for ideas and let tumblr wait. Maybe I can ship my car to sqidd or biminilx.
I know heat is bad. Planned on bigger heat exchanger with triple pass fans. After that, unsure. Guess I will reread again for ideas and let tumblr wait. Maybe I can ship my car to sqidd or biminilx.
Are you saying a 15 gal reservoir has 15 X's the surface area as a 1 gallon reservoir?
I did the math
A 15 gallon 6 sided tank has 5.431 x the surface are of a 1 gallon 6 sided tank meaning a 1 gallon tank has almost 3 times the surface area per unit of volume as a 15 gallon tank. It's not linear as you suggested. That ratio gets even wider the greater the volume differential.
When the car is moving the underhood temps aren't much higher than ambient. Inside the trunk it won't matter if the car is moving or not the heat is not vented out of the trunk. Agree about loss using long aluminum lines.
That's because there is no other place to fit a diff cooler and even if they could there will be little to no airflow in the undercarriage at the rear of the car which is getting a constant flow of heated air from the engine, transmission and exhaust. If they are not providing any means of forcing a constant supply of cool air thru the HE located in an unvented trunk they are wasting their time. I don't think any professional race car builder would even attempt to argue what I stated here is wrong.
Agree, it will take longer to heat a higher volume of water. It will also take longer the cool a larger volume of water. Nothing gained here. With an IC the system is only heat loaded during boost where a low volume of water will cool faster allowing the system to recover faster for the next heat cycle. With a large reservoir of water it needs to cool both the IC and all that volume of liquid. On a street car the plastic factory "burp tank" won't act as a heat reservoir
Keep in mind the faster you move the water thru the HE, the less time it spends in the cooler to shed the heat. This is a bit of a balancing act.
I think this has more to do with the level of heat water can absorb and how slowly it gets transferred to the air which is what I was getting at. The delta between boosted air passing thru the IC vs. ambient passing thru the HE is quite high which is why the HE is so much larger than the IC. I've heard of guys spraying water thru the HE which makes it much more efficient but that will make a mess.
I never said they make sense.
I've never heard a convicting argument what benefit a large "in-trunk" reservoir provides with respect to cooling.
I applaud your design efforts with the lower intake I think that should be fairly effective reducing IAT2 temps. The trunk mounted reservoir with long aluminum lines and to a lesser degree the surface area of a large reservoir itself will shed heat but the fact its located in the trunk plus the large volume of water stored inside will greatly diminish it's ability to cool the system further. The best solution here is a larger HE and a more efficient IC system like the one you designed. A large reservoir in a sealed trunk used to cool the fluid doesn't make much sense which appears to be something we both agree on based on what you stated above.
Good debate!
side note: I would add some stiffening ribs to your polymer lower. Large flat surfaces are not every stiff it's likely it will bulge at every boost cycle. That and lots of heat cycles will likely fatigue the lower which could burst over time. That's what I was getting at when I made my inquiry but didn't get a response.
I take that as a compliment
You're on SVTP and I hope you have an SVT vehicle so you therefor have above avg intelligence sir.
I'm definitely interested in seeing what squidd can come up with, I don't play around. You want a test car I'm 30 min south. Last time we were going to meet up I blew my OPGs testing for NMCA.
Cars built now and ready to rock. Just went 10.009@145
-J
Balls! I went through that too fast and screwed up. You're correct. The 1gal tank has a volume to surface area ratio of 1:1. The 15gal tank has a volume to surface area ratio of 2.5:1. Oops!
As for the rest, I just don't have the time to get into it any deeper. Good stuff though!
No biggie, I've been known to fudge a few details here and there and appreciate it when someone points out I took an improper turn.
I'm more interested in seeing the finished results on that intake keep up the good work.
Does a Killer Chiller have any place in this discussion? I believe it can produce below-ambient IAT's without running any complicated plumbing to the trunk. I have no personal experience with this system, I'm just repeating what I have read. I have no personal axe to grind whatsoever, so please don't all pile in on me 
.
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I spent years doing testing of cooling system components on S197's. Almost all of it with a 12-channel data acquisition system. One channel dedicated to underhood temp. The only time I have ever seen an underhood temp within 10deg of ambient was with a Tiger Racing hood and moving above 50mph. Running a stock GT500 hood had underhood temps no lower than 100deg. With highs reaching 175deg.
False. When they come from Ford the diff and trans coolers are mounted under the car where the fuel tank used to be.
There is plenty of airflow under the car. Lots of race cars run the coolers on the bottom. There is certainly more airflow than in the trunk. Which is where they move them to. They move them for a reason.
I'm talking about top level race winning race cars built by a race shop? Cars that are anywhere from $140,000-350,000. These are not playtime cars. I'm guessing since they mount them in the trunk, they would argue what you stated is wrong.
If you want to let's say run the car wide open for a mile and the heat exchanger can't keep up there is absolutely something to be gained by a reservoir of water. You will have more time under boost before the body of water is at a temperature too high to be effective. You have less time that you can run WOT before a smaller or no tank gets to an ineffective water temp. Yes, it may take longer to cool that volume of water. But if you're no longer at WOT, you have that time.
I’ll restate though. I’m not a fan of tanks unless they have ice in them.
False. If the air in the intake manifold is hotter than the water going through the IC then the IC will spend its cooling capacity cooling that air. The air in the intake manifold is not ambient. Even when cruising. The IC also cools the body of the intake manifold/blower because they all contact each other.
The only way your theory hold water is if the air in the manifold and the manifold body itself are at ambient (or slightly above). And that is far from reality. You're looking at a minimum of a 30deg delta for the air and a 80deg delta for the manifold body.
You're looking at this as first order effect only. You haven't taken into account the multitude of other effects/situations that take place in a cooling system.
Actually no. It's always more beneficial to move the water faster though the system. I know this is hard to get your head around, it took me a while, and some schooling by a thermal engineer. The heat exchanger becomes more efficient as the water temp in it rises. It's all about heat transfer rates.
I do agree you want to stuff as much heat exchanger in the car as possible first (more time spent cooling). But after you have maxed out the available space the only way to improve the system performance is to move the water faster.
There is a point where you can move the water faster than you need too but there is no such thing as moving it too fast. All the way up to infinity will show heat transfer gains. But from a practical standpoint you don't need to move the water faster than it needs to go to remove all the heat it absorbs at the IC. You can't get a pump that will run faster than that (not even close) though, so it's a moot point.
It's really quite simple. You run the biggest heat exchanger you can stuff in the car. Then you put the highest flowing pump you can. You will still be short of the "perfect" cooling capability. Ok, that's not necessarily true. It depends on how much boost you're playing with. At 10psi the stuff I have been doing keeps up no matter how long you stay in the gas. After about 20sec the IAT's plane out and don't get higher. System equilibrium. So there is enough heat exchanger and water speed to get the job done. I don't know how well the system works at 25psi because no one has run one long enough to see what happens over the long run. This gets back to the heat over time thing.
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