Difference between a heat exchanger and Oil cooler

Scott

Member
Lifetime Supporter
#21
Bob, are you using one or two pumps?

Joel, it would be interesting to see how they plumbed the left/right intake-manifold-char air coolers. Perhaps there is a dedicated pump/circuit for each cylinder head. My supercharger has two inputs and two outputs so I could follow a similar approach. That would add complexity, weight and cost, but the serial vs. parallel decision is mute.

Cam, it would be useful to know which statements you take issue with. I’m just trying to understand the car’s systems and build the best car that I can. I’m no expert and I haven’t done a thermo calculation in 30 years, but I’m confident in the turbulence, delta-T and dwell time statements for rational SL-C purposes. In any event, I’ve spent time/money having C&R design/fabricate a custom radiator and I’m going with an electric pump which flows less than the OEM one that it’s replacing… so, I shouldn’t have any issues with turbulence or dwell time.

I’m not sure what your point is about what happens at 1,000 gph. That’s >6x what the mechanical pump does at redline. Mach 1 is only 5x faster than a SL-C doing 150mph… do you worry about sound barrier issues when discussing aero mods?

With less confidence… it’s my understanding that the LS7 (and I assume most) mechanical pumps flow too much fluid at speed. However, rather than creating a dwell time / overheating issue, the increased flow overcools the coolant. This causes the thermostat to restrict flow to keep the engine at the target temp. This is why an electric pump which flows only 1/3 of what a mechanical pump flows at max RPM can keep the car cool. I’ve spoken with two endurance/road teams using the same electrical pump that I’m using and they have seen a max 75% duty cycle. The mechanical pump is a slave to engine RPM and to get it to flow enough at idle it overflows at speed.

I’ve always wondered if the HP gains claimed by electric water pump manufacturers were BS because converting mechanical to electrical and then doing the reverse doesn’t save power. However, if the mechanical pump is overflowing and over cooling, then it’s wasting energy fighting the thermostat. The electric pump’s ECU reduces the duty cycle in this scenario which means that the alternator does less work… and I assume that’s where the power savings come from.

If you’re referring to the one vs. two or the serial vs. parallel parts, then those are the areas that I was looking for feedback.

I’m not very familiar with the twin-turbo car, but it’s clear that it’s an air-to-water and not an air-to-air cooler. There are two turbos and two coolers. I’m not sure if there are one or two pumps/circuits. If we assume a ¾” line that’s either ½ or the same size as the line used for the engine cooling system. While the heat exchangers are angled to the air flow, they are going to get a lot of air. They are higher quality than the radiator that ships with the kit and the two of them combined are probably almost as large as the radiator. In addition, the air isn’t preheated by the condenser. My guess, it that the system works well.
 
#22
Good info Roger, mea culpa. When I was designing turbochargers 15 years ago air to water intercoolers were still somewhat in their infancy - they’ve really taken off since then. I left the world of forced induction 10 years ago and didn’t stay current with trends.

When I see “intercooler” my brain automatically defaults to air to air because that’s what I worked with back then. No way could you cool hot air with that puny radiator! (Because you’re not, duh) The FI interchiller is a real step change in cooling technology.
 
#23
Scott - my example of 1000gal/s flow rate was turning your example of stagnant airflow on forced convection cooling. If you have a system based on forced convection cooling and you eliminate the forced convection then obviously it’s not going to be very efficient. No, you’re not going to drive your car slower to improve heat transfer at the radiator because you’re eliminating the convection heat transfer.

I’m not sure how your example of quenching metal in water then waiting for it to come to room temperature applies to forced convection cooling and dwell times. I think you were trying to make a statement regarding delta-T’s importance versus dwell time?

That said, I’ll eat some crow as I had it in my head that you were talking about an air to air system and that photo just didn’t make any sense to me - until Joel reminded me that the LT4 system uses air to water cooling.

Going back to dwell time and my (mistaken) assumption that you were talking about pumping air through a liquid cooler just didn’t make sense. Bob’s reference about making sure your intercoolers are properly bled should have tipped me onto the fact that you’re discussing air to water intercoolers.

On the serial vs parallel routing, set yourself up to run both and take some measurements. Your system losses are going to be less with a parallel system and the plumbing is going to be similar since you’d be running lines across the front either way if you run 2. Put some ducts in front so you maximize your forcing function otherwise you’re not going to have enough delta-p across the intercooler, especially if it’s at a sharp angle to incoming airflow. Ok I think that’s the only useful thing I’ve got :)
 
#24
Scott,

I have a Hellcat which has a similar setup.It’s parked at my father in law’s place for the winter to make room for the SLC, but at some point I’ll get a good look at the plumbing and see if it is setup in Series or parallel. If I had to guess I would think in series, but just a guess. I’ll let you know.
 
#25
The shop that does my tuning and machine work has a few 1000HP+ CTSV customers. All using a single pump. (LSA has only one in and out) ..
On my car I have an aftermarket pump that draws from the 1gal tank. -12AN line feeds the blower. Then a -10AN "Y" tee sends hot coolant to left and right cooler. Coolant then returns back to tank. To be honest .... I am nervous it won't be enough to prevent heat soak, so I have the car set up to run E85 which will help with temps. (and a little more HP:)) ....
 
#27
Controversial is right !! I made many calls. Custom fuel cell company said it's fine ... Just don't leave it in over the winter.
They suggested run one tank of regular fuel through the car before storing for extended time. I did change all the fittings, lines, pumps, regulators, and injectors ..... NOT cheap !
 
#28
The shop that does my tuning and machine work has a few 1000HP+ CTSV customers. All using a single pump. (LSA has only one in and out) ..
On my car I have an aftermarket pump that draws from the 1gal tank. -12AN line feeds the blower. Then a -10AN "Y" tee sends hot coolant to left and right cooler. Coolant then returns back to tank. To be honest .... I am nervous it won't be enough to prevent heat soak, so I have the car set up to run E85 which will help with temps. (and a little more HP:)) ....
Bob, This layout makes a lot of sense to me, so each intercooler both get the same amount of hot coolant vs. running in series where the first intercooler has the hottest coolant and the next one in series has coolant with a somewhat lower temperature. Referencing the discussion above on delta-t, your setup will have the highest delta-t in each Intercooler.

By they way, I really like those CNC Intercooler mounts you designed, they look great.
 
#29
Here is a pic of the Hellcat Intercoolers, they are connnected in series and the auxiliary Intercooler is plumbed in first to take some of the heat out so the main Intercooler throws off less heat which is mounted in front of the condenser and radiator.

Here is the description verbatim “With Hellcat, right from the start, due to the larger and better designed twin screw, there is less heat generated in the supercharge to begin with (the temperature does not exceed 220 degrees), thus, there is less heat to dissipate through the front mounted intercoolers. Yes, it is INTERCOOLERS like in TWO, with the supercharger coolant entering the first, driver side mounted intercooler before heading out for the main (unfortunately) center mounted main intercooler. Although the main intercooler still obstructs the radiator flow, there is considerably less heat being expelled through the main intercooler than in case of LT4. Also, the first intercooler has its own air intake-through the driver side fog light opening”

F34E6101-00E5-4656-B2EC-51F961869860.jpeg
 
#30
Not sure if this is much help....but in any case. I have a twin-turbo V12 engine in my Mercedes. The "charge coolers" for each side are very nicely made aluminum boxes with a small radiator inside through which the cooled coolant flows to cool the incoming compressed intake charge. Recently, I replaced one of these for an unrelated reason and took a look at the radiators inside. The radiators look exactly like the oil coolers used on the car elsewhere. The size and spacing of the rows and the fins, the wall thickness, etc.
 
Top