[Tommeh]

I noticed that the new M3/M4's will have water to air intercoolers which are practically 0% pressure drop and much better IAT temps. Plus, you can drop ice in your water tank at the track to get even better performance.

I was looking at universal kits and they don't seem that expensive for the parts. Im sure it might take some engineering to get the all the fans and tank to fit, but seems worthwhile.


Was wondering if anyone has seen this setup on a N54 previously?

[Lux3m35i]

To make the discussion shorter, IMO it isn't worth it to swap to an water cooled intercooler. In theory water and air cooled intercooler can reach nearly the same efficiency, depending on the environment.

If you would change to an watercooled intercooler you will add more heat to the existing water circuit. Probably you will need to add a second (active cooled?) radiator to reach the expected IAT temps, you will need a good cooling concept. The added radiator and water will also add some weight to the car. Secondly, the M4 intercooler is installed directly before the engine intake to get get a better efficiency of the whole intake manifold, that's probably the point of watercooled intercoolers. The chargepipe between an ordinary aircooled intercooler and the engine intake is heated by the engine and therefore the IAT will rise a bit. I cannot imagine that a watercooled intercooler will fit in our N54 enginebays, that is why the M4 has a "powerdome" hood.

If you are adding ice into the cooling system it will drop IAT temps yes, but how long will it last? Doesn't seem practicable.

Btw: Seems that the normal operation temp of our cooling water is about 90°c? Seems quite high to cool the intake, so you probably need a second water circuit.

[bantam]

every engine that I know of is going to require a separate water circuit for the intercooler.

I kind of looked into it, thinking the same things as you (removing the restriction across the intercooler, improving response by reducing total intake volume) But I do not think that the benefits will be proportional to the amount of development and expense for the system.

At that point, you might as well use methanol injection to lower IAT.

[Tommeh]

Yeah, I am piecing together 4-AN fitting for my methanol system right now. Was just a thought based on the design of the new fleet of BMWs in production.

[SfValley335i]

probably wouldnt be any better than an Air to Air intercooler because of how hot our motors run

[Tiago@VRSF]

Water/air cooled kits are great for drag racing since you can just add ice when necessary but they're not the best idea for the street since water has a higher specific temperature.

This means water takes a longer time to cool/heat in comparison to air. There's also still pressure drop with a water/air intercooler, just less since there's less internal surface area and shorter pipe routing.

Retrofitting a water/air intercooler would require significant permanent modification to fit everything in place since there's quite a few additional components necessary and it's not something worth going through the effort for.

Air/air intercoolers are using in motorsports for a reason, I wouldn't be surprised if people turn to converting the existing S55 water/air intercooler to air/air once they start raising boost levels.

[Jase 320d]

Charge Cooler

I ran one on a diesel
(It couldn't take the boost pressure)

:O

[techwhiz]

Remove the current FMIC.
Put a radiator in it's place along with an electric water pump.
You will need to fit the plumbing along with the water/air exchange unit un the charge pipe plumbing and route new plumbing around where the exiting FMIC is located.

An alternate method would be a hybrid radiator/exchange unit and route the plumbing in a similar manner .

you can do it, but why not just get a larger FMIC? For the expense of a retrofit, you could spend that money on something else.

[Tiago@VRSF]

You also need a separate water tank and extra fluids, which all add significantly more weight. Once done, you'd still be down grading.

[Mit_Boost]

Originally Posted by Tommeh

I noticed that the new M3/M4's will have water to air intercoolers which are practically 0% pressure drop and much better IAT temps. Plus, you can drop ice in your water tank at the track to get even better performance.

Was wondering where you got this? Air/Water vs. Air/Air has been debated to death, each has their pro's & con's. Here's my .02

• Air/Water -- Superior for cars that see short aggressive pulls (Drag Strip/High Speed Trap Events -- Texas Mile, etc.). Water offers significantly better IAT reduction as long as the water temp are kept low, but once the Water Temp has gone above Cooling Efficency, the only way to bring temps back are stop the car (either to let it cool down or change fluid). This has become a problem with some of the E9x M3 supercharger kits since some are Air/Water (ESS/Gintani/VF Engineer) and others are Air/Air (Evolve & Active). On longer drives, cruises, you can see the Air/Water cars "losing" power after repeated pulls b/c the water temp has exceeded an efficient cooling temp.
• Air/Air -- Superior design for cars that see high passive airflow (Street/Race Track Cars). Offer better IAT suppression over prolonged driving. With a proper, high quality FMIC design (not some BS ebay garbage), Pressure Drop can be very low. If necessary, Meth can be added and used as a cooling agent.

Honestly, going Air/Water is a waste of time on the N54 and I am really not a fan of it on the M3/M4 since it is primarily marketed as a "race track" car for the street. Let's also step back and think of the very common high power cars (Supra, GTR, Porsche Turbo), they ALL capitalize on the high passive airflow and use Air/Air intercooling.

[MidwestGolfBum]

Originally Posted by Mit_Boost

Was wondering where you got this? Air/Water vs. Air/Air has been debated to death, each has their pro's & con's. Here's my .02

• Air/Water -- Superior for cars that see short aggressive pulls (Drag Strip/High Speed Trap Events -- Texas Mile, etc.). Water offers significantly better IAT reduction as long as the water temp are kept low, but once the Water Temp has gone above Cooling Efficency, the only way to bring temps back are stop the car (either to let it cool down or change fluid). This has become a problem with some of the E9x M3 supercharger kits since some are Air/Water (ESS/Gintani/VF Engineer) and others are Air/Air (Evolve & Active). On longer drives, cruises, you can see the Air/Water cars "losing" power after repeated pulls b/c the water temp has exceeded an efficient cooling temp.
• Air/Air -- Superior design for cars that see high passive airflow (Street/Race Track Cars). Offer better IAT suppression over prolonged driving. With a proper, high quality FMIC design (not some BS ebay garbage), Pressure Drop can be very low. If necessary, Meth can be added and used as a cooling agent.

Honestly, going Air/Water is a waste of time on the N54 and I am really not a fan of it on the M3/M4 since it is primarily marketed as a "race track" car for the street. Let's also step back and think of the very common high power cars (Supra, GTR, Porsche Turbo), they ALL capitalize on the high passive airflow and use Air/Air intercooling.

The part in bold is a very good point. The majority of cars that are going to have high horsepower but need to be somewhat driveable are going to have air/air.

In my M3, I can certainly tell the difference between when there is higher water temps in the Air/Water cooler and for the added benefits of having it at the track, it becomes much more of a pain in the ass for day to day driving for longer distances which is why I prefer my 335 for those times.

[pwr hungry]

To put it simply, why would you use an air to water radiator and then a water to air intercooler? That's like charging an electric car with energy produced by burning coal. You're converting energy an extra time and each time you lose efficiency. Air to air intercooler is the best for this platform and I promise you that people will be swapping their air to water m3/4 intercoolers to fmic air to air.

[Mit_Boost]

Originally Posted by MidwestGolfBum

The part in bold is a very good point. The majority of cars that are going to have high horsepower but need to be somewhat driveable are going to have air/air.

Thanks.... The one "exception" are the TT-Lambos, which I really wouldn't even consider anywhere as drivable as the Supra/GTR/Turbo Porsches because those are realistically weekend toys AND doing Air/Air in one of those cars is near impossible.

[DavidZ]

I'd imagine the TT M5/6 and M3/4 have separate water circuits for the air-to-water intercooler and engine coolant (don't see much good with trying to intercool with hot engine coolant)? If so, does they use the same coolant?