slayerx7

iTrader: (4)

Just curious if anyone has had or tried such an Idea? Any notable results? I searched to no avail.

I ended up with 2 stock ones a while ago, and I realized ran together it could be a twin intercooler set up. Not worrying about the fitment at all (as it doesnt really apply), functionally would there be an advantage to running 2 smaller (aftermarket even) IC's? I have BNR stage 3 Seq. turbos, and planning to run about 18-19lbs on a decent Streetport. Or for all intents and puropses would it be just plain better to run a larger single Front or V mount? I got the idea from Porsche turbos, apparantly running twin intercoolers from/to the front of the car. I could be mistaken, but even so its where this idea came from.

Just hypothetical at this point, but Im starting to gather ideas and funds as the Rotary bug has bitten again (this set up will be going in a 1st gen, but thats besides the point)

Rxmfn7

iTrader: (4)

https://www.rx7club.com/showthread.p...n+intercoolers

tt7hvn

iTrader: (5)

according to the link above, totally not worth it

off topic; i have seen someone do twin radiators before somewhere on this forum

Elombard

The Porsches have twin (in some cases triple) rads, the intercoolers are in the back and I thought they were one divided cooler (one for each turbo) but connected in the middle.

I think you would induce lag too, one of the benefits of the V mount is the short pipe lengths and shorter lag time. With the long path you would need for the twins set up it might be annoying.

dguy

iTrader: (8)

Heat exchangers are significantly more efficient in parallel due to delta T than in sequence however I think you'd just F yourself with flow restrictions and plumbing.

arghx

iTrader: (3)

Every twin intercooler setup I've seen from the factory has two turbos each feeding their own independent intercooler, and then depending on the design there may be dual throttlebodies (Z32 300zx) or a Y pipe near the single TB (Vr-4).

Because sequential turbos need a charge control valve, the charge air has to be combined right after the compressor outlets. Combining the air and then splitting it apart the combining it again just seems inefficient.

slayerx7

iTrader: (4)

LMAO! I love how thats the very next post! Perhaps I should have put the smic into the search box but that didnt occur to me. Anyway thanks for the info! - Happy Halloween!

.:FoRuM56:.

Be cheap and just weld the two factory units together lol.

Nateness

iTrader: (7)

Think of it this way, while you are doubling the surface area (good), you are also reducing the velocity (bad) and DOUBLING THE PRESSURE DROP (the WORST). It has been done, but seriously, unless this was for some technical design exercise where you had to use either one factory IC, or two plumbed in parallel, this would not be a worthwhile idea.

On the other hand, if you've got BNR stage 3's in Seattle, we need to meet up so you can let me witness the performance difference from stock twins =]

fendamonky

iTrader: (6)

Get A/I and a VMIC.

/thread

Chaotic_FC

If you're going to be looking into fabbing up some custom intercooler setup you might as well go with the best thing out there... air to water.

it is proven to be the best.

just make sure you get a heat exchanger with more surface area than the core of the cooler, and you will never have a problem on the street.

not to mention the advantages of having such a small amount of charge time from the short tubing/small core.

calculon

iTrader: (29)

By what measure are they the best thing out there?

How are they proven to be the best?

Nateness

iTrader: (7)

Its the basic heat transfer properties of air versus water. In general, water has a convection coefficient that is about 4x higher than air.

The downside to air/water is that you still need an air/air heat exchanger somewhere else in the system. You also need a pump, etc. You could say its about 4x as complex as a simple air/air

MakoRacing

iTrader: (12)

Also more weight It does cool better, however it adds another system that has the possibility of failure.

NissanConvert

iTrader: (1)

You don't need another a:a cooler, an external a:w cooler helps. you'll probably end up with higher average temperatures since it will take the water (given it's thermal mass) a lot longer to cool back down after a WOT run.

Nateness

iTrader: (7)

Forgive my typo, I thought it was pretty obvious that you would use an w/a heat exchanger to dump the heat out of the water loop though

The charge temps are really limited by either:

1) a/w heat exchanger
2) water pump flow rate
3) w/a heat exchanger

One of these three parts is going to limit the rate (BTU/kW) at which heat can be taken out of the charge air stream. For an all out race car, I would expect heavy consideration to be given to an a/w intercooler system before an air to air is used. The primary downsides (as someone already pointed out) are weight and complexity. Adding more parts to ANY system will increase its tendency for failure. That is inherant in all engineering designs. In general, I would expect an a/w system to have lower charge temps than an air to air system of equivalent core size.

NissanConvert

iTrader: (1)

I could be wrong, but in a sustained racing environment I would tend toward the a:a unless you're using some sort of race chassis with more ducts than you can shake a stick at for heat management.

I think the opportunity to get lower than ambient temperatures with an a:w system benefits those competitions that are short full throttle blasts- drag racing, hill climbing, etc. The hot water can be drained and replaced afterward.

Until the heat is taken back out of the water (which will take longer than it would for an a:a system) you're going to be heating the intake charge. For street cars that will only see infrequent stabs of the throttle a:w makes sense, temperatures stay more stable most of the time. But for a car that will see sustained high throttle, i don't think you can beat a well engineered a:a system.

bencb44

iTrader: (2)

Just curious, but could you have the turbos y-ing together near the throttle body, and put the ccv there?

Chaotic_FC

it is very possible to run an air to water intercooler on the street.

you just have to have a big enough air to air core to cool the heat exchanger.

it is proven to work better than a conventional air to air cooler, even after repeated wide open throttle runs, while on the street.
hell, look at some production cars that have air to water intercoolers, such as the zr1, even the bugatti veyron...

there is also a thread that talks about it on the street:

https://www.rx7club.com/single-turbo-rx-7s-23/water-air-intercooler-street-drift-use-773521/

calculon

iTrader: (29)

I never said that it was impossible, I was asking why you think that they're the best thing out there.

Unless you are keeping ice in your reservoir, there is no physical way that it can get a charge cooler than ambient. The fact that there is a secondary cooling loop is going to reduce the cooling efficiency once the water becomes warm (which will happen absolutely in a street car). Add the fact that they're heavier, STILL require a heat-exchanger that needs to be able to breathe well (just like an air-to-air), and have an associated electrical load are all additional limitations/cons. I'm not saying that they're garbage or that they're even a bad idea for some set-ups. What I AM trying to say is that you are wrong in saying that they are the superlative solution. Like anything else, they have their purpose and, if correctly engineered and installed, can be effective.

FWIW, the ZR1 has an air-to-water because it uses a roots-type supercharger. There is no way to use an air-to-air. The Veyron uses air-to-water because it is a mid-engine quad-turbocharged W-16. Looking at the engine bay, it is obvious that trying to stuff air-to-air intercoolers back there with the commensurate ducting would've been an exercise in futility. These are both examples of application specific requirements and engineering trade-offs, NOT "proof" that air-to-water is the best thing since sliced bread.

Chaotic_FC

i never said it was the "best" setup.

but it defiantly is the best from an engine performance standpoint.

it absolutely will cool your engine better than an air to air intercooler, and it will have a much smaller core, which can be extremely close to the engine, for a much shorter charge time.

the water will stay cool as long as you have a big enough heat exchanger (which is not very big, maybe half the size of a stock radiator)


from a complexity standpoint it defiantly is not better, and from a weight standpoint it isn't either.. but it makes up for its weight many times over with the extra power potential it has.

calculon

iTrader: (29)

Like I said, that is only true if you have ice in your reservoir. Obviously, that can't be done in a true street car for sustained drives. The water will heat soak and will be less effective at removing heat from the intake charge. Even in a hypothetical (i.e. - ideal) setup, the water can NOT get cooler than the ambient temperature. Its "superior" ability to cool is certainly very limited if even existent.

Please provide some evidence or at least some sound reasoning to back your statements.

Jordanz3

cool idea

slayerx7

iTrader: (4)

I would but only 2 problems with that. 1. - I dont have a motor anymore, for the twins to go on to. Problem #2 - I dont have a body for the lack of motor, nor the twins. Other than that sure, sounds like fun! lol