SMIC vs FMIC

[YoshiBishi]

Okay, this has probably been beaten to death on other forums, but I didn't see a topic about it here...

I have a 1st gen with stock SMICs right now. I am currently running 380AWHP. I do not plan on going above 450AWHP, since this is more of a fast street car rather than a track car.

I have heard about issues with FMICs and making cars run hot as well as possibly having to remove the crash bar. Is this true for all FMICs, or just certain ones? Removing the crash bar is something I do not want to do.

How do SMICs compare to FMICs in cooling ability?

What are some good FMICs and SMICs?

Thanks for the help guys!

[mb7050]

I would choose smics over a fmic,
FMIC decreases the airflow through radiator and your extracting heat from the FMIC to the already hot radiator. Then all the heat leads directly into the engine bay.

And there is enough room in these cars to fit smics big enough to support up to 1500hp if needed !

Don't be fooled by the common myth that a biggest intercooler is always better , it´s NOT true !
It´s all about maximizing thermal efficiency and minimizing pressure loss .
Bigger IC does slow the boost response(more space to compress) .
I have noticed that intercooler flow ratings are often overrated (especially ebay intercoolers) so beware !
You can check flow ratings for different core sizes at http://www.bellintercoolers.com/_pag...omAirCore.html ( yes flow rating varies with manufacturers and core styles but generally there should be no major differences except super cheap chinese cores)Your better off avoiding the cheap chinese cores in the first place.





Bell Intercoolers - Custom Intercooler and Core Solutions

any size you want you can even send them your ic´s and they will make a bolt on set for you. stock sidemount size is 8x7x2.6 . 8x8x4.5 will fit easily and cover about 700 whp (bell cores) . Few 3s owners have send them stock ic´s in the past you can ask them they might even have ready design (bolt on for 3s) (8x8x4.5) or (8x8.4x3.5) .

8.1x8x6 cores 2.25" in out P/N A600081080BB225 (Bell intercoolers) would cost you about 480 $ (2011) each assembled with end tanks. You cant go wrong if you order from Bell they know everything about intercoolers !. they are rated 911 cfm each (1811cfm combined "should" be enough for atleast ++ 1000hp flow wise)
(1 psig pressure loss across the intercooler core and a charge-air pressure of 10 psig)
They would be overkill for my application but still not ´too large´.

It´s easy to figure out what kind of flow numbers you would want from your intercooler cores..
Me for example. I´m shooting for 650awhp
So for example 650 AWHHP, or about 780 CHP, requires a total Air-Flow of about 1,180 CFM, at compressor Inlet Conditions, or about 590 for each Intercooler .

http://www.bellintercoolers.com/_pages/aachart450.html
lets take a A=4.50" C=8.10" B=8.00" core for example, its rated at 683Cfm each 1366Cfm total $225.00 A450081080
to keep things simple it takes about 150 cfm per 100chp so two of these cores will cover about 700awhp roughly flow wise. 1 psig pressure loss across the intercooler core and a charge-air pressure of 10 psig .



sidemounts core sizes
OEM 3000gt: 8x7x2.6= 146 cu. in
DSM : 6 x 8 x 3-7/8" = 186 cu. in
HKS : 8.5''x8''x2.75'' = 187 cu.in (x2)http://www.horsepowerfreaks.com/part...ide_Mount/4240
Dejon : 8''x8.75''x4'' = 280 cu.in (x2) (as they were before)
Dejon : 8''x8''x3.5'' = 224 cu.in (2x) (as they are now) http://www.3sx.com/store/comersus_vi...dProduct=26508
Gene : 8x10"x4.5" = 360 cu.in (x2) (Bell cores rated 800+ cfm each "should" be enough for 1000hp !)
Alamo : 6"x8 3/4"x 6" = 315 cu.in (x2) (discontinued)




some good reading :

#1 start here ARE Cooling (Aluminium Radiators & Engineering P/L)

Frontal area: This is a rapidly decreasing function. If the proper core size is used, then doubling it will definitely not double the efficiency. More likely, doubling the core would raise the efficiency about 5% and cost twice the necessary amount and add substantially to the weight.

When adequate space exists for a large IC, the decision must must be made about the direction in which to orient the core. Unless overwhelming reasons dictate otherwise, the core should always be constructed to provide the greatest possible internal flow area. The direction of flow is unimportant. .

1


2


lets say that #1 core have three times more air passages than #2 core. #1 core will flow more than three times more than #2 core !

Tube length is the second biggest consideration, as a tube twice as long as another will have nearly twice the drag at the same air velocity.

Example

Boost: 10 psi
Ambient temperature: 70 F
70% compressor efficiency
Cooler #1 1.0 psi pressure drop
Cooler #2 2.0 psi pressure drop

I won’t go through the actual math in detail, but under the above conditions the compressor discharge temperatures will be as follows:

Using Cooler #1: 197.0 F
Using Cooler #2: 208.2 F

To get an intake manifold temperature of 100 degrees, cooler #2 has to be 78% efficient. While cooler #1 only has to be 76 % efficient.

If the increased pressure drop causes the compressor efficiency to drop to 65%, the compressor discharge temperature with cooler #2 rises to 218.6 F and the cooler has to be 80% efficient to compensate.

In addition cooler #2 will have more boost lag and more exhaust gas reversion.

intercooler thermal efficiency

T_in : intercooler inlet temperature (or post compressor temperature).
T_out : intercooler outlet temperature.
T_ambient : ambient temperature.

Pressure Loss/drop
Corky Bell has suggested that pressure gauges mounted on the inlet and outlet of the intercooler. The pressures will be read at engine redline.

END TANKS:

Perhaps the greatest potential for improvement (in
intercoolers) rests in the design of the tanks on each end of the charge
cooler.Here the wrong approach can muck up both airflow and cooling
efficiency.

simple example (good to keep in mind when purchasing intercooler) :

You will notice that there is an 8% difference in
the loss coefficients of 8.22b vs. 8.22d. Ok big deal. Well as a matter of fact it is
a big deal. Now figure in the other end tank bringing the loss total up to 16%,

I like pictures

Most of the charge flows through the bottom 35% of core, with the top 65% causing detrimental pressure drop until high boost is reached. Worse again if other pipe is on the bottom too !!

The 2 corners cause large eddies & the square inlet corners small eddies which restrict flow & distribution across the core window. Worse if pipe is on bottom other end !!

Not perfect, but very good & very cost effective. Nowhere near as important to have diagonally opposite tanks like both designs on the left. Very small eddies & small uneven distribution across core window

by far HKS sidemounts have the best end tank design for 3s .

tested through computation, the reason for the small endtank is not because it produces even airflow across the core. Simply put, the volume of air that goes through the intercooler forces the airflow to be pretty even across the core because of the restriction imposed by the core tubes. The small endtanks are to improve throttle response by reducing system volume. In other words, you get the same power from the small tanks as you would from large tanks but you get better throttle response with the smaller tank.

Don't forget the ducting
( prolly the single most important thing you can do to improve intercooler efficiency)

Links:
(general flow info M&I Power Technology Incorporated )
(Intercooler flow effects from various end tank designs http://dvdtfab.com/intercoolertestlab.pdf )
(Heat Exchanger Theory and Intercoolers Intercooler Theory )

[mh3kgt]

I never ran into any overheating issues with my cx racing fmic. Love it and the fitment was great. I probably wont ever see over 450awhp with my 15g's so the core I have now I feel is very adequate. If I get 19t's in the future I think it will still suffice.

[YoshiBishi]

Did you ever determine if your surging is caused by your FMIC?

[mh3kgt]

Nope haven't tried out balance tube or anything yet. I upgraded turbos same time as FMIC tho, so there's nothing to say it's the FMIC at all, could be just larger turbos moving more air cause the surging. I've heard people say they get surging even with stock smics.....

[MADMarc]

+1 for no overheating issues w/a front mount. Last summer was friggin scorching and it still didn't over heat. I have the dual core fmic that oohnoo fabbed the pipes for.

[GTO Assassin]

I honestly believe if you're over heating with a FMIC, you're doing something wrong or something IS wrong. I've driven in traffic, 1st and 2nd gear stop starting WOP, drags as well as long distances without ever over heating.

Scotty

[YoshiBishi]

Dual core vs single core FMIC?

[mh3kgt]

dual core allows you to keep stock IC piping of you use oohnoo's kit. Single core needs custom piping unless you buy the full kit with piping included. That's about the only main difference other than dual core makes it look like your car is grinning, and single core doesnt lol

[Chatzvr4]

Dual core vs single core FMIC?

this all depends on which single core you are talking about. a typical cx style core will not utilize the entire core as the air does not get to the top of the core as much as the bottom of the core. The dual core is actually a single core with 4 end tanks acting as two cores.
Now if you use one of our larger FMICs we change the angle of the end tanks allowing the air to flow through the entire core more efficiently.

Thicker side mounts will result in less air getting to your oil cooler. So if you go this route i would recommend a GZP FMOC

Either way both setups are good for street use