setup: gsr + tiny turbo + E85 = 250-280whp @ 13-15psi
use: road racing & autocross



My bumper grill / inlet is approx 31" x 6"
I found a custom FMIC with garrett core size of 23" x 6" x 2.5"


Even if I get a 10-12" tall FMIC, my grill space is only 6" TALL, so I don't se any benefit at all with getting anything larger than the SPACE which air will hit/pass through.

Q1:
Is my thinking flawed?

I wanted to use oil cooler on the backside of the FMIC, for that reason i think 2.5" is better than 3" core. I don't think I'll be loosing cooling efficency by going with 2.5"

Q2:
Is my thinking flawed?

I know I'll be 100% fine for drag & street use.

Q3:
Should I be a little worried about "heat soak" during 15 min road racing sessions or autocross use.

 

that core shouldnt having a problem flowing/cooling the air from that "tiny turbo"
i also dont think that their is any reason for a oil cooler eather

 

see thread
https://honda-tech.com/forums/forced-induction-16/oil-cooler-type-plate-fin-vs-tube-fin-2676172/

 

Honestly your thinking more clearly then most people on here. Unless your maxing out your intercooler flow capacity (pressure drop) or surpassing it's ability to cool (heat soak) then there's is no need to up it's size beyond what your looking at.

what i would focus on if your concerned with airflow and cooling eff. is to make some very simple ducts that block air from going anywhere but through the ic/rad. This can anything from some simple adhesive backed foam to create a good seal to building aluminum/tin walls that direct the flow. Also don't forget once ducting is done a good fan with a properly build shroud will only increase the cooling eff.

For oil cooling a simple cooler mounted in the air flow is a good start but i would look into upping system capacity before i would worry about where i'm placing the oil cooler or how large it is. It's harder to cool the oil when there is less of it to absorb the heat in the first place. Same reason why people run larger capacity radiators instead of super expensive solid copper cores of similar capacity. make sense?

Hope this helps.

 

I completely forgot about making modifiations to my bumper to "divert" are propertly. Thanks!

You made great points about cooling.
I do have full DA radiator in my EF, I didn't want just go with a half core radiator unless I needed clearance for my turbo/manifold (which I don't at this time).

Also I'm running a Moroso oil pan 5.25 quart. Which will be nice for added oil capacity, as an fittings already & backdoors in the oil pick up to prevent oil starvation while turns...

I'm using a volvo 10x4x2" oil cooler with -6an fittings & oil sandwhich adapter.

 

here is a picture that explains the ducts better. Now this is an extreme case but you get the point.