I post this here just because Im curious if this is true for the ka24det setup. Admins: move this if it is in the wrong section I heard on a forum somewhere that instead of using a larger, taller intercooler, to use an intercooler about half the height and the result will be a quicker spooling time. Now I heard this might be true for the ca18det but is the true for the ka while still cooling enough to be efficient?

There is actually a bit of math that can be done for the volume of air and its efficiency. But too small will cause the air to not flow well enough through the FMIC and cool off well. But at the same time, you can have a FMIC that is too big and therefore the air's velocity slows down due the sudden increase of internal volume the air has to fill up before going back through the charge pipes to your intake.

I'll leave this here for now since it's focusing on the KA at the moment but if it becomes more about the FMIC in general, it'll get moved.

wanna buy a 180sx ca18det side mounted intercooler? its good enough for the DET, so it might be enough for your application. let me know

no intercooler = fast spool time, hot air
FMIC = a bit slower spool, but cooler air

i run a small but long FMIC on my ka24e. i figured since i would only be pushing 10 lbs from a T3, i wouldnt need a big guy, so i would try to keep a quicker spool with a smaller FMIC. now im not sure if it worked or not since i havent driven the car without an IC or with a bigger one... but the FMIC does its job just fine. honestly i dont think it makes TOO much of a difference bigger or smaller. i just figured it wouldnt hurt to buy one according to the theory i believed would work

Cooler air means better spark and more efficient combustion and exchange of fuel/air/spark to power.

i'm not sure about air temps or turbo lag or anything, but a smaller style would probally fit in the s12 opening better, with out haveing it hang under the lip to low, or haveing to cut the bumper and covers up drasticly, like i seen done for the bigger styles

My goal, which goes for whatever motor I swap in, for the ka is around 250hp. My guess is that I probably wont need a huge front mount but then again I dont know how much boost it'll take to hit that mark. Would anyone suggest using a t3/t4 turbo or would this be a little overkill? Also at what point is it smart to swap out your pistons for a set of Wisecos, or CPs?

Ok, one thing nobody has really answered here was the question of what works best with a KA. The reason why they probably didn't answer that part of your question is because it's not really the determining factor. While ever part of an induction system (including an engine) plays a part, the real consideration goes with which turbo, intercooler core, and boost level you are running. Of course, a KA24DE has a higher compression ratio than, say, a CA18DET, and that will also promote a faster spool and more power at the same psi than a CA18DET, but you're asking about turbo choices and intercoolers, so let me stick to that.

Like any setup, the intercooler is just one jigsaw puzzle piece of a larger integrated system that includes fuel. If you pick a T3/T4, it's overkill on a moderately improved fuel system, because you will never utilize the entire boost map, and will add more lag from the larger wheel. A T3/T4 however can flow more air in a denser, colder temp than a smaller turbo, which has to spin more times per second to make the same boost levels.... that extra spin creates more heat, which means more expansion during the air's travel through the intercooler piping and intercooler itself.

But let's stick with what you're trying to figure out here. Your goal is 250hp. The two things that govern choice of turbo are overall budget and power goals. You gave us one of the two, so we can work with that. 250hp on a KA24DE standard longblock is attainable with a standard T25G from an SR20DET, but requires a lot more supporting mods, like full 3" exhaust, big intercooler, lots of boost... The T25G can do it, but it's spinning like crazy to do so, so the air temps leaving the compressor are kinda hot... the intercooler does change that, BUT...

A T28 would be better suited for this. You would be able to make the necessary boost levels without spinning the turbo as fast, which means less heat in the outlet air... that means you can go with a smaller intercooler, because the air isn't as hot to begin with. A T28 will still hit pretty damn hard. You could probably get away with a medium-sized core, instead of a large one.

My suggestion for your power range is a T28 turbocharger, with an intercooler like this:





That bumper was modified further to make it fit behind the stock crash bar, but this was to give you an idea of the ideal size for your desired power goal. This is actually good for more than 300hp, given you get air to it.

After 250-275hp, the KA24DE stock longblock is going to begin to have issues, and you'd really need to build the bottom end at least, with some thick rods and forged, lower compression pistons. The above intercooler will take you higher, but once you get into seriously BIG horsepower, you're going to want to go to something more like this:





That's Bart's car... Bart is primarily a drag racer, so a bigger IC is better for him... and wold also be better for any car at over 350hp, regardless of the type of racing you do.

Here's another large-opening hacked version of the bumper, a bit more modest compared to Bart's car:




You don't necessarily have to hack out half your bumper and all of your crash bar. You could do what I'm going to do, which is this:

(photo is of Keith's car, who's IC is more like the first one above, but assume it's like the second one above based on my photochop)

Factory crash bar:


Cut out...


...and plate or brace welded in:


Blocked:


Unblocked:


You could leave it like that, or paint that top part of the IC black, or all of the IC black, or do what I'd do, and use a mesh kit on the new upper airdam.

Doing this will also send more air through the top of the IC to the top of the radiator, so that's a nice bonus.

Somewhere I found someone on (I think) nicoforums who has an S12 and did exactly this... I have the pics somewhere on my photobucket or hard drive, as soon as I find them I'll edit this post and put them here.

Edit: found the pics...

On my setup(the black bumper), I'm going to run an SE V6 lip and a front splitter to direct the air upwards towards the IC some more. I also need to make a shroud near the bottom of the license plate area to the top of the IC to keep the air directed to the IC instead of all behind the bumper support. For now though, I don't have enough power to justify doing all the work =P

Yeah, that's why I want to put on my SE lip, too, later if I turbocharge... but to some extent, you need more forward surface area... diagonally-directed air isn't going to like the sudden change of angle when it hits the bar n' plate setup.

Hung, what's the dimensions of your IC core?

Honestly, I don't know lol. I never measured it and it came with the car so I just used it. I'll measure it later for you OR you can show up on the 21st and check it out yourself. That's next sunday. I'm hoping we get a big turnout for a Socal S12 meet, because then my brakes will be done and we can cruise around.

hahahaha, omg. thats my car arro. thats the people that had it before me that swapped in the sr. thats with no support, and i still dont have a front bumper support. PM me the link arro


current bumper pics

That JDMSport IC is the same exact one I have, I bought it because it's narrow enough to fit right between the area above the front frame rails with 90 degree couplers (right in front of the radiator).
Cheap too, and it does a really good job.

I use water injection as well, though not really for it's chemical intercooling properties, but it's still worth a mention. If you want the fastest spool and shortest charge piping, you might want to consider alcohol+water injection, it can do a better job than any intercooler when set up correctly.
The problem is that it causes a fluid dependency, like your engine oil... Run out of juice, you might go boom! ...Not quite, but it does pose an issue.

My budget is probably going to be around 5k to start off, maybe more depending on my sign-on bonus. Im crunching numbers to see if that will be enough to get me a decent suspension setup, lsd, and maybe a start on my motor swap. Ill definitely want to build the motor first before it gets bolted in that way I wont have to pull it later on down the road. As an alternative to forged pistons was to get the newer ka, lower compression, pistons. Or maybe just a set of forged pistons. Is this a good idea?

5K for everything? Including a motor build? Not likely. 5K is enough to build the engine and buy a couple other things, but not enough to do it all.

Run with your stock KA24DE, do your suspension, do your exhaust, do your other crap, like wheels and tires... that will take up most of your 5K, especially if you need to do any bodywork to get the car clean again (do you?). The turbo shit will cost another 2-3K, then an engine build.... the parts alone could run you close to 4K. Run with a stock KA24DE with other mods, while gathering your turbo build/conversion parts, then once you have everything and the time/money to tear down and rebuild, THEN do it.