NA KA24E Intake & exhaust plan?

[Nanaimo]

HelloI have an '89 240sx that's mostly stock, but with a previous custom exhaust that "looks fairly close to stock", according to my mechanic.

I use it as a daily driver, but for me that includes a 50km trip up a paved mountain road most days (so power is important). Also I live in a medium density neighbourhood on a steep hill with a LOT of kids and often come home late at night (so quiet is important). A few of my neighbours have ricers or just plain rusted-out cars, so I can get a bit louder and still fit in.

The current exhaust appears to be 2" from the Cat-back, not mandrel bent, but with no sharp bends, and with a resonator and fairly large muffler. It sounds slightly quieter than stock.

The current intake system is stock except for a K&N air filter.

The exhaust systems mechanic at my garage gave me an estimate for a custom cat back: mandrel bent 2.25" and a high flow muffler (no resonator). Actually, he recommended removing the cat -- which is legal here -- but I don't want the emissions or noise to increase that much.

The other mechanic (same garage... Nissan specialist) gave an estimate for a custom cold-air intake and battery relocation, which would work out to about the same as if I bought a kit, imported it, and had it installed.

So my questions are: does this sound like a good plan, might it be worthwhile to do just the intake, and can anyone venture a guess as to how much louder the new exhaust would be?

[Nanaimo]

anyone?

[tryiian]

difficult decision... i`d wager the intake will do you better for mileage/power gains, especially if you havent changed your filter in forever. Getting a high flow 2.25 would do pretty good for you also though, so... it`s a pretty tough decision to hafta make.

[FliMSiCaL]

well, 240 exhaust is 2 inches stock. so its not slightly bigger than stock (unless you compare to most 4 cyls, than it is). The exhaust on our 240s is also rectrictive as hell, and imho recommend that be the first thing done. Don't expect huge power gains tho, I/E doesn't produce a whole lot more at the wheels. Also careful on what muffler u get, a lot of them are louder on 240's than on other cars, simply of the higher than normal displacement of the 2.4 litre.

[Ni2s4s0aSnX]

if you are going to do it yourself, which you would probably be better off doing, if you know what you're doing. You would be better off probably buying an Injen intake, which would probably cost around $200, with an Injen cold air extension, which would cost probably around $120. Also if your looking for a performance exhaust for the ka, the Apexi GT Spec is probably the best one to go with, it will cost you around $400, and if your looking for something that is quieter, the Apexi has a SuperSilencer, that will cost you around $80, but it still wont be as quiet as stock, probably not even close
Modified by Ni2s4s0aSnX at 9:46 AM 5/9/2005

[Coupe_Devil]

I say go for the battery relocation kit and the custom cold air intake. A shorter intake tube will increase throttle response and keep intake air away from the hot *** radiator.

For exhaust, depends on yo flo ya know. If you got the green. get a high quality mandrel bent exhaust, preferably IMO the HKS Hiper in 65mm. Best bet on improved flow and still keepin it fairly quiet.

Either way go for a 2.5-3" exhaust mandrel bent.

[s13sr20chris]

if the price is decent then custom stuff is ok. 2.25 mandrel bent with a decent muff will be much better than stock. should be worth a few whp. on the intake it might be better to just get an injen or even make your own.

[Nanaimo]

For all who are recommending kits, I'm not in the US, so shipping for large car parts is prohibitively expensive, plus there's currency exchange fees, 14% tax, and 6% import duty. It actually ends up cheaper to get the parts custom made. (If someone knows of a 240 performance parts dealer in BC, please let me know)

Also, all of the intake kits I've seen put the filter in the stock location and run 80cm of tubing over the radiator instead of using 30cm to put the filter where the battery normally is.

Quote »Either way go for a 2.5-3" exhaust mandrel bent.[/quote]I have mentioned that this is a mostly stock NA KA24E, right? I'm not convinced I'd need anything bigger than 2.25.

Quote »if you are going to do it yourself, which you would probably be better off doing, if you know what you're doing.[/quote]I don't. Which is to say, I know how in theory, but have neither experience nor tools. My mechanics have both experience and tools.

Quote » Injen intake, ...$200, cold air extension, ... $120.[/quote]Plus a few hundred for taxes, duty, and shipping, plus annother few hundred to get it installed... and it costs just as much.

And it still would have the induction air running over the radiator, and worse yet the intake would be down low... It rains a LOT here. Water inside engines is very bad.

[Ni2s4s0aSnX]

That changes it now that I know you're not in the US. Also, you can buy a bypass valve for the intake to eliminate most rainwater from getting into the intake. And the Apexi Gt Spec probably isn't a good thing if you're only looking for a 2.25 inch. The Apexi GT Spec is a 3.74 inch exhaust on some applications. But you wont get much performance from the 2.25 inch because the stock is 2.00 inches. And damn, taxes are really that much? That's crazy. You wont get much power with the 2.25, you at least need a 3.00 if you're looking for performance.

[240DRFT]

pdm racing is in bc. check out northwestnissans.com, there are guys from bc there and they can help u too. maybe u can go to one of the meets coming up soon

[KAcoupe]

why change your stock intake you know that little black box underneh it that is a cooler box and you are getting are from down in the fender you that=cold are and with the ka your intake sits right by what the header which has hot air running off it so the box is keeping the heat awya from it so keep it stock sav your money and you wont have to worry about hydrolocking.......same thing as the injen just not a pretty and expensive

[4gotn1]

i say get the custom intake, and relocate the battery. i did that and it did make a difference in responce opposed to my old intake. and i run a 3in exhaust and test pipe, while it is loud, ungodly loud, it really makes a difference in how the engine pulles in the mid-high rpm range. and with a obx header i havent noticed any loss in the bottom.

[Nanaimo]

I'm having the work done today. I'll post pictures in a few days.

[Nanaimo]

Here is the new intake. The filter is located just beside the mouth under the bumper (beside and ahead of the radiator).

[Nanaimo]

Here is the battery relocated to the stock airbox location, which required moving the vapour canister.

The Mechanic connected the AIV to the new intake. I had asked for one of those mini-filters to be put on it directly (it doesn't require vacuum or cold air). I'd have just removed it, but it's supposed to reduce backfiring when you have a bigger than stock exhaust.

[Nanaimo]

Note that I now have to move the battery to get at the fuse box.

[Nanaimo]

Seems to be quite a difference. There's no chassis dyno on the Island though, so I can't measure it.

[DriftSpecial180]

I'm looking to build an intake like this. What did you need to do to relocate the battery to the other side?

[Nanaimo]

My mechanic took out the factory airbox, put the battery tray there (the battery tray was spot-welded in place, so it took some doing to get it out), moved the vapour cannister out of the way, extended the positive and negative battery leads, and set up a couple of new ground points.

Warning: do not plumb the AIV to your Cold Air Intake. Put one of those mini filters on it instead. If it gets vacuum, it'll suck exhaust back into the engine and not let air into the exhaust, which causes bad idle, lost bower, and slight backfiring when downshifting.

[240marcuSX]

how about cleaning up the exhaust side of your engine bay now? like the vapor cannister, and aiv. it would look much better.

[Nanaimo]

how about cleaning up the exhaust side of your engine bay now? like the vapor cannister, and aiv. it would look much better.

I don't care about looks that much. I care about reliability, power, maintainability, and emissions. If I took out the AIV and vapour canister it would make the emissions worse for only a slight weight reduction.