Naturally aspirating a KA24DE

[sumyunggai]

i was wondering what it would take (parts, ballpark cost, planning, etc.) to naturally aspirate a KA24DE to over 200 hp preferably 220whp. the car still has to be drivable as a daily driver and street legal in california. any info u have would be helpful. i'm not to specific on details yet. just throwing the idea out there to see what kind of feed back i get.

please leave ur opinions that force induction or nitros is better out of this thread. i'm looking for just the facts.

[DrifterBoy240]

well i am going ka n/a, i am doing the itb setup i dont know what hp im going to be getting out of it but i know its gonna cost me at least 9k for what im looking at though i know of a site that has stuff for the KA n/a but i cant remember it right now i can get it to you ill pm it to you and a place that makes some cams to if you'd like.

[Nismochick240]

what year is ur 240? i have some 91 cams for sale if yours in 92+... they're a small upgrade

[240DRFT]

well i am going ka n/a, i am doing the itb setup i dont know what hp im going to be getting out of it but i know its gonna cost me at least 9k for what im looking at though i know of a site that has stuff for the KA n/a but i cant remember it right now i can get it to you ill pm it to you and a place that makes some cams to if you'd like.

are u saying that the itb's are gonna cost u 9k or the whole project? and by the way, pm's are disabled.

[sumyunggai]

oops forgot the year. its a 91 with a later year 240sx KA24DE, i think a 97 or 98.

[InsanityInc]

what year is ur 240? i have some 91 cams for sale if yours in 92+... they're a small upgrade

No. They aren't. All 240s with secondary butterfly valves have the same camshafts. 240/248 adv. duration.

[wilfonzo]

ive always heard that on 91's the valve cover is slightly different color and the exaust cam and the intake cam are exactly the same

[sunnys14]

there is no point to spend like 2k on NA products (intake, header, exhaust, cams, lightened flywheel, lightweight pulley, electric fan conversion, ecu upgrade) and run low 15s/hi 14s. people have done it b4 including me and it isnt really all that worth it...

[tonynalli]

or you can do those obligitory bolt ons and more....sohc pistons,port and polish,bored otu throttle body, bored out plenum, jwt cams,ecu, ud pullies, down pipe, headers,flywheel, lightweight drive shaft,lsd, safc and there are more but im to tired think right now...but im probably going build a na soon but who knows.

[vvaffle]

exhaust, lightened flywheel, lightweight pulley, electric fan conversion, ecu upgrade can all be carried over to turbo if they are dont right originaly. So you are left with intake(the filter is caried over), cams, and the header which. I think the cams and the header can both be sold for half of the retail price so you wouldn't end up losing that much. If you went with ITB's you could carry those over as well if you planned it right.

[Nismochick240]

insanity-- do some searchin 91 cams are A SMALL UPGRADE for the new ka24de's...

[dickie]

the cams were the same for the s13 iterations of the ka24de. you COULD put the s13 cams in your s14 ka-de, if you wanted to.

[InsanityInc]

insanity-- do some searchin 91 cams are A SMALL UPGRADE for the new ka24de's...

Do some searching? You're honestly telling me to do some searching?

If your car has secondary butterfly valves, you have the 240/248 duration cams. That means from 91-94.5. If your KA is a very late s13 model KA or a s14KA, then it has no butterfly valves in the intake manifold and 232/232 duration cams. The "91 cams are better than the rest" thing is a complete myth. 91-93 and most of 94 are all the same cams.

[Bigvinnie]

i was wondering what it would take (parts, ballpark cost, planning, etc.) to naturally aspirate a KA24DE to over 200 hp preferably 220whp. the car still has to be drivable as a daily driver and street legal in california. any info u have would be helpful. i'm not to specific on details yet. just throwing the idea out there to see what kind of feed back i get.

please leave ur opinions that force induction or nitros is better out of this thread. i'm looking for just the facts.

Well I live in Cali and can tell you what you can do.
larger TB I would recomend just getting the stock OEM TB enlarged. Stock is 60mm, 65mm will do you just fine.
You will need "mildly aggressive" cams either PDM or Jim Wolf. 91-94 hot cams don't cut it.
An ecu retune mega biki rom prefered "self tuning" $300

To pass smog you can't use a compression higher than 10.1:1 on 91 octane, and you cant advance the cams (INT) and distributor any further than 23BTDC. Intake cam must be advanced with the distributor or else you get hydro carbon levels that wont pas the smog test.
Port the intake side of the head.

That should put you at about 210CHP.

Headers and all the bolt ons are at your expense, for what ever small increases in power that they would make.

ITB'S aren't legal in most of the counties in CALI. Only 3 counties allow the use of no visual and only a idle smog check....

[sumyunggai]

thanks bigvinnie thats exactly the kind of advice i was looking for. how do u know all of that? have u done it before or heard of others doing like that before? what would the price tag be on that? an aproximate price range would be fine


and thanks to the rest of you giving advice. its helpfull. anyone else have info on the thread topic?

[Bigvinnie]

I've actually watched a few people I know do this with there KA's, that have been trying to fool the smog techs for years. I actually have some of these mods done, and am actually looking to get rid of my Jim Wolf tune and SAFC for the Mega Biki, I've been told that with the Mega Biki you can make a tune that is ultra Lean and efficient compared to a Jim Wolf tune.
Looking to get the Super tech pistons, JWT cams and a adjustable timing gear for the intake side.
I know one of the smog tech guy's, and went in for testing on just the advanced timing of the distributor, the roller indicated that at 1560RPM my hydro carbons were raised and would not pass smog at 25MPH. On the DOHC KA's, for smog testing you are allowed -/+ 3 degress from the 20BTDC on the rollers. This is why the cam needs to be advanced as well as the distributor, (so that you don't choke the engine on advancing the timing), this will allow you to pass and was advised from the smog tech.
I would of completed my setup sooner than later but I had gotten caught up buying a fidanza aluminum flywheel, and stage 2 6 puck sprung clutch, the DC sports header/catco cat/pacesetter exhaust all in 2.5". The DC sports collector is only in 2.2", make a note that the DC sports header is not legal for smog, but DC sports had redesigned the header twice in order to get the exemption and that hopefully in the future it will be legal. Greddy is reproducing a better header in there 4-1 design for OBD2KA's should be out in a few months.

If you chose to go the route of higher compression with your set up make shure that you get a gasket that will put you in the right CR there are smaller gaskets that can put your CR to far from being legal, and you can actually get some knock and ping from only being able to use the 91Octane.





Modified by Bigvinnie at 7:02 PM 11/12/2005

[Bigvinnie]

OOPs here is the price tag, failed to mention it earlier.

Biki Rom $300.00
Super tech pistons $489.00
JWT cams $700.00
enlarged TB should only cost between $150~$200 depending on the machine shop that does it.
Head porting is free if you know how to use standard ebrasive kits, if not about $300.
$150, for a adjustable timing gear.
Full gasket kit from http://www.hybridka.com/ for $130, always liked gabed z (devious KA keep bringing the KA info)I am willing to back his products.
If you have OBD1 KA's it is recomended to remove the butterfly's, you should be able to do this yourself in 6-8hours.

If you can do the work yourself it will cost you roughly $2139(lets just say $2200), if you have some one do it at a shop add $1500 to that pricetag.
OEM rods are fine as long as you stay withing 6000RPM, if you redline your KA alot, (which isn't recomended) you should order some crower, or eagle rods from http://www.nizzx.com.
Sorry for reposting, forgot that you asked for a relative price.


Modified by Bigvinnie at 7:06 PM 11/12/2005

[vvaffle]

If you have cams that move your powerband up you might want to go above 6000rpm to make the most out of it wouldn't you. Also, don't hear much about people using aftermarket pistons on NA builds. Can you go into a little why the super tech pistons over any others? One more thing, are the eagle rods availible now? I thought they were still being developed. If you do all of this, wouldn't you expect significant gains from a full exhaust system and maybe ITB's?

[Bigvinnie]

If you have cams that move your powerband up you might want to go above 6000rpm to make the most out of it wouldn't you. Also, don't hear much about people using aftermarket pistons on NA builds. Can you go into a little why the super tech pistons over any others? One more thing, are the eagle rods availible now? I thought they were still being developed. If you do all of this, wouldn't you expect significant gains from a full exhaust system and maybe ITB's?

Well you need pistons to bump the CR up unless you plan to mill the head (for NA builds after market pistons use thicker rings than the stock OEM, recomend the super techs because they are coated and there price at http://www.ka24de.com were reduced by $100 in savings), I chose the super tech's for there 10.5:1 CR and I can bring it down to 10.1:1 using a slightly thicker gasket. I don't recomend milling the head because of valve clearance issues. You can use SOHC KA pistons, but I have never been able to find a gasket that would drop that CR low enough for smogable reasons, (but that would be the best budget low buck set up if you could find a gasket thick enough). If you know how to weld you can always clover leaf weld the head to bump the CR, but it takes precision and calculation to get each dome to the 10.1:1 CR.
As far as cams Crower is the only company that I know of that can make you a set of highly aggressive cams that can put you over 6000RPM, but then the KA wouldn't be smogable, and would have a rough idle. That is why PDM and Jim Wolfe are known as mildly aggressive cams that keep you within smog limitations. So I don't find getting rods over the stock OEM reasonable the KA will make peak power at 5960RPM with the mildly aggressive cams. I guess that all depends on how hard you drive your engine, if you would want stronger forged rods.

Eagle rods were a seasonal option sold through Nizzx and I don't know if the sell them still or if they are on back order, I haven't ordered anything from there in 6months.

A full exhaust such as the 3" doesn't pass the cali Db for smog testing a 2.5" exhaust does, (you may be able to get away with 3" at some stations though). Like I said earlier, ITB's are only legal in 3 counties of Cali, if you get pulled over in any other county you can be sited to a smog referee in your county. Politics here suck a$$.


Modified by Bigvinnie at 7:32 PM 11/12/2005

[vvaffle]

Would clover leaf welding be prefered to getting different pistons if you were trying to up your compression? I don't know what the exact laws in New Jersey are but i guess I will have to find out. Don't think they are as bad as in California.

[deviousKA]

"clover leaf" welding of the combustion chamber is an excellent alternative to pistons with a larger dome volume. Thing is, what your doing when clover leafing is increasing the quench area of the combustion chamber. Properly designed, quench area helps to direct the charge of both the intake and exhaust gasses to the port and helps with premature ignition (detonation). Quench area is only effective when the piston top comes within the proper proximity of the "quench pads". This proximity should be no less than .040" and becomes more effective at closer ranges of .030". A flat top or near flat top piston will be able to take the most advantage of the quench area. Excessive quench area without a proper piston proximity can actually work against you and cause premature ignition.

So, in regards to a ka24de for instance, welding "clover leaf" into the chamber without a piston to take full advantage you are only gaining the reduction of combustion chamber volume for compression ratio purpose. The stock ka24de pistons have a dish that begins approx. 3/8" from the edge, anything beyond that you are not taking advantage of your new quench area as a flat top piston would, and you may have some pre ignition issues.

In other words, do both for best results.

[Bigvinnie]

Like I said for myself I chose super tech pistons for a couple reasons.....
This is what is stated on the website.

This set of 4 phosphate coated forged pistons come complete with Chrome Moly steel wrist pins, wire clip locks, and specially designed gas nitrided rings for high levels of forced induction and nitrous oxide applications. The gas nitrided rings included with this set are the very best and strongest currently available on the market! Furthermore, these pistons have extra thick ring lands to handle extreme use. Supertech pistons are currently in stock and ready to ship.


Defenitely the biggest bang for your buck pistons IMHO. I defenitely wont need clover leaf welding for quench surface area. save myself some time and money.

The whole purpose of leaving the dome size quench area stock is knowing that I can use 91octane from what other builders have done making really lean tunes.
I wanted originally to make my engine an 11.1:1 engine, but after realizing that there wouldn't be much play in advancement and no matter how lean the tune would be I would be stuck using 100~106octane, not my cup of tea since it isn't offered in Cali, well atleast 2 counties I know of do sell 101octane out by L.A, not close to were I live unless I filled up at Infinion in Napa every wednesday........LOL (like that was going to happen).
Or I would have to switch to a ethanol fuel and there are only 2 stations offered in Cali so that wasn't going to happen either. I could possibly just keep the engine at 10.5:1, but then there is the risk of using higher octanes supposedly 96Octane, and the chance that I get less room to play with advanced timing.

After all that has been discussed with some builder buddys of mine it is best to leave it at 10.1:1, also that the EGR equipment is still functional to keep NOX emissions low enough, and engine tempratures stable without having to alter or modify other sources of the KA.
The piston swap and thicker gasket in my opinion is the most affordable effective way to keep the engine on 91octane, without causing (knock and ping).

There maybe other small upgrades that I may need such as iridium spark plugs, and SCI ignition and coil, just as an insurance measure to prevent any early knock and ping.

If other people have any other info on what I have built on please add. My build is going to happen once my truck is paid off.





Modified by Bigvinnie at 8:37 AM 11/13/2005

[vvaffle]

I am guessing that having access to 93 octane instead of 91 wouldn't allow you to use much higher compression at all. So if you were going to do clover leaf welding, you would have to go with something like 9.6:1 compression pistons if you planned to be on 93 octane, right? (I think I have heard that someone makes those)

[Bigvinnie]

I am guessing that having access to 93 octane instead of 91 wouldn't allow you to use much higher compression at all. So if you were going to do clover leaf welding, you would have to go with something like 9.6:1 compression pistons if you planned to be on 93 octane, right? (I think I have heard that someone makes those)

There is a little more planning involved than that, if you plan to pass smog emissions though. You have to take into effect chamber tempratures from raising compression, not just the type of fuel you have access too. Fuel only prevents knock and ping, it defenitely won't prevent higher chamber temps do to raising the CR. If you have to high of a CR inevetably you won't pass smog. 10.1:1 is that fine line to passing the smog test on the rollers from what I understand. If you live in a county that is only affected to idle smog checks you have a better chance of getting away with running higher CR's upto 11.1:1.

I understand where you are getting at though for you, you feel that clover leaf head is more effective for you because it is more of a bolt on app, then having to rip open the engine for higher CR pistons. I guess you are trying to keep it really simple. One thing you will need to look out for when you do the clover leaf welding is to make shure that there aren't any hot spots in the dome it can cause knock and ping. Clover leaf welding should only be done by experienced proffesionals.


Modified by Bigvinnie at 12:03 PM 11/13/2005

[TrueSlide]

Would the stock intake manifold even support that??!? Even with a larger TB wouldnt the stock intake manifold kinda hold it back from potential?

[Bigvinnie]

Would the stock intake manifold even support that??!? Even with a larger TB wouldnt the stock intake manifold kinda hold it back from potential?

Yeah it will support it especially once it is ported and honed with the intake side of the head. It won't be the best for top end results, but it will defenitely be better than stock.

[sumyunggai]

does anyone have dyno charts of a NA KA24DE?

[jonah blanks]

jus wonderin, do u hav a cat-back on ure 240?

[HashiriyaS14]

220whp on an NA KA24DE isn't really a practical goal.

If you have really any aspirations whatsoever of going fast in a straight line, either go turbo or swap to an LS1 or something.

NA KA's can be very enjoyable, but only if you recognize their strengths (nice midrange power).

Here's someone who had a great idea for NA KA tuning, this might be what I end up doing:

http://forums.nicoclub.com/zerothread?id=182671

[FliMSiCaL]

I would suggest that anyone doing cloverleaf should have a spare head laying around. I am a decently experienced mig/tig/stick welder, and even i will put serious planning into welding ANYTHING made out of aluminum. I dont know much about smog testing, and i could be totally off in assuming that they test for total allowable emissions in certain categories. In the case however, for people that have custom ecu tunes and such. Could you not pass smog by switching to a much leaner tune for the duration of the test? I ask mostly because i saw a contractor at our plant adjust a LARGE burner of ours from over 2000ppm Co emissions to 1 ppm just by changing the fuel/air mixture. If this doesn't make any sense to al of you, i'll re-explain when i'm sober :P