KA n/a build questions

[Daotoad225]

I have a 1991 240sxse hatch 5spd

JDM VLSDCross Drilled rotorsFully rebuilt (stock) suspension excluding;KYB GR2 gass shocksWhiteline springs

I am building an 'all-motor' KA24DE;

- Arias 10.6:1 pistons - PDM - Racing cams - Custom intake ported and polished - DC Sports header - Custom cat-back exaust (maybe w/testpipe) - Nismo adjustable FPR - Walbro FP - (all other internals stock,....)

WHP goal = 300 - 400

Question 1: What stock internals should I replace to achieve this goal? Any help is appreciated (crank balance?) (valves, springs?) (clutch??)

Question 2: I am currently deciding what injectors to use, is 370cc too big, too small?

Question 3: Do I need a SAFC (or similar) to maintain fuel mixture, or is it possable to tune w/o?

Question 4: What am I forgetting? Im sure someone out there will notice someting that I have forgotten about

[Ajax]

I don't think you would need to replace anything else if all is in good condition, although valves and springs might be a good idea depending on the cam specs.Rods are already forged, so you probably don't need to replace them. I replaced mine which was probably overkill; and I had a full balance job done too (this may be worth it depending on how beat up the engine was to begin with).You probably don't need 370cc injectors, but others more knowledgeable than myself should chime in on that.SAFC is one option, but there are other methods out there (I ended up going JWT retune, though in hindsight, I think I might have been happier going a different route).I hope this helps, I'm sure others will have more thorough info as well.Bottom line: Make sure all other stock components are up to the task (spark plugs, water pump, etc.)

[JNM240]

There is no way you're going to make 300-400 whp on an all motor NA KA, esp with that setup. You'd be lucky to get to 200rwhp with that, even tho it'd be awesome to drive. You might want to look into electric fan conversion and possibly ignition upgrade, as well as aluminum flywheel to get those horses to the ground.

And yes, it is possible to retune your ECU by yourself. Check out the ECCS forumas at HybridKa.com. It will take some patients and learning, but it is possible. Then you can put any size injector in there you want, because you'll be tuning the ECU to that.

[elgarvo616]

yea, 300-400whp is not going to happen with an NA KA. even those robello(?) race KA's dont even make 400whp

[Ajax]

WHP goal = 300 - 400

Funny, I kind of assumed that the rolling smiley indicated that he was being sarcastic.

[DjPantsSpecR]

yeah im gonna assume you were kidding too, before you make an *** of U and ME (assume? get it, anyone?) anywho...

200whp sounds closer, i would say **** the rods and **** those pistons too

go to nissan and get the early model "88" (build year) SOHC pistons, you can even order them from nissan 1mm over, with rings i think its gonna cot you something like 350, i cant remember from when i was quoted

but you'll need to get those pistons flycut for the valves because the compression will be about 11.8:1. Now you could use the 89 build year or older style SOHC pistons and with the 1mm overbore you would still be sitting pretty at 11.2:1, and you wont need to get the pistons flycut.

now you are a little closer to that 2.5 liter

fasteners, no one said anything about fasteners, chances are you are gonna want to rev the piss outta this thing to make any high end, adn for that get ARP everything you can get, mains, rods, and head. also replace the bearings while you are doing all this ****

and then look at getting an entirely custom intake manifold, i am seeing these more and more these days or you could shell outa 600 bones for the excessive motorsports one.

NA is expensive, but it cant be beat for a fun daily driver, i gotta run to class or else i would stay here and rap, but ill be back once i fix my computer at home

[corn322]

I say make your own intake with ITB's and headers, tune them to work with your cams.

[Daotoad225]

go to nissan and get the early model "88" (build year) SOHC pistons, you can even order them from nissan 1mm over, with rings i think its gonna cot you something like 350, i cant remember from when i was quoted

but you'll need to get those pistons flycut for the valves because the compression will be about 11.8:1. Now you could use the 89 build year or older style SOHC pistons and with the 1mm overbore you would still be sitting pretty at 11.2:1, and you wont need to get the pistons flycut.

now you are a little closer to that 2.5 liter

fasteners, no one said anything about fasteners, chances are you are gonna want to rev the piss outta this thing to make any high end, adn for that get ARP everything you can get, mains, rods, and head. also replace the bearings while you are doing all this ****

and then look at getting an entirely custom intake manifold, i am seeing these more and more these days or you could shell outa 600 bones for the excessive motorsports one.

NA is expensive, but it cant be beat for a fun daily driver, i gotta run to class or else i would stay here and rap, but ill be back once i fix my computer at home

Thank you for the info.

I dont think I am willing to spend 600 on the intake alone, but I do havesome 'fabricator' friends who might be able to help in that department.so if I understand you correctly, the '88' SOHC pistons are taller than saythe '89' pistons? I wonder what a machine shop will charge for that kindof custom work...

What about headgasket? metal bead, or?

[nvrplzd240]

dont mean to be a d*** or anything...but found this and thought of this thread

[zerepdivad]

dont mean to be a d*** or anything...but found this and thought of this thread

haha c'mon man don't scare him away............

[VinceSez]

YEEEEEEE BOYEEEEEEE!

[DjPantsSpecR]

pssssssh....

yeah, in another thread deviouska posted a nice piston chart comparing the two piston types and overbore and the result in compression

i believe he says the early pistons have a 2cc dome and the others have a dish. i dont remeber the size. but the dome necessitates the flycut.

[Bigvinnie]

If you are doing all that work you might as well get a Crank Scraper and windage tray. Might as well do a Knife edge (to the crank) through IPP for $250 as well. Get better balanced harmonics, and a bit more HP with a little more higher rev with those added. Keeps your oil cooler too.If you are going to run that 10.6:1 CR you can upgrade your injection rate to 330CC's and pull a cool 40donkeys right there.Also add a tuned ecu to the list. Using the higher CR pistons on a stock tune, and injectors will actually not show very high numbers in HP. The engine will run too lean and the knock sensor will automatically retard your timing to prevent detonation.

[Daotoad225]

If you are doing all that work you might as well get a Crank Scraper and windage tray. Might as well do a Knife edge (to the crank) through IPP for $250 as well. Get better balanced harmonics, and a bit more HP with a little more higher rev with those added. Keeps your oil cooler too.If you are going to run that 10.6:1 CR you can upgrade your injection rate to 330CC's and pull a cool 40donkeys right there.Also add a tuned ecu to the list. Using the higher CR pistons on a stock tune, and injectors will actually not show very high numbers in HP. The engine will run too lean and the knock sensor will automatically retard your timing to prevent detonation.

call me a noob if you want, ive never heard of a crank scraper? 330cc's will add 40 'donkeys' i assume you are reffering to horses. I intend to tune the ecu myself or if it looks too difficult i will get a tuned ecu, or get a safc

does anyone here know much about the "secondary butterfly valves" I think this is what nissan calls the scv, or swirl control valve ??? I have read about removal, but it seems that it is a performance enhancing feature of the engine? help me out folks!

[SMoKeM240]

you wont even get 200whp with that.. i did 10.5:1 comp bored .40 pistons, light weight crank pully, knifed edged crank, ported head and 3angle, short ram intake, header with full exhaust, tuned ecu, blah and it was still slow.. good luck

[nelson8708]

if you did all that and your car was still slow meaning not in the low 14 then that so called ecu tune must suck. Here is a pic of a single cam with 298whp. A few of the upgrades are: 12:1 comp., header back exhaust, custom intake, under drive pulley and a tuned ecu. Last i heard he ran a 13.2 spinning the tires down the track. I want to see what he does when he installs the bottle. The second pic speaks for its self.

[nelson8708]

yeah

[deviousKA]

Damn, nelson, who owns that sohc? If possible, let them know I would like to meet/talk with them, and would be interested in offering them some very good deals/sponsorship of some sort. Not to common to see these setups in S-chassis.

Looks like they put some good thought into the design, the picture doesnt load completely but are the injectors mounted underneath the runners?

That is a devious trick

I doubt it is putting down 290 wheel, NA. If it was, it would running a lot faster than 13.2. With that sort of power on that NA 2.4l setup he could easily lay down low 12's or even 11's with good drivetrain configuration. I guess you mention wheel spin, though, interesting.

What NA tuning are they running BTW?

You ever see the induction setup I had on my old sohc? The engine was completely built, 10.5:1 compression ratio and sitting at 2502cc.

I still have it, dont really have anything to put it into yet though, need a tube chassis. I didnt get a good chance to tune it out in my 240sx, I was already getting 10-12 mpg and still lacking fuel. I designed my intake manifold wth staged sequential injection in mind, but with the fuel prices going up and up and lack of cash to spend on too many "secondary cars", I sold the chassis.

And 240sx are heavy *** cars anyways, imho.

[Bigvinnie]

you wont even get 200whp with that.. i did 10.5:1 comp bored .40 pistons, light weight crank pully, knifed edged crank, ported head and 3angle, short ram intake, header with full exhaust, tuned ecu, blah and it was still slow.. good luck

Obviously some one ripped you on the ecu tune...Just for future reference a stock FJ24E had a compression of 11.1:1 that engine made 238hp at the flywheel, mind you that this is a stock engine from Nissan that was manufactured in only Europe and Japan for the Silvia, (it wasn't even modded yet).It is a less effecient engine than the KA24de (which is much more modern), since the KA uses a pentroof dome head over the FJ, FJ used a hemispherical head design. This means that the flame front on the KA is stronger. Both the KA and FJ share pretty close similarities to the rod stroke ratio, this means in comparison to (boreXstroke) the 2 engines are very similar in producing close to the same power output.KA uses a 89mm bore FJ uses a 92mm bore so you can see where the slight differences are in it's stroke. FJ also used a fully counterweighed crank, unlike the KA, FJ was rev happy past 8000RPM.Number one killer of the DE's is the long runners to the mani, and it makes the engine anemic at higher RPM, manifold and header modification will literally multiply it's power output.

EDIT: corrected some info.


Modified by Bigvinnie at 2:18 PM 4/30/2006

[SMoKeM240]

i think your right about the ecu, cause i changed it back to the stock one and it felt faster.. the car was alot faster, just i dont think it was 200hp. my goal was 200whp and i never got to dyno it

[SMoKeM240]

[SMoKeM240]

KA24E block bored .40 overBlock DeckedHead- 3 angle valve grind, shavedcompression 10.5:1Intake Manifold-Butterflys Removed, portedToga High Performance Rods/Main bearingsToga High Performance Oil PumpOBX Header to 2.5" straight pipe exhaustUnorthodox Underdrive PulleyCenterforce stage II clutchLS auto SS Clutch LineElectric FanK&N Intake Filter with custom short ramOBX short Throw shifterRetuned ECU

most the stuff i had done

[Seishuku]

Just for future reference a stock FJ24E had a compression of 11.1:1 that engine made 210hp at the flywheel, mind you that this is a stock engine from Nissan that was manufactured in only Europe and Japan for the skyline, (it wasn't even modded yet).

There is no FJ24E.The FJ24 was rated at 238BHP, was carb'd with 11:1 CR, and was never made into production. It was for the 240RS Group B rally car. Later put out 278BHP.

The FJ20E was rated at 150BHP, ran 9:1 or 9.5:1 compression.

[Bigvinnie]

There is no FJ24E.The FJ24 was rated at 238BHP, was carb'd with 11:1 CR, and was never made into production. It was for the 240RS Group B rally car. Later put out 278BHP.

The FJ20E was rated at 150BHP, ran 9:1 or 9.5:1 compression.

Yep my mistake you are correct sir it is FJ24 (not the FJ24E). Nissan made this as a rally series engine. Designed for the 240RS(Silvia) platform (not skyline) Although early production skylines (DR30 RS-turbo) used the FJ20et,(DR30 RS) used the FJ20e.You are also correct with the hp rating according to this article.http://www.fastroadandtrack.co...713bb

I also picked up the base HP on the FJ24, it claims that they only made 238BHP.....http://www.fj20.com/

Appoligies I was up way past my bed time I was a nervous wreck...Sorry.

[deviousKA]

There is no FJ24E.The FJ24 was rated at 238BHP, was carb'd with 11:1 CR, and was never made into production. It was for the 240RS Group B rally car. Later put out 278BHP.

The FJ20E was rated at 150BHP, ran 9:1 or 9.5:1 compression.

Yep. The engine itself basically came in kit form, race only direct from nissan. Usually these were bought 2 or 3 at a time with spare parts of course.

There is maybe 3 or 4 real fj24's in the states, tops. Maybe 15 or so left worldwide.

[Bigvinnie]

There is maybe 3 or 4 real fj24's in the states, tops. Maybe 15 or so left worldwide.

True too that, I went searching for an FJ24 hoping to find one for a 510 project. There was one in U.K that could of been delivered to me for $18000.00 (yeah right I can't afford that!) . This engine is extremely rare, and I didn't know how rare it really was until I saw the price tag. This is Datsun/Nissans racing breed engine, this engine is well engineered, and is still admired by many datsun owners. For beeing carburated it outperforms todays Honda F20/22 MPI engine. Outperforms on all levels NA 4bangers with peek torque at about 6000RPM, and peak HP at almost 8000RPM, this engine is a monster high rev 2.4litre.I only brought about the point that if you aren't making over 200WHP on an NA KA with high compression something is seriously wrong. Many of the engineering that went into the KA is direct geometry from the L/Z/FJ if you compare the bottom ends and rod stroke ratios to these engines they are very comparative. Infact KA is nothing more but a re-engineered and up to date l/z engine. With todays MPI and proper ecu tuning the KA should make pretty good numbers, and having a much larger stroke than the FJ24 should produce that peak power much earlier in the power band somewhere around 5600~6000RPM, if built right (that also means a completely redesigned manifold for the DE's). I'm not saying it is an FJ that would make upto 170BHP out of the box, but a properly built NA KA can make decent numbers. If most of these NA KA guy's followed the tricks of these oldschool datsun enthusiasts we could be on the right path to some serious NA KA engine building. But then again no one here takes NA KA seriously and would rather boost.
Modified by Bigvinnie at 7:31 AM 5/1/2006

[boznuttz]

Too much cash, not really worth it for my wallet size.

[Bigvinnie]

call me a noob if you want, ive never heard of a crank scraper? 330cc's will add 40 'donkeys' i assume you are reffering to horses. I intend to tune the ecu myself or if it looks too difficult i will get a tuned ecu, or get a safc

does anyone here know much about the "secondary butterfly valves" I think this is what nissan calls the scv, or swirl control valve ??? I have read about removal, but it seems that it is a performance enhancing feature of the engine? help me out folks!

OOPs didn't see your question earlier. Well I'll be nice this time, but you should search. I've listed these parts myself.A crank scraper breaks the windage oil cloud and oil that disturbs harmonics to the crank. As revolutions increase oil heats up and causes a cloud to form, also due to oil frothing and flinging through the bottom half of the engine. A scraper literally does what it says and scraps oil off the crank and drops it into the oil pan before it is sprayed and frothed through out the engine. It prevent's engine starvation, drops engine oil temp, and increases rev and hp. This is infact a great piece to utilize for a wet sump system, you should also get the windage tray keeps oil from blowing upward or out of the tray. The 2 items are under $110.http://www.crank-scrapers.com/index.html

330cc injectors are simply injectors that have an increased pulse width. They can spray more fuel in a shorter period of time during the fuel cycle or very simply when the combustion chamber will demand fuel. Stock injection on the KA is rated at 270cc injection. If you plan to increase your Compression ratio, the fuel size should be increased, since the engine will literally be compressing more atmospheric elements (specifically O2). This is also beneficial to keeping cylinder temprature cooler, fuel mass is denser than O2 actually prevening a light lean mixture from causing detonation, if you have a KA24de then more than likely the knock sensor will catch this problem from happening. Although this is still bad and a performance killer, as knock signal increases timing is retarded, retarded timing only slows down the acceleration process that increases momentum and power, so yeah you will lose HP.Now if you are looking to build a high compression KA and you are asking how to remove secondary butterfly's you shouldn't be building at all. First off I would do away with the stock DE manifold, (it is garbage) and it only makes the KA anemic at higher RPM. The engine is literally losing 20~30HP in stock trim due to it's long runner length. Although if you just want a torque monster go ahead keep the damn thing. If you want to use all the stock devices chop the flange off of the SOHC manifold, and weld a flang so that it can be used on the DE. Then remove the butterfly's and give it a port and hone job. The e series mani is much more effecient and utilizes top feed injection, this is a much better combination to use on OBD1 KA24de engines, vacuum lines, TB everything should line up with a custom DE flange.Several companies have manifolds that you can use such as xcessive motor sports, and even KA-T (although none of these companies use the stock smog equipment such as teh EGR BPT-AICV systems). Look around for a mani that some what uses a slightly larger TB roughly between the stock 60mm~70mm. I know for a fact that http://www.maxbore.com can take the stock TB and increase it's diameter size by 2mm. 62mm total from stock.


Modified by Bigvinnie at 9:17 AM 5/1/2006

[Ajax]

I'm glad there is some good discussion coming out of this thread. I wish it had happened before I had gotten the engine rebuilt in my car. Once my bank account recovers, I'm going to have to find some better injectors and source a new intake manifold (either Xcessive or get a friend to custom make one).I'm getting more and more excited about getting my car done! I should be posting dynos at the end of the month.

[nelson8708]

Damn, nelson, who owns that sohc? If possible, let them know I would like to meet/talk with them, and would be interested in offering them some very good deals/sponsorship of some sort. Not to common to see these setups in S-chassis.

Looks like they put some good thought into the design, the picture doesnt load completely but are the injectors mounted underneath the runners?

That is a devious trick

I doubt it is putting down 290 wheel, NA. If it was, it would running a lot faster than 13.2. With that sort of power on that NA 2.4l setup he could easily lay down low 12's or even 11's with good drivetrain configuration. I guess you mention wheel spin, though, interesting.

What NA tuning are they running BTW?

You ever see the induction setup I had on my old sohc? The engine was completely built, 10.5:1 compression ratio and sitting at 2502cc.

I still have it, dont really have anything to put it into yet though, need a tube chassis. I didnt get a good chance to tune it out in my 240sx, I was already getting 10-12 mpg and still lacking fuel. I designed my intake manifold wth staged sequential injection in mind, but with the fuel prices going up and up and lack of cash to spend on too many "secondary cars", I sold the chassis.

And 240sx are heavy *** cars anyways, imho.

I dont think that he was putting down that much power either. Last i heard the guy who built it was trying to sell it. Yes the injectors are under the intake and if you look close it has custom flanges on each runner for and direct port nitrous system. I got the pic of that singel cam a few months ago....i cant remember where i got it.