Ideal KA24DE Fully Built Engine??

[deviousKA]

Yes, my terminology was backwards. Continueing:

Nissan says .040 maximum overbore. Period. You want to go higher, be my guest, but don't whine when it busts into a water passage or you crack a block in two.

Show me these cars, and dyno sheets, and tell me technical specifications on who decided to make a stroker crank for you and the ludicrous amounts it cost. You think you can push an engine with a bore out to the limit you suggest and a ridiculous stroke like you suggest and expect it to not implode? You overrev the sucker once and you're looking at piston speed I don't even like to think about.

Most people who try to extract more than 100hp per naturally aspirated litre are looking at very large bore short stroke engines (IE, S2000 engine). These rely on a high redline to be able to achieve maximum power, also at the cost of a torque loss. The KA is plainly not that. The people that have extricated THE MOST proven NA horsepower on a KA have done it with an 11.0 to 1 ish compression ratio, stock stroke, and individual carburated throttle bodies. They got about 240whp. Also keep in mind, that no street driven 240 has this setup as far as any of our knowledge goes. It's insanely expensive and doesn't yield itself to any real street use. You can maybe get 200rwhp on a high compression setup with every bolt on imagineable, an ECU retune, and some fine dyno tuning. Maybe. Very few have been able to. You want to not deal with a turbo and the hassles you get there.? Go get an N20 setup. 100-shot and you are right at your power goals.

I really hate to be rude, but please do not post uneducated things and speak them like the truth. This does not help people that are reading the boards to learn. I will not comment on what I said again, because there is no need.

honestly, do you beleive what you say is true? if so you have a lot to learn about the ka and engines in general.

I hope you dont feel the need to comment any further, because this thread is full of your wasted posts already.

[trpower7]

You bring me the proof that says otherwise. It's all simple. You bring me someone that's done it, someone that has it, give me a dyno sheet, I'll believe you. I am an expert. I have built engines. I have bored and stroked engines. I have seen people decide to spend a lot of money to make a powerful NA KA.

You heard of the problems Nissan is having with the QR25DE? Gobs. I'd take the SR anyday over QR, the whole really-long-stroke thing is murder for the kind of thing most people want to do with these style engines. You find me a machine shop that'll make you a stroker crank for a KA for any less than a grand. Quotes I've gotten from large, professional engine builders have run from about $900 to as much as $1600. And that's assuming I give them a block and crank to fool around with for an extended period of time.

You want to overbore a KA that close to a water passage. Let's say I get really liberal, and go to .080 over. I've increased it to maybe (I'm not doing the math at the moment), .1L more. For that kind of risk, no thank you. Then let's put in this mythical stroker kit of yours, and we'll bring it up even more to 2.7L. So now we have a .3L larger, still undersquare (and by the way, ANYONE knows that getting two words mixed up is not even close to not knowing what each is and what each represents), far past Nissan specified clearance engine. That alone, may net you AT MOST 40ish crank hp, translating to about 36ish whp. That brings to a little sub-200 range. Ok, so now you have to make 60 more hp. You can do it with some high compression, bolt-ons galore, radical cams, the usual deletes (AC, mechanical fan, UR pulley), and an ECU retune then some major dyno time and tuning. At the end, you'll have an engine that is super fine tuned, MIGHT run on pump gas, and will be pretty damned near close to maybe 250hp. Maybe. We've seen high compression KAs gain no more than 10ish hp.

If any of this is incorrect, you show me how. You give me numbers, spec sheets, dyno pulls, technical specifications, and cars you have that have proved otherwise. So far you have provided none of the above. You go find me ANYONE With a dyno proven 260hp NA KA, and I'll stop. Until then, this is what logic and theoretical research yields to be the optimistic truth. The closest anyone has gotten was that SCCA championship car; which btw was tuned right to the edge and used an EXTRAORDINARILY expensive ITB kit that was a one-of-a-kind. Not to mention, it was an all out race car.

Once again, my original point was that you won't do it. You simply will not. I can gaurentee right now, that you won't get there. It simply costs too much, requires too much work, and is too complex for anyone but a professional racing and engine building team. It's likely you probably wont' even start.

[TrunkMonkey]

You say the KA is to oversquare (but you mean undersquare) to stroke more, I guess you never heard of a QA25DE, eh?

i'm not sure what you'r trying to imply here, but the KA and the QR are not related to each other. they just both happen to be undersquare engines.

The KA hasn't even been scratched yet, to make claims that stroking it or that 100hp per liter are impossible or outragiously expensive just shows your limit, not the blocks limit.

building an all motor KA is outragiously expensive, especially since there's no "already taken" path to follow. nissan motorsports, rebello, nasport...the builders of these high performance all motor KAs aren't goint to sneeze a word as to how they do it.

-demetrius

[TrunkMonkey]

On the subject of overboring a ka, it can be done. I have bored a ka block until i hit a passage to see how much material was available (because i use/sell 91.1mm overbore piston kits, thats .080" over btw). I feel that 91.5 is the furthest one could go, any more than that and hotspotting will be a problem.

i accepted your explanation of how much you overbored your block, but i may have made a mistake. i would really like to see pictures of your pistons installed in a 240sx KA block with two consecutive cylinders being measured by a micrometer. you told me earlier that you didn't want to give away too much info because you were selling them, and i understand that. but if you are selling them, then the secret is already out.

i would feel more comfortable if people could see exactly how much room won't be left between the cylinders after installing these pistons.

Btw ka24e truck blocks seem to have the thickest cylinder walls, although not as thick as z20 siamesed block when bored to same spec.

the truck block's cylinder walls is thicker than what block? i seriously doubt the 240sx's since the blocks are basically the same.

Also, i have seen and talked to a few people who have increased the displacement of their KA, besides me. 98mm stroke 91mm bore (2600) is one setup i have seen, and i know of a super stroker 2.7l project as well. Problems with this other than what has previously been mentioned is that the valve diameter becomes to small to flow for the displacement. Larger valves and major porting is a must.

just a note, and this isn't directed to deviousKA, but if you have to use a different block other than the KA's to change the engine's displacement, then it's no longer a KA. i've sen it mentioned in several threads where building a "KA" involved using a different block. the block itself determines what engine it is.

Btw. 260 na hp is a much different from 260 turbo hp, especially on the track

ain't that a fact .

-demetrius

[TrunkMonkey]

You want to overbore a KA that close to a water passage. Let's say I get really liberal, and go to .080 over. I've increased it to maybe (I'm not doing the math at the moment), .1L more. For that kind of risk, no thank you. Then let's put in this mythical stroker kit of yours, and we'll bring it up even more to 2.7L. So now we have a .3L larger, still undersquare (and by the way, ANYONE knows that getting two words mixed up is not even close to not knowing what each is and what each represents), far past Nissan specified clearance engine. That alone, may net you AT MOST 40ish crank hp, translating to about 36ish whp. That brings to a little sub-200 range. Ok, so now you have to make 60 more hp. You can do it with some high compression, bolt-ons galore, radical cams, the usual deletes (AC, mechanical fan, UR pulley), and an ECU retune then some major dyno time and tuning. At the end, you'll have an engine that is super fine tuned, MIGHT run on pump gas, and will be pretty damned near close to maybe 250hp. Maybe. We've seen high compression KAs gain no more than 10ish hp.

you're being to generous with your numbers.

overboring .08 to achieve 2.5L is for bragging rights. the standard .04 doesn't net any gains, and i'm sure the .08 nets double that. you will not see a 40 hp gain with an increase in stroke. you will see a nice jump in torque, but no where near a 40 hp gain.

the more you increase your stroke, especially on an undersquare engine, the more you lower your redline. if you're trying to achieve 100 hp per liter, this is the opposite of what you want to do.

If any of this is incorrect, you show me how. You give me numbers, spec sheets, dyno pulls, technical specifications, and cars you have that have proved otherwise. So far you have provided none of the above. You go find me ANYONE With a dyno proven 260hp NA KA, and I'll stop. Until then, this is what logic and theoretical research yields to be the optimistic truth. The closest anyone has gotten was that SCCA championship car; which btw was tuned right to the edge and used an EXTRAORDINARILY expensive ITB kit that was a one-of-a-kind. Not to mention, it was an all out race car.

260+ hp KA's do exist, but they are all race engines.

-demetrius

[deviousKA]

i cant comment on much now as i need to leave soon.

My engine being 2.5l is a side effect of the particular pistons i put in. I was not trying to acheive this primarily, my goal was getting over 10.5:1 CR without spending loads on custom pistons. I was to a bit wary at start but seeing as i have the facilities, tools, availability of engines and such i decided with my machinist that it was a good idea and worth a shot. I will have my head off in the next coming weeks as i am getting a shipment of cam regrinds and valve train parts from my distributor. i will snap a pic (you can imagine, .080" less material between bores, .040" per bore)

the comparison to the 2.6l mitsu engine has nothing to do with using a different block with the ka. That engine is a 91.1mmx98mm and 12 valve (similar to the florida 2.6l ka).

I have not tryed to express stroking the ka crank to gain ultimate hp. In fact, if you have followed any of my discussions and/or builds you would know my projects are on the other side of the spectrum. Although i do defend what can be done because i have personally seen or had experience with these projects.

The mexico cast ka24e truck block DOES have marginally thicker cylinder walls vs. ka24e 240 block (i have compared over 10 subjects) This comment has nothing to do with de other than the fact that the E and DE 240 cylinder walls are very likely identical.

I will try to find the person to post and comment on the 2.7l, i have no knowledge of this engine other than knowing it is being done.

[03frontyka24]

i'm not sure what you'r trying to imply here, but the KA and the QR are not related to each other. they just both happen to be undersquare engines.

Yes, but the QR is more undersquare than the KA and still has a 6100 RPM redline stock.

It was a response to some ignorent statement that went "The KA is already an oversquare motor, you try to stroke it any more and you're looking at a very rough, 5K RPM redline engine."

Do you agree with that statement?

As far as expense, it will be more expensive than a turbo, but it isn't impossible as some have claimed. The fact that you would be working in a vacuum means it would be a lengthy process if you wanted to save a buck, you would need a block to do mock ups with crank journal offsets, you would need to spend a lot of time with a dremel in your heads and manifolds, etc..., or you could pay a few grand here or there instead, but it certainly is possible.

Like the turbo route, you can turbo a KA for $1500 if you shop junkyards, wait for deals, and do it all yourself, you can turbo one for $5000 if you buy a kit and pay someone to put it on for you, or you could turbo one for $10000+ if you were building a professional race car. You are throwing around figures here based on how the racers do it.

Hell, you can stroke a SA20DET with a $8000 dollar kit made for racers, undersquare it for a few more ponies, but you can also stroke it for a fraction of that, the same with the KA if you want to spend the time, pick up a spare block for a few hundred and play with it.

There are shops grinding stroker cramks for other engines for a couple hundred, sure they won't know the ideal grind or have jigs made, but believe me if you ask around you can find someone who will grind one at your risk, especially if you have that spare block. Its been done by low buck racers before. Finding the right rods, porting and polishing, fitting bigger valves, etc... It can cost a fortune, but it doesn't need to, you can do a lot of stuff yourself, sure you will have a lot of trial and error, but so did the first guy to turbo a KA24, and I'm sure the experts were telling him to drop in an SA20 instead.

Me, I'd just throw a buick 231 in if I wanted a rocket, the KA24 is not the best engine choice for performance, it was designed for reliability first. The SA20 isn't any better, not as good for the money as a KA turbo. Neither can touch a buick V-6 NA with a trick or two in it, and cloning the turbo grand national setup isn't that hard, the 231 is well known and relativily low buck.

Of course where I live I don't have emission inspections, it gets tedious swapping engines once every year or two to get tested, and truthfully I am happy with my truck, if I wanted a fast car I would get a mustang or Z28.

[Jonny 290]

If I was trying to hit 260 on a KA, I wouldn't stroke it.

I'd destroke it.

Piston velocities are BAD on the KA at high revs. I'm pretty sure that would help out somewhat, although I'm not positive.

Destroke, 12:1 comp, race gas, tuned headers, fat cams, retainers and springs.....yeah, it could be done.

would it be fun at 75 in third? oh yeah.would it be fun in rush hour? dear god, no.

trailer queen for sure.

[trpower7]

Absolutely. Also, talk about some serious tuning work and every bolt on under the sun. And then you get your doors blown off by a KAT. Hmmm.

[03frontyka24]

Destroking a KA might be a mistake. Sure you could build more revs, but the KA is not really built for high revs, you are better off going with its strengths.

I don't know why people think 1.1 undersquare won't rev, it defies all logic to assert that when there is absolute proof otherwise, and by maximizing displacement first you more easily stay within the rev limits of the upper end. without lots of modding.

Anyway, a NA mid 200's KA will easily match or beat most KAT's and SR20's, and all nissan plants will be left in the dust by a $2500 mouse motor.

[Nathan]

by maximizing displacement first you more easily stay within the rev limits of the upper end.

It's not the upper end thats the problem though, cams and springs will get it ready to go for MUCH higher revs, its the physical piston speeds at high rpm's. The stresses they put on rods, rod bolts, wrist pins etc. is very high.

[03frontyka24]

It's not the upper end thats the problem though, cams and springs will get it ready to go for MUCH higher revs, its the physical piston speeds at high rpm's. The stresses they put on rods, rod bolts, wrist pins etc. is very high.

Like I said, look at the qa's 100mm stroke, a stroked KA won't get more undersquare than this. The QA has a factory 6100 redline, the same as my KA.

There is no reason a stroked KA can't rev high, it can't rev as high as a destroked KA obviously, but the extra displacement makes up the difference.

The QA has lighter rods and pistons, You would need to makie sure you did the same in a stroked KA, but this is not uncharted territory, it is just uncharted on a KA.

Saying it is impossible is kinda silly. I don't see why anyone would do it outside of meeting some engine rules for a racecar though. If you want a performane KA a turbo is easier, if you want a performance engine the KA is a poor choice to start with, but it isn't impossible, or even that hard.

[TrunkMonkey]

Like I said, look at the qa's 100mm stroke, a stroked KA won't get more undersquare than this. The QA has a factory 6100 redline, the same as my KA.

which KA do you have? none of the 240's have a redline that low.

There is no reason a stroked KA can't rev high, it can't rev as high as a destroked KA obviously, but the extra displacement makes up the difference.

The QA has lighter rods and pistons, You would need to makie sure you did the same in a stroked KA, but this is not uncharted territory, it is just uncharted on a KA.

Saying it is impossible is kinda silly. I don't see why anyone would do it outside of meeting some engine rules for a racecar though. If you want a performane KA a turbo is easier, if you want a performance engine the KA is a poor choice to start with, but it isn't impossible, or even that hard.

the more you stroke an engine, the lower it's redline. there's no way to get around it. i'm pretty sure engine manufacturers are conservative with the redlines that they set with their vehicles, but from what i've read and heard from several sources, the KA in stock form) just gets scary between the 7500-8000 rpm mark. sure, you can rework the valvetrain and bottom end, but like you said, what's the point?

if you want a high revving engine, buy a honda.

just a note, it's the QR25DE, not the QA.

-demetrius

[95hardbody]

I think he's probably talking about a truck. On my '95, the redline starts at 6000, which is what I've seen on every other Nissan truck, including the DE-equipped Frontys. I also think this is where the rev-limiter is set (6000 rpm) on the trucks. I don't really ever rev mine past about 5000 rpm or so (even though peak HP is at 5200)...it just gets too harsh and loud. What is the redline on the 240s? I didn't figure they'd be different from the trucks...you know...same engine and all.

[TrunkMonkey]

iirc, the SOHCs have a redline of 6400 rpms. the DOHC powered S13s have a 6900 rpm redline, and the S14s have a 6500 rpm redline.

someone chime in if any of these are wrong.

i'm pretty sure cams have a lot to do with where the redline is set on the KA.

-demetrius

[s13ofdoom]

my 90 240 E reds at 6400 i think the DE is differnt

[deviousKA]

the redline is lower on the truck kas because of the cams. they develop hp at lower rpm than 240sx.

Stroke is a factor of rpm due to its effect on piston speed, it is not the only factor. Properly balanced, lightened, and with stronger components the ka rotating assembly is known to rev safely to very high rpms. With cams to match a ka developing peak hp at 8000rpm is not as far out of reach as one would think.

[s13ofdoom]

devious ka u have all those cars??????? u have a nice collection and one day i hope to rival it

[trpower7]

The KA cannot rev safely to very high RPMs in it's current stroke. Plain and simple. Maybe 8K a few times, and it isn't making power there to boot. Go look at a dyno graph of most all NA KA's. It is far out of reach. You won't do it. No one will do it. It doesn't make any sense to do it. It isn't economically smart to do it.

[twistex]

well My ka24de race preped 17:1 Revs to 9200 RPm with the snap of my fingers. I built with my own hands. the rod/stroke ratio is perfect for high rev motors. I dont care what all u say about the ka and all ure disses to this motor. I know what they can do and thats it. I will get video footage on this if thats what it takes !anyways I LOVE KA's and KA's LOVE ME, and MY NUTZ

[TrunkMonkey]

well My ka24de race preped 17:1 Revs to 9200 RPm with the snap of my fingers. I built with my own hands. the rod/stroke ratio is perfect for high rev motors. I dont care what all u say about the ka and all ure disses to this motor. I know what they can do and thats it. I will get video footage on this if thats what it takes !anyways I LOVE KA's and KA's LOVE ME, and MY NUTZ

care to tell us what you did to get your KA to rev to 9200 rpms?

-demetrius

[twistex]

well ..sit and think for a second !

im running carbs .. basicaly itb's im getting more air and gas then u will ever get out of a stock injection setup.. unless u wana go twm or somthing to get smoother ride. I have some fat cams in it .. i got reground .. way bigger then pdm or jmt cams .. they make cams for injection. with carburtation u can get way more lift and duration in the mix. full motor balanced lightend and knifeedge crank and alum flywheel. fordge rods and pistons. put realy stiff valve springs in because at around 8200 to 8500 the stock ones will float and u will bend ure valves.

if u want cam specs i can let u know .. put it this way with a lift .430 duration .230 and .050 i pulled easy up to 8500 rpm .. i have a bigger lift / duration cam in the motor now ! 9200 all day long .. just for drag .. car dont run for long periods of time like road racing.. but thats my next plan is to get one reving to 9200 rpm all day long !

[Jonny 290]

17:1? Seriously?

You running alky or anything? Jesus!

That's some serious compression.

[tl1000sga]

Yeah, I would like to see pics of this motor.

Who did your cams?

[deviousKA]

devious ka u have all those cars??????? u have a nice collection and one day i hope to rival it

yeah i do, i guess it is a collection of sort, i just came across them all and couldnt pass up.

twistex engines are in his sig

[xxtrizz]

you know I hate to bring this post up again but I guess twistex kinda killed the argument with his engine haha.

Deviouska could you give me a run down of a streetable KA sohc that you have running and what kinda mods you put into it to make it reliable and strong on the street/track?

[lofapoo]

260rwhp on a KA-D? That would take some SERIOUS time, money, and risks. I'm just going to keep this simple and ignorant, go turbo or n2o :p

[raging panda]

Can someone explain to me what to do about ecu when you carb the KA? I think about it, but all I can come up with is either no ecu, ecu w/o maf and injectors, or standalone. I might try this on my S13 because its cool, but I want a low cost so if its standalone thats out of the question.

[deviousKA]

all you stock ecu needs to do when you run carbs is work all of the lights and body electrical of the car. you can just unhook all engine wiring, except maybe the oil sender. Might be wise to run some type of aftermarked o2 sensor and a/f reader so you can tune it.

So all you need to run a carb setup, is the carb setup, different fuel pump, vacuum distributor and older nissan type ignition or aftermarket like msd. Thats basically it

[raging panda]

Could you leave the distributor connected to the ecu so it would spark, or does the spark function stop without the things you would disconnect? And the fuel pump, is that regulated by the ecu how?