Still confused about why SR > KA

My engine is sitting on 199K+ and with only 3 cylinders working I was told from the mechanic that the engine will be dead soon. So I started looking around at options, mainly a new (lower mileage) KA or an SR.

But after looking around and seeing that an SR20DE was roughly 150 hp and a KA was at 155, I started thinking and basically. My question is:

If u threw the same turbo on both then wouldnt the KAT > SR20DET?

I would think that a KAT setup would give u far greater torque than a DET setup while keeping the weight down in the car from the swap. Also, having greater access to parts would be a plus if something did arise.

Additionally, I plan to track the car in the future after its no longer my daily driver and have heard that the SR is better for track and the KA is better for drag. Why is this? Is it the powerband or delivery of power?

Well any help clearing this up or helping me understand would be appreciated. Thanks.



P.S. I've been on this forum for over 2 years and I know I dont post a lot anymore but that doesnt mean that Im not always reading the threads, mags, and basically dreaming about this setup, so dont flame me. I've read the faqs here, on KAT and zilvia. (Im not new to this forums flaming history.)

ive also heard the KA is better for drag then SR myself, but also you have to consider that the KA has a much lower redline, im not sure of the exact number, something like 7000? while i know a built SR can handle 9000 revs.

SR head is more effiecient then the KA also .. just some food for thought.

as a daily driver i would go with a SR20DET , not a turbo'd SR20DE as having a factory turbo'd engine in your car rather then an engine with a turbo added on later, should be a lot easier to maintain and a lot less hassle if done correctly. this also applies to a KA

just my 2 cents:2cents:

ive also heard the KA is better for drag then SR myself, but also you have to consider that the KA has a much lower redline, im not sure of the exact number, something like 7000? while i know a built SR can handle 9000 revs.

Wouldnt some valve springs be able to correct that by upping the redline?

SR head is more effiecient then the KA also .. just some food for thought.

Im confused. What do u mean by its more efficient? Like its able to produce more power with less effort? If so, how and why?

as a daily driver i would go with a SR20DET , not a turbo'd SR20DE as having a factory turbo'd engine in your car rather then an engine with a turbo added on later, should be a lot easier to maintain and a lot less hassle if done correctly. this also applies to a KA

just my 2 cents:2cents:

I live in the nazi state of California so Im trying to avoid going SR, even though its looking like get a new ka-t/SR and get it installed for about $5k or go get a car I dont want for way more than $10k, which myself nor my parents can afford.

Im not 100% sure of why, but im pretty sure even a built KA cant rev very high, maybe stroke? 2.4 is a lot liters someone correct me if im wrong.

as far as head effieciency, i cant offer much technical information.. just that i remember cruising KA-T.orgs forums and hearing the KA guys say that the SR Head was more effiencient , i think it has to do with Higher RPM air flow crap. :X

living in cali would suck, im lucky to live in FL where anything goes, for having to avoid getting your SR legalised, a KA-T would probably be better, but i have no idea if they are capable of passing smog tests.

hopefully that helped a little!

ok im going to add some food for thought since i dont do it very often and this is actually a legit question.

#1 if you have a ka, you can honestly rebuild the motor for 2000 bucks (or less, depending on you skills) and turbo it for only a fraction more (if you wanted the same setup as a SR (aka t25 or t28)

#2 yes with the same turbo the ka will produce more torque due to the greater stroke.

#3 yes the sr is more "rev happy" than the ka, its becuase of its decreased stroke.

#4 supposedly on the SR the head is concidered its weak point...so Grim you kinda have it the other way around ;)

#5 if you improve the head of the ka you are just as capable at high rpms as a sr, and its been proven. the only reason a sr would be more reliable at high rpms is because of its decreased stroke.

#6 as far as im concerned they are both great options...but i say hell if your smart and know so people you can easily get a ls1 in a 240 for the same price as a mildly built turbo'd ka or sr, and be more reliable and have nearly the same power...theres some food for thought :D

have a nice day :lol:

living in cali would suck, im lucky to live in FL where anything goes, for having to avoid getting your SR legalised, a KA-T would probably be better, but i have no idea if they are capable of passing smog tests.

hopefully that helped a little!

The KAT should pass the smog test just not the visual if the tester knows anything about cars, and that my car is not supposed to have one.


ok im going to add some food for thought since i dont do it very often and this is actually a legit question.

Thanks drift. I for sure thought I was going to get flamed for people thinking that I was starting another sr > ka thread.

#1 if you have a ka, you can honestly rebuild the motor for 2000 bucks (or less, depending on you skills) and turbo it for only a fraction more (if you wanted the same setup as a SR (aka t25 or t28)

I can change my oil, brakes, sparkplugs, etc., fix a couple of things that go wrong, change my exhaust for a fix it ticket and that kind of stuff, but to do the entire rebuild, no way.

#2 yes with the same turbo the ka will produce more torque due to the greater stroke.

#3 yes the sr is more "rev happy" than the ka, its becuase of its decreased stroke.

so in a racing setup/situation, would the ability to be more "rev happy" trump the fact that the other guy has more torque? From my understanding, if u can get to a desired speed quicker (w/ torque) u should be faster even though u have to go into another gear than someone that can pull longer (more rev happy) cuz it takes longer to get there. Is my reasoning wrong?

#4 supposedly on the SR the head is concidered its weak point...so Grim you kinda have it the other way around ;)

#5 if you improve the head of the ka you are just as capable at high rpms as a sr, and its been proven. the only reason a sr would be more reliable at high rpms is because of its decreased stroke.

So kinda what I got from that is that stock the sr is built better than the ka but the ka can be upgraded easily to be at or better then an SR in terms of performance.

#6 as far as im concerned they are both great options...but i say hell if your smart and know so people you can easily get a ls1 in a 240 for the same price as a mildly built turbo'd ka or sr, and be more reliable and have nearly the same power...theres some food for thought :D

I dont know anyone that has a shop, works on cars, or someone that "knows a guy". Its just me, my 240, my gf that hates the 240, my buddies that are just as bad as chicks when their talking about cars, and cali. laws out here.

have a nice day :lol:

Still confused but now about different things.


On a side note, whats up with the RX7? I havent seen any new pics or vids up since u did a test run when u first installed the engine w/o an exhaust. I remember it sounded killer...

For your case if you are going to drive this car on the road and be legal in Cali your best bet is to go with a KA.

There are a lot of people in VA that believe in KA's. They make great power.

You already have one. You don't have to go out and buy a $2000 sr swap and then install it.

You can take the extra money rebuild the KA and turbo that.

I'm not being BIAS I have a SR20det but where I live they don't smog cars so I can drive a sr all day with no problems.

ok heres the lowdown.

the SR is a slightly better designed motor. that said they are both 20 year old motors and have their weak spots. theres no real point to making a ka rev higher. you have to basically reengineer the motor and you wont get a ton more hp. the basis of the motor was to provide midrange torque for those altimas that it went into. now the 240sx head was designed and built in yokohama as opposed to the altima/pickup truck head which was built in mexico. so the head is good but still designed around a long stroke motor that has too high a rod ratio to rev very high. you can change stroke but you cant change rod ratio very much. but thats ok, build the valvetrain and raise the rev limit a little bit. i wouldnt go above 7k though.

there really is no replacement for displacement. turbos can make use of this to spool faster and provide a much fatter torque band. the reason everyone thinks the SR is a better motor is because of its design. the aluminum block, fully counterweighted crank, and forged pistons and rods help, but the KA has forged and shotpeened rods, a forged crankshaft, a very stout iron block, and a good head/valvetrain. its all about preference, but overall performance the ka24 has more potential. it takes more to unlock it, but you dont have to buy a whole new motor. the SR is not a god motor, its a shitty small 4 banger that was way overbuilt from the factory, with a turbo hanging off the motor. the ka24 was a motor that wasnt overbuilt, but has more potential if only because of its size.


its sort of true that the ka is better for drag racing and the sr is better for drifting, but not totally true. you can make more power and torque with a KA, and drifting doesnt require tons of hp, but people get caught up in the SR's higher redline and wide use. id prefer the flexible low down torque of a KA so if i drop the revs too much i can still recover a drift. wide flat torque bands are the name of the game in drifting. id say if anything the only thing an SR is better for is time attack and such, since its lighter.

id say if anything the only thing an SR is better for is time attack and such, since its lighter.


First: That was a damn good answer to my question and the first time anyone has actually made a knowledgable answer about why either of the engines is better.

Second: I thought that the sr swap makes the car heavier? I might go sr if the swap reduces weight. My ultimate goal is to have a track car, not for drag but like u said time attack and scca like AWD.

SR20 swaps weigh about the same as a stock KA. once you add a turbo and other stuff the KA will weigh more. keep in mind though, most SCCA rules will put an SR swapped 240 or even a turbo'ed KA 240 in a class with tube frame race cars. you dont see alot of 240s in scca because although they handle well, their motors suck n/a. you just cant get the power n/a without sacrificing durability. find the race/track/organization you want to compete in before you choose your path.

well, this is gonna piss some people off (except maybe D-Bo). but if you do some research, adn I dont mean asking someone else, I mean READ about the different Nissan mills, instead of running out and buying an engine just because someone else thinks it makes them cool cause they got them an sr, you'll learn quickly that the sr20 really isnt that great af an engine, if you just want a fast car yes either one is great but if you want supercar kind of performance you're gonna have to pay for it and I would reccomend somthing a little better engineered.

^^^ uh huh. exactly.