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SR20 vs. KA24


Guest tejas74260

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Guest tejas74260

alright...i really wanna go the four cylinder way...(please dont tell me to get any other engine besides the ones in the topic) and i wanted to compare the two engines.

 

now, heres the setup i would want...try to be making about 250-300 HP thats good for street (i.e. punch the throttle and youre movin...no lag)

 

heres the turbo i wanna use : Garrett GT28RS (disco potato)

 

ive tried seaching about the KA, but havent really found a lot.

 

now...the big thing leaning me towards the KA...im sure it's MUCH cheaper than the SR...so i'll let you guys loose comparing the two engines making that power with that turbo...advantages and disadvantages...thanks a lot!

 

Mark

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I think the KA idea is actually pretty good. There are TONS of really cheap factory replacement parts for the KA, and like you said, the engines are a dime a dozen.

 

The only problem w/ the KA is that it CANNOT be over reved!!! The majority of ppl who turbo their KA and crank up the boost get carried away, and rev it past redline. Rods tend to break on the KA motors when you either crank up the boost too high, or when you rev it past the factory set limits. With the extra $$$ that you'll be saving, get a good set of pistons, rods, and a metal headgasket. . . maybe a set of cams if you want to spend a little extra. The Intake cams on the 1st gen Altima is 248 deg. like the exhaust cam on the 240, so there's a cheap upgrade.

 

But about over reving it, though. . . This is only possible w/ aftermarket or reprogramed ECUs, but that'd be advisable, anyway. The JimWolf ECU, for example, raises the redline to 73 or 7500. . . BAD IDEA!!! When tuning the KA motor, or any street driven motor for that matter, don't rev it over the factory limit. EVER.

 

Kenny

http://www.rbmotoring.com

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This is a debate that has been and will be going on forever. The Sr is a good engine. To decide which engine is better we must first know what the intended purpose is for.

 

If you are using the engine to drag race, I will say the the Ka is probably the way to go, no matter how you put it there's NO replacement for displacement. The Ka is a pretty stout engine. On stock internals the Sr will be able to handle more boost, but for the extra cost you could rebuild the Ka to be bullet proof. The extra .4l will make gobs of usable torque as well as spooling up any turbo much quicker reducing lag for those great 60' times. As far as the tranny the Ka is known to be just as strong as the Sr, there is really no advantages of the Sr 5sp over the Ka 5spd.

 

If you are going to be using the engine for drifting, auto x, or basically anything besides drag, the Sr is going to hold down the crown. In an environment like that, revs are important. The engine will be in a high rev environment for extended periods of time, not good for the 96mm stroke Ka. Even though the Ka has a good rod to stoke ratio ~1.74:1, the long stroke makes for high piston speeds, that is why most high revving cars like Hondas have a short stoke and are usually over square, with the exception of the b18(a, b, c1, c5).

 

I honestly think the choice is ultimately up to you, I posted something like this between the Sr and the 1jz, I learned that no one can decide for you, just give you some advice to only help you "discover" the right engine for yourself.

 

A word of advice I learned from a very experience engine builder, RPM stand for Ruins Peoples Motors, that is true with any engine, even the rev happy s2k. The more you rev the engine, the quicker it will die, some engines tolerate it better than others, but it will kill the engine quicker.

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The Disco Potato is a hyped up turbo that doesn't deliver the power for the money. The stock S15 or S14 Silvia turbos have dynoed at high power output with similar response, and for MUCH less money.

 

A good turbo for what you're trying to do would be the Garrett GT2871R. It's about the same price as the Disco, but will make more power with great response. The Disco Potato is just too small for the money invested.

 

 

When considering which motor to go with, also consider what you will need to add if you want to turbo the KA. You will need injectors, a computer, manifold, turbo, intercooler, etc... The stock SR20DET front clip will have all this stuff already. Of course the stock SR20DET fuel system can only support about 250-270hp safely, so reaching your goals will still require upgraded injectors and a Z32 MAF would be advisable on either engine.

 

If you want to learn good technical stuff on both engine choices, go here: http://www.freshalloy.com and look at the basic and advanced 240sx forums. Some of the most powerful engines of both types are built by people on that forum.

 

If you go there and ask which engine is better, you will start a ten page discussion on that point.

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KA's suck, final answer.

 

That is not the right answer, ignore that. Do what ever you feel is right man. The cost of building a KA will be more than taking a stock sr and upgading the turbo and fuel management.

 

If you are mechanicially inclined rebuilding the KA is not bad for drag. It all depends on your driving style and the performance that you want to vehicle to have.

 

I had an s13 swapped 240sx, and I got destroyed by a turbo ka at the track once. He was running the same boost, and a similar turbo. He made more hp/tq per lb of boost, especially tq.

 

If you are not mechanicialy inclined, the sr is the easier way to go, since it's already turbo, and has stronger internals.

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Guest tejas74260

yeah, im not really mechanically inclined...but that really depends on your basis of comparison. I'm 17 years old and i want to learn how to do all this becuase i plan on having a profession in this business. i already know a lot about cars but i want to learn to work on them. i've already learned tons about actually WORKING on the car.

 

reason for KA...i think i will be able to achieve better street drive-ability with that engine, and the smaller disco potato or stock s15 turbo. i dont care about huge power or anything, ive read articles about guys tuning on pump gas with 10PSI making 300HP or more (with the KA and stock internals)....thats using the AEM EMS, which is what i plan to use.

 

my 260z is not my everyday driver...i have an accord for that. this is my car that i fix up for "weekend driving", basic fun street driving.

 

i would rather spend more money on the KA making it as good (and hopefully better) as a mildly modified SR because i get to learn about how to work on the car. (not machine work on the engine, i'll have that done :D )

 

either way, my friend and i are gonna pull out my L26 engine next week and this project will begin full swing around christmas time. i plan on making more than 250 HP but prob. a little less than 350, just to keep more problems that happen as the power gets higher than that.

 

thanks for the help guys, i will def. keep you updated!

 

Mark

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KA's suck' date=' final answer.[/quote']

 

Here is why I say KA motors suck for turbo use. When I use the term SUCK, I am really referring to the gross expenditure of money that it takes to make minimal progress in the implementation of a turbo system on to said KA engine. OK, even if you get a 20 dollar KA motor, you are going to spend almost 2000.00 getting it to boost and run in any car. At this point, you are still stuck with the weaker bottom end, who knows how many miles, and you have just paid to have less than a STOCK SR ENGINE. Now if you spend the straight 2000.00 and get a SR front clip, you start out with 200hp and a factory turbo setup, and an engine that most likely has a lot less miles than a run of the mill KA engine. There are even more angles than this to think about KA vs. SR. SR parts are getting very common, at least FOR ME :twisted: and 300rwhp daily driven cars are getting less and less rare and mysterious.

 

BOTTOM LINE AS FAR AS I WOULD REFER ANYONE IN MY SLIGHTLY INSANE MIND IS TO STEER CLEAR OF ANY INTENTIONS TO MAKE A KA ENGINE DO ANYTHING BUT TOW OR CRUISE DUE TO THE SIMPLE LOGISTICS THAT FOR THE SAME PRICE YOU WOULD PAY TO MAKE A FAULTY KA TURBO SETUP WITH HIGH MILEAGE AND RIGGED UP PARTS-YOU CAN DO IT MUCH NICER AND RELIABLE.

 

 

IN A NUTSHELL

KA'S SUCK, FINAL ANSWER.

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Guest tejas74260
KA's suck' date=' final answer.[/quote']

 

you know, no offense, but youre acting really childish and i would apprecaite it if you wouldnt say anything at all if that's all youre going to contribute. i really respect this community for its being mature when dealing with arguments, so dont spoil it for me by acting like teenagers around my age (17) thank you

 

Mark

 

sorry i didnt catch the explanation you had...it didnt load or something

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Guest 240zJake

As i said in another post...

One of the main reasons the SR20 get so much attention is because of its aftermarket support, if you pick up a copy of the November 2004 issue off Super Street magazine they do a head to head comparison of the SR20 vs. the KA24 and the SR has a whole page of after market parts that can boost the engine to 550 plus hp, while the KA has a quarter page. Because of its increased popularity, parts are easer to find and the upgrade path is more worn making it easier to make big power on the SR, it has been done on the KA, but to nowhere near the extent of the SR...

 

Its totally up to you and your wallet :D

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KA's suck' date=' final answer.[/quote']

 

Here is why I say KA motors suck for turbo use. When I use the term SUCK' date=' I am really referring to the gross expenditure of money that it takes to make minimal progress in the implementation of a turbo system on to said KA engine. OK, even if you get a 20 dollar KA motor, you are going to spend almost 2000.00 getting it to boost and run in any car. At this point, you are still stuck with the weaker bottom end, who knows how many miles, and you have just paid to have less than a STOCK SR ENGINE. Now if you spend the straight 2000.00 and get a SR front clip, you start out with 200hp and a factory turbo setup, and an engine that most likely has a lot less miles than a run of the mill KA engine. There are even more angles than this to think about KA vs. SR. SR parts are getting very common, at least FOR ME :twisted: and 300rwhp daily driven cars are getting less and less rare and mysterious.

 

BOTTOM LINE AS FAR AS I WOULD REFER ANYONE IN MY SLIGHTLY INSANE MIND IS TO STEER CLEAR OF ANY INTENTIONS TO MAKE A KA ENGINE DO ANYTHING BUT TOW OR CRUISE DUE TO THE SIMPLE LOGISTICS THAT FOR THE SAME PRICE YOU WOULD PAY TO MAKE A FAULTY KA TURBO SETUP WITH HIGH MILEAGE AND RIGGED UP PARTS-YOU CAN DO IT MUCH NICER AND RELIABLE.

 

 

IN A NUTSHELL

KA'S SUCK, FINAL ANSWER.[/quote']

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This is how I feel, personally I would not go with the KA. If I had a choice, the Sr would be an easy choice for me. I would never put the disco potato on the ka, it's too small. People have made 300whp on 10psi but not with that turbo, trust me.

 

If you already have the Ka motor, ie with the 240sx, then it's okay. Personally I would go and buy the Ka, ti's more work, especially if you're not trying to push big numbers.

 

If all you want is 300whp go with the Sr, run the disco potato and call it a day.

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I have decided to swap a KA motor into my 240Z datsun with a powerglide behind it. I think the argument should be based on what type of power you are looking to make. If you want the standard 300-400hp then the SR might make sense. However, once you start trying to reach the higher hp #'s the KA motor seems to make more sense. Even if you get a hell of a deal on an SR you are still in the hole $1000-$1500 for the cost of the base motor when compared to the KA. Rods for the KA and SR are the same cost and pistons are also the same cost. Head porting is the same cost, but cams are a bit more expensive for the KA motor by ~$250. The KA has a cast iron block(plus) whereas the SR is an aluminum block. I would prefer the cast iron block for increased rigidity on a high hp motor. The KA heads are said to have a higher flow potential from what I have read. This will need to be verified and the extra 20% discplacement is always a plus for generating torque. I believe the problem of the myth regarding the KA is due to a lack of effort to use this motor. Go to the KA-t.org site and you can see several folks making 530hp@wheels and revving to 8K using the KA motor. I am shooting for an honest 650-700hp@wheels and will be sending my KA motor to Peformance Airflow Technologies for the $5K super massage! :D

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:shock: I'd also like to see +500hp daily driven KA motors (pump gas is my definition of a daily driver). The highest hp I've seen a KA produce (@ the wheels) is 490ish. And that was pushing it, too. I wanna know what they do to keep it from blowing?

 

The only thing that I could think of is to change the crank to a shorter stroke, that'll allow a better rod ratio. . . but we're in the US, and noone wants to spend that much to "downgrade" even if it does make a bullet proof motor.

 

-The weakness of the SR is the head (can be bandaged w/ a cheap rocker arm stopper, and eliminated w/ a more expensive lash killers)

 

-The weakness of the KA is the bottom end (can be bandaged w/ a set of expensive pistons and rods, and COULD be eliminated w/ a shorter stroke crank w/ longer rods). . .

 

I really do hope that someone w/ $$$ will be motivated enough to attempt this mod. . . As I mentioned in another post in a different thread, I don't have the $$$ :cry:

 

Kenny

http://www.rbmotoring.com

 

Edit: As for the ppl complaining about the AL block of the SR. . . the KA rods are a much weaker link than the SRs AL block could EVER be. And for the $$$ you'd spend building the KAs bottom end, you could just sleeve the SR, and call it a day.

 

The only reason to go KA is torque, nothing else. It's not a "better" motor than the SR, it's power production is different.

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Kenny, you sure have a lot of bad things to say about that motor.

 

Here, follow some of the links here that show 500+hp KA-T's.

 

http://www.ka-t.org

 

Be sure to click on the names of the guys along the top as well, several of them have some pretty powerful street cars with KA24DE's in them.

 

543hp here:

 

http://forums.freshalloy.com/ubbthreads/showflat.php?Cat=&Board=UBB9&Number=67824224&Forum=UBB9&Words=ka%20record&Match=Entire%20Phrase&Searchpage=0&Limit=25&Old=6months&Main=67795629&Search=true#Post67824224

 

 

I do realize there have been a lot of botched turbo jobs on KA's in the past, but if the motor is built and tuned properly, its been proven it will hold up for a long time. Most of the ghetto KA-T's out there that keep blowing up are guys who can't afford good engine management, and don't bother with it.

 

I, personally, am a big fan of the SR20DET (I've built many of them, my last was 395rwhp on stock internals) But, I can't listen to the stuff you're putting down. I reccomend the SR over the KA anyday, but it ain't THAT bad.

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Oh, don't get me wrong, 1bad180sx. I'm not saying the KA is crap. That's not the impression I'm trying to give. I'm just trying to explain that the AL block of the SR is a far less limiting factor than the KA rods.

 

I'm actually planning on keeping the KA on my 240SX. The thought of the KA has crossed my mind, but I've already have a KA in the SX. . . besides the SR is just easier (for me, at least), and the low end torque shouldn't be a problem in that light of a car.

 

And like I mentioned, I'd LOVE to see a destroked KA motor (2.3 or 2.2) that revved to 8k. I think it could have far more potential than the SR. The main thing limiting the KA to go over the 600 limit is simply the RPMs. The rod ratio just isn't there. . .

 

I do have some plans w/ the KA powered SX, but 1st things 1st. . . I gotta do one project @ a time. lol.

 

Kenny

http://www.rbmotoring.com

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We should not argue about which is better, but let us see how the motor performs once it is built. Then we can make the comparison. BTW, is there a crank that has less stroke that can be swapped? I know a few 1.8L Honda motors that make 600hp@wheels so why is it not possible for a KA? The stock rods may be crap, but who runs stock rods in a 600hp SR? I have already begun work on the intake by chopping off the runners and decking them so I can send it to the machinist. He will port the manifold and then send it back so I can fab the intake. He will let me know the optimal runner length and then finish the wet flow bench testing. Let us see what happens. BTW, they are currently getting 350hp@flywheel N/A on these motors.

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