Power Difference in KA24E and KA24DE??

[ghettomateo777]

I've just started learning about cars and I have a 90 240sx Fastback (180sx). I just found out that my car has the KA24E, not the KA24DE. I know this seems like a stupid question, but how much power difference is there between the KA24E and the KA24DE??

[95nismo240]

not much at all. its like a 5hp difference. the only real main difference is the the E is single cam and the DE is dual cam

[ghettomateo777]

Yah I found that out. I researched what the SOHC and the DOHC are and what they do, and DOHC is better. I was just wondering if it will hamper on performance.

[:: orion ::]

KA24E is rated at 140HP...

KA24DE is rated at 155HP.

They respond similarly to modification, so the SOHC always has a ~15HP disadvantage.

- Brian

[scruffy63]

also the ka24e is a little safer to boost if you have one with the 8:6:1 compression.

[ArticDragon192]

KA24E is rated at 140HP...

KA24DE is rated at 155HP.

They respond similarly to modification, so the SOHC always has a ~15HP disadvantage.

- Brian

And an inferior head.

[ghettomateo777]

also the ka24e is a little safer to boost if you have one with the 8:6:1 compression.

I'm a newbie when it comes to technical stuff for cars. Can you explain the compression for me.

[deviousKA]

Cams being so important to a decent NA build, the sohc ka24e has a flat out advantage. Cams are cheap, wide variety of grinds available, and easily installed and adjusted for. A sohc with even a very mild performance grind will easily outperform a dohc with stock cams at higher rpms.

The sohc also has an advantage in the weight department, not only in overall weight but in reciprocating valvetrain mass. The dohc has 2 timing chains (one being dual), and 4 timing chain gears vs. one chain and 2 gears of the sohc. Also the sohc obviously has only 1 cam that weighs just about equal to each of the dohc cams. The sohc does have rocker arms that add some weight above the valves (roughly 65% of total rocker weight), although the dohc has buckets and shims that sit on top of its valves (100% of total bucket/shim weight). The sohc has valvesprings with stiffer spring rate and can handle more lift/duration with oem springs.

The 3 valve arrangement of the sohc ka only has a disadvantage in flow in the exhaust (about 30cfm difference, on a flow bench) in stock form. This is somewhat marginal and can be worked to flow equally due to some of the factors ive have listed above as well as others.

What im trying to point out here is that the sohc should not be discounted so easily. Both cylinder heads have their advantages, neither could be called "better" than the other overall. One large advantage of the dohc in NA form is the combustion chamber volume and chamber design. In basic terms, high compression setup is easier to accomplish.

And remember, the fastest KA in existence is a SOHC. That is, unless, there is a dohc ka24de pushing over 700hp running under 8 seconds in the quarter mile and pulling wheel stand in the process.

[ghettomateo777]

Cams being so important to a decent NA build, the sohc ka24e has a flat out advantage. Cams are cheap, wide variety of grinds available, and easily installed and adjusted for. A sohc with even a very mild performance grind will easily outperform a dohc with stock cams at higher rpms.

The sohc also has an advantage in the weight department, not only in overall weight but in reciprocating valvetrain mass. The dohc has 2 timing chains (one being dual), and 4 timing chain gears vs. one chain and 2 gears of the sohc. Also the sohc obviously has only 1 cam that weighs just about equal to each of the dohc cams. The sohc does have rocker arms that add some weight above the valves (roughly 65% of total rocker weight), although the dohc has buckets and shims that sit on top of its valves (100% of total bucket/shim weight). The sohc has valvesprings with stiffer spring rate and can handle more lift/duration with oem springs.

The 3 valve arrangement of the sohc ka only has a disadvantage in flow in the exhaust (about 30cfm difference, on a flow bench) in stock form. This is somewhat marginal and can be worked to flow equally due to some of the factors ive have listed above as well as others.

What im trying to point out here is that the sohc should not be discounted so easily. Both cylinder heads have their advantages, neither could be called "better" than the other overall. One large advantage of the dohc in NA form is the combustion chamber volume and chamber design. In basic terms, high compression setup is easier to accomplish.

And remember, the fastest KA in existence is a SOHC. That is, unless, there is a dohc ka24de pushing over 700hp running under 8 seconds in the quarter mile and pulling wheel stand in the process.

So what your sayin is that SOHC isn't bad. That's kool...I just want to make the car look good. I would like to upgrade the exhaust system, intake, and headers. I'm still thinking about a Silvia front clip, and I might possibly swap the engine when this one wears out. Should I stay with the KA24E or swap it with a KA24DE and I was wondering which engine would be better for a turbo??

[Veriest1]

The KA24DE and KA24E have been shown to respond about the same to boost.

[dfw240_EE]

If there is anything I detest about my DOHC it's that stupid chain setup.

[grip_racer]

and your sohc has a better powerband than the dohc.

at least in my opinion. the motor pulls better to redline because power doesnt drop off as much as with the DE motor.

[gumby]

sounds like ghetto blaster is looking for a can of worms

nice writeup on the diferences in the heads

[B-TownSX]

Correct me if I'm wrong but the power steering of the SOHC and DOHC are on opposite sides. If you were going to do a ka24e swap to a ka24de or sr20det, you are going to get some extra work. Unless, if you don't care for powersteering.

[kakapoopie]

what about gas mileage? is there much of a difference there? Im seriously thinking of buying an S13, but im still in highschool so i need something that will give me decent mileage. theres alot of SOHC over here for cheaper than the DOHC but i never knew the SOHC had it's own advantages. I also like the pig nose better . Are there any other differences between the 240sx pre 91 and 91-93 other than the engine?

What do you guys think?

btw right now i have an MKIII supra but its nowhere near roadworthy

[dickie]

if you already have a mkIII, get a civic or something if youre worried about gas mileage. more than 10mpg better than a 240.

[kakapoopie]

no...im trying to get rid of the MKIII...lemme put it this way, it has no windshield wipers

its just a total rustbucket, and it would be cheaper to buy a 240 than try to get it to running condition.

I'm planning on having the 240 as a DD and thats it, the supra is pretty much taking up space and im not gonna work on it since 240's are faster anyway

[dfw240_EE]

I wouldn't be so sure, the Supra is a devil of a car. The S13 in stock form really isn't all that fast. It's a sharp performer to be sure, but not a roadburner.

Though I am not familiar with the MkIII so I can't say much. On a limited budget if you can't work on the Supra for awhile, it may be better to get rid of it.

[kakapoopie]

yea ill prolly get rid of it, i really dont have time to work on it either, cuz i'm studying design (hoping to become a car designer someday), which is a full time kind of thing.

the MKIII is a piggie though, i think its like 3500lbs or something, and mine is n/a, so its not that fast. It might be allitle faster than the 240, but its also a gas guzzler and wouldn't keep up in the corners.

anyways, back to my original question, hows the gas mileage on the SOHC

theres a 90' 5speed 240sx for sale near me i might go see on monday thats got 110k mileage and is supposed to be in "incredible condition" for $1700. Does that sound like a good deal?

[dfw240_EE]

OK, my '92 DOHC gets about 21-22mpg city only and about 28mpg strict highway. Edmunds.com lists the 90 SOHC at 20/27mpg. So that should give you a general balpark guess.

[kakapoopie]

ok thanks...cant escape these gas prices anyway.

i should be going on monday then to see a pre 91 wish me luck