KA24DE and KA24E research, looking for input

Information on the naturally-aspirated KA24E and KA24DE engines.
RykrosGT
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Hey everyone... first post on the forums, but I've known about the site for some time and I've been searching around and picking at posts for the past week or so. Been contemplating an S13 or S14 Silvia, and have pretty much decided on doing up an S13 in the next year or two.

I've done my research on the KA24DE, E, SR20DET, and CA18DET ... and based on everything I've seen I've decided to go with either the CA18 or the KA24... -leaning heavily on the KA24 work for various reasons...the top of which is off-boost drivability... so here's my question (inquiry, really)

I know that the 89-90 has the KA24E, and 91+ had the KA24DEFrom what I've read, for NA applications the SOHC E would be the better choice ... but I am not after an all-motor 240.My question that I have searched adamantly for (and bonk me if I missed it) is:

Are any noteworthy differences between the E and DE that might make one better than the other for a turbo application?

This stems somewhat from a small debate a friend of mine have had about 4 valve heads versus 2 valve heads, flowrate and pressure with having additional vales even though they are smaller, fuel economy and flow, etc and so forth.

I've worked a bit with my turbo Ford vehicle (XR4Ti; Garrett T3-equipped 2.3L SOHC Pinto engine WOOT!) and obviously it puts out a great deal of power so it doesn't "bother" me if the E end up being the better choice. Just that much less internal resistance in another cam, additional valves, etc.

Any feeback and bouncing of ideas with discussion is appreciated.

Thanks guys


RykrosGT
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hmmm.. no opinions? =)

Turbo_Nismo_EC
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Well it has been proven time and time again that 4 small valves breath better than 2 big vlaves. Now being that the KA24E has two efficient small valves on the intake means that it breaths in well, it's just not as efficient breathing out. Now, for ME, building a SOHC KA was the way to go because I have a 95 HardBody truck and I didn't want to have to change the motor, ecu, wiring harness, and all that so simply using the KA I had was a more economical solution for ME. Now whether or not the KA24E like boost as well as the KA24DE, I don't know, as I haven't got my JWT fuel set-up back yet so I haven't installed my turbo, but we will soon find out. I'm gonna be running like 10-12 psi so we'll see what she does, and IF I can hook it up, you know, being it's a truck.

Turbo_Nismo_EC
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Oh yeah, also remember that the KA24DE has a higher compression ration than the KA24E, so that could also affect the advertised horse power, not giving the 4-valve head all the credit.

Goodbar6
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Heres my unintelligible (sp) thinking on this:

The SOHC KA24E has 2 intake valves and one exhuast valve The DOHC KA24DE has 2 Intake and 2 exhuast valves.

A turbo relies on how much air you can flow through the exhuast, so looking at the big oversimplified picture, i would have to say the DOHC 16vlave would probably be able to spool a bigger turbo quicker then the SOHC 12 valve.

Please someone correct me if i made huge mistakes!Tyler

RykrosGT
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I'm not really concerned about compression ratio, as I'm going to be rebuilding the block and setting it up with lower-compression pistons, etc anyhow.

So I suppose I'll be searching for 92-93 model years to get an S13 chassis with a KA24DE

As far as valving, essentially I came to that conclusion with him... that two smaller valves can make up for the surface area (flow etc so forth) and then some, versus a larger single valve... because obviously... you can only make one circle within a circle so large... in order to match the surface area of the two smaller valve circles you'd have to pretty much have one big, somewhat oval, valve.

What I didn't know (or I just forgot?) was that the KA24E was a 3-valve setup.

So I can understand the valving argument, and thanks to those who have replied so far. -so now I'm under the assumption that there are no other significant differences between the 12v and 16v KA engines? What backs up the argument that the E has better NA potential than the DE and supports the power better? Significant ECU differences? Or is it just compression-ratio related?

Turbo_Nismo_EC
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testis 1..2..3?

Turbo_Nismo_EC
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OK it worked.

Now, from what I have learned, there are differences in the motors themsleves. If you want to know EXACTLY the differences between the two motors...like all the details, call Nissan Motorsports at (310) 538 - 2610. They helped me a ton with building my KA24E. They can give you ALL the nitty gritty on the two.

I have forgotten a lot about the details they have given me so instead of making a mistake I will just refer yo to them...cool?

Hope this helped:ylsuper

Turbo_Nismo_EC
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Oh yeah, but what I was saying about the compression ratio is that the KA24DE has a higher compression ratio than the KA24E. This would make more power in the KA24DE. What I was saying is that the head is not the entire reason that motor makes that much more power on the stock motor. That is why I think the SOHC head will be sufficient for producing ample power. I would suggest lowering the compression ratio in the KA24DE, but the KA24E has a pretty low compression (9.0:1) anyway which is pretty boost freindly. However, the KA24E pistons, so I was told by JWT, have a weak piston where the rings are and at over 5-7 psi, they tend to malfunction. OK..that is my 2 cents for the day.

Lates:alcoholic :beerchug :beer :ylsuper :slap

RykrosGT
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OK, thanks for the replies guys. I spoke with Nissan Motorsport (already had their number, was inquiring about other stuff too anyhow) and basically they said aside from cams, and compression ratio...(and obviously heads) they're the same. The guy there spoke with one of their resident "gurus" =) So... piston design is the same, block design is the same, etc. He just said don't go over 15psi ;) hehehe... but I'd rebuild the motor with lower compression pistons anyhow.

Thanks guys. Looks like a KA24DE for me... then the fitting into an S13... fun. =)

Goodbar6
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Good, im glad we got that all figured out! Make sure and update us on any progress or new info ya find!Tyler


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