KA24E vs DE Which one can rev higher?

[Var]

If you race prepped either the KA24E or KA24DE. Which one could rev higher?

If both had racing rods, bearings, pistons, headwork, and camshafts that made power at high rpm's..in theory which one would be "happier" at high rpm's. Does it make a difference that the DE has more moving valvetrain parts? Or would both motors pretty much both be similar because they have the same bottom end?

[sykikchimp]

With the stock crank, both will be limited to about the same. ~7K

[mistaanime]

hehe..juss get a apexi rsm...it cancels the limiter..i do have one for sell..juss to let ya know..

[Var]

Ya that's exactly what i was thinking. Get a chip and my engine will safely rev to 9 grand

[Rennen]

Do a search on oversquare and undersquare engines, the KA isn't really made to rev high. Revving to 9 grand is kind of silly if you look at a stock KA dyno, you need to better define the "race prep".

-Matt

[Var]

Originally Posted by Rennen

Do a search on oversquare and undersquare engines, the KA isn't really made to rev high. Revving to 9 grand is kind of silly if you look at a stock KA dyno, you need to better define the "race prep".

-Matt

sorry i was trying to be sarcastic. The post was about which engine can rev higher and if you read my original post, i DO define race prepped. But some guy figured he would try to sell me rev limit chip figuring i didnt know shit and i was looking to rev over 7 grand without actually making more power after redline. so i says..ya gimme your chip that will magically make my car rev higher...haha. It may rev higher once..

[DuffMan]

Originally Posted by mistaanime

hehe..juss get a apexi rsm...it cancels the limiter..i do have one for sell..juss to let ya know..

Yeah except a RSM doesnt remove the rev limit, it removes the speed limit.


To answer the question, the KA solid valvetrain is pretty good at high rpm with upgraded springs, its the stock crank thats the limiting factor, so they are both about the same.

[Var]

Ok thanks for the input. I have a single cam and i like it. I've always been planning to build it and sometimes questions pop up in my head. Thanks again

[andrave]

you could destroke the KA24DE and rev high.
then again the ka24E has hellacious NA support, I believe it was used in the truck racing stuff like the ford 2.3, so there are tons of parts, including twin sidedraft carb kits and cams that come on at 6k...

[zenkiDori]

there are SCCA GT cars that run SOHC KAs that rev to 9k. it's possible but expensive.

[Rennen]

Ah, sarcasm tends to own me over the internet

What I meant to say is that that an Oversquare engine(bore longer than stroke) is better at making high RPM power and is "happy" there. While Undersquare motors tend to make more low end torque in truckish applications. So depending on whether your "race prep" rods/pistons/crank focus on boring out the cylinders(higher RPM) or focus on increasing the stroke(more low end torque) they could help or hinder your goal...... but I guess to your original question. Either engine will be about the same. If you have a SOHC, I would just go with that. I have a spare KA24E just sitting around waiting for me to try some NA tricks to .....

-Matt

[crioten]

matt: did you and james have fun lifting that into your car?

[knightrider]

well, my expirience with my single cam, and my jim wolf ecu with no rev limiter, and jg cam. the engine loves to rev, it makes loads of power 3k+ it doesnt seem to let off either, and ive done plenty of over revving, at dd10 i was trying to blow up my car by doing donuts on the skidpad in 2nd gear at 7k for about a minute. i stopped when my tranny started smoking, the motor however didnt even stumble. it ran strong for the rest of the day at dd10 and is still running, and after i got home, i changed my tranny fluid, which looked like hell. and ive got no problems with the engine still, i think the only thing that might kill this motor, is a bottle of nitrous, and a 150 shot. btw, ive got 160k on the odometer, and besides the drifting and donuts, i take good care of my car, that might have sumthin to do with it.

PS rumor has it that a shop had tested the limits of a KADE and it sustained 22 minutes at redline. hehe. dont remember what failed though.

[nismospec]

Originally Posted by westboroughpimp

sometimes questions pop up in my head. Thanks again

a question should pop up asking you why dont u go with a DOHC

[ledzeppelin240]

And then another question pops up why listen to someone who has no backing to statements???Maybe he is just talking out of his ass?Or maybe having 16valves allows for a little bit better flow, but could the intake runners have anything to do with it, there was a thread on DOHC vs SOHC but it wasnt related completly...These are all little things that can affect a engine when all that money is being put into it.

[9524tee]

i had a built sohc ka ... crashed the car but anyways ... i got it to rev to about 8500 rpm,s after 4800 bucks worth of work on it , worth it you may ask ... kinda lol , but i have done just as much work to my current ka which is a dual cam , and id say that my sohc i had revved higher and easier than my dohc does . hope it helps .

[ryan hagen]

ideally the de should be able to rev higher, haveing no lifters cause of the shims. the E has a valve train with lifters and all them moving parts at high rpm have a chance of moving in all differnt directions, but i heard some one say they were worried about shims blowing through the valve cover but the wayt he shim is in the bucket i cant see that happening unless they are running under ground cams and didnt re shim, which theyd be running some hard core slop............

[sykikchimp]

Having 2 cams would allow independent tuning of overlap with cam gears which of course wouldn't be possible with the SOHC.

I would think the DOHC motor COULD ultimately rev higher, and produce more power.

fyi - the stock crank has some really bad harmonics aroun 76-7800rpm.

If you really want a badass high revving KA, you will need to destroke it with a custom short stroke crank, get longer rods, bore out the cylinders like .050, and raise compression to about 12-13:1.. Get some custom higher duration cams, and some badass valve springs.. adjustable cam gears, adapt some ITB's on there, and DAMN!@

[andrave]

you could most of that with factory parts (albeit not all nissan ones).
I know someone that did it.

[Var]

Originally Posted by nismospec

a question should pop up asking you why dont u go with a DOHC

The question has been swimming around my head for 6 months now. But instead of asking that question straight up and getting a bunch of newbish opinions from everyone, i ask different questions(like this post) that ultimately will make the decision for me.

Imagine how stupid the thread would be if it read

"What's better SOHC or DOHC"

There's no better. I'm trying to learn about things rather than just do what someone else thinks is tight.

[Ghettokracker71]

Ask DeviusKA(sp) about SOHCs....from what I understand hes gotta couple beast ass ones....

[andrave]

thats who I'm talking about... think he has some badass DE's too
he keeps tight lipped tho.

[GlacierFreeze]

Originally Posted by sykikchimp

fyi - the stock crank has some really bad harmonics aroun 76-7800rpm.

Stock crank is supposed to be half counter weighted (sp?). Wouldn't that have something to do with the harmonics? If so, wouldn't having it fully counter weighted help out a decent amount? But then what about piston speeds?

[deviousKA]

KA, in and of itself, can withstand 8k+ rpm properly balanced and prepped. That is with stock stroke and crankshaft. There is really no arguement to this because it has been done many times (aside from race-only engines). This has to do with the rotating assembly, much headwork and design changes need to be done for this to be realistic.

Destroking is something rarely discussed as far as ka is concerned. Many times you will read that it is impossible, or terribly expensive to do. I have been working with 2.2-2.4l destroked ka24's for the last 2 years. These have mainly been topped off with ka24e heads, but recently i have been working with the ka24de platform. Just incase anyone is wondering, these combos are done using different blocks and different crankshafts (and different rods/pistons as well).

As far as what is better for high rpm, ka24e or de, what would you call high rpm? The ka24e design has been proven to flow efficiently for decent hp, upwards of 9500 rpm. This is with a 2.2l displacement, oversquare design, long rod ratio engine. This of course has some very "different" design as far as headwork and cams, compared to using 2.4l long stroke displacement.

I believe that the de platform has more potential for efficient flow characteristics at high rpm. This, like noted before, has to do with the seperate cams, and excellent valvetrain design (second only to the qr and similar, for a nissan 4cyl) <imho. The ka24de valvetrain design is basically identical to rb series, and same design as toyota 4age and others. Cam and port setup for the particular geometry of the engine is the most important! Both and e and de valvetrains properly set up can handle many more rpms (and flow well btw) than you could get with a stock crankshaft and rotating assembly.

And now for the goods, various destroke setups i have personally built.

bore x stroke
90mm 86mm 2.2l ka24de, 1.75 r/s fully balanced (z20 crankshaft/z22 block/altima ka24de head)
91.1 92 2.4l ka24e 1.79 r/s fully balanced (z22 crankshaft/z24 block/ka24e head)
90.2 88 2.3l ka24e 1.70 r/s fully balanced (z20 stroked crank/z20 siamesed block/ka24e)

These shorter stroke crankshafts (z20, l20, l18, l16 all fully counterweighted btw) will fit directly into any z or l series block. This along with the fact that the ka24e head can be used with these blocks, and ka24de as well, makes for a variety of possible combinations. There are many necessary modifications i wont go into here, but you can get an idea of what "can" be done. Fitting of the shorter stroke crankshafts into a ka block is not a viable option (i can tell you why if anyone wants to know). This picture compares a half counterweighted crankshaft (bottom, like ka) and a fully counterweighted style (l16,l18,l20,z20 datsun and others)


I usually keep tight lipped haha, just like andrave said, mainly because i could fill 10 pages on info pertaining to this subject and i hate to type. This is just a super basic glimpse of what is possible.

[andrave]

and we are all humbled by your prescene.
you must spend way too much time with your head in motors, man...
thanks for the info.

Everyone gets intimidatd with engines thinking that there are "limits" inherent in any design, but in reality... just like you could look at a block of wood and with the proper tools, time, and training, make anything from it, an engine is similarly just a block of metal.
and if you hit a limit, you can often fabricate/substitute/machine your way around it....

[ryan hagen]

to understand the valve tain and why pushrods suck:

http://www.nissanperformancemag.com/april03/nerds/

[da man]

ok so i know this thread is old as **** but i wanted to see if there was in new progress/updates on the subject.
i originaly found it at ka-t.org heres the link

www.ka-t.org :: View topic - KA24DE Bottom End Modifications

and someone on there put a link to this one. this one is more indepth (imo)then the other so if anybody can bring this back much appreciated

[S-Verteen]

Ive read this thread on ka-t .org i respect the strive for cost effect. I tried contacting the guys from import dps for the build specs on there ka and to ask the rev limit with no luck. I believe there was a corr pro 4 truck running dual cam ka24de and 280 cams. right now im @7500 on 272s but always want more power!

[sr23det]

the chances of 2 posts that's 7 years apart