Ka24de RPM POWER RANGE QUESTION.

[Dmurphjr]

Ok so I drive a 1993 Nissan 240 and everything I hear is that power is down low and not up top. A post I read earlier a guy sed he shifts at about 5500rpm bcuz his car doesn't make power passed that.
So my question is what is up with my car? It doesn't make anything for power till about 5000 ta 5500 rpms and it's a very noticeable difference.
The only things I know that are done to my car are a 3" exhaust header back and a cold air intake.
Could it have cams? A tune? What? The odometer currently has 194k does not burn oil, smoke, no funny noises or anything.

Can anyone help me out?

[OutToWinPAHC]

Good reading - http://www.epi-eng.com/piston_engine_te ... torque.htm

Also dyno sheets, you will tend to notice that most NA piston gasoline cars have a similar characteristic. That around 5000-5300 the HP curve crosses the torque curve. Your buddy is shifting where TQ is the highest and TQ is real. The KA is not a revhappy motor, it's not a fully counter weighted crank which limits how high you can take it. The intake design is also designed for a more low end torque design. If you want to know what your car is doing, put it on a dyno and see where it make its max torque and HP.

[Dmurphjr]

What I'm trying to say is my ka24de doesn't start making power till about the same spot everyone says there ka24de quits making power.
It's like just the opposite of everything I hear about the ka24de.

[Dmurphjr]

Also if I shift anywhere around 5k-5.5k the motor bogs.
If I shift anywhere sooner than the split second it gets to the rev limiter it drops right out of the power band

[Jabberwocky]

When I put the Centerforce Dual Friction clutch in my old KA it made the car pull totally different. The dual frictions have weights on the fingers in the pressure plate, and the faster the clutch spins the more those weights spread, making the clutch grab harder. It made mine pull noticably harder from about 4000-5500rpms...it was hands down the best $300 or so I put in to that car.

Might not be why your car runs the way it does, but from my experience it made mine run kinda like what you're describing.

[alms24sebring]

Good reading - http://www.epi-eng.com/piston_engine_te ... torque.htm

Great link, thank you

[Mercury_Hg]

Ok so I drive a 1993 Nissan 240 and everything I hear is that power is down low and not up top. A post I read earlier a guy sed he shifts at about 5500rpm bcuz his car doesn't make power passed that.
So my question is what is up with my car? It doesn't make anything for power till about 5000 ta 5500 rpms and it's a very noticeable difference.
The only things I know that are done to my car are a 3" exhaust header back and a cold air intake.
Could it have cams? A tune? What? The odometer currently has 194k does not burn oil, smoke, no funny noises or anything.

Can anyone help me out?

Could it be your timing?

[Dmurphjr]

Idk that's what I'm trying to figure out. What would make it pull hard up top not down low like everyone says it does

[OutToWinPAHC]

When you figure out what pull is get back to me

[benz88]

i find 2nd and 3rd gear pull hardest between 3-5K after that i shift.

[THE_ROOK_671]

What hes saying is that on the dyno it reved out/limited to only 5100-5300 rpm? After that it fell on its face...the stock rev limiter is what 6700-6900 rpm if im not mistaken on the ka24de's. There was a sohc that pulled its full range a couple weeks back. So my question is with the above statement, What would cause a lower than stock limit? Also this was not only on the dyno but on highway
pulls it would not go past 5100-5300 rpm? Possible valve flow interuption?

It did 3 pulls on the dyno two in 3rd gear and one in 4th gear
like preivuosly stated right around the 5k area it falls out of the powerband on the dyno.

[neverlift]

bad knock sensor or wiring gives a very big boost in power at 5500rpms... like hitting the spray almost(a solid 70whp on my boosted ka) on an na ka its got to be good for about 20~30whp.
Some have experienced this with cts as well.

answer this does it feel 'ok' on power then hits 5.5k and ~screams~ to redline?
Knock sensor was what caused me this, my boosted ka felt soft till 5500rpms then would rape those last 1500rpms like a switch was cut on(cause it was a switch(at 5500rpm the stock ecu stops reading knock and advances as normal.

[THE_ROOK_671]

It seems ok on the road power wise but then again almost stock ka, it just barely starts making power at 4500k then shuts down as if like you said theres a switch i should be making an extra 30hp as you mentioned, ill let the video do the talking.

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[costa_rican13]

so if i disconnect my knock sensor ill get more power after 5500 rpms??

[asoomal]

What no....

If it senses a knock, it'll retard the timing...like really retard the timing before 5500RPM. So when you hit 5500 RPM, it'll feel like you hit major VTEC...in reality it's just running how it's supposed to at that rpm. Think of it as a major bog.

[costa_rican13]

sorry im kinda retarded. lol not really but anyways, so if its bogs then how would that be vtec? because wouldnt that mean it would be faster if it was "vtec" style? sorry for the noob questions even though i should know this already having my car for 3 years.

[asoomal]

Well, it's s*** to begin with in the first place. When you hit 5500 RPMS, that's what it should be pretty much from 3000 and on. (When the knock sensor is retarding the timing).

VTEC as in....1000 RPM-5500 RPM = Nothing

5500 RPM - Over9K RPM = Happy Time.

[idreamofs13's]

Had to erase my first post as I didn't quite think it through before I typed.

/hijack
in an attempt to translate airplane engine speak into car speak, are the intake and exhaust runner length the same as intake and exhaust manifold lengths? and, would cam lobe profiles refer to getting tuned cams?

I've got the engine parts list made up for the KA I intend to keep and I hope to get a map that includes a flatter torque curve for DD.
/hijack

[neverlift]

what I m saying is if the issue is a knock sensor related issue, when you hit 5500rpms the motor will feel like you GAINED 30whp, well you probably gain like 20, when the ecu detects knock or the sensor/wiring is bad it just retards ignition timing from anything over half throttle to wot from 1000rpms~5000rms(5400 is when the map goes back to normal advane). When you cross that point in the map the car screams feeling like vtec or a small spray of nitrous.

NO removing the knock sensor wont make your car faster, it will exhibit poor performance and bad mpg...

[THE_ROOK_671]

How does a knock sensor give you horsepower? isnt a knock sensor just a safety device? allowing retard timing to prevent further
damage to your engine? correct me if im wrong, but i think it sounds like a fuel cut??? any help would be appreciated...could the mass air flow be sensing a faulty reading at 5k causing a premature fuel cut which lead to that early rev limiter?

[Dmurphjr]

bad knock sensor or wiring gives a very big boost in power at 5500rpms... like hitting the spray almost(a solid 70whp on my boosted ka) on an na ka its got to be good for about 20~30whp.
Some have experienced this with cts as well.

answer this does it feel 'ok' on power then hits 5.5k and ~screams~ to redline?
Knock sensor was what caused me this, my boosted ka felt soft till 5500rpms then would rape those last 1500rpms like a switch was cut on(cause it was a switch(at 5500rpm the stock ecu stops reading knock and advances as normal.

Yes you've got that pretty good. So I need a new knock sensor?
Mine I think has been moved to the head insted of on the block or somethin.

[neverlift]

that s*** was like a plague to me on my last motor. New motor it was still an issue(same harness new sensor) but I went rom tune and eliminated the knock feedback entirely, its not even plugged in now. I tried 3 sensors before giving up lol, all removed and installed under the manifold in oem location.

[Dmurphjr]

that s*** was like a plague to me on my last motor. New motor it was still an issue(same harness new sensor) but I went rom tune and eliminated the knock feedback entirely, its not even plugged in now. I tried 3 sensors before giving up lol, all removed and installed under the manifold in oem location.

Nice lol thanks man