Dynoed my KA24DE... something wrong here

[g.lay]

123 hp
138 ft-lbs

injen short ram
300zx fuel filter
walbro 255 fuel pump
3' custom exhaust
deleted cat
new coolant temp sensor
new cap & rotor
new spark plugs
aiv removed

from idle to 4000 rpm power ouput is smooth,a/f ratio is fine
4000-5000 running rich between 15:1 and 16:1
5000+ running lean between 12:1 and 13:1
the engine really falls flat after 4000 rpm adn the dyno graph becomes really rough and spikey


anyone know what could be causing this problem?

thanks

[BigVinnie]

I know for a fact that removing the AIV and it's vacuum lines will have you running rich. Especially if you are still using the stock ecu. If you remove part of the vacuum system, the On Board Diagnostics switches into a safe mode and dumps more fuel, and retards timing.

[SoSideways]

from idle to 4000 rpm power ouput is smooth,a/f ratio is fine
4000-5000 running rich between 15:1 and 16:1
5000+ running lean between 12:1 and 13:1
the engine really falls flat after 4000 rpm adn the dyno graph becomes really rough and spikey


15:1 and 16:1 is really lean.

12:1 and 13:1 is a little more rich.

14.7 is stoich.

Anything above that numerically is lean, and lower than that is rich.

[Phlip]

What year is this car?
How many miles are on it?
Your output is actually quite close to what I have seen posted before, even with your (still rather) minor modifications.

[SpeedMonkeyInc]

Its a little backwards from what I would have thought with the Walboro. IIRC those raise the base fuel pressure to something like 50psi. I am not very familiar with N/A air fuel ratios, but your numbers do seem off.
KAs do pretty well with just bolt ons, but even with headers you are not going to see much more than 140 or so whp.
Check out the dyno charts on Orion:S14's website

http://www.ka24development.com/dyno_charts.html

[g.lay]

http://xs75.xs.to/pics/06140/DSCF0.jpg

Sorry about the lean/rich mixup. Heres a pic. The 240sx is a 91 HICAS with 137,500 miles.

Thanks for the help so far.

[SoSideways]

That looks a little lean until 5000rpm.

What's your fuel pressure set to? Is your TPS in good working condition and is reading the right range of voltages?

What's your timing set at?

[mellojoe]

That looks really lean. You need to get back in there and do some tuning or something. You want to be under the redline.

[g.lay]

well the ecu is throwing no codes so i assume the tps is fine

fuel pressure is stock,unmodified other than the walbro

timimg i am unsure of,if everything else is fine would that be the culprit?

[SoSideways]

Well, your graph looks pretty damn lean, so if I were you, I'd look into why your car's running lean like that.

Fuel injectors dirty and clogged? Too much timing advance? Spark plug too hot and gapped to wrong size?

[Maeda]

15:1 and 16:1 is really lean.

12:1 and 13:1 is a little more rich.

14.7 is stoich.


Do you have any idea what you're talking about?

The ecu will set the afr at around 16:1 under part throttle conditions. Try it. My cars like that, and so is everybody elses that I know, short of those that run standalone.

NA KA = Sorry buddy. 140rwhp is what you're going to get. I know it's depressing.

Best thing you can do is check if your timings cool and maybe advance that a lil bit.

[phrozen]

pshh 160hp here with less mods then that

[Maeda]

You da man!

I forgot to add... COMPRESSION CHECK THE MOTOR!

[SoSideways]

Do you have any idea what you're talking about?

The ecu will set the afr at around 16:1 under part throttle conditions. Try it. My cars like that, and so is everybody elses that I know, short of those that run standalone.

NA KA = Sorry buddy. 140rwhp is what you're going to get. I know it's depressing.

Best thing you can do is check if your timings cool and maybe advance that a lil bit.

I was just trying to tell the guy that he had his numbers backwards. He said 12:1 was lean and 16:1 was rich. I just told him 16:1 was the lean number, and 12:1 was rich.

And yes I do know that the KA runs lean under part throttle, I see my friend's KA-T hit 16 to even a dip in the 17s when he is just cruising around, accelerating in vaccum still. As a matter of fact, he had a toasty O2 (the 1 before the cat) and his car ran lean as hell, to the point where the car studdered and "bogged" from a stop, when the car was cold. It's now better with a Bosch O2 from Autozone.

As for my car? I have an SR with the O2 unplugged (cause it's dead) and I am running a little rich, but damn, car feels better the way it is than with the O2 plugged in.

[S14DB]

Most KA's run lean when you add I/H/E. SAFC should get you back into the safe zone.

[g.lay]

Actually if I had 140hp I would be happy. Reread the graph,I'm sitting around 121 hp thats why i'm concerned.

[Maeda]

KA = No HP.
Don't fret. My car only makes 220 horsies, but it makes 300 lb/ft of torque. :D

[shayrgob240]

KA = No HP.
Don't fret. My car only makes 220 horsies, but it makes 300 lb/ft of torque. :D

what's done to it, if u don't mind me asking?

[kazuo]

pshh 160hp here with less mods then that

...

...on a Dynapack.

Cheater.

Anyway, a couple years back when I did a dyno day with some guys, one of them had a stock '95 KA24DE in his S13, he put down around 125whp on a DynoJet.

Make of that what you will.

[Maeda]

what's done to it, if u don't mind me asking?

I insTalled an Up facing fishing pole, theRes a Bit Of carrot on it.

[A Spec Products]

i dynoed my stock KA once

it had like 210k on it

120hp
124tq

that was on a dynojet / at that time compression was fine

maeda's setup is the best KA-T setup in the world, super top secret spec

[thejester03]

I insTalled an Up facing fishing pole, theRes a Bit Of carrot on it.

Ahahaha......

Safc did wonders for my AF ratio, still needs a little fine tuning, but putting down a noticable amount of more power.