itb write up request...

Information on the naturally-aspirated KA24E and KA24DE engines.
User avatar
NismoGreg
Posts: 267
Joined: Thu Dec 11, 2003 11:05 am
Car: '93 s13 fastback se, '87 200sx se v6,'91 integra ls

Post

I was just wondering if someone would like to do a step by step write up on how they installed their ITB system on a dohc. Can you use a stock ecu? Do you have to eliminate your MAF? Would be a good thing to have in the article section.


PandaS14
Posts: 173
Joined: Wed Oct 06, 2004 8:22 am
Car: S14

Post

Funny you should ask, I recently did a writeup for my setup.

Remember, this is only one way to do it...

Quote »Just recently got this project running, so I might as well do a writeup.

Here goes.

Intake mani and TB's

First, get some 01' or higher Suzuki GSXR 1000 or 750 Throttle Bodies.

Then get an extra intake mani.

Cut the runners off approximately 6" from the head flange.

Go to Home Depot and get some rubber plumbing couplers. They're about $5 a piece with clamps.

Clamp the Mani and TB's together to yield this...









And with the couplers trimmed down, and the velocity stacks on...





Now make 2 brackets that brace the TB's to the mani, for extra strength.

I used 3/4" by 3/16" steel. You can find this at Home Depot. Bolted one end to the TB's and the other slips under the mounting point for the PCV rail. Make one per side. Should look something like this...



Now make a bracket for the throttle cable to slip into. I used 1 1/2" angle iron. This can also be found at Home Depot. Make it to bolt onto the mounting surface that the EGR used to sit on.





Get a SOHC throttle cable. The DOHC one is wayyyy too long. The SOHC cable is too long too, but better than the DOHC one. The end of the Nissan throttle cable that slips onto the throttle wheel fits in the Suzuki throttle wheel perfectly.

get two air boxes from a 01' and up GSXR 750. These have the shortest velocity stacks. Each airbox has two short stacks, and two long ones. Once you have 2 boxes, you will have two full sets of velocity stacks to help you achieve the best powerband down the road.



That's it for the manifold part of things.

Now the fuel management.

I chose to use a MegaSquirt (MS) because of price, and because, well, I love DIY stuff as you can probably see. haha

Get your board and bags of components all lined up like so...



Build the stimulator first. This will help you learn how to make proper solder joints befor you start soldering the actual MS together. The stimulator hooks up to Megasquirt and stimulates the MS such that it thinks it is running an engine. What this does is allow you to make sure all of your MS is built and running correctly before trying to start the car with it. It also allows you to download new codes to the CPU chip as you see fit, without having to have the MS in the car. Very trick.



Follow the MegaManual at http://www.megasquirt.info and you will end up with this...



Now build the pigtail for the wiring harness...



and here's a better pic of how many wires there are. This is the entire engine harness. Stock one gets removed completely.



that's basically it for the MS.

Now for the ignition setup.

I chose to run a distributorless system off of early 90's Ford Escorts. This system uses a trigger wheel that is mounted to the crank pulley to fire the ignition instead of a gear driven distributor. This has many advantages, the first of which being that it is more accurate than the stock distributor. It also gives full control of the ignition timing.

from left to righ in the pic below, we have the EDIS module, the VR sensor (reads the trigger wheel on the crank pulley) and the Coil.



Here is a picture of the spark plug wires modified to fit down the spark plug holes in the valve cover. the boot that connects to the plugs has about a 30 degree bend in them so I bent them back straight, and trimmed the boots until they slid down into the holes in the valve cover.



Next, you have to get a trigger wheel made. I have a friend who is a CNC machinist, so he made one for me, as well as prepping the crank pulley for the wheel.



And the wheel fit onto the pulley looks like so...





Now make a bracket to mount the VR sensor onto. I put mine where the A/C compressor used to be. just some more of the angle Iron used before, long enough to mount the sensor on, facing the crank pulley.

Next, make a block off plate for the hole that the distributor used to occupy. I made mine big enough to mount the new coil to, as that is as far as the plug wires would reach. Just simple 1/8" thick steel. when finished it looks like this bolted to the engine, with the new coil mounted on it.





On a side note, here is the stock KA24DE timing map I scaled down. I have used it and it works great.



Putting it all together.

Now pull off your stock intake mani, and take out your engine harness. You will no longer need either of these. bolt the new mani onto the engine, it should look something like this...











You can also see in those pics the wiring harness was finished. It's simply following the diagram, running each wire to each sensor.

the only things that were not on the diagrams were the tach signal, water temp gauge and the switched ignition power supply. the Tach signal was cake, run a wire from the Clean Tach Out pin on the EDIS module to the Tach input on the back of the gauge cluster. That's it. Speedo will still work. Run a wire from the second temp sensor in the intake mani to the coolant temp input on the back of the gauge cluster. that's all for that. And the B/R wire coming from the igntion switch on the steering column needs to be tapped into to get switched power to MS, and the ignition components.



However, the wiring diagram for the ignition is slightly off. the polarity of the VR sensor wires is opposite than in the diagrams, so wire that up accordingly.

I used the stock injectors for now, but I have some SR injectors lying around waiting to go in. Stock injectors will be enough for now.

for the brake booster, I used the stock PCV rail, and ran one line from its output to the brake booster. Has worked great. I also Tee'd a 1/4" vacuum line out of this line, on it's way to the booster, for the fuel pressure regulator. Before doing any of this, I measured the vacuum in this line, and in the rest of the intake mani under all braking conditions, and the booster did not affect the vacuum in the engine. This being so, it is safe, and fine to run the vacuum for the FPR from the brake booster vacuum line.

the TB's come from the factory with a vacuum line from each port Tee'd into one. this is used for the map sensor. Simply run a line from this to MS. the MAP sensor is inside the MS box.

Then swap out the throttle cables, and hook the SOHC one up.

Finally, plug the EGR hole in your header.

If I recall correctly, this is about it for what I did on this whole project to get it running. for the specifics of the MS building and whatnot, and the ignition specifics and diagrams, visit http://www.msefi.com and http://www.megasquirt.info.

I specifically did not go into extensive detail in these areas because it is covered very well at those two sites.

So finally start it up and get it idling correctly. Do this by adjusting the screw that adjusts how far open the throttle plates are at "closed" so it has an idle speed you like, and adjusting the fuel amount in the MS. You can then get your own wideband to tune it, or take it to someone. Wichever's clever.

After tuning it, GO DRIVE IT! Don't forget to give yourself a pat on the back too!

Please forgive me if I have forgotten anything, it is a very long project, there is so much to do. I may have left a few small details out, but this is the major stuff.

Driving impressionsI don't have it tuned very well yet, but I can tell you that throttle response is immediate. The engine also revs up MUCH quicker. It does not feel like the lunky old KA. It's a whole new engine. This definately made it come alive. It is, of course MUCh louder also. It no longer sounds like a KA. Sounds way more pissed, like an engine with 2x the displacement.No dyno slips yet, but once I get one, I will be certain to post it up, as well as a video/soundclip.

CheersScott Slater[/quote]

User avatar
deviousKA
Posts: 1355
Joined: Tue Aug 12, 2003 5:04 pm
Car: 90 240sx NA /72 Datsun 510 NA /86 corolla GTS NA
Contact:

Post

Nice writeup Scott!

Nothing to add really, except for one thing. Anyone doing similar setup on a 89-90, the CTO (clean tach out) from the edis module will not push the oem tach. The signal must be taken from both of the coils (edis 4 post coil = 2 coils), and isolated/combined with a couple regular diodes and a zener. If the dual cam tach is used in s13 you should be able to use the CTO.

Also, if anyone is truly interested, I could draw up some interfacing schematics for using the MSEFI/EDIS system on S13, using stock fuse/relay box.

K A+

User avatar
NismoGreg
Posts: 267
Joined: Thu Dec 11, 2003 11:05 am
Car: '93 s13 fastback se, '87 200sx se v6,'91 integra ls

Post

Thnakyou, nice write-up

Veriest1
Posts: 3686
Joined: Wed Apr 14, 2004 5:23 pm
Car: '96 BMW M3
'93 Nissan 240SX coupe dd

Post

Wow, apparently I completely missed the first time this was posted.

Thanks for taking the time to put that together panda.

Graphfixz
Posts: 1697
Joined: Sun Jun 08, 2003 3:43 am
Car: Black 91 240SX Hatch
Contact:

Post

PandaS14 wrote:Funny you should ask, I recently did a writeup for my setup.

Remember, this is only one way to do it...
how much did it all cost?

PandaS14
Posts: 173
Joined: Wed Oct 06, 2004 8:22 am
Car: S14

Post

all the parts totaled about $925.

However now I'm selling my MAF, Harness, ECU, Distributor, Fuel rail .... etc and it's making back a substantial chunk of that for me.

Graphfixz
Posts: 1697
Joined: Sun Jun 08, 2003 3:43 am
Car: Black 91 240SX Hatch
Contact:

Post

great!

so how loud is it? Got an audio file?

sokon
Posts: 9
Joined: Mon Mar 28, 2005 5:49 am
Car: 92 240sx
Contact:

Post

alright you got quick response and what else? more power? also how do you keep the air clean... you know like a k&n filter.

this thing just look confusing

USDM240
Posts: 777
Joined: Wed Mar 17, 2004 10:21 am
Car: 1993 Nissan 240SX Limited Edition 'vert

Post

man, thats hot! its weird because i was talking about this at the shop today with the guys. i was wondering how hard it would be to ITB the DOHC KA. now i know.

PandaS14
Posts: 173
Joined: Wed Oct 06, 2004 8:22 am
Car: S14

Post

no audio file yet. I'll get one soon.

I haven't dyno'd the setup yet, but yes, it does make a lot more power. I was maxing out the stock injectors at 6300rpm, before I put in my SR injectors. The stock ones are good for roughly 200rwhp so if it's running correctly, it's making quite a bit of power.

I'm not using anything as of now to filter the air. I will when I get it all tuned and everything else finished. Too much other stuff to worry about now to do that.

mirra32
Posts: 276
Joined: Mon Sep 06, 2004 11:03 am

Post

daum....this is sick....i've seen this before but didn't think anything of it...get a dyno of this set up....how would this work with a turbo set up....or is that a whole different retarded question.. ....good info.....

man that would clean up my engine bay big time....
Modified by mirra32 at 9:19 PM 7/24/2005

User avatar
HashiriyaS14
Posts: 14298
Joined: Fri Dec 05, 2003 8:02 pm
Car: '95 Nissan 240SX
'08 Honda Accord
'08 Honda NPS50
'03 Kawasaki Ninja 250
'60 Honda Super Cub
Location: DC Metro Area
Contact:

Post

Fantastic write-up. This should be a sticky, I bet there will be a lot of people out there putting ITB's on their KA's in the next year.


User avatar
frapjap
Posts: 13175
Joined: Thu Jul 01, 2004 2:46 pm
Car: '99 Pontiac Firebird Trans Am
'07 Subaru Legacy
Location: South Coast Massachusetts

Post

commenting to watch this thread grow!

crzycav86
Posts: 3836
Joined: Tue Aug 05, 2003 1:28 pm
Car: 93 Nissan 240SX KAT

Post

Fabulous.

It makes me wanna buy another ka that I can keep NA.

Do you have high compression pistons yet?

comablack783
Posts: 206
Joined: Thu Aug 05, 2004 5:27 pm

Post

that looks sick? can this be done to SOHC? is it possible to run this with a turbo?.... sick, just sick...

Veriest1
Posts: 3686
Joined: Wed Apr 14, 2004 5:23 pm
Car: '96 BMW M3
'93 Nissan 240SX coupe dd

Post

SOHC --- Sort of. The intake manifold design is different so you can't just cut it off like on the DOHC. You'll need to modify a NISMO intake manifold (expensive) or use Webers for the NISMO intake. You could also have a machine shop make a plate up with runners spaced for the Gixxer TBs.

Turbo--- Yes. You would need to find a way to fabricate a plenum and it doesn't have to be a particularly great one at that. Just make sure it's big. The connectors between the TBs and the manifold should hold the boost. E46 M3s have a set up similiar to this from the factory that gets boosted frequently.


User avatar
flohtingPoint
Posts: 3564
Joined: Tue May 13, 2003 2:46 pm
Car: 2004 Z16 Corvette Z06
Location: Washington DC
Contact:

Post

Brilliant write up, makes me wanna come read up in the KA section more =)


Return to “KA24E / KA24DE Forum”