*EDIT* Here's a link with all the missing images. You can thank vancouverbc for being awesome.

Missing Images

The following DIY will outline the parts you can remove (and the parts you can keep) on the S13 intake manifold when doing a KA-T build.

Overview of the parts

The intake manifold can be seperated into an upper portion and a lower portion. Most of the emissions control/idle/coolant stuff is located on the lower portion, with the exception of the PCV system which gets vaccums from the upper portion. I will explain further.

Upper portion is on the left, lower portion is on the right. In between is the mounting hardware for the manifold. Note also that there is a gasket that fits in between these two parts (Advance Auto has both intake mani gaskets - this one and the one between the mani and the head - for 6 bucks).



Aux. Parts

Most of the parts that you NEED to keep when pulling emissions stuff off of the mani are right here on this cardboard box.



Note also that there are a couple other small things that I left on the lower portion while painting that you will need as well. You will see these parts in later pics and also it will be obvious what is necessary, as everything fits together in unison so you can't just exclude something and forget about it without obvious dangling parts.

What you keep

I dont have a list of everything that you can throw away, but I do have pics and info on the things you need to keep. Everything else, you can assume, may be removed and disposed of/sold.

This is the back of the completely assembled lower portion of the intake mani:



Okay starting from the top right, the rusty brown part is the begining of the EGR. Note that I have blocked the exit hole there with that plate I made (shaped sort of like a house with a roof). You need to make sure you get a good seal here.

Directly below my EGR block off plate is a big thick metal pipe. This runs in between the AAC (Auxidrialy Air Control Device - commonly refered to as the IACV- Idle Air Control Valve. This valve, with the purple plug on it, lets air into your intake manifold to regulate idle speed) and the front of the engine, where it needs to see a vaccum before the throttle plate (more on this later).

You can't see it in this pic, but that large pipe also has a small branch off of that goes into another necessary valve which is associated with the IACV/AAC (this is the part with the red spot on it).

Note that both the AAC/IACV and the other valve have electrical connections (total of 3) that need to remain. These go towards the throttle body and attach to a plug up there.

See to the left of the part with the red spot on it, there are some small metal hoses. These were used for various emissions related vaccum lines. You will not need these specifically, but they are a pain to remove and you can use them yourself to transport vaccum if you would like later on for things like your BOV or whatever.



This is the "underside" of the lower intake manifold. The rear of the mani is to the right, the front including the throttle body is to the left. Towards the top you can see that long metal pipe for the IACV/AAC that I mentioned above. Also you can see the branch off into the other valve (with the green sticker, this is the one that had the red spot on it in the pic before). Below the pipe you can see one vaccum hose that comes out of the intake manifold, makes a curve (upsidedown U) and goes into a metal pipe (next to the fat rubber hose). This is a vaccum that goes up towards the front, that USED to be used for the charcoal canister. Remember to follow this line and mark which one it is up front, because this vaccum will need to be plugged (or used for your BOV if you want to be crafty). If you dont plug or use this line, your idle will be very high and it will take you forever to find out why.

Also note the big fat rubber hose next to that vaccum. This is a coolant line that just rons from front to back on the manifold. It is the return line from the heater core.

Below that large rubber hose is a series of small metal pipes. These can be removed like I said, but they are a pain and you might want to use them for yourself.

Below those pipes you can see the long black (shiny) wire that runs from the valves in back to the plug up front. I zip-tied these to the small metal tubes to keep everything neat.

More on what you can keep



This is the front of the intake manifold. Note that I put the upper and lower together in this pic so you can see how things fit together.

Starting from the right on the upper intake manifold, you can see two sensors - one red, one blackish. These are coolant sensors that you obviously have to keep. When youre doing all this messing with your intake manifold, I reccomend taking these out and re-teflon taping them up for for a good seal.

To the left of those sensors you can see the small metal tube sticking out that are referenced in the other two parts above. This is the tube coming from the IACV/AAC. To this you need to attach a hose that will go to a plug in your intercooler piping after your IC and before the throttle body.

Below the throttle body you can see the plug from the wires that came from the valves in the rear of the manifold. This meets up with a plug that I will show you next.

There is nothing you can really remove from the front of the manifold here except the vaccum hoses that come off of the small metal tubes that I mentioned earlier (the ones I said were a pain to remove.) Just plug them all up (one of these is the charcoal vaccum I mentioned earlier, which has to be plugged of course).

There are some funky coolant lines around this area that you ned to pay attention to but nothing you can modify. All of it stays stock.

Electrical



In this pic I am holding all of the plugs that connect to stuff on the front of the intake manifold. I seperated all of these wires from the bunch that, stock, runs across the top of the upper intake manifold below the fuel rail. Note that this bunch of wires does NOT include the injector wires.. I did those seperate for the sake of neatness.

You can see in my hand all the plugs that are on the front of the mani... also in this bunch (although you cant see it) is the plug that goes on the distribuitor. You can see the clips for it on the front of the upper timing cover there. I just reccomend doing it this way for neatness sake.

PCV system

The PCV system is another part that you shouldnt remove from the intake manifold. The vaccum ports for it are located on the underside of the upper portion of the intake mani, here:



The port on the pipe there connects to a vaccum hose that connects to a funny looking box which bolts on to the side of the block near the throttle body. Keep all the vaccum lines and hardware associated with this system.

Overview/Wrap Up

The finished product for me:



Note that I did not include any information on the fuel lines. This is because I used a custom top feed rail and line setup on my engine, so I dont really have too many pics and info about it. Basically the fuel feed is on the front of the rail (comes from the filter), and the return and fuel pressure regulator is on the rear of the rail (which goes to the return line, of course). You dont have to keep the stock system the way it is, but you obviously cant remove it completely either. Picking what you want to do with this is a matter of preferance.

Well thats just about it! I'm sure I missed a thing or two and I may be incorrect once or more than once haha... So any questions feel free to ask, and any corrections feel free to post.

Also for those who are interested, the manifold finish is Duplicolor Cast-Coat Aluminum (500 degree) rattle can paint. I reccomend it highly for people looking to refinish their manifolds without getting too crazy. I went from this:



To this:



With just some engine degreaser, wire brush, a couple coats, and some dry time. Very easy and it looks pretty nice.

Wow... definitely one of the best write ups ive seen. I was going to take off my intake runners one day to replace that damn knock sensor and all these pictures definitely should help in seeing where things are.

Thank you for the write up!

BTW, questions for you.. To remove the intake runners, I know I have to remove the PCV vacuum lines and coolant hose... what else do I have to remove?

im in the process of doing the same thing with my intake manifold. I took off alot of crap. All of the hard lines are gone since i dont have carbon canister.

i also am bypassing the throttle body coolant line since its one big loop and shortening it to one single line.

theres a sensor that i have no clue of. it has vacuum going to it and the harness plug is towards the back of the fuel rail kinda. i might have to post pics. i dont know what it is. from what i remember, it has a hard line that is dedicated to it. (ive tried looking at the anti-detail FSM pics and maybe its the EGR temp sensor?? i dont know)

i just ditched BPT and EGR, capped the rusted part with plate.

for the PCV, i have each port blocked off and will be running the PCV to a catch can which is fed vacuum from the intake pipe (between mafs and compressor).

nice write-up foster mani looks great too.

ill probably be doin the same over summer, except goin with black for the mani.

FAT, maybe i'll do a writeup for the SOHC.

sil80

sil80drifter wrote:FAT, maybe i'll do a writeup for the SOHC.

sil80

that would be cool If you don't I will (in a few weeks here)

Thanks fiznat for the writeup. very helpful.

Thanks for the compliments guys! NICO has already given me so much, theres no reason I cant give back a little.

ILikeMy240sx wrote:questions for you.. To remove the intake runners, I know I have to remove the PCV vacuum lines and coolant hose... what else do I have to remove?

You only have to move one of the PCV hoses, the main center one that connects to the PCV box. Thats a lot easier than trying to remove each of the individual runner vac lines.

Also you will of course have to remove your fuel rail or the lines (the rail is probably easier though), and disconnect the plugs for the TPS, coolant temp sensors etc etc up near the throttle body. Also there is the coolant line from the heater core that attaches to the firewall. ...Oh and the ground that is connected to the mani. There are a bunch of little things, you'll find them when you cant pull the mani out haha.

Keep in mind that you wont be able to take off the upper portion of the manifold alone without at least loosening the lower portion. The studs on each end for both the block/mani and upper/lower areas keep you from pulling the top part completely off. Its really easier to just take the whole thing off at once, since its really no more work than just the top.

Heres a pic of the engine with the mani off to give you an idea:

is the little black rectangle box above your alternator part of the PCV system? thats mine thats bolted to the timing cover.

A quick note about teflon tape for sealing sensor sending units. Some sending units (not all) are grounded through the body of the sending unit. If you apply a heavy amount of tape, you could actually prevent a good ground. This will make the sensor or gauge erratic or simply wrong. Note that this is extremely common on temp and oil pressure sending units.As an alternative, I prefer to use the thread sealing compound from Loctite. You still get metal to metal contact, but once the sealer cures, you have a guaranteed seal without having to overtighten. Much like Permatex Ultra Black, the stuff is liquid gold for us DIY bums.

^^and it is removable?

fiznat wrote:

maybe im confused on something, but dont you have your coolant return line plugged into your pcv valve????? i dont want anyone to get confused and do this if this is what i think is happening. i assume it is for a temp place to put the hose......

haha no its not on there, the angle is just kinda funny so it looks like it. You can actually see the (much smaller) hose that DOES connect to the PCV to the left of that big hose... it passes right next to ("behind" as you view it from the pic") the coolant hose and into the PCV box. Good catch though, you had me scratchin my head for a minute there!

That hose that looks like it goes into the pcv hooks up to a port on the upper portion of the intake manifold. If you ever want to replace this part, it is called the "crossover" pipe.
Modified by fiznat at 11:55 AM 3/30/2005

Great write-up!!

Note on the PVC small hoses. Check those for cracking. That funky curve and heat will harden those hoses in no time.I did my setup a little different. Single point of vacumm, take from the lower manifold, connected to the stock PVC valve.I plan to use a catch can inline and remove the valve.Great time to clean that side of the engine, change mounts, replace PVC, install oil pressure gauge and replace thermostat.Also, try to clean the inside of the mani with some carb cleaner.

Also, does anyone tried to use the EGR por for nitrous?I am talking about the allen plugs above the AIV air lines on the lower manifold collector. (see pic above)

pr240sx wrote:Note on the PVC small hoses. Check those for cracking. That funky curve and heat will harden those hoses in no time.

Thats true. I actually already replaced my hoses, the first time I did it I broke 3 of them in half. Also since I'm building a high-boost setup, I think I am going to secure vaccum hoses like that with better, screw-type clamps. I've heard of them blowing off, and I really dont want to take the mani off to fix them later on. You def want to check EVERYTHING under the intake manifold for this kinda stuff, because once you put the mani on you can wave goodbye to easy access to anything.

As far as the PCV, lots of people have different ideas on what to do. I oped to keep the entire PCV because (1) it performs a vital function (crank case vent), and (2) it does not get in the way of anything. Once you put the mani on the engine you'd have to really look to see if the PCV was there or not. Theres no real gain that I can see from removing or altering the PCV, while there ARE risks involved if you want to change it. Eh. Up to you!

mods, i think this qualifies as a sticky..........

Jookmasta wrote:mods, i think this qualifies as a sticky..........

I'd like to further that and nominate this for a write-up of the month/quarter for the front page also.

To keep things legal for most states, there should be a disclaimer: "Off-road use only." - HAHAHAHAHA

***EDIT: why don't we bring the "articles" section back, like the one we have on 240sx.org - that way, we won't end up w/ a billion stickies, but just one: "Install/DIY articles"

I'm adding it to the Sticky list as we speak.

Great write up man. Everyone can benefit in someway from this. I can now get everything straight in my head so I don't have to pull the mani.

fiznat wrote:As far as the PCV, lots of people have different ideas on what to do. I oped to keep the entire PCV because (1) it performs a vital function (crank case vent), and (2) it does not get in the way of anything. Once you put the mani on the engine you'd have to really look to see if the PCV was there or not. Theres no real gain that I can see from removing or altering the PCV, while there ARE risks involved if you want to change it. Eh. Up to you!

doesn't the pcv system pull oil vapors into the intake manifold when there is vacumm? it wont open while in boost but it still leaves residue

Hence the catch can and PCV hoses re routing.

sil80

yes this should b nominated for article of the month for may.........i think the timing chain one was done in march so that can get the april slot...........

Quote »Theres no real gain that I can see from removing or altering the PCV[/quote]that was in response to this, sorry i didn't know he was using a catch can

i agree, great article.

you do the best freaking write-ups, great job.

Did you notice any disadvantage to removing the EGR?

That is to say, the EGR aids in atomization, and for that reason lowers the NOx emissions, and reduces the engines tendancy to detonation on low octane fuel with relatively high compression (e.g. 9.5:1). So, that said, wouldn't removing it in turn cause a retardation of the ignition time, triggered by the knock sensor. Also, I just overhauled my motor (kept the EGR for fear of this detonation problem), did you notice this, or were you forced to run higher octane fuel, if so, was it any faster after removing all of the emission components? When you removed the EGR, did you leave solenoids for it and BPT, did you remove the butterfly valves (SCV system, and perhaps the solenoids), did any of this make a difference.

Ive got one big question. Im removing my emissions. The fuel presser regulator is connected to the emissions web. when there removed where (exactly) do I need to run the vac line for the FPR????? help me

the FPR vac line comes directly from the manifold itself. Over near where the brake booster vacuum hose connects there is a smaller nipple used specifically for the FPR.

sup guys i just got another KA from a 95 240 (s14). i have and s13 with a dohc in it already ( blown ) i read that i have to swap the plenums and i can see why. when doing this what should i watch out for and or get befor i start this small adventure.

ps also when i got the motor it was laying on its side. when i open the butterfly aboutu 4-5 tbs of oil came out. and that was all. IS that ok or should i just get a new motor

Chezedik wrote:That is to say, the EGR aids in atomization, and for that reason lowers the NOx emissions, and reduces the engines tendancy to detonation on low octane fuel with relatively high compression (e.g. 9.5:1). So, that said, wouldn't removing it in turn cause a retardation of the ignition time, triggered by the knock sensor. Also, I just overhauled my motor (kept the EGR for fear of this detonation problem), did you notice this, or were you forced to run higher octane fuel, if so, was it any faster after removing all of the emission components? When you removed the EGR, did you leave solenoids for it and BPT, did you remove the butterfly valves (SCV system, and perhaps the solenoids), did any of this make a difference.

The EGR doesn't aid in atomization, it aids in reducing the overall temperature of the combustion limiting NOx creation.

As far as detonation is concerned the EGR plays no role, because at WOT the BPT and EGR are closed. The EGR only opens at partial throttle situations to reduce cruising emissions.

Fiznat, forgive me for asking a stupid question. Heck I don't even have a repair manual, but isn,t the pcv valve on the valve cover; which on the ka is just a hose? Please corect me if i,m wrong. I'm sure you guys know more than I do and I dont want to confuse anyone. Good job on a much needed write-up!