ITB project is under way

[j-z]

welp fellas, i got tired of staring at my gsxr itbs that have been sitting in my closet since xmas. today i finally started to get them running on my car. got the stock mani off, and hacked it up. then cleaned it up a bit, and did some jb weld work . im planning on running with the stock maf and ecu, and then slap an afc on there.. i was going to make a custom mani, but cutting the stock one was alot easier and cheaper. im probably going to make a plenum out of fiberglass just because i have all of that stuff here. im just doing this project to get my hands dirty. i havent done anything to my car in a while. although, im still planning on putting a ls1 in there . .sorry for posting without pics. they should be up when ever i finish the project which will be by next weekend. i just wanted to get a thread up incase i encounter any problems.

[NismoGreg]

cant wait to see pics. You should do step by step write up

[j-z]

something i just though of. PANDA, where did you get your couplings from, and how much were they? thats all i really need to source out. thanks if you can tell me. also, is it ok to block off the air pump? i believe thats the thing that goes into the bottom of each runner.

[deviousKA]

Sweet, j-z, cant wait to see your setup with the maf! I remember seeing someone do this on ka24de with the suzuki throttles, built a fiberglass plenum and used the maf. I think it was club240.

Keep everyone updated!

[1991S13]

If you guys don't mind me asking...

How do you use a MAF with ITB's? I thought you had to switch to a MAP Sensor with Megasquirt or something...

[j-z]

you make a plenum around all of the throttle bodies. then its just like stock after that. hey devious, do you know about the air pump thats on the front side of the block?

[deviousKA]

I dont know of any air pump? Ive never really worked on s14 240sx personally. This unit connects to the vacuum rail/system on the underside of the manifold? Only thing i can think of that has air pump or "smog pump" is 70/80's US cars. Are you possibly referring to the pcv valve/housing?

You can delete much of the vacuum mess, although you will have to work around the oem system and its error code system !

To be honest I dont really know, but you will want to simplify your vacuum/emissions system as much as possible.

[PandaS14]

good to see someone's trying this with a plenum and stock computer. I contemplated it long ago.

I used rubber plumbing couplers that you find in Home Depot's plumbing section. They come with a metal sleeve around them and clamps on each end. I just ditched the sleeve. I used these because I didn't want to fork out for silicone couplers, and they were right down the street. You can get straight couplers, or a kind of reducer, which is what I got. Just take your mani and TB's in there and see what fits. I also did a lot of trimming to get them to look as best as possible, and whatnot.

What you are referring to is the PCV system. I used that rail for my brake booster vacuum line. the outlet on the rail is the same size as the one on the brake booster, so I just ran a line inbetween the two. You can delete the PCV system is you want, but you will throw ecu codes. Hell, you're gonna throw a ton as is. Just make sure you don't pull vacuum for whatever device you need vacuum for, off of just one runner. This can mess with the air flow on that port. Tee'ing all of them into one also averages the vacuum differences, which is beneficial too.

[Red coupe]

How do you use a MAF with ITB's? I thought you had to switch to a MAP Sensor with Megasquirt or something...

Ive been reading most the treads on your guys' work and its looking really good. I too curious on how you are hooking the MAF up. Does it just monitor one of the intake plumes? I read most of the other threads but I must have missed this part of your set up.

[Dattebayo]

Its just perfect that you asked that because, ahem, IT WAS ANSWERED TWICE IN THIS VERY THREAD!!! Pay attention dammit!

WHen you put a plenum in with this ITB system, wouldnt you have problems with the air flow?

I understood that having an equal length intake was just as beneficial as an exhaust header as well. Are you sure that going back to the plenum is not pointless as you will retain alot of the stock problems?

[SSS]

WHen you put a plenum in with this ITB system, wouldnt you have problems with the air flow?

If the plenum is designed properly, no.

[j-z]

yeah i eliminated everything. i have a vacuum manifold on my car already, so that will come in handy now for sure. its coming along good now. i got the throttles attatched to the mani, and gettting the mani prepped real nice. also picked up some foam and glued it together, so i can use it to lay my glass over. should be done by the weekend. i cant wait.

[SSS]

good to see someone's trying this with a plenum and stock computer. I contemplated it long ago.

I too am doing a plenum setup with my GSXR 1000 tb's, using the stock ecu but re-tuning the eeprom for the ITB's and using a Z32 MAF. This will be in a fwd U12 chassis, hopefully i'll be the first. I'm not too keen on the rubber couplers though, could cause a problem when i'm boosted.

[PandaS14]

^^^^^

About the couplers. if your runners were spaced perfectly, and coupled, there would be no problems. People use couplers on intercooler piping with no ill effects. so it shouldn't be a problem.

[SSS]

Yeah i'm aware of that panda, but it's another thing down the line that could cause headaches; say if one of the couplers starts deteriorating.I'm having some flanges machined up to bolt on these ITB's to the modified stock manifold.

[j-z]

its done! today i got them mounted on and running. i have a few bugs to fix. i should have known better than to plug the egr hole with jb weld. it def isnt as responsive as it was stock. i think i have to adjust the tps a lil bit to fix this. what do yall think? my brakes are a lil weak, so i think i need more vacuum for them. the rubber couplings colapse under vacuum, so i need to source something better for that out. she does seem to breathe better up top though, but its still doesnt pull as hard as it did stock. other than that, no other problems. im gonna work on it some tomorrow and see what i can do. if yall have suggestions please let me know. also, i removed all of the emissions shlt, maybe that might have something to do with it...

[InsanityInc]

Try putting in a set of s13 cams (or JWT/PDM if you don't care about smog or money). Also, make sure your A/F didn't go in the toilet.

[SSS]

TPS will play a big role in throttle response, i certainly found that out.My TPS when closed would read 0.3V, i swear i'd adjusted it to 0.4V; when i got my consult cable i checked it and bingo, 0.3V.Adjusted it approx 0.42V (between 0.4 and 0.5V is what is specified from nissan) and throttle response picked up significantly.

Are you using a plenum? If so, check for any air leaks.

[j-z]

yes, im using a plenum with the stock maf. i know there are no leaks coming from that bltch. im bout to go out and fiddle with everything, so ill let yall know how it goes. thanks for the input. SSS, is your car driving with the ITBs? whats your setup?

[j-z]

much better results today! now im pleased and happy with all the countless hours ive spent on getting this shlt together. throttle response is most def improved and so is the top end. i can tell it breathes so much better on the top now. it pulls linear all the way till redline now (no bs). it wants to keep going, so i just give her as she wishes. i can tell it needs some cams, and that would help TONS. dont worry because that is next on the list, and then a header. i do know that i need to try and get my stock throttle rotor mounted on though because the gsxr one is way to small. all i did was get the tps right on the money and bam! oh yeah, the brakes are all good now. i had the nipple on the valve cover "Td" in with the booster line, and that was causing it to lose vacuum. i havent taken care of the rubber couplings yet, but i found some napa radiator hose lying around that i will try. panda, i highly suggest you get rid of those things before you even get it running. my exhaust note changed quite a bit. it used to be real deep and sounded like a turbo exhaust without the spool. now it changed to a higher pitch, and a lil bit more raspy. it still sounds good though. it sounds like it needs to be on a road course, fo real. hopefully i can get some pics up for yall soon. she looks damn sexy in the bay.

[s1ndicate]

Interesting.... more and more Iam becoming interested in ITB, but I do want to see dyno sheets and an average $$ cost and some research before diving head first into something that I don't know much about. I have lots of questions, let me write them down and I will start a thread.

[nonchalant rage]

what are you doing as far as vacuum goes? are you using a vacuum box like the golden eagle one, maybe a custom one? are you using anything to tune them? what cams are you running?

[PandaS14]

Glad to hear it's running better now.

What was it that you suggest I get rid of before I get mine running? I've already got 300 miles on my setup with no probs. Just curious...

[j-z]

panda, i was talking about the rubber couplings. i dont know about yours, but mine collapse big time under vacuum. i didnt know you got yours running. so how is it with the MS? as far as vacuum goes, i already had a vacuum manifold on my car that i made. its aluminum and polished. also, it cost me about $200 for everything to get the itbs running. im running stock cams as well which i need to change out desperatly. anyone wanna donate for a good cause?

[InsanityInc]

panda, i was talking about the rubber couplings. i dont know about yours, but mine collapse big time under vacuum. i didnt know you got yours running. so how is it with the MS? as far as vacuum goes, i already had a vacuum manifold on my car that i made. its aluminum and polished. also, it cost me about $200 for everything to get the itbs running. im running stock cams as well which i need to change out desperatly. anyone wanna donate for a good cause?

Just get rubber couplings that are meant for automotive intakes (like your intake tube uses). Those are thick enough that they shouldn't collapse. Also, try and leave as little bare rubber as possible (i.e. shove the metal parts as close together as you can).

[PandaS14]

Mine is running well. The more I tune it, the faster it gets. Much faster. haha I love it. on mine I havn't had any problems with the couplers collapsing. I've got the TB's butted up against the mani, and couplers holding them together. There is no space that is just coupler. I also have the brackets to stiffen things up that take the weight of the TB's off of the couplers.

Very cool that you have been able to do it for so cheap. Post some pics!

[InsanityInc]

By the way, what did you do to attach the plenum to the throttle bodies anyway?

[deviousKA]

Nothing much else to say, but SWEET!

[SSS]

SSS, is your car driving with the ITBs? whats your setup?

Not yet unfortunately. Still trying to work out the details for the plenum and getting the flanges machined and welded to the GSXR 1000 ITB's; since it's going to be boosted i prefer to have flanged connections. The biggest thing is trying to overcome the clearance required for the MC on cylinder no. 1 (it's a front wheel drive U12 chassis)

My setup will be:- Z32 maf, stock ecu re-tuned by myself- 3" intake pipe to plenum w/K&N pod- GSXR 1000 ITB's with 460cc/min injectors in the injector ports- stock 240cc/min injectors in the same OEM placement in the cut down stock lower manifold- vaccuum log T'd off all 4 runners for brake booster, boost gauge and map sensor for tuning and ignition retard via my SMT6 piggyback for high boost (once boosted; keeping the piggyback as it's driving the 460's once a certain boost level is reached)

Got all the parts except for the map sensor, just a matter of getting it all together.

Glad to hear you got your setup running much better.

[SSS]

I'd also love to see how you did your plenum setup.