# homebrew 16v ITB intake manifolds



## freeze plug (Oct 26, 2006)

Can you guys post some pics up of manifolds (16v preferred but anything will do) that you have fabricated from scratch or made from a lower runner section? I have a few ideas brewing and would just like to see what the best route would be at this point. I have a feeling i'll just be slicing up a 16v lower and welding aluminum extension tubes on to mate with gsxr ITB's. the search didn't yield much!
thanks!


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## need_a_VR6 (May 19, 1999)

*Re: homebrew 16v ITB intake manifolds (freeze plug)*

I just cut the 16v lower and used silicon couplers.


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## freeze plug (Oct 26, 2006)

*Re: homebrew 16v ITB intake manifolds (need_a_VR6)*

thats what i planned on, but there are some people that have lengthened the setup a certain calculated distance from the intake valves. just trying to see what other options are


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## need_a_VR6 (May 19, 1999)

*Re: homebrew 16v ITB intake manifolds (freeze plug)*

It's easier to do the tb's with a coupler and get custom stacks the the other way around, especially if you can't weld.


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## freeze plug (Oct 26, 2006)

*Re: homebrew 16v ITB intake manifolds (need_a_VR6)*

I plan on learning tig over the winter, but even if I don't, i know a someone who tigs very well so he can do it for me either way


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## atrujillo1991 (May 24, 2006)

*Re: homebrew 16v ITB intake manifolds (freeze plug)*

I just used silicon couplers as well.
Bump for a fellow square owner


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## freeze plug (Oct 26, 2006)

*Re: homebrew 16v ITB intake manifolds (atrujillo1991)*

haha nice! my square is about to go into hibernation mode....


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## atrujillo1991 (May 24, 2006)

*Re: homebrew 16v ITB intake manifolds (freeze plug)*

Mine's about to go into daily duty


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## freeze plug (Oct 26, 2006)

*Re: homebrew 16v ITB intake manifolds (atrujillo1991)*

hows your heat


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## xr4tic (Dec 10, 2001)

I have someone welding mine up, so I don't have any final pics yet, but here it is mocked up:








It's four 45 degree aluminum mandrel bends, with the ends squished and shoved into the flange (barely) Once it's welded up, I can do a final fit test and see how long of a runner I can get away with.
Silicone couplers are fine if you don't want to add any length and don't mind them pointing straight into the hood. With longer runners and a bend, they'll get into the airflow, assuming a smaller radiator is used.


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## atrujillo1991 (May 24, 2006)

*Re: homebrew 16v ITB intake manifolds (freeze plug)*


_Quote, originally posted by *freeze plug* »_hows your heat

SUCKS.


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## Justin 123 (Apr 11, 2005)

*FV-QR*

I don't mean to divert, but what radiator is being used above? Thanks.


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## freeze plug (Oct 26, 2006)

*Re: homebrew 16v ITB intake manifolds (atrujillo1991)*


_Quote, originally posted by *atrujillo1991* »_
SUCKS.










lol what year is yours? mines a 66....still good old 6v too.
and thanks to those who posted some pics http://****************.com/smile/emthup.gif


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## xr4tic (Dec 10, 2001)

Full Race Honda CRX EF radiator
http://www.full-race.com/catal...ff2f3
If you do buy it, don't get the fan (I did), you can find it for much cheaper elsewhere, it's a Hayden unit, you can get a nicer Spal unit for about the same price.


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## 91turbo (Mar 9, 2003)

*Re: (xr4tic)*

i used a cut lower manifold. measured the calculated distance to achieve enough internal distance for swirl volume. then i welded the ITBs right onto the manifold. this eliminated all the spacers, long bolts, and mounting ears. then i just modified the linkage to open all the way across with equal distance. everything is alot cleaner and there is room to spare for filters/stacks and the factory 16v upper water neck. i had a shop port the internal area so that is a straight smooth shot after welding. eliminates the step inside the runners and gives a true internal throttle body port.







and they are for sale at this time.


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## freeze plug (Oct 26, 2006)

*Re: (91turbo)*

thats a great idea actually....have any pics?


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## atrujillo1991 (May 24, 2006)

*Re: homebrew 16v ITB intake manifolds (freeze plug)*


_Quote, originally posted by *freeze plug* »_
lol what year is yours? mines a 66....still good old 6v too.
and thanks to those who posted some pics http://****************.com/smile/emthup.gif 

'72







I'm looking at it through my window as I type wishing I would have been more productive today and taken the front down an additional 2 clicks


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## freeze plug (Oct 26, 2006)

*Re: homebrew 16v ITB intake manifolds (atrujillo1991)*

nice! pics?


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## freeze plug (Oct 26, 2006)

*Re: homebrew 16v ITB intake manifolds (freeze plug)*

anyone else?


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## 91turbo (Mar 9, 2003)

*Re: homebrew 16v ITB intake manifolds (freeze plug)*

for those that wanted pictures of my ITB's and manifold. here you go.


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## NTRabbit (Mar 28, 2001)

*Re: homebrew 16v ITB intake manifolds (91turbo)*









Here is the build thread too:
http://forums.vwvortex.com/zerothread?id=3348593


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## freeze plug (Oct 26, 2006)

*Re: homebrew 16v ITB intake manifolds (NTRabbit)*

damn, both very slick setups http://****************.com/smile/emthup.gif


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## dmitry88 (Apr 26, 2006)

*Re: homebrew 16v ITB intake manifolds (freeze plug)*

http://****************.com/smile/emthup.gif


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## bazoldskoolmk2 (Sep 4, 2008)

*Re: homebrew 16v ITB intake manifolds (atrujillo1991)*

dirty dawg


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## jackyltardvaark (May 30, 2005)

*Re: homebrew 16v ITB intake manifolds (bazoldskoolmk2)*

















Used stock bottom manifold and welded 2" od pipes to it. And attached with silicone hose


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## junn (May 6, 2008)

*Re: homebrew 16v ITB intake manifolds (jackyltardvaark)*

thats nicee i like the valve cover too http://****************.com/smile/emthup.gif


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## Sciroccoracer7 (Apr 28, 2005)

Here's my lower half, just cut the flange off and relocated it so I would still have injector cups.








I made the upper half out of u-bends










_Modified by Sciroccoracer7 at 5:20 PM 1-1-2009_


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## Moteleb (Jan 10, 2009)

here's my setup, I cut lower intake to keep only 1/2 or 3/8 inche length runner, I weld 4 vise kinked tube (Heating a little bit before deforming is really helpfull) I finally got 4 rubber unions to a hardware store for 10$ each. I use Digifant plastic cup at std locations for injectors. On GSX throttles, I put NPT/barb fittings to plug vacuum for brake booster. I use this setup for daly use(Summer time). 


















_Modified by Moteleb at 10:27 PM 3-6-2009_


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## freeze plug (Oct 26, 2006)

*Re: (Moteleb)*

just started mine, finally. any more pics? I took out the CIS injector cups, what do I need to use conventional style injectors, DIGI cups?


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## impulse byer (Mar 8, 2003)

*Re: (freeze plug)*

Here is my crappy pic of my itb manifold








I cut off the runners flat and welded on strait aluminum pipe for a better fit with the silicon.
This is my twin carb manifold i made.








It was still in the fitting/testing stage but you get the idea. when you get the injector cups out you can use Dodge diesel drain pan plugs. They ae the right 22mm x 1.50 thread pitch you just need to grind down the flange to fit.
A better pic for 2 years ago..










_Modified by impulse byer at 8:38 AM 6-4-2009_


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## freeze plug (Oct 26, 2006)

*Re: (impulse byer)*

well, im not plugging the injector holes, just getting new seats for the new(er) injectors


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## goofydug (Feb 5, 2004)

I read that the filters that are covered on the face really restrict air intake, fwiw.


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## secondgen (Jan 9, 2004)

*Re: (goofydug)*


_Quote, originally posted by *goofydug* »_I read that the filters that are covered on the face really restrict air intake, fwiw.

More than you'd think! I had to completely re-tune my housemate's 16V when he went from generic cone filters to the UNI full foam ones.


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## freeze plug (Oct 26, 2006)

*Re: (secondgen)*

started mine the other day, just trial fitting.
cut lower mani with 98-99 gsxr 750 single butterfly ITB's


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## Mk2 SAiNT (Jul 10, 2007)

*Re: (freeze plug)*

I just saved myself the hassle from starting a new post about this whole subject.
I just recently purchased a GSXR 1000 ITB and will be bolting this up to my one of my projet motors. I'm not too sure if I'll be doing it on the AEB 20v or the 1.8L 16v.


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## darks_aint (Jan 16, 2010)

*Re: (Mk2 SAiNT)*

yo mk 2 saint do it on the AEB plz as i'm doing a N/A 2.0L 20v engine on a tall block and i plan to run ITBS i have a number of choices either the toyota 20 v itbs or the GSXR itbs it wud be nice to exchange ideas


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## yeayeayea (May 29, 2005)

*FV-QR*

v1
















v2
















honda radiator, switching back to stock now that the carbs are closer to the head. v3 of the manifold coming soon with better runner angles on the outside runners so the couplers arent stressed as much.


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## Mk1 God (Oct 18, 2001)

Here is my setup, cut manifold with rubber couplers


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## franque (Jul 12, 2008)

*Re: (Mk1 God)*

What's that valve cover off of?


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## Mk1 God (Oct 18, 2001)

*Re: (franque)*


_Quote, originally posted by *franque* »_What's that valve cover off of?

It's a modified 16v valve cover I made


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## Krol9 (Jun 28, 2007)

my itb`s


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## Breadfan5968 (Mar 25, 2007)

*Re: (Mk2 SAiNT)*


_Quote, originally posted by *Mk2 SAiNT* »_I just saved myself the hassle from starting a new post about this whole subject.
I just recently purchased a GSXR 1000 ITB and will be bolting this up to my one of my projet motors. I'm not too sure if I'll be doing it on the AEB 20v or the 1.8L 16v. 

Noel, ask Brendan for help / info. I believe Stef had the same setup on her red mk2.


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## GLX-GLX (Nov 15, 2006)

*Re: (Breadfan5968)*


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## 86Franklin (Apr 5, 2008)

*Re: (GLX-GLX)*

mine. not itb but you know
home from my friends fab shop








mock up








mounted with carbs


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## yeayeayea (May 29, 2005)

*FV-QR*

i have to redo my outer runners (cyl 1 &4) to correct the coupler alignment, and was planning on doing them just like you have franklin, that manifold looks excellent http://****************.com/smile/emthup.gif


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## 86Franklin (Apr 5, 2008)

*Re: FV-QR (yeayeayea)*

thanks. i could have made it myself but it wouldnt have turned out anything close to that. each runner is four pieces welded together not a smashed piece of pipe. i like it, and sooner or later ill get it powder coated.


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## ps2375 (Aug 13, 2003)

*Re: FV-QR (86Franklin)*

Here's ours mocked up on the spare head. I bought the manifold on the Vortex (I don't remember who fabbed the mani), But I had a local muffler shop make the oval runners round and fit over the throttlebodies. I added 3 set screws per runner, to lock onto the groove already on the bodies. And since this pic, I've mounted them and sealed the gap with Dirko sealant, thus no couplers. It also has a 1.8T fuel rail. The motor is not assembled yet(being rebuilt after sucking up a oil pickup bolt







)
























Now I need to find some sock filters to go over the stacks. Any idea's? I'm gonna throw the mani and ITB's in the car and stop at some local bike shops and see if they have any ideas.


_Modified by ps2375 at 7:17 PM 2-24-2010_


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## 86Franklin (Apr 5, 2008)

*Re: FV-QR (ps2375)*

i don't know what your budget is but i'd try and find some individual k&n's to go one them. by the look of the ridge on the stacks right before the coupler makes it seem like they were stuck in some type of box or plate. i also suggest something like this http://www.merlinmotorsport.co...28235


_Modified by 86Franklin at 9:49 PM 2-24-2010_


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## ps2375 (Aug 13, 2003)

*Re: FV-QR (86Franklin)*

The ITB's are from a GSXR750, iirc. All that looks nice, but I'll try to find a source in the usa. By the time something like that gets here, half the auto-x season will be done, and we'll have to re-tune for it some. I think I'm looking for individual filters, also. We should have plenty of room in front of the ITB's as the Honda radiator is arriving tomorrow(2-25). So cool air will be plentiful for the motor. http://****************.com/smile/emthup.gif 


_Modified by ps2375 at 10:11 PM 2-24-2010_


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## 86Franklin (Apr 5, 2008)

*Re: FV-QR (ps2375)*

they have them in the us but thats just the first link on google that popped up. and i you're looking for individual filter k&n are the way to go


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## ps2375 (Aug 13, 2003)

*Re: FV-QR (86Franklin)*

Yeh, I have been looking for a few weeks now, and have done google searches, and have a bookmark on my laptop for some, ITG, I think. I wanna try local, then I can test fit on the ITB's. Since it is an auto-x/hillclimb car only, I have considered a fine screen over the end of each stack also. I don't know how that could benefit/hinder power.
The motor is a 1.8 16V, fully balanced, some porting on the head, 276* or bigger cams, stock CR(for this version), and a TT race header . It made 123hp on CIS and stock cams and exh mani and unbalanced.


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## 86Franklin (Apr 5, 2008)

*Re: FV-QR (ps2375)*

while screens offer better air flow the only thing they protect against is rocks pretty much. i have also read that direct air flow into the head without any restriction can hinder power but i can't prove that or have seen it proven, just something i have read so idk. i've seen many carbed or itb'd track cars just run the screens and they survive so it must be alright. also i just swapped a 1.8 16v in my car (see a few post up) but mine isn't built really at all.


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## ps2375 (Aug 13, 2003)

*Re: FV-QR (86Franklin)*

http://****************.com/smile/emthup.gif for your alt mount.







and the mani looks quite good also.


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## ps2375 (Aug 13, 2003)

*Re: FV-QR (ps2375)*

Found some UNI sock filter locally that will fit over the stacks. http://****************.com/smile/emthup.gif I will be picking the other 3 up tomorrow. http://****************.com/smile/emthup.gif


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## Brad_16v (Mar 15, 2010)

i've only seen a setup like this once...
In my opinion i think it should be making more torque than ITB's with short intake runners,
then again im not sure
im interested in running a setup like this
weighing up my options 1st
can any of you guys shed some light on this matter?? 
Opinions,views, comments, criticism gladly welcome


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## yeayeayea (May 29, 2005)

*FV-QR*

I actually have a manifold cut for use in that same scenario, but in the end
runner lengths are way long
hot air from above the exhaust
would only be good if you hacked up a 50mm manifold IMO
air still has to make a ~180* bend to get into the head


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## Brad_16v (Mar 15, 2010)

*Re: FV-QR (yeayeayea)*

So you recon it wont work well?


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