# ITB conversion - MAP and Vacumn



## H2Zero (Apr 25, 2003)

Dear All,
I did my search and could not find what I needed. Will be converting to ITB from AE101 and going Megasquirt. My concern for now is how will I get the car to idle as i would be using open trumpet. Your advice and pictures if any much appreciated.


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## Muffler Bearing (Apr 4, 2004)

dont know what an ae101 is, but the throttles i got from a gsxr750 have vacuum ports on each barrel that i will be using for map vacuum.
search for 'vwralley' he used similar throttles on a 16v in his bunny.
-j


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## psykokid (Apr 2, 2002)

*Re: ITB conversion - MAP and Vacumn (H2Zero)*

tap each intake runner after the throttle plate and combine all 4 lines to make one to pull map/vacum from.


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## VWralley (Mar 30, 2002)

*Re: ITB conversion - MAP and Vacumn (psykokid)*


































_Modified by VWralley at 8:28 AM 12-6-2006_


_Modified by VWralley at 8:30 AM 12-6-2006_


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## H2Zero (Apr 25, 2003)

*Re: ITB conversion - MAP and Vacumn (VWralley)*

VWralley.... thanks for the pic. You guys r great. From the pic am I wrong to say that VWralley tapped 2 vacume line out of each throttle? I presume one if for the brake servo?
AE101 is a model of Toyota where they used individual throttle bodies. I have an vacume inlet come from the left and right throttle. Do i still need to tap the 2 in the middle or what I already have is sufficient...?
Cheers guys. 

_Modified by H2Zero at 12:32 AM 12-7-2006_


_Modified by H2Zero at 1:40 AM 12-7-2006_


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## urogolf (Dec 10, 2000)

*Re: ITB conversion - MAP and Vacumn (H2Zero)*

pic of mine
1 small line from each is for the map sensor 
the other small is for the fuel pressure regulator 
and the big one is for the brake booster








i am using a diesel choke cable to adjust idle on mine as needed http://****************.com/smile/emthup.gif


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## VWralley (Mar 30, 2002)

*Re: ITB conversion - MAP and Vacumn (urogolf)*

i did not have to tap the bodies, those lines are from the factory bike that way. however, the larger hose does not have vacuum, i have yet to find out what it does, the are 4-1 then capped off. the smaller set i run 4-2-1 to the MAP, seems to work just fine. 
for the brake booster, i tapped the inj holes for the barbed fittings. at first i had all four tapped. this isnt necessary, you only need one. which i fixed and you can see in the final install pic (outside) that i only use one now http://****************.com/smile/emthup.gif


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## Vento_Gareth (Feb 3, 2003)

*Re: ITB conversion - MAP and Vacumn (VWralley)*

I just machined and tapped in some fittings for the vacuum line T-pieces so all 6 housings can be bridged to give a constant vacuum over all the housings. I tried it just running of cylinder 6 housing and it caused running problems at idle and messed up the mixture on that cylinder.


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## VW81Rabbit (May 20, 2006)

*Re: ITB conversion - MAP and Vacumn (Vento_Gareth)*


_Quote, originally posted by *Vento_Gareth* »_









This problebly sounds awesome


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## xr4tic (Dec 10, 2001)

*Re: ITB conversion - MAP and Vacumn (VWralley)*


_Quote, originally posted by *VWralley* »_i did not have to tap the bodies, those lines are from the factory bike that way. however, the larger hose does not have vacuum, i have yet to find out what it does, the are 4-1 then capped off. the smaller set i run 4-2-1 to the MAP, seems to work just fine. 
for the brake booster, i tapped the inj holes for the barbed fittings. at first i had all four tapped. this isnt necessary, you only need one. which i fixed and you can see in the final install pic (outside) that i only use one now http://****************.com/smile/emthup.gif 

Is there a reason you decided to just do 1 line instead of all 4 for the brake booster? just looks, or did it cause problems?


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## VWralley (Mar 30, 2002)

*Re: ITB conversion - MAP and Vacumn (xr4tic)*

it is only necessary to run one. i switched and it acted exactly the same. i looked at a ton of carbed cars and none ever ran more than one port for the brake vac. http://****************.com/smile/emthup.gif


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## Digital:K (Dec 18, 2006)

*Re: ITB conversion - MAP and Vacumn (xr4tic)*


_Quote, originally posted by *xr4tic* »_
Is there a reason you decided to just do 1 line instead of all 4 for the brake booster? just looks, or did it cause problems?

I used to run 4. I noticed a slight difference going down to 1. Very slight...


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## Geoff Rood (Apr 30, 2001)

I remember reading feeding all four cylinders into a small ( 2 cubic inch?) vacuum reservoir delivered good readings. I'm going to use this approach when I start fabbing my intake up.


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## H2Zero (Apr 25, 2003)

*Re: (Geoff Rood)*

you got pic of that reservoir?

_Quote, originally posted by *Geoff Rood* »_I remember reading feeding all four cylinders into a small ( 2 cubic inch?) vacuum reservoir delivered good readings. I'm going to use this approach when I start fabbing my intake up.


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## Geoff Rood (Apr 30, 2001)

No, I just read about the application of ITB's. Basically it'd be a small reservoir that would equal the pressure readings of all four throttles to provide an overall reading. No four cylinders are ever going to breathe EXACTLY the same.


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## mk2dubbin (Mar 16, 2002)

*Re: (H2Zero)*


_Quote, originally posted by *H2Zero* »_you got pic of that reservoir?

just put a small lawnmower fuel filter in your map line.


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## patatron (Aug 10, 2003)

*Re: ITB conversion - MAP and Vacumn (VWralley)*


_Quote, originally posted by *VWralley* »_it is only necessary to run one. i switched and it acted exactly the same. i looked at a ton of carbed cars and none ever ran more than one port for the brake vac. http://****************.com/smile/emthup.gif 

Carb manifolds are different though, they will equalize as all 4 chambers arent really separated.


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## H2Zero (Apr 25, 2003)

*Re: (mk2dubbin)*

apart from brake we also need vacumn for idle, fpr and a/c so would appreciate more info/pic please.
Thank U..


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## Digital:K (Dec 18, 2006)

*Re: (H2Zero)*

too much thinking, mine work great w/ just one hose going to the booster.


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## SIR ANDROID184 (Feb 13, 2007)

*Re: ITB conversion - MAP and Vacumn (VWralley)*


_Quote, originally posted by *VWralley* »_










whats the specs on your ITBS....year and model thanks


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## H2Zero (Apr 25, 2003)

*Re: ITB conversion - MAP and Vacumn (SIR ANDROID184)*

I tap No.1 for vacumn going to the brake booster. Now that i have taken the inlet apart I notice the chamber are all back which means the mixture is screwed. really appreciate if some here could post clear pictures as what they have done ... cheers.


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## Salsa GTI (Aug 29, 2000)

*Re: ITB conversion - MAP and Vacumn (H2Zero)*

the car wont run correctly using speed density any way..its just for the brakes...run it on alfa-N..and call it a day


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## H2Zero (Apr 25, 2003)

*Re: ITB conversion - MAP and Vacumn (Salsa GTI)*


_Quote, originally posted by *Salsa GTI* »_the car wont run correctly using speed density any way..its just for the brakes...run it on alfa-N..and call it a day

I am running on Alpha-N. I just want to know why the No.1 chamber which I tap for brake is black?


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## Salsa GTI (Aug 29, 2000)

*Re: ITB conversion - MAP and Vacumn (H2Zero)*

thats a puzzler for sure


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## H2Zero (Apr 25, 2003)

*Re: ITB conversion - MAP and Vacumn (Salsa GTI)*


_Quote, originally posted by *Salsa GTI* »_thats a puzzler for sure









it has been suggested that could be due to the butterfly not being sync properly.... any confirmation?


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## Salsa GTI (Aug 29, 2000)

*Re: ITB conversion - MAP and Vacumn (H2Zero)*

butterfly sync will screw up the world....and cause that as well....HAd it happen with the Extrude A Body ones...on a 16v....it was running great...then the owner smashed the throttle hard to the floor..and it ran like ass after that..popping and carrying on.....back to the shop re synced all the plates good as new....and tightned the piss out of them and loosened up the throttle cable a little








re synce them and it willl probably go away


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## H2Zero (Apr 25, 2003)

*Re: ITB conversion - MAP and Vacumn (Salsa GTI)*

thanks guys...


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## chrisbmx68 (Aug 14, 2003)

here is what I will be using if my car ever runs again. Machined nipples to press into the injector bungs using an injecotr oring 
















then tying them all into a 6 port vac manifold.


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