# ITBs and CIS?



## Southcross (Jul 2, 2004)

Anyone with experience in Individual Throttle Bodies and CIS fuel management? Theory? Design? I'm doing research...
*EFI is OFF TOPIC*


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## Jettaboy1884 (Jan 20, 2004)

*Re: ITBs and CIS? (Southcross)*

USRT is currently putting together an ITB setup that can work with CIS.
Many people feel that you will negate the true essence of ITB's by going with CIS because you will have to duct them through the fuel distributor and "loose" the whole ITB look. However, several people have gone this route successfully.
Based on what I read, hear, and my common sense, I believe that going with a CIS/ITB's setup will gain throttle response, but be more troublesome to tune at idle. With as short of an intake tract as possible, it will undoubtedly sound wicked raw. http://****************.com/smile/emthup.gif 
A couple pics I have:


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## Southcross (Jul 2, 2004)

very interesting.... very very interesting. I love the CF manifold. One thing I guess I didn't think of is the placement of the coldstart valve, assuming you want to even run one LOL
For a daily driver I could see Idle tuning being an issue, if you were building a SSCA or a Drag car "idling without stalling" is a luxury


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## epic.banned (Feb 25, 2008)

*Re: (Southcross)*

I also saw a setup where the guy didn't use a plenum and had the throttle cable lifting the fuel dizzy plate and opening the throttles.


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## Holden McNeil (Jul 26, 2004)

*Re: (epic.banned)*


_Quote, originally posted by *epic.banned* »_I also saw a setup where the guy didn't use a plenum and had the throttle cable lifting the fuel dizzy plate and opening the throttles.


unfortunately lifting the plate isn't exactly as linear that guy assumes... Using his setup with cause all sorts of rich and lean conditions and basically it'll never run right (except maybe near idle)... and yes I saw the video








I started down this path but scrapped it due to the modifications needed to mount the throttle bodies...
My old ABA/CIS/ITB thread for reference: http://forums.vwvortex.com/zerothread?id=3224050


_Modified by Holden McNeil at 3:49 PM 4-10-2008_


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## epic.banned (Feb 25, 2008)

*Re: (Holden McNeil)*


_Quote, originally posted by *Holden McNeil* »_
unfortunately lifting the plate isn't exactly as linear that guy assumes... Using his setup with cause all sorts of rich and lean conditions and basically it'll never run right (except maybe near idle)... and yes I saw the video








I started down this path but scrapped it due to the modifications needed to mount the throttle bodies...
My old ABA/CIS/ITB thread for reference: http://forums.vwvortex.com/zerothread?id=3224050

_Modified by Holden McNeil at 3:49 PM 4-10-2008_

I was trying to find the video to post it, but I agree completely with you about the tuning conditions with it.
At that point carbs would work much better than trying to attempt that.
CIS + ITBs+ Plenum would work decently though


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## Southcross (Jul 2, 2004)

hmmm..... I LOVE IT! gives me some dastardly ideas








I'd assume it doesn't have to be a "plenum" as long as they pull from the same source at the CIS air meter.


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## Jettaboy1884 (Jan 20, 2004)

*Re: (Southcross)*

Yes.
*All* of the air coming into the engine needs to come through the fuel distributor.


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## epic.banned (Feb 25, 2008)

*Re: (Jettaboy1884)*

a plenum would allow for power band tunning in the RPM's http://****************.com/smile/emthup.gif


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## Southcross (Jul 2, 2004)

*Re: (epic.banned)*


_Quote, originally posted by *epic.banned* »_a plenum would allow for power band tunning in the RPM's http://****************.com/smile/emthup.gif 
well, what "benefit" would there be to the power band? Top end, bottom, middle? As compared to individual runners to a single "collector" at the CIS distributor?


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## Holden McNeil (Jul 26, 2004)

*Re: (Southcross)*


_Quote, originally posted by *Southcross* »_well, what "benefit" would there be to the power band? Top end, bottom, middle? As compared to individual runners to a single "collector" at the CIS distributor?

now that's an interesting take on the idea.... individual runners that terminate at the air plate boot.... hmmmm it would probably look something like an equal length long tube exhaust header but with a throttle body in each runner.... providing you can come up with a solution for providing enough fuel I'd imagine this would work rather well!!! http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


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## epic.banned (Feb 25, 2008)

*Re: (Southcross)*


_Quote, originally posted by *Southcross* »_well, what "benefit" would there be to the power band? Top end, bottom, middle? As compared to individual runners to a single "collector" at the CIS distributor?

It is similar to tuning plenum size on a normal engine, you would be able to tune for RPM. You could probably gain some low end out of using a plenum but have a loss in top end.
I think the "individual runners" coming to a collector at the fuel dizzy would be more of a restriction than a full plenum


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## Southcross (Jul 2, 2004)

*Re: (Holden McNeil)*

essentially the reverse of those custom header/turbo manifolds, 4-to-1... but 1-to-4... and no stealing ideas








I'm willing to give just about anything a try, only the Dyno will really show for sure what happens (unless you happen to have a flow bench to try it on). I think if its done right, air flow shouldn't be impeded and actually should increase in velocity as it passes from CIS distro to runner to ITB


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## epic.banned (Feb 25, 2008)

*Re: (Southcross)*


_Quote, originally posted by *Southcross* »_essentially the reverse of those custom header/turbo manifolds, 4-to-1... but 1-to-4... and no stealing ideas








I'm willing to give just about anything a try, only the Dyno will really show for sure what happens (unless you happen to have a flow bench to try it on). I think if its done right, air flow shouldn't be impeded and actually should increase in velocity as it passes from CIS distro to runner to ITB


I think having such long runners will only hurt top end power. Having ITB's you are trying to gain power and response across the all of the RPM's
Given a plenum will keep some of the benefits away but not all of them


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## B4S (Apr 16, 2003)

*Re: (Southcross)*

Toyota did the 'de-merge collector' intake in the late 90's, on the corollas IIRC. I've seen it, very funky. Right after the TB, it branched off into four long tubes to the intake ports.


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## Holden McNeil (Jul 26, 2004)

*Re: (B4S)*


_Quote, originally posted by *B4S* »_Toyota did the 'de-merge collector' intake in the late 90's, on the corollas IIRC. I've seen it, very funky. Right after the TB, it branched off into four long tubes to the intake ports.

You mean like the one that Josh from Nothing Leaves Stock is putting on his 16vTT


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## epic.banned (Feb 25, 2008)

*Re: (Holden McNeil)*


_Quote, originally posted by *Holden McNeil* »_
You mean like the one that Josh from Nothing Leaves Stock is putting on his 16vTT

























Damn, how come I haven't seen this creation from josh yet? The man is pretty crazy with his stuff 
http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


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## Southcross (Jul 2, 2004)

insane minds and their expression in insanity... I love it
The only problem I forsee in my design is allowing for engine movement/etc.


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## 88mkII16v (Feb 4, 2006)

i did find this... appearantly older celica guys run our cis on their cars and theyre making these for an intake... i think it looks fairly simple to make and i may try it. http://www.obrasmechanicos.com/cis12.jpg
edit: im not sure what to do for a TB though.


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## Southcross (Jul 2, 2004)

*Re: (88mkII16v)*


_Quote, originally posted by *88mkII16v* »_i did find this... appearantly older celica guys run our cis on their cars and theyre making these for an intake... i think it looks fairly simple to make and i may try it. http://www.obrasmechanicos.com/cis12.jpg
edit: im not sure what to do for a TB though.
well, that design wouldn't be "ITB" (individual throttlebody)... still interesting


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## 88mkII16v (Feb 4, 2006)

i know its not but its still something intriguing... it gives a good idea for something you could create


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