# 8v cis 1.8l intake



## g3mccotter (Mar 13, 2006)

I am just wondering the best way to go about enlarging the piping from the cis to the throttle body. I bought a 3" pvc but I dont see any way that the rubber boot on both ends will go around it cause they are about 3 inches i believe and cant be stretched. I was wondering if cutting a small slit in the boots just enough to fit the pvc in and hose clamp around would be fine? I have searched and not found much, what have others done? I rotated the top of my rubber boot thing coming off of my cis so it faces straight towards the tb. I think with just a straight pvc from there to the other boot and possible cutting the pvc at a little angle might help i should be able to clamp them both down well enough to seal. 

The hose clamps aren't large enough either so I believe a 4" clamp will need to be there

Any suggestions? Thanks


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## g3mccotter (Mar 13, 2006)

3" pvc wont work even with cutting the boots because the outside diameter of 3" pvc is 3 1/2" its just too big. What about using dryer hose instead of pvc. What I have heard some people using from lower down on the intake. Would that not be as good because its ridged on the inside and not smooth like pvc?


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## NooB! (Mar 19, 2011)

Tried the local custom exhaust shop for a short length of 3 inch? They could probably put a custom bend or two to make it fit right. Shouldn't be all that much to have one made.

(Been trying to figure out the same thing on a digifant system. The snorkle from the air box to the TB just doesn't look like it flows all that well.)

Am new to these cars, so... Do know it is not covered in the Bentley beacuse I looked for it.


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## g3mccotter (Mar 13, 2006)

Well there are lots that say they just use 3 inch pvc. Its 6 bucks at loews so thats cheap. I heard some use silicone or something. I just want it to be able to be 3" all the way and not have to size it down a ton at both ends. I imagine something thin like metal how you were saying would work its just pvc is too thick to wrap the rubber boots around.


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## Seax_Smith (Jun 1, 2007)

pvc is 6 bucks and 3" aluminum is $16 +s/h.... not a hard choice for me

http://www.siliconeintakes.com/prod...d=757&osCsid=69221ecec0ccb65bae8e9176894106dc

Couplers: http://www.siliconeintakes.com/prod...d=617&osCsid=69221ecec0ccb65bae8e9176894106dc


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## g3mccotter (Mar 13, 2006)

make the whole thing out of silicone? I dont know how else I could use that


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## g3mccotter (Mar 13, 2006)

i appreciate the help i just dont know how to use it. If i used the pvc that is 6 somthing and two couplers that are 6 something it will be around 13 with tax which isnt much less than just that aluminum which you wouldnt need couplers.


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## WaterWheels (Aug 14, 2005)

This is another one where I just have to ask, sorry, "why"? Now if the factory parts are no longer sold, discontinued, then I can understand the need for a workable replacement. I am sure good used parts are still out there and many companies do already sell aluminum "Power Pipes" to fit most cars though, so why fabricate? Has someone convinced you that it is going to transform your engine into a beast? Increasing the tube size will do nothing, OK maybe a pony at max engine speed on a cold day. Air flow is something you can't determine just by looking at something. And even if the large tube did provide much more flow, how is the engine going to take advantage of this increase? Did you increase the valve size? Did you have the ports flowed? Are the throttle blades now larger? etc. etc. etc. So again the question everyone hates to be asked of them, why?


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## g3mccotter (Mar 13, 2006)

yea my buddy (dubseven) calls it micro modifying haha. yea im not expecting any hp increase just throttle response if anything, if there is hp to be had thats sick but i doubt it. I am about to p&p the head match the exhaust mani and intake mani. Possibly go with oversized valves I dont know yet. The reason why I dont just buy the abd is that its 75 bucks which is retarded for a piece of pipe. Which also makes me believe there has to be a reason why they would sell such a thing for some sort of performance? I appreciate your concern. And I do have a larger TB and ported intake mani so hopefully it will help that.


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## WaterWheels (Aug 14, 2005)

g3mccotter said:


> . . . just throttle response if anything . . . The reason why I dont just buy the abd is that its 75 bucks which is retarded for a piece of pipe. Which also makes me believe there has to be a reason why they would sell such a thing for some sort of performance? . . . And I do have a larger TB


Nope, any increase in throttle response reported is just seat of the pants feeling which lies. It is the same as washing your car, it seems to run better when you do but it is just that you feel better with a nice clean shiny car. Adding a oversized tube along the intake track will do nothing but "slow" the air flow and cause at worst more lag. There is a reason the plastic tubing VW used narrows down, they could have just used a same size tube the entire lenght.

Yes, brand name parts often cost or seem to cost way too much. The fact that ABD sell such an item is, for lack of a nice way of saying this, people like yourself. To be honest I have never read their ad, but would bet they do not claim any kind of power improvements. Maybe it claims to smooth out the curves in the intake, that's true. There are so many products sold that do zip but with good advertising and unknowing buyers, money is to be had real easy. Companies also gamble a lot on the fact that buyers can't or will not do any testing, as in dyno, to check claims and returning a product is often more trouble then just sucking it up.

Larger throttle body? From what/where? Your engine already came with the largest VW/Audi installed so what have you replaced it with?


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## Glegor (Mar 31, 2008)

WaterWheels said:


> Nope, any increase in throttle response reported is just seat of the pants feeling which lies. It is the same as washing your car, it seems to run better when you do but it is just that you feel better with a nice clean shiny car. Adding a oversized tube along the intake track will do nothing but "slow" the air flow and cause at worst more lag. There is a reason the plastic tubing VW used narrows down, they could have just used a same size tube the entire lenght.
> 
> Yes, brand name parts often cost or seem to cost way too much. The fact that ABD sell such an item is, for lack of a nice way of saying this, people like yourself. To be honest I have never read their ad, but would bet they do not claim any kind of power improvements. Maybe it claims to smooth out the curves in the intake, that's true. There are so many products sold that do zip but with good advertising and unknowing buyers, money is to be had real easy. Companies also gamble a lot on the fact that buyers can't or will not do any testing, as in dyno, to check claims and returning a product is often more trouble then just sucking it up.
> 
> Larger throttle body? From what/where? Your engine already came with the largest VW/Audi installed so what have you replaced it with?


just like how all those guys are selling boat bilge blowers as electric turbos on ebay.. just clamp an air filter on it, call it an electric turbo, and sell it to idiots all day long for 250 bucks.. 

LMFAO.. always thought those were pretty awesome. (completely useless)


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## vwturbofox (Jul 31, 2010)

Glegor said:


> just like how all those guys are selling boat bilge blowers as electric turbos on ebay.. just clamp an air filter on it, call it an electric turbo, and sell it to idiots all day long for 250 bucks..
> 
> LMFAO.. always thought those were pretty awesome. (completely useless)


I have seen those and claim like 40hp or some bs why not just bolt on a leaf blower onto your car :laugh::laugh.Yeah reaplcing that tubing doesn't do anything does you car see crazy rpms do have a big cam etc other wise wont do sh**.throttle response not really maybe more noise from it.


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## Glegor (Mar 31, 2008)

vwturbofox said:


> I have seen those and claim like 40hp or some bs why not just bolt on a leaf blower onto your car :laugh::laugh.Yeah reaplcing that tubing doesn't do anything does you car see crazy rpms do have a big cam etc other wise wont do sh**.throttle response not really maybe more noise from it.


yea, +800 mpg, and +1200 hp if you install one of those "electric turbos"

the electric turbos ive seen, have a planetary drive, with 3 electric motor hooked to it usually, and cost many thousands of dollars.. they were electronic controlled and everything..


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## g3mccotter (Mar 13, 2006)

Look the three of you all from the pacific northwest. Yea screw me ill just drive it off a bridge I guess. I am never gonna have any power with it anyways i shouldn't even be trying to enjoy working on such an inferior engine.

Fox's had a larger throttle body stock. You can also buy an 80mm aftermarket one that is a large single butterfly valve as opposed to two valves.

I guess I will wait till i stroke it twin turbo it and spray it before I make that little pipe bigger. Thanks for the help guys I really appreciate it. :thumbup:


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## WaterWheels (Aug 14, 2005)

g3mccotter said:


> Look the three of you all from the pacific northwest. Yea screw me ill just drive it off a bridge I guess. I am never gonna have any power with it anyways i shouldn't even be trying to enjoy working on such an inferior engine.
> 
> Fox's had a larger throttle body stock. You can also buy an 80mm aftermarket one that is a large single butterfly valve as opposed to two valves.


Before trying to make a response like you have here, do your homework first. We "three" are not all from the Pacific Northwest. I am in Germany which is a long long way from that part of the woods. Fox models use the same size throttle bodies as other Volkswagens of that time frame. Now if you were talking of installing one on an old Rabbit then yes, it would be a little larger. It's just like people who say they installed an Audi 5000 throttle body on their Golf II GTi engine, big deal, same size. Yep you can geta single throttle bodie, or at least you could before but I don't believe they are still sold, but the gain there is just like installing a large intake tube. You lose drivability due to the single size and how much it opens with a small amount of pedal travel. On a modified race engine it could be an improvement, but very small and one if not the last thing to do after all other modifications are done.

So take the sour grapes attitude and stick it in a box on a shelf for some other place and read, learn, plan, save and execute. There is no such thing a easy/free performance modifications, at least none worth a damn.


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## Glegor (Mar 31, 2008)

WaterWheels said:


> Before trying to make a response like you have here, do your homework first. We "three" are not all from the Pacific Northwest. I am in Germany which is a long long way from that part of the woods. Fox models use the same size throttle bodies as other Volkswagens of that time frame. Now if you were talking of installing one on an old Rabbit then yes, it would be a little larger. It's just like people who say they installed an Audi 5000 throttle body on their Golf II GTi engine, big deal, same size. Yep you can geta single throttle bodie, or at least you could before but I don't believe they are still sold, but the gain there is just like installing a large intake tube. You lose drivability due to the single size and how much it opens with a small amount of pedal travel. On a modified race engine it could be an improvement, but very small and one if not the last thing to do after all other modifications are done.
> 
> So take the sour grapes attitude and stick it in a box on a shelf for some other place and read, learn, plan, save and execute. There is no such thing a easy/free performance modifications, at least none worth a damn.


FWIW, the intake pipe does nothing, i have an 85 gti that got an ABD big bore, it did NOTHING. the K&N did more than the big intake did..

and my car wasnt COMPLETELY STOCK either.. it had a good exhaust, a nice cam, K&N, and a good tune.. my car ran good, and i noticed no gains from the intake tube. might have even lost a tad off the bottom end from it..

and another FWIW, the big throttle bodies are kinda retarded if you ask me. i adapted a big ford TB to my GTI for a short while.. but i liked the feel of the progressive TB so much, that i went back to it..

i like being able to have a throttle stop before the secondary opens, cause if you stay out of the secondarys, then you get really good mileage!

car got worse mileage, cause i was always on it more than i wanted. didnt really do anything for power either..

like i say, it didnt take me long to bolt my stock TB back on there..


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## vwturbofox (Jul 31, 2010)

g3mccotter said:


> Look the three of you all from the pacific northwest. Yea screw me ill just drive it off a bridge I guess. I am never gonna have any power with it anyways i shouldn't even be trying to enjoy working on such an inferior engine.
> 
> Fox's had a larger throttle body stock. You can also buy an 80mm aftermarket one that is a large single butterfly valve as opposed to two valves.
> 
> I guess I will wait till i stroke it twin turbo it and spray it before I make that little pipe bigger. Thanks for the help guys I really appreciate it. :thumbup:


I say just put the pipe on and see what happens its easy to switch back if you dont like it.Yes over here in the pacific northwest we build fast street cars thats the way i like it big power in small cars :laugh::laugh:


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## g3mccotter (Mar 13, 2006)

Yea my bad it was just two of them from pn. one just posted twice. I had no problem with your response either waterwheels. I was saying pm because you guys are so critical. It had nothin to do with the speed of your car.


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## g3mccotter (Mar 13, 2006)

my throttle body was significantly smaller than the fox one.


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## Glegor (Mar 31, 2008)

vwturbofox said:


> I say just put the pipe on and see what happens its easy to switch back if you dont like it.Yes over here in the pacific northwest we build fast street cars thats the way i like it big power in small cars :laugh::laugh:


we like modifying our economy cars! :thumbup:

(especially the diesel variety!)


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## Glegor (Mar 31, 2008)

g3mccotter said:


> my throttle body was significantly smaller than the fox one.


then someone screwed with it.. because i currently have 2 different cars with CIS, one with CIS-L and one with CIS-E.

both cars have the SAME throttle body. ones in a GTI, ant one is in a lowly golf GL.

the only cars i have seen with significantly smaller throttle bodies, are the mk1 cars.

the Fox didnt get a bigger throttle body, it got the same size as the Digi, and later CIS engines.


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## g3mccotter (Mar 13, 2006)

88 cabbys got the mk1 tb. Read the "research" i did before upgrading tb

http://forums.vwvortex.com/showthread.php?4778283-8v-throttle-body-upgrade


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## WaterWheels (Aug 14, 2005)

g3mccotter said:


> 88 cabbys got the mk1 tb.


That is correct and I had forgotten we were talking about a CIS version, that's my mistake (assume to much). The Cabby came with both Dififant II and CIS in 88' and was thinking we were talking about a Digifant model. That mistake does not change things though. I know you have been told and sold on the "Power Pipes" being an upgrade to flow in some advertised way, that's fine if you want to go that route. Just understand that you will see no gains except in your head. It might look better than the plastic factory part, that's also fine if you just care about the looks. It might give off a low hard to hear deep growl kind of sound if you use the aluminum one, also fine if you want that noise. But as a performance modification or up-grade, you will reap nothing. My only concern is that you a) don't think you are doing any performance improvement b) hope to swing you towards learning before buying/doing and c) not turning your car into looking getto for the sake of a few bucks and false information.


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## g3mccotter (Mar 13, 2006)

ok fair enough. thanks for the heads up


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## Glegor (Mar 31, 2008)

WaterWheels said:


> That is correct and I had forgotten we were talking about a CIS version, that's my mistake (assume to much). The Cabby came with both Dififant II and CIS in 88' and was thinking we were talking about a Digifant model. That mistake does not change things though. I know you have been told and sold on the "Power Pipes" being an upgrade to flow in some advertised way, that's fine if you want to go that route. Just understand that you will see no gains except in your head. It might look better than the plastic factory part, that's also fine if you just care about the looks. It might give off a low hard to hear deep growl kind of sound if you use the aluminum one, also fine if you want that noise. But as a performance modification or up-grade, you will reap nothing. My only concern is that you a) don't think you are doing any performance improvement b) hope to swing you towards learning before buying/doing and c) not turning your car into looking getto for the sake of a few bucks and false information.


any ideas why they never changed the cabby from the mk1 style? and why they went straight to the mk3 style?

a convertible mk2 would be titties!!!


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## WaterWheels (Aug 14, 2005)

I have no idea what goes through the heads of the desiners at VW or any auto manufacturing company. I would take a guess and say that in like most cases cabriolet models come after a year or more of production once sales prove good and some easy way to reinforce the structure is found (cabriolets have to be stronger in some areas to be approved). It would make no sense to have to re-design the entire vehicle to come out with a convertable and I guess that is why the mk2 was skipped. The mk3 came out with one and sales did not do real well so that could be why VW skipped another two model changes. The mkVI is coiming out with a cabriolet this year so I guess they have had new requests for another one. But this is all just guessing on my part as I have never read or heard any real reasons, and don't go looking for any either.


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## chois (May 12, 2000)

FWIW - I dyno tested a 3" tube vs. the stock hourglass tube on my A2. The big tube lost a few lb-ft and hp (just a few).

On the track the big tube does have a crisper throttle response, that was apparent in a rolling start (road racing), but at the end of the day the stock tube is the better choice IMO.


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## Glegor (Mar 31, 2008)

chois said:


> FWIW - I dyno tested a 3" tube vs. the stock hourglass tube on my A2. The big tube lost a few lb-ft and hp (just a few).
> 
> On the track the big tube does have a crisper throttle response, that was apparent in a rolling start (road racing), but at the end of the day the stock tube is the better choice IMO.


 i knew my butt wasnt lieing.. it felt like my car was slower off the line with an ABD tube..


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## Mowgli87 (Jan 13, 2006)

I can tell you from personal experience that judging an air flow system by just looks is a crap shoot, at best. To really get an idea of how the air is moving through the system, you either need some really good fluid analysis programs (and the computers to run it) or flow bench comparisons. The later is actually pretty easy to accomplish if you a handy DIYer. 

The design of the stock pipe that VW used is a venturi. They are used in flow situations where a decrease in pressure is desired (at least for a certain section of tubing). Along with the decrease in pressure, an increase in velocity is achieved. Typically when you increase the velocity of intake air it will give the engine more torque at lower rpm. I guess that could be at least part of the reason for decrease in power that chois saw in his comparison. And the extra power on a rolling start was probably just increase volume flow at higher engine speeds. 

At the end of the day the most effective way to make more power in ANY engine is to increase it's volumetric efficiency. Whether that comes by means of porting, forced induction, or even intake system resonance tuning doesn't matter. Each method with give you different characteristics. 

/My $0.02


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