Did I get the wrong throttle body to modify?
01-23-2009, 08:32 PM
#1
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Did I get the wrong throttle body to modify?
I pulled one out of a 100CS PN 322 075 061 A..
But what I needed to get is out of a 97 A6 PN 345 078 063 T, right?
Oh well..back to the salvage yard..
But what I needed to get is out of a 97 A6 PN 345 078 063 T, right?
Oh well..back to the salvage yard..
01-23-2009, 09:01 PM
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They're all the same...
The only thing you need to check is that the TB is from an auto transmission car if you have an auto. If you have a manual, you can use a TB from auto or manual.
And then there are the rare "S" TBs...
And then there are the rare "S" TBs...
01-24-2009, 06:59 AM
#6
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Re: They're all the same...
This TB is not "thick" enough around the primary, It's width does not look like it could be bored out as wide as the pictures I'm seeing. If I did I think it would go outside the radius. From what I gather I would like to go the ,XTB route. I'll post a picture of what Im trying to explain shortly.
And unfortunatly I don't have the funds for either one of your SXTBs, EDIGREG the Fuchs are almost done. They look great, and ideas foe tires? Something MS would be ideal. Maybe Falken 912 or Proxy 4s?
And unfortunatly I don't have the funds for either one of your SXTBs, EDIGREG the Fuchs are almost done. They look great, and ideas foe tires? Something MS would be ideal. Maybe Falken 912 or Proxy 4s?
01-24-2009, 07:58 AM
#7
None of the throttle bodies ever made were "thick enough" to modify to the extent...
<center><img src="http://pictureposter.audiworld.com/711/rsxtb.jpg"></center><p>
they are being done today. Thats why TB's need to have epoxy putty packed tightly around the outside of the primary venturi to build up that thickness so they can be bored more than they could otherwise. This requires a lot of effort getting those outside walls ground and roughed-up then meticulously cleaned to provide a good "tooth" for the epoxy putty to adhere to on the outside of the throttle body. Once that area is built up sufficiently you can then start boring work on the inside.
You cannot just "hog" these things out with some power tool and hope for the best. While there's nothing hard about boring a throttle body at least "some" measure of forethought, common sense and understanding of the project MUST take precedent over just running a grinder around the inside of a hole to make it larger.
they are being done today. Thats why TB's need to have epoxy putty packed tightly around the outside of the primary venturi to build up that thickness so they can be bored more than they could otherwise. This requires a lot of effort getting those outside walls ground and roughed-up then meticulously cleaned to provide a good "tooth" for the epoxy putty to adhere to on the outside of the throttle body. Once that area is built up sufficiently you can then start boring work on the inside.
You cannot just "hog" these things out with some power tool and hope for the best. While there's nothing hard about boring a throttle body at least "some" measure of forethought, common sense and understanding of the project MUST take precedent over just running a grinder around the inside of a hole to make it larger.
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01-24-2009, 08:15 AM
#8
Pic 2; Prepping the throttle body for boring...
<center><img src="http://pictureposter.audiworld.com/711/xtbprep1.jpg"></center><p>
This pic shows one side of the TB prepped for its epoxy build-up. The entire area, even the VERY tiniest nooks, crannies and surface area needs to be roughed up for the epoxy to adhere to. Your adhesion is only as strong as extent of your "preparation" allows. This is NOT the place to "scrimp", cut corners, compromise or half-hearted attempts as EVERYTHING you do "after" this relies on that epoxy being there, 100% sealed and intact... FOREVER!!! If you miss a spot, no matter how tiny or seemingly insignificant you risk losing the entire epoxy cover and having it fall out. If that happens the car is DEAD on-the-spot until that epoxy or throttle body is replaced. And it's easier to start with an ENTIRE new TB core than to try to apply new epoxy back on a TB that has been pre-bored and lost one of its epoxy walls.
If there's any grease, hand-oil or even finerprint on this area when epoxy is applied it will likely fail.
And epoxy has to completely cover the boring that will happen later. That means it has to cover this area entirely and beyond or once bored there's insufficient surface area or wall thickness beyond the bored area to hold the epoxy long-term. And the epoxy on the outside must be shaped and countoured so it doesn't interfere with any of the TBs butterfly shafts and/or linkage.
This pic shows one side of the TB prepped for its epoxy build-up. The entire area, even the VERY tiniest nooks, crannies and surface area needs to be roughed up for the epoxy to adhere to. Your adhesion is only as strong as extent of your "preparation" allows. This is NOT the place to "scrimp", cut corners, compromise or half-hearted attempts as EVERYTHING you do "after" this relies on that epoxy being there, 100% sealed and intact... FOREVER!!! If you miss a spot, no matter how tiny or seemingly insignificant you risk losing the entire epoxy cover and having it fall out. If that happens the car is DEAD on-the-spot until that epoxy or throttle body is replaced. And it's easier to start with an ENTIRE new TB core than to try to apply new epoxy back on a TB that has been pre-bored and lost one of its epoxy walls.
If there's any grease, hand-oil or even finerprint on this area when epoxy is applied it will likely fail.
And epoxy has to completely cover the boring that will happen later. That means it has to cover this area entirely and beyond or once bored there's insufficient surface area or wall thickness beyond the bored area to hold the epoxy long-term. And the epoxy on the outside must be shaped and countoured so it doesn't interfere with any of the TBs butterfly shafts and/or linkage.
01-24-2009, 08:48 AM
#9
Pic 3 Applying the exterior putty
<center><img src="http://pictureposter.audiworld.com/711/xtbputty.jpg"></center><p>
In the pic above you can see 2 prepped, epoxied and pre-bored TB's and how the epoxy putty looks once applied and fully cured. I can get away with more precise epoxy placement and smaller amounts of epoxy used because all my TBs are CNC'd. Given that I can know within millionths of an inch where my epoxy needs to be placed as every one is fixtured in a CNC mill. Every one is bored with a tapered "velocity stack" bore that ALWAYS blows thru the exterior walls at "exactly" the same place, diameter and depth. When hand-grinding you'll want to use more/thicker epoxy application over a broader area because you cannot have the control and repeatibility of the CNC with a hand-held grinder and can't be sure where you risk grinding "through" or "outside" the epoxy you've applied.
These TB's are ultrasonically cleaned before and after epoxy has been applied and/or ANY machine work for additional cleanliness and to assure no debris gets into the butterfly shafts needle bearings.
This is about the best I can do for you as far as help. Just "think" about this while you're doing it, go slowly and be careful and you'll be fine. And don't try the taper wall/velocity stack idea when hand-grinding. If it's not a "perfect" taper in EVERY way and at a VERY precise and VERY specific "inclusive" angle it'll flow DRAMATICALLY "less" than a parallel-wall/straight-bore venturi of the same inlet diameter.
Good luck!
In the pic above you can see 2 prepped, epoxied and pre-bored TB's and how the epoxy putty looks once applied and fully cured. I can get away with more precise epoxy placement and smaller amounts of epoxy used because all my TBs are CNC'd. Given that I can know within millionths of an inch where my epoxy needs to be placed as every one is fixtured in a CNC mill. Every one is bored with a tapered "velocity stack" bore that ALWAYS blows thru the exterior walls at "exactly" the same place, diameter and depth. When hand-grinding you'll want to use more/thicker epoxy application over a broader area because you cannot have the control and repeatibility of the CNC with a hand-held grinder and can't be sure where you risk grinding "through" or "outside" the epoxy you've applied.
These TB's are ultrasonically cleaned before and after epoxy has been applied and/or ANY machine work for additional cleanliness and to assure no debris gets into the butterfly shafts needle bearings.
This is about the best I can do for you as far as help. Just "think" about this while you're doing it, go slowly and be careful and you'll be fine. And don't try the taper wall/velocity stack idea when hand-grinding. If it's not a "perfect" taper in EVERY way and at a VERY precise and VERY specific "inclusive" angle it'll flow DRAMATICALLY "less" than a parallel-wall/straight-bore venturi of the same inlet diameter.
Good luck!