Throttle body adapter for 75mm TB

[vtraudt]

Who makes/sells throttle body adapter to fit 75mm (RS4? 077133062) on stock (60mm) intake?
The 034 I found says "S4", which I think are 70mm (078133062) only.

[vavJETTAw36]

Who makes/sells throttle body adapter to fit 75mm (RS4? 077133062) on stock (60mm) intake?
The 034 I found says "S4", which I think are 70mm (078133062) only.

Nick Audlee

But I recommend that you have him weld a flange on it and bore the intake out to match the TB, otherwise, bottle neck is still a bottle neck.


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[vtraudt]

weld a flange on it and bore the intake out to match the TB

That is a good idea since I have a spare manifold to play with. Will talk to my designated tig welder and look up some example photos how its done.

Since flow losses are accumulative, any reduction of loss is a gain. There is a post from Issam somewhere where they tested various TB on small port SEM and engine dyno. Pretty realistic.

[vavJETTAw36]

That is a good idea since I have a spare manifold to play with. Will talk to my designated tig welder and look up some example photos how its done.

Since flow losses are accumulative, any reduction of loss is a gain. There is a post from Issam somewhere where they tested various TB on small port SEM and engine dyno. Pretty realistic.

If it helps




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[vtraudt]

Thanks. Will take a look at my spare manifold tonight to see if there is a natural 'cut line' the could be used for a weld on flange to avoid the step down flow losses.

[vavJETTAw36]

Thanks. Will take a look at my spare manifold tonight to see if there is a natural 'cut line' the could be used for a weld on flange to avoid the step down flow losses.

I port matched the manifold to the flange using a 3 inch hole saw. The flange bore will guide the hole saw. You’ll still have to sand it smooth and polish a bit as the bits of aluminum will make the opening rough. But I found that to be the easiest way to port match.


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[A1 A2 German]

Something to consider is if you find the 70mm flange only, like myself, is you simply clock the TB ~5mm over from the 70mm holes drill and tap and now have a universal multi-tb use adapter plate which helps with resale too. All plates are aluminum so easy to do, and will not need to be bored out itself as hole is still bigger then 75mm.

At that time I didn't have a ~3" holesaw to portmatch the manifold so marked out a hole and a ~tungsten bit on a die grinder made short work of the cast aluminum manifold and smoothed it out as much as possible.

[vtraudt]

Something to consider is if you find the 70mm flange only, like myself, is you simply clock the TB ~5mm over from the 70mm holes drill and tap and now have a universal multi-tb use adapter plate which helps with resale too. All plates are aluminum so easy to do, and will not need to be bored out itself as hole is still bigger then 75mm.

At that time I didn't have a ~3" holesaw to portmatch the manifold so marked out a hole and a ~tungsten bit on a die grinder made short work of the cast aluminum manifold and smoothed it out as much as possible.

I hope to just cut the original (have a spare) manifold and weld on a flange (port matched to my 75m TB, drill/tab). That also opens up the diameter into the manifold (rather than stepping down, creating another flow loss).
Probably better than spending $100 or so on a 4x4 inch plate of aluminum with a few holes in it.
Either than, or make the adapter myself from 10mm alu bar stock. hole saw for rough work, then tungsten bit or put on lathe.

[ChanceA4Parks]

Get a router and router table. Aluminum is quick work for a router and it's incredible versatile. You can purchase flush bits to port match and step downs to widen a hole. The finished product doesn't have to be polished or sanded, because it will be as smooth as your guide part. I did a post a while back "kind of" showing how I do it. I've been able to "machine" my own 2.7t compressor housing to fit my RS6 turbos. I port matched an 2.7t cylinder head to a 2.8 head to match the rs4 mani. Next is the throttle body. I'll take a few more photos this time if anyone is interested.

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[vtraudt]

Get a router and router table. Aluminum is quick work for a router and it's incredible versatile.

For now I stick with my tungsten tool and a power drill. Not as 'nice' and probably more painful. Just not enough room for another tool setup.
But you are right, alu is nice to machine (compared to turbine housings for example); did port match my current manifold to the AEB head I am running. And a few other heads (i guess first was a 3 liter swap into a Mercury cougar (with the Mazda/Ford 2.5/3.0 engine family).

[vavJETTAw36]

Get a router and router table. Aluminum is quick work for a router and it's incredible versatile. You can purchase flush bits to port match and step downs to widen a hole. The finished product doesn't have to be polished or sanded, because it will be as smooth as your guide part. I did a post a while back "kind of" showing how I do it. I've been able to "machine" my own 2.7t compressor housing to fit my RS6 turbos. I port matched an 2.7t cylinder head to a 2.8 head to match the rs4 mani. Next is the throttle body. I'll take a few more photos this time if anyone is interested.

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Off topic but you seem to know a thing or two about taking down aluminum. What would be the easiest approach to polishing the inside of an rs4 throttle body y pipe?


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[ChanceA4Parks]

Start by working your way down grits with carbide bits(finer and finer). Then work your way down with (scotch bright style) ball drill attachments (harbor freight) and a heavy rubbing compound. Move to polishing balls on a drill with heavy then light rubbing compound. Finish with a good aluminum polish. Same will work with polishing any aluminum, but use sand paper and automotive scotch bright pads on large areas.

[ChanceA4Parks]

I think I'll be able to mod the RS6 throttle body to work on the 2.7t. Ive got the tb sliding into the oem RS4 tbb. I should be able to use the original bolts and holes. It looks like a big enough difference to make some extra horses for sure. I also modded the 034 carbon y-pipe to accept a 102mm inlet and 75mm outlets. Im ready to drive this thing again

[ChanceA4Parks]

Here's the RS4 pressure y (ported to match throttle body) ,the RS6 throttle body, and the RS4 intake manifold all playing nice together. I just need to port the intake to match tb. Polish everything and then moving on to the next task at hand.
20190524_221927.jpeg20190524_221510.jpeg20190524_221438.jpeg20190524_221427.jpeg

[vtraudt]

Here's the RS4 pressure y (ported to match throttle body) ,the RS6 throttle body, and the RS4 intake manifold all playing nice together. I just need to port the intake to match tb. Polish everything and then moving on to the next task at hand.
20190524_221927.jpeg20190524_221510.jpeg20190524_221438.jpeg20190524_221427.jpeg

Nicely done! What size is the RS6 TB (ID obviously)?

[ChanceA4Parks]

Ill measure it to be exact but I want to say its 3.5" or 89mm.

[vavJETTAw36]

How are you sealing the TB to the TBB?


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[ChanceA4Parks]

Im actually going to go the oem way. Oring on the inside edge of the tbb (I'll notch a small track for it to rest in. Slide the tb into the oring. Its actually pretty damn snug and sealed already. I'll rather be safe though.

[ChanceA4Parks]

I changed how I am going to seal everything up. I will weld 90mm v-band clamps to both sides like I have done on the intake mani side. There is also a couple of pictures of how I used a router to port the intake mani to the new size. There's some measurements in there as well 20190531_020824.jpeg20190529_224218.jpeg20190531_020814.jpeg20190529_202609.jpeg20190529_202627.jpeg20190529_202604.jpeg20190529_202845.jpeg20190529_015332.jpeg20190529_015358.jpeg20190529_023051.jpeg

[vtraudt]

Sidenote: what is the tool in this photo? https://www.audizine.com/forum/attac...0&d=1559323458

[ChanceA4Parks]

Sidenote: what is the tool in this photo? https://www.audizine.com/forum/attac...0&d=1559323458

Its something like this-

https://www.rockler.com/pattern-flus...ight-1-4-shank

It attaches to a router. You have to make sure the bearing is on the side that is the closest to the router chuck.