924Board.org

[augidog]

I Picked up a Audi tb after going through all the Audi wrecks they had .Besides smashing my finger, it was way too much fun!
I finally came up with an older version which I think will work really well.
The Primary is the same but the secondary is much larger.
I'm not looking for HP but for better throttle response in the low end. A snapier acceleration.This is a direct bolt on replacement with no modification to the intake at all.
I'm not porting the intake because the plates open fully without porting. I've also read of ported manifolds causing a stumble on WOT with no other engine modification.
I picked this unit for many reasons. Idle adustment screw. 2 vacuum connections in the same front and back locations of the primary plate.(those who wish to keep all oem vac line intact can still do so)
The only modifications I did on the TB was to remove all the TPS sensors and swap the throttle cable hookup off the old 924 TB (a simple nut to change both), this way I can always go back if I need to without ruining my new cable.
Maybe someone will recognize the year Audi it came from. The car had a overhead cam. Another interesting feature was the primary has a "wedge" on it. I think it might be for smoother transitioning to the secondary?It's not in yet so the jury is still out.
Take a look at the pictures.

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1978 924 95 mile daily driver.
Audi TB/POR174M/High Flow Cat/2.25" exhaust
I knew that positive thinking thing wouldn't work.

[Chrenan]

This is the one I used pictured below. Worked great, one TPS switch was identical to the 924, the lower one was different, so with a few new bolt holes drilled in I was able to mount the lower TPS switch from the 924. Then I blocked the large opening seen on the left side of the throttle body and all worked well. Also swapped the throttle cable hookup off the old 924 throttle body as did augidog. I've noticed better throttle response in the low end and also snappier acceleration. Plus, at wide open throttle the engine now has a growl that it definitely didn't have before.


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1987 951 - M193 Version for Japan

[augidog]

Chrenan,
I have 8 primary and 14 secondary. I see you have 8 on your primary.What is the secondary? I bet it's the same except for the vacuum port configurations on the body itself. So therfore the 5000 had the same plates as the earlier Audi's so anyone can just look for the options they need like tps or vac ports. I'm going to have to modify the 924 throttle cable attachment a little lower by removing the large rubber cable guide and cutting the stem also.
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1978 924 95 mile daily driver.
Audi TB/POR174M/High Flow Cat/2.25" exhaust
I knew that positive thinking thing wouldn't work.

[Chrenan]

Hmm, I can't remember what the number on the second plate was, but I may have a picture of it on my home computer. I measured the plates at 28mm for the primary and 52mm for the secondary.

I think the stem and black plastic Audi throttle cable holder on yours look the same as mine. When I installed the 924 throttle cable attachment, I heated it and bended it so it was straight. With this modification I had no clearance issues with the hood, no need to cut the stem. However, it would be cleaner looking with a shorter stem and that ugly black Audi cable holder removed. I also have no hood insulation, that may make a difference.
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1987 951 - M193 Version for Japan

[augidog]

I measured the plates at 25mm for the primary and 52mm for the secondary. I wonder why they eliminated that wedge and made the primary 3 mm larger on yours?
BTW do you have a vacuum gauge in your car? I just read that if your vac does not go to 0 on WOT your losing much to air flow restrictions. Mine sits at about 4 right now without the new TB on.
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1978 924 95 mile daily driver.
Audi TB/POR174M/High Flow Cat/2.25" exhaust
I knew that positive thinking thing wouldn't work.

[Chrenan]

I do not have a vacuum gauge on my car, but I do have a vacuum brake bleeder with a gauge, maybe I can rig something up?
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1987 951 - M193 Version for Japan

[keithiopian]

what year/model did the TB come off of?

[CBass]

[Benji0301]

I recently found an Audi TB at the scrapyard from an Audi 100 which I beleive is the same as your 5000. The primary on mine is 34mm & the secondary is 52mm. It only cost £10 ($20) so I will keep an eye out for any more as I assume it will improve your lower end performance with a larger primary. I will post it on the forum if I find any more.

[CBass]

VW and Audi used that throttle body on all of their 4 cylinders up until 1993, and even a few after that. The 16v's used them as well, into the mid 90s.

The only differences are in the linkages, but most will work on a 924.

Looking at my 52mm throttle body, the WOT switches from the 931 manifold will transfer over onto the VW body with no difficulty.
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'81 931 in various states of assembly

[Benji0301]

Hi all,

Did I read somewhere that you have to drill a 1/8th bit hole in the primary so that it will idle correctly?

Dale

[Chrenan]

I didn't drill the hole, I had no problems on my old engine. However, on my newly modified engine, I find the idle adjustment screw doesn't alter the idle until it is unscrewed further, which means I may need a little more bypass air as a default, which means I may drill the hole.
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1987 951 - M193 Version for Japan

[CBass]

Cleaned up my '80 manifold and tig welded up the cold start injector holes today. Tomorrow I'm porting it for my '91 Passat 2.0 16v auto throttle body. It's a 52mm throttle body with a TPS, same casting as the audi unit but with much slicker linkage.

Bolts on, if you take a mild skim out of the #2 runner along the top of it to clear the TPS. Crappy camera phone pics forthcomign.
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'81 931 in various states of assembly

[OutOfTheBox]

your being misinformed tig welding your 5th injector hole up, has no performance benefit

[Lizard]