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Audi Throtllebody and TPS Conversion (smaller pics!)

 
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endwrench  



Joined: 07 Dec 2002
Posts: 1629
Location: Victor, Montana

PostPosted: Mon May 15, 2006 1:42 pm    Post subject: Audi Throtllebody and TPS Conversion (smaller pics!) Reply with quote

OK, this may be of some interest to you guys who are considering an EFI conversion or just upsizing to an Audi TB. Fisrt you can see the difference in size between the 2 TB's.





I'm doing this because I am supercharged and I figured it may be worth it. I understand it may not be a great mod for standard NA motors but to each their own. This TPS conversion still applies to the stock TB. First thing you need to do is remove the return spring setup. Grind the end of the shaft off with a bench grinder or what ever you have.



After this you need to pry and pull all the stuff off.



Mark and cut the shaft leaving exactly 1"



Making sure the throttle is closed, draw a line thru the center of the shaft perpindicular to the base.



If you use a wide felt tip pen, this will give you a pretty good guide as to how far you need to grind and file the shaft. I used both a grinder and hand files. The knifed edge is about 1\2" long and an 1\8" wide. Narrow is better.



Now is the hard part for most. You need to fabricate a spacer for the TPS. It needs to hold it center on the shaft so it should really be done on a lathe. I would be glad to supply these to anyone for $5. It needs to be .700" long and look like this.





After you have the bushing you can line up where the holes need to be drilled and tapped for the screws. I used #10x24 screws cut to length. I would cut the boss off next to the right side screw before drilling and tapping. Mine was off center due to not doing this. It works fine.



The TPS I found to work with this is from an 85-86 Dodge 2.2L Throttle body injected engine. Not PORT. The hardest part of finding a TPS was finding one that turned in the correct direction. Otherwise many others would work with this mod. NAPA Part # 2-1915. Iff you look at this new one you will see the holes are not slotted for adjustment. You can also see it is made of plastic and is easily slotted with a drill, dremel or zip tool.



Here is what it looks like mounted up.



On to mounting it to the intake. It will bolt directly up and function but it is shrouded. You can see in this picture were I colered in the part I am grinding out.



This is after.



And this is what it looks like after mounting it and my new 44lb injectors, fuel rail, insulated inserts and smaller blower pulley!! Time to start tuning.



Todd
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'79 924NA. Rebuilt 9.5:1, MSDS header, Mega Squirt Injection, MJLJ-EDIS Ignition, 1.6L Whipple Charger and Intercooler, 10lbs Boost, 944 Trans, Custom HD Clutch.
"simsport" said....superchargers are better than turbos its official!....


Last edited by endwrench on Wed May 17, 2006 5:13 am; edited 3 times in total
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Joes924Racer  



Joined: 03 Nov 2002
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PostPosted: Mon May 15, 2006 4:02 pm    Post subject: Reply with quote

awesome dude. I mean endwrench.
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Min  



Joined: 04 Nov 2002
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Location: Vernon, British Columbia, Canada

PostPosted: Fri May 19, 2006 5:06 pm    Post subject: Reply with quote

Awesome writeup endwrench. I figure I should mention however that there is other ways of doing this sort of thing as well. For example, if your running a megasquirt, you can run without a tps. Which is what I'm going to be doing. You can also get yourself whats called a string pot. http://www.celesco.com/ which you can just hook onto the throttle linkage.

Min
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P924  



Joined: 14 May 2006
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Location: Belgium

PostPosted: Sat May 20, 2006 1:40 am    Post subject: Reply with quote

Nice... and how many horsepower does it make with the supercharger?
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endwrench  



Joined: 07 Dec 2002
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PostPosted: Sat May 20, 2006 5:21 am    Post subject: Reply with quote

I like the "string pot" idea. It would definetly be easier. The only reason I do not like the idea of using the MAP instead of TPS would be cold start tuning. After you are tuned it may work well but I have had to use the "clear flood" mode several times during tuning. I think this can only be used with a TPS. Not sure though.

I have no idea how much HP. Just MORE!

Todd
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Min  



Joined: 04 Nov 2002
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Location: Vernon, British Columbia, Canada

PostPosted: Sat May 20, 2006 7:48 am    Post subject: Reply with quote

Your right, you lose flood clear when not using a tps. I'm going to hook flood clear up to a switch. So I can just flick it on if I need flood clear mode. After its all tuned it shouldn't be a issue.

Min
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macBdog  



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PostPosted: Sat May 20, 2006 10:11 am    Post subject: Reply with quote

Ok so if you remove those springs to mount the tps, what returns the throttle to closed?
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endwrench  



Joined: 07 Dec 2002
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PostPosted: Sat May 20, 2006 1:23 pm    Post subject: Reply with quote

macBdog wrote:
Ok so if you remove those springs to mount the tps, what returns the throttle to closed?


Hey, it's all about the go, not whoa!!

I guess I should have posted this pic too. Sorry about that!



Todd
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sequential  



Joined: 18 Nov 2005
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PostPosted: Mon May 22, 2006 11:40 am    Post subject: Reply with quote

Todd,
Nice ! It was good to do the TPS, the only way is the correct way , others who don't will at a later date as they pay the price for shortcuts..

How much boost currently. do the drivability then find a dyno for the full power stuff, it will be safer and better.
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endwrench  



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PostPosted: Tue May 23, 2006 11:06 am    Post subject: Reply with quote

sequential wrote:


How much boost currently. do the drivability then find a dyno for the full power stuff, it will be safer and better.


Well, speaking of shortcuts my chincy-cheap homade blower pulley just self destructed. I was making about 7lbs boost with 18% overdrive. It held together long enough to let me know I am going to build a "good" pulley with 40-50% overdrive next. The lowend response was incredible with the smaller pulley. Of coarse the upper HP was better too. I could also see my intake temps go up less than 10F at 7lbs so 10-12lbs should be fine.

Closest dyno is 100 miles away. I'll wait and see if I really "need" to or not!

Oh yea, hate to admit it but you were correct in wondering if I could keep the engine cool or not with the intercooler in place. It cools fine above 40mph but I had to install a switch on the fans to keep it cool on a hot day in town. It holds thermostat temp with the fans running though.

Todd
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