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1977.5 Audi AAN Project
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Herr-Kuhn  



Joined: 03 Jul 2012
Posts: 30
Location: Northern, KY

PostPosted: Wed Feb 13, 2013 10:02 am    Post subject: 1977.5 Audi AAN Project Reply with quote

I am starting this thread so people can follow my project build on here. Last May, I picked up a 1977.5 924 in Rally Yellow color with plaid interior. My car came from an original family and spent most of its life out in the North West before coming back to Cincinnati via Indianapolis.

I originally thought all of the panels were decent enough on the car, but as it turns out both front fenders and the front valence panel were garbage...as was the roof panel since the original owner put in what I refer to as a stereo shop sunroof.

Luckily, I was able to find a roof panel from a 1984 944 and got very lucky in locating two perfectly rust free front fenders and a valence panel from a 1987 924S. This is important, since the fenders on the 924S have the rolled lip to allow for slightly wider tires.

The project will encompass all aspects of a high-performance build. The basics are as follows:

Engine: Audi AAN (20V turbo inline 5 cylinder from a 1994 Audi urS4) Power goal is 450 HP at the flywheel.
Turbocharger: Garrett GT or GTX series, dialed to 24 psig
Clutch: Spec Stage 3+
Driveline: 931 with G31 transaxle and LSD
Charge Cooling: Front Mount Air to Air Intercooler
Brakes: Porsche 928S4 with Porsche 928S4 front rotors. System will run Audi Hydraulic system for bower boost.
Suspension: Ground Control Coil Overs with Torsion Bar delete. Big 944 sway up front and 924S sway in rear
Wheels: Porsche 928S4 (7" Front, 8" Rear)
Tires: Hope to run 215 Front and 225 Rear, likely DOT race tire for traction
Interior: 80s Vintage Sport Seats with Yellow/Black Plaid inserts, Leather covered dash

At present all of the exterior body work on the car is completed. Across the summer, we completely chemically stripped the body and repaired all of the previous half-assed repair work under the paint along with replacing the front sheet metal and the roof skin. The car was sprayed in RM Diamont DP25 primer and block sanded (3X) and then painted in Glasurit single stage 22 line paint. Finally it was wet sanded in 2000 and then machine jitterbugged in 3000 before being machine buffed and glazed.

Once I finish my sedan, I will be able to get the 2.0 liter engine pulled out of the chassis for good such that I can paint the engine bay and start the layout for the installation of the inline 5 AAN. One of the major benefits of keeping with the Audi power plant is that I can use the factory 931 bell housing and the 11mm factory Audi spacer to marry the AAN to the 931 driveline.

At present, I have just completed converting a set of early 80's 928 hubs to fit the 924S spindles. This allows the use of 928S4 front brake rotors (hat style) and allows me to retain the mechanical speedometer. The hubs were modified internally to accept a very nice set of Timkin tapered roller bearings with about 40% more capacity as compared to the factory bearings for the 928 hubs. All that remains for the front brake conversion is to make an axial to radial mount block to properly mount the large Brembo calipers.

I have many videos on the body work up on youtube for review. Part one starts here:

https://www.youtube.com/watch?v=W9ZfhjJ0KfQ

This is a long term project that will be done to the absolute best possible standards in making my 1977.5 stock looking 924 as quick as possible for street and light competition use. The end goal is to keep the car under 2700 lbs and for it to have 450 HP, yet be able to easily achieve 30 MPG in daily drive use.[/img]
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Paul  



Joined: 02 Nov 2002
Posts: 9305
Location: Southeast Wisconsin

PostPosted: Wed Feb 13, 2013 3:13 pm    Post subject: Reply with quote

Nice work, thanks for saving another 924!
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
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Herr-Kuhn  



Joined: 03 Jul 2012
Posts: 30
Location: Northern, KY

PostPosted: Thu Feb 14, 2013 1:23 am    Post subject: Reply with quote

Back in 1989, when I purchased my first 944 the thought was that the 924 was not worth having. Now that early 80's 944s are trading at $2,500 and are completely ratted out I rather like the old school look of the 924.

Like the early 928, you can see the design intent Lapine had when he came up with the 924's shape. Both cars were smooth and clean, free from bolt on wings and other non functional appendages. One of the things I really like about the 924 is the lack of plastic body parts. Sure, you have to be careful with the front valence on the parking stones, but the nose of the car looks really sweet without any air dams or plastic on it. It looks very light and scalpel-like up front. These cars are known to be faster on the long tracks than 944s due to the lower frontal area. They don't handle the corners quite as well with the narrower wheels, but I figure with a really good set of springs, shocks and the right tire, the car should be able to be plenty quick for the occasional track day or autocross.

I've come to realize that whilst the 2.0 liter is a good little engine, it is horribly anemic, even in factory turbocharged form. It probably has a lot to do with getting used to driving 600 HP 928s over the last 5 or so years, but still the 2.0 liter can hardly push the car out of its own way. Not to mention it is very buzzy. The inline 5 cylinder AAN by comparison is a total gem that easily makes power to 7,000 RPM and revs like a well oiled singer sewing machine.

I was going to do a 914, but they all were so pricey and require much metal work due to rust. Since I already owned a pretty ratty urS4 winter beater this marriage just made sense.
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ideola  



Joined: 01 Oct 2004
Posts: 15489
Location: Woodstock IL

PostPosted: Thu Feb 14, 2013 1:56 am    Post subject: Reply with quote

Sounds like a really cool project. Would love to see some pix!

As for your t-bar delete, did you do anything to gusset the upper shock mounts?
_________________
15 981 GTS | 88 924S SE | 82 931 Holbert | 82 931 Rallye | 81 937 | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 80 US 931 | 80 931 GTR | 79 Sebring | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition | 77 Martini
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Paul  



Joined: 02 Nov 2002
Posts: 9305
Location: Southeast Wisconsin

PostPosted: Thu Feb 14, 2013 2:02 am    Post subject: Reply with quote

I've watched the first 4 ten minute videos so far, and am extremely impressed with level of skill and care going into this restoration
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
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Karpaazio  



Joined: 03 May 2011
Posts: 121
Location: Finland

PostPosted: Thu Feb 14, 2013 7:35 am    Post subject: Reply with quote

Really nice that someone is doing this swap over here! I've had similar plans because I have an extra 924 lying around and those urs4's are quite cheap in sweden right now you can get one for about 1500-2500€. I have had these plans because I need a new daily now for the winter because my daily got crashed by a girl.. So maybe I'll also be doing this in the future.
_________________
Porsche 924 1978 Cabrió:
http://www.garaget.org/?car=219790
Porsche 924 widebody (next up?)
Toyota Crown LS110 1983:
http://www.garaget.org/?car=260537
Audi a6 2.7tt quattro 2000 daily driver
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Herr-Kuhn  



Joined: 03 Jul 2012
Posts: 30
Location: Northern, KY

PostPosted: Wed Feb 20, 2013 3:08 am    Post subject: Reply with quote

I'll see if I can get some photos up in the near future. I had a lot of spare time last summer due to being on my 2nd early retirement! With that said, I never see a reason to do something half way. I'm sure when I'm done, I can sell the car and get all my money back and probably more because it will be totally unique. At least this is what I tell my wife. The paint was started in July and was finished in mid September. Not too bad considering it was totally stripped down.

I'm struggling to find a used LSD for my snail shell...most of these bone yards just don't even have a clue what you're asking and furthermore they are too lazy to look. I did score a set of sport seats from a turbo so that means it should have the LSD, correct? The guy claims he looked and turned the wheels and they were in opposite directions which would mean open diff. I'm probably going to bite the bullet and go with a new Quaife for the snail shell. I only gave $175 for the snail shell and tube, so it's not so bad.

I'm hoping to get the engine pulled here in the next several months so we can paint the engine bay to match the rest of the car and then start the fitment of the AAN into the car.

I need to do a new video on the brake upgrade. I've found a very cost effective way to convert the older 928 hubs to fit the early 944 and 924 turbo spindles. Getting the turbo S front suspension items is stupid expensive and then you still don't have a way to drive your speedometer. I'm hoping I don't have an issue with the smaller diameter spindle on the LH side (the hollow one). I have seen these break off on the track but that is with severe abuse. The bearings I have in the hubs are really super heavy duty and they just required the bores in the hubs to be properly bored out and stepped down to fit. It is really pretty simple.

On the coil-overs...ground control assures me there have been no failures on the rear because the top bolt is in double shear on the frame member. Additionally, the lower bolt is massive. Right now I think this only works on the later aluminum trailing arms (like on the 924S). I have a full rear suspension setup from a 924S...my car is way early, so I have to figure out how to get just the arms off that and onto my center section. My car's torsion bar tube mounts to the chassis very differently than the later 924 and 944 setups. There were a lot of changes made in 1979.

Dropping the torsion bars seems to be the way to go, because then you can easily lower and balance out the car at all 4 corners just with the spanner for the coil-over springs. The entire setup is amazingly inexpensive and you get any number of possible spring rates and Koni gas adjust sport shocks. After working on 928 suspensions, this will be an easy one. Some keep the torsion bars out back due to class restrictions, but then you have to fiddle around with where to set the bars and the springs...it's silly. They had it right with the 928...adjustable coil overs on all 4 corners...set it and align it and you're done. The rear suspension on 924/944 is basically bug IRS (1974 I think). The front is Scirocco/Rabbit/Jetta.

I'm also planning to engineer my own a-arms for the car from 7050 aluminum and they will be made to accept the cheap steel a-arm ball joints so they can be easily repaired if a joint goes out. I have a set of 86 early offset 944 a-arms and quickly realized what a piece of crap they are. Both ball joint sockets were worn (into the casting) and each a-arm was bent (floor jack and towing idiot). The cast 944 series aluminum a-arms are garbage and I would never use a set...specifically when you can buy brand new steel arms for like $20.00 each. I need something a little stiffer so I'm thinking about just water jetting (then post machining) a set of truss style arms. It's all in one basic plane so it will be easy to figure out.

Have to love the fact that this suspension is basically left over VW parts that can be easily modified and upgraded.
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the_mad_electrician  



Joined: 16 Nov 2009
Posts: 1073
Location: Central Georgia

PostPosted: Wed Feb 20, 2013 3:20 am    Post subject: Reply with quote

I don't even lie to my wife, I flat out tell her I'll never get my money back out of cars. That being said I did break even with my 77 because I sold it in peices.
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81 924 N/A

2004 Ranger "Edge"

2005 Mazda 6
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Andrew NZ  



Joined: 22 Jun 2004
Posts: 744
Location: New Zealand

PostPosted: Wed Feb 20, 2013 11:39 pm    Post subject: Reply with quote

Herr-Kuhn wrote:
On the coil-overs...ground control assures me there have been no failures on the rear because the top bolt is in double shear on the frame member.


It's the chassis rails in the early ones that have the problem, not the bolts. Mine cracked before I reinforced it. Have a look at a later 944 when you get a chance and copy what the factory did on the later cars.
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Andrew
1977 RX924 rally car
12a bridgeport
www.race4-dcup.co.nz
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Herr-Kuhn  



Joined: 03 Jul 2012
Posts: 30
Location: Northern, KY

PostPosted: Mon Feb 25, 2013 11:12 am    Post subject: Reply with quote

Thanks for the feedback on the rails...this was one of my big concerns going that route. That may be a reason to retain the torsion bars and just use the helper spring coil-over on the rear to not put the entire weight of the car on the frame rail, where it clearly was not designed to do so. That's still a messy solution, but I know I need more spring rate out back for sure.

I assume your car was running without the torsion bars when this failure happened?
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Andrew NZ  



Joined: 22 Jun 2004
Posts: 744
Location: New Zealand

PostPosted: Mon Feb 25, 2013 9:06 pm    Post subject: Reply with quote

Yes. Not too much work to reinforce things in advance though compared to your engine conversion! It's easier to change the height with out the torsion bars in there.
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Andrew
1977 RX924 rally car
12a bridgeport
www.race4-dcup.co.nz
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xanderdeg  



Joined: 08 Jul 2012
Posts: 286
Location: Vancouver, BC, Canada

PostPosted: Tue Feb 26, 2013 6:55 pm    Post subject: Reply with quote

I've been watching your videos and I wanted to take a moment to comment that I really admire how much appreciation you have for the car. People tend to neglect these cars often so it's great to see somebody speaking about the car with such respect. I'm also extremely impressed with the respect you have for your work.

You are the definition of perfectionist, keep up the good work!
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Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11344
Location: PacNW

PostPosted: Wed Feb 27, 2013 7:13 am    Post subject: Reply with quote

Herr-Kuhn wrote:
On the coil-overs...ground control assures me there have been no failures on the rear


Not so.
_________________
Toofah King Bad
  • Shaggy (1980 931) - Got Boost?
  • Red (1987 924S) - Pro44/Spec944
  • Weiße Scheiße (1987 924S) - In Progress
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the_mad_electrician  



Joined: 16 Nov 2009
Posts: 1073
Location: Central Georgia

PostPosted: Wed Feb 27, 2013 8:38 am    Post subject: Reply with quote

I'm just wondering what is wrong with running some fatty torsion bars.
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81 924 N/A

2004 Ranger "Edge"

2005 Mazda 6
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Herr-Kuhn  



Joined: 03 Jul 2012
Posts: 30
Location: Northern, KY

PostPosted: Thu Feb 28, 2013 11:50 am    Post subject: Reply with quote

I'm not opposed to the larger torsion bars but I think availability has become somewhat of an issue these days. Glad to see that some people have feedback on the coil overs out back. I was concerned about the frame member there having issues...it's a lot of weight and force put into that part of the frame under heavy cornering. Maybe a set of huge bars out back is a better way to go? It's not like I need to lower the car all the time...once set, that should be it.

Right now the project has been somewhat back-burnered as I have a customer's 928TT on the lift getting some serious power upgrades and then I have to have my sedan back on the road. In the midst of all of this, I'm shopping for a set of hub dyno pods and trying to make sense of all the units out there and which one is best.

I'm pushing to have the engine pulled out of the 924 by May so we can blow some fresh paint on the engine bay and then I can start the mock-up of the AAN in there. I just hate pushing cars around between my house and the shop...since it's downhill to my shop! I have 1 quart of the Glasurit 22 line left for the engine bay and repairs. As long as the engine bay is shiny with no runs, I'll be happy.

Thanks for the feedback...I do feel like I'm saving this little car and I hope it's worth it in the end. It should make a really stealthy little sleeper and I think the inline 5 engine is totally ideal for the conversion.
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