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 Post subject: 924 for drag racing, it may upset the purists.....
PostPosted: Fri Nov 18, 2016 11:12 am 
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Skype ID: B A Kopasz
Hi, first a bit of an introduction and background......many many years ago I drag raced air cooled Volkswagens (of the beetle variety), then marriage and a mortgage stopped all that fun, so I bought a 924 to a play with. This received 944 body work, suspension and few other bits and pieces, namely a turbo gearbox and turbo engine. Then the turbo failed so it was parked up to be repaired but the kids were growing and money was tight! Fast forward 15 years or so and after a divorce the only thing I'm left with is my non running 1976 924 that's spent a decade in a very wet garage. I decide that building another race car would be a good way of loosing lots of money and rather than start with a proven platform for a drag car I might as well do something with my tired and neglected Porsche. So after moving it to a nice dry garage and pulling it to bits, followed by lots of coffee, then some beers, a plan was formed...............replace the floor, work out a better alternative to the rear torsion bars (too fiddly to adjust for track conditions), throw a cage in, source a better engine (something easily available, lightweight and tunable, so a VW 1.8t was the idea), and more importantly convince my fiance that it was a great idea! After the beer had worn off, I source a couple of engines, lots and lots of cutting discs, a new welder and an agreement that if I didn't complain about a couple more horses appearing in the field and a horse box appearing on the drive, then I could do what I wanted in the garage, winner!

So let's get started, first out with the corroded floor.......

[url][URL=http://s154.photobucket.com/user/bruceakop/media/Porsche/image-20.jpeg.html]Image[/url][/url]
[url][URL=http://s154.photobucket.com/user/bruceakop/media/Porsche/image-10.jpeg.html]Image[/url][/url]
[url][URL=http://s154.photobucket.com/user/bruceakop/media/Porsche/image-17.jpeg.html]Image[/url][/url]

No going back now......


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 Post subject: Re: 924 for drag racing, it may upset the purists.....
PostPosted: Fri Nov 18, 2016 12:12 pm 
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Joined: Wed Nov 07, 2007 12:00 pm
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Location: Kingston upon thames
Welcome aboard Bruce

That looks like an interesting project, surprised you didn't go the LS route

My friend Fred has a similar looking car :D
Image

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924S 1987 Guards Red
924S 1987 Alpine White

Boxster 2.7 Arctic Silver 2000
Boxster S Meridian silver 2001 Sold
928 S2 Prussian Blue 1986 Sold
993 C4 Arena Red 1997 Sold


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 Post subject: Re: 924 for drag racing, it may upset the purists.....
PostPosted: Fri Nov 18, 2016 2:00 pm 
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Skype ID: B A Kopasz
Thanks for the welcome, I didn't go the LS route as I wanted to stick with an engine that parts were available off the shelf locally. I also wanted to keep the whole project really lightweight.

So floor out, the shell levelled out and clamped down, time for the start of the new floor.....

[url][URL=http://s154.photobucket.com/user/bruceakop/media/Porsche/IMAG0075_1.jpg.html]Image[/url][/url]

Followed by rear suspension and gearbox mounts.....

[url][URL=http://s154.photobucket.com/user/bruceakop/media/Porsche/IMAG0065_1.jpg.html]Image[/url][/url]


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 Post subject: Re: 924 for drag racing, it may upset the purists.....
PostPosted: Fri Nov 18, 2016 2:11 pm 
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Joined: Wed May 14, 2014 3:14 pm
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Wow! That's an interesting build :D looking forward to seeing it progress... Best of luck and keep the photos coming :D

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1998 Boxster 2.5 - Silver for everyday
1993 968 Coupe - Guards Red needing TLC
1989 944 S2 Cab - Guards Red for summer fun
1982 Rothmans 924 2.0 NA - for a stand out blast anytime, anywhere
2004 Mazda MX5 - Silver for the wife and country road blasts


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 Post subject: Re: 924 for drag racing, it may upset the purists.....
PostPosted: Sat Nov 19, 2016 9:31 am 
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Skype ID: B A Kopasz
Time for for more coffee and head scratching about alternative rear suspension ideas........I wanted to get rid of the rear torsion bars as they offered no easy way to adjust spring rates and although they offered infinite ride height adjustment doing so isn't quick. So initially out with nearly new 30 mm torsion bars (they now look lovely propped up in the corner of the garage as long as I forget how much they cost!), and onto some alternatives. I looked at coil over rear shocks but even changing spring rates on those is a bit of a pain, which left me with the idea of push rod operated springs and shocks absorbers as that would give me quick ride height adjustment and more importantly by changing the pushrod and belcrank positioning it would give me a way of easily adjusting doing rates. So after a few scribbles and calculations on the back of cereal box, a couple of motorbike rear shocks and springs were bought and a piece of 1/4" steel was turned into the belcranks.
[url][URL=http://s154.photobucket.com/user/bruceakop/media/Porsche/IMAG0515_1.jpg.html]Image[/url][/url]
Followed by a couple of pushrods and rose joints....
[url][URL=http://s154.photobucket.com/user/bruceakop/media/Porsche/IMAG0485.jpg.html]Image[/url][/url]
Which when thrown together gave me this......
[url][URL=http://s154.photobucket.com/user/bruceakop/media/Porsche/IMAG0522.jpg.html]Image[/url][/url]
[url][URL=http://s154.photobucket.com/user/bruceakop/media/Porsche/IMAG0523_1.jpg.html]Image[/url][/url]


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 Post subject: Re: 924 for drag racing, it may upset the purists.....
PostPosted: Sat Nov 19, 2016 10:22 am 
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Very nice, I really like the direction this is going, real engineering,!and you can sell the bars put some cash back in the slush fund

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 Post subject: Re: 924 for drag racing, it may upset the purists.....
PostPosted: Sat Nov 19, 2016 7:40 pm 
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Very interesting project, I'm looking forward to the progress updates.


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 Post subject: Re: 924 for drag racing, it may upset the purists.....
PostPosted: Sun Nov 20, 2016 11:19 am 
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Looks like a cool project.
Your pushrods look very much like kart track rods?

If they are just be aware they bend very easy.


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 Post subject: Re: 924 for drag racing, it may upset the purists.....
PostPosted: Sun Nov 20, 2016 11:34 am 
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Now that I had a rear suspension set up that was really easy to adjust, I was able to play around with the ride height. This is where the next problem reared its ugly head........camber, or as the spotty kids who frequent McDonald's car parks say....stance!! For those of you that have lowered the ride height of a 924/944 you've probably noticed that the lower you go, the more negative camber the rear wheels have, now whilst this may not be bad thing for throwing a car around a bendy track, it really doesn't help with straight line acceleration.
[url][URL=http://s154.photobucket.com/user/bruceakop/media/Porsche/IMAG0358_1.jpg.html]Image[/url][/url]
The easiest solution to this problem was to do what the VW racers found out many years ago, which was to swap the suspension arms over from side to side. In other words take the right hand side diagonal suspension arm, turn it upside down, and fit it to the left hand side, you then need to cut off the shock absorber tower as it is now on the upper side of the arm and weld it back on the underside of the arm, then repeat for the other side. This gives the rear much less negative camber.......I hope it makes sense? I apologise for no pictures of the arms being flipped, but the result ends up like this
[url][URL=http://s154.photobucket.com/user/bruceakop/media/Porsche/IMAG0361_1.jpg.html]Image[/url][/url]
So now I can have a decent ride height with minimal camber, adjustable damping and rebound, with the ride adjustable about 150mm and the spring rates adjustable, all with 2 19mm spanners and in about 5 minutes. Next job is to see if I can make the engine fit....


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 Post subject: Re: 924 for drag racing, it may upset the purists.....
PostPosted: Sun Nov 20, 2016 11:41 am 
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Tony..........the picture doesn't show the pushrod size very well, they are about 30 mm diameter rods with M12 joints. How thick are the kart ones? I can always weld a sleeve over them for extra strength if you think it is needed. Thanks for your comments.


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 Post subject: Re: 924 for drag racing, it may upset the purists.....
PostPosted: Sun Nov 20, 2016 11:48 am 
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Ahh, thats way bigger than kart trackrods.

Kart rods are 10mm od with a 8mm rod end.


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 Post subject: Re: 924 for drag racing, it may upset the purists.....
PostPosted: Sun Nov 20, 2016 11:56 am 
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Tony, I've just looked at the picture I posted and I think that not only is there nothing to scale it, I also think that those rods are the first ones I mocked it up with, so are only M10 ends, which when I fitted I thought they were too thin!


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 Post subject: Re: 924 for drag racing, it may upset the purists.....
PostPosted: Mon Nov 21, 2016 1:06 pm 
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So a bit more of an update before work. Now that I had a few cross members in place of the rusty floor and a rear suspension that worked, it was time to try a fit the VW/Audi 1.8 engine. The conversion has already been covered in detail by a couple of members on here but I did a few things differently. I cut the rear of the bellbousing out so that I could use a concentric release bearing as my AP clutch wouldn't work with the standard VW clutch arm, I mounted my engine on solid mounts so effectively the engine and transmission become part of the chassis and I fitted a Holset HX35 instead of the K04 turbo.
[url][URL=http://s154.photobucket.com/user/bruceakop/media/Porsche/IMAG0004.jpg.html]Image[/url][/url]
[url][URL=http://s154.photobucket.com/user/bruceakop/media/Porsche/IMAG0802.jpg.html]Image[/url][/url]
[url][URL=http://s154.photobucket.com/user/bruceakop/media/Porsche/IMAG0862.jpg.html]Image[/url][/url]


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 Post subject: Re: 924 for drag racing, it may upset the purists.....
PostPosted: Fri Nov 25, 2016 1:32 pm 
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With the clutch fitted to the new flywheel, the engine fitted to the bellbousing and the bell housing fitted to the torque tube, the whole lot would fit into the shell. So after feeling smug that it now all fitted, I decided that the 40 year old front inner wings and radiator supports were just too horrible to bother tidying up, so with a couple of fresh cutting discs it went from this......[url][URL=http://s154.photobucket.com/user/bruceakop/media/Porsche/image.jpeg.html]Image[/url][/url]
To this...........
[url][URL=http://s154.photobucket.com/user/bruceakop/media/Porsche/image-4.jpeg.htmlImage[/url][/url]
No turning back, now I had to find a suitable way of holding all the front panels in place, surely it couldn't be that hard?


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 Post subject: Re: 924 for drag racing, it may upset the purists.....
PostPosted: Fri Nov 25, 2016 5:38 pm 
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I guess that opens the door for a bit of space frame work

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