Julian Allen

A few years ago I put my track time on hold. I had been racing a 951 S, going to 5-6 events a year. The car was tired, and I had two in college at the same time. And then a wedding. And then another wedding. Long and short of it was, there was not cash to keep the car in good form. So, I embarked on upgrades and rebuilds. Until an eBay ad showed two 968 chassis, one a turbo S and one a turbo RS. Seems the cars had been Freisinger's and they found their way into the states. The RS of course had a cage, but it wasn't the newer cage on the red or the white car. And I had some cagey ideas of my own. So, I watched the S closely, and bid to win. I brought it home in late 2001.

I started by taking lots of pictures. And got lots more from the fellow who bought the RS chassis, as well as Bruce Corwin when he owned the white car. Searched for factory solutions to roll cages in coupes, and made my plans.

I cut out the rear deck, fueling hose covers and the spare tire well. I removed the coil and power steering pump brackets. And the parking brake stuff. And the hood release brackets. The car already came without a lot of undercoating, and a sunroof delete roof. I bought some steel and borrowed an hydraulic bender. Made mockups and patterns, and (a large pile of misbent tubing later) managed to create a cage that looks a lot like the modifed Matter cage you see in RS's 1 & 4, with the braces to the front strut towers and to the rear shock upper mounts. I seam welded, well, nearly everywhere. I built brackets for a dry sump tank in the passenger foot well, and isolated it from the rest of the cockpit. I put in a mount for a fuel cell.

In the 951, rear tire width was always an issue, particularly when the car was lowered and given negative camber, because the tires always rubbed on the inside of the rear wells. I sacrificed the 951 to see how the rear elements were put together, then modified the 968 to accept Kevlar tubs. I added flares like you've seen on the yellow car Kelly-Moss participated in, and, well, can you say 335's in the rear? They're a snug fit, and the final rubber is still quite a ways off, but I now have that flexibility.

The factory RS's have air jacks, so I added the tubes to mount them. Only the factory gave three and I couldn't put the rear one in because I wanted the fuel cell to be a little further back. So I put in four, at the corners of the floor.

In the 951 I successfully used the front "frame" elements as a channel for air to the brakes. Always liked the carbon fiber ductwork you see on 996 and 997 race cars, but that sort of one off work can break the bank! So I inlet a 4" tube ahead of the wheel well, and inside the well forward of the strut. 4" ducting is much more flexible and doesn't kink as much as 3", so I could deliver more air to the front brakes. I used an aluminum "plate" to deliver the air into the center of the rotors, although for the new car I may make this out of stainless.

And then I moved from Florida to Alabama. The project stopped for a couple of years for various reasons. Over the past two years I worked to complete the welding--mounts for this and that, trying to look ahead so I wouldn't get a finish on the car and then sand it off to mount something I forgot. Probably a good thing to have a pause, because some safety features get better (I added mounts for a right sided net).

Finally I made arrangements to dip the car--to remove the factory primer and undercoating, as well as clean up some light rust that had appeared in places. I've posted on other forums about my experience, but the short version is NEVER take your car to Wauchula, FL and I'd highly recommend the shop in Allentown, PA. After stripping, it's been well washed, phosphated, and now is powdercoated.

I then had the outside of the chassis, and the plastic body parts (doors and hood) painted to match the powder, brought everything home and started assembly. My wife says my shop looks like an auto parts place! And, speaking of parts, I would be remiss if I failed to mention the tremendous help I have received from Buddy Kennedy, now retired, who managed parts at Brumos Porsche. He, and Richard Pittman at PowderTech Plus in Orange Park, FL have provided me with help beyond measure and I gratefully acknowledge their assistance.

Well, that's a start of the tale. More to follow . . .

There are lots of photos in this thread--Internet Explorer doesn't manage this well but all the photos load promptly on Google Chrome. Of course, YMMV!

Julian Allen

First, here's the car the way it appeared when I picked it up after the successful eBay bid:







Some detail shots before I started working, showing how the factory mounted belt anchors and the intercooler, the

reinforcements for the front swaybar mount, as well as the corners over the rear shock top mounts.

Julian Allen

These are cage construction pictures. I based my design on the "improved" version of the 968 factory race cars, with

some gussets and braces.



















I took the roof off in order to complete the top welds, and removed the headliner retaining clips:






With the roof off and the car on its side it's easier to see the other cage elements.

Julian Allen

I did a good bit of seam welding--wish I had been able to strip everything before turning my hand to this.

Julian Allen

One thing I had made was some transmission flanges. The S/RS transmissions had larger flanges, like 928's and 911

turbos, so higher torque and HP could be managed. But, the flanges on a 968 are unique to our transmissions--similar

but not quite the same as those from 911 transmissions.

The factory had some, but I was a little late and got, well, the last one. Only one. So, to have the ability to use

the larger S/RS axles I had Quaife make some reproductions. Here's some shots.







I had always wondered how "traditional" front wheels could have centerlocks. It's fairly straightforward when the

front is like the rear with a bolt from the inside and paired ball bearings, but haven't you wondered about the

front?

I was able to obtain a set (the factory actually sold them that way in Weissach) of centerlocks for the car.

Here's the front: a modified (billet) hub with outside threads where the hub/grease cap would go, and a screw on cap

with an integral stud for the centerlock.



Here's the hub without the cap so you can see the threads:



And here's the rear--just like seen on 964/993/996 racers from the factory, with a slightly different center bolt.



Once the bolt is torqued down, a "locking cone" fits into slots machined in a standard rear hub, keeping the bolt

from coming loose when you remove the wheel.






The axles are different. The shafts are 28 mm rather than the 26 mm of my 951. The inner CV is 108 mm and

uses 10 mm bolts. The outer CV and the stub axle are made together, which allows a larger CV which will still fit

inside the trailing arm. That's the way the cup cars and current factory race cars are made also.

The half shafts are 28 mm rather than the 26 mm of my 951.
Pix:

Julian Allen

Here are some shots of the rear brake lines in place.




And these are shots of the insulation in the tunnel installed. This is the factory 944 turbo insulation.











Air jacks in and plumbing work for them--I'm using Goodridge hardline. I think the main valve will be in the back at

the hatch key lock opening.


The Kevlar wheel tubs are in--riveted to the remaining upper part and the enlarged sheet metal.




The fuel cell is in--pumps (active and reserve) are in the tank and the exhaust will be exiting to the right

(passenger) side in front of the torsion bar carrier.



Some other interior shots



and looking back through the windshield opening

Julian Allen

And this is the mount for the wing, one on each side with a slot cut in the rear panel. They are 1/16 steel with a

dimpled hole machined to "embrace" each other and then tig welded together and to the bar. It's like a somewhat flat

boxed beam with a central brace.


Progress is progress!




Here's the front suspension, nearly complete. The struts have been rebuilt, just waiting on some welding of a

backing plate with 4" brake cooling duct to mate to the 4" duct let into the longitudinal member of the frame.




And this is the rear suspension. The brakes are from the 964 Turbo S LeMans (GTS) car. The half shafts are factory

968 turbo pieces.




This shows how I plumbed in cooling lines for the transmission. There's a pickup welded to the right side of the

case (when everything was apart) with a mesh filter, then goes to a Tilton pump mounted above the trans crossmember,

across to a small Mocal cooler with fan located above the crossmember on the left, then back to the transmission to

return inside the gearset case. I plan to revise the lines with quick disconnects so I can remove the transmission

without spilling a lot of lube.




Here's a shot of the half shaft at the transmission--the joints and flanges are discussed above.

Julian Allen

This is the hydroboost pump for the power brakes. This system was first used in 964 and 993 turbos, and is in both

the #1 and #4 factory 968 TRS cars. It's what allows the triangulation of the strut towers back to the cage, because

the original vacuum booster was in the way. Fits well here where the carbon canister would be in a street car.




Picture of a rear wheel all mounted up--someday to see the asphalt!




And, since the car was up on the lift I took this shot of the inside to show cage elements.




I'll try to get some other photos up later today. Thanks for everyone's interest and encouragement.



This is a view of the rear shelf with the wiring, airjack and shock canister plumbing.




This shows how the hydroboost unit fits in. The brake fluid reservoir is for that unit. I have adapted a stock

reservoir for the brakes, and have made a mockup bracket and will use that as a pattern to make the permanent one.




The dry sump tank fits where the battery was. Inside the cockpit this area is closed off and there's a large drain

in the floor. The resisitors will be used to dump the alternator output when the master off is switched.

Julian Allen

This shows how I modified a 944 tank with the 968 "loops" and some spacer blocks. 3M makes a "slippery"

(polypropylene) plastic adhesive that may not be attractive but it works great. The location is unique because of

clearing the NACA hood duct, hood bracing, and intake plumbing.




And this is a view of the dash with its previous instruments--probably will keep some of these and end up with a

MoTeC display in front of me. Brake balance lever is to the rear of the center tunnel, and the other box is for the

adjustable swaybars. You can also see the bottom of the dry sump tank.





At this point I had slowed progress with the car, so here are some engine shots:

The clutch comes from Tilton and is a 3 plate carbon/carbon 7.25" arrangement, with a bolt on starter ring. No

sensor provisions, because I plan to put that on the crank snout.





Flywheel:



Mounted on the crankshaft:

Julian Allen

Rods are Carrillo's with SPS bolts: I used these in my previous motor and was well pleased, now reworked and ready

to install:



And progress on the short block showing the crank in, Raceware studs, and the rods and pistons in place:




Some years ago I obtained a Troutman thermostat, which uses the 911 Behr element to route the hot oil to the cooler

(and cool oil back to the engine). So, the photos show the cooler mounted (it's an Earls unit) along with the

plumbing to the thermostat.

RajDatta

Julian, the pics dont seem to be showing up. Very curious and excited to see them.

Julian Allen

I have worked on the wiring and have nearly completed the non electronics part. All Tefzel, and I used Deutsch

connectors that allow me to remove the dash fairly easily. Here are a couple of photos of the backside of the dash.

The dashboard, by the way, is a Crawford Composites piece, weighs about two pounds, and I used it with Autometer

gauges in the previous racer. Plans are for a MoTeC SDL, so the part with all the holes will receive a cover piece

of carbon fiber--like a blank slate--to mount things to.









I'm using P&B toggle circuit breakers which function as both switch and circuit protection. Although it may look

like a large number of switches close together, effectively this is the fuse panel. Most of the breakers share a

common buss bar, but some receive their line power from a relay.


And here are some shots of the other side of the dash.





You can see the fire extinguisher switch, master off (from the 996/993 cars), and the starter switch all on the left.

In the middle you can see the circuit breakers and the "ancillary" panel, which holds a reverse indicator, fuel pump

selector switch, defog switch, standard 944 light switch, and a foglight switch. There's a reserved space for the

map switch. And, there's a flasher switch (might be useful for full course cautions) which is interesting: the

switch is shared by the new Beetle and the Carrera GT! I saw it in a photo of a recent RSR (maybe an 09?) and PMNA

provided the bracket to mont the switch to the panel. On the right you can see the (recessed) box with the

extinguisher battery and electronics, and an hour meter (the only gauge I'll keep from my old car). The rectangle in

the middle used to house a lap timer, but the center net blocks my view of this area, so I haven't decided what to

put in its place. Finally, you can see the swaybar adjuster box to the right of the shifter. Progress is progress!



This is the way I arranged the outside switches for the master off and the fire extingisher. I'll be using only one

wiper--the center spot--and keep it vertical, which will then sweep to the drivers side and back.

Julian Allen

I have some shots of the manifold. JME barrel valve--something I have wanted since Jon first put photos up on his

website.

Julian Allen

In constructing the Lexan hatch, I searched and read over a couple of years, and came to the conclusion that a

combination of fasteners and urethane would be the ticket. I had my prior 944T car's frame, and the first thing I

did was strip the powdercoating off. I hate this part of the work.
I purchased my Lexan from Apex Performance (http://www.apexperformance.net/) and was very pleased with

this--it required minimal trimming to fit perfectly. Came with a sprayed on coating of plastic which both protected

the finish while I procrastinated, and came in handy during the work.

Here is the frame with my choice of fastener location. You can see both sides of the frame. I wanted to have the

fasteners far enough from the edge, but was also trying to have a tapped hole and avoid a nut on the inside. 8-32

screws filled the bill: I used stainless black oxide coated screws from Fastenal.





Most of the holes turned out well, with full diameter threads in two locations. I drilled from the inside, because

the groove in the glass mount side wasn't in line with my desired location. 25 or 30 fasteners.


Here's the trial fitting, using welding clamps to hold the Lexan in place. It was easy to see where it was too

tight, and a little rasp action fixed that.
The supports came from Crawford Composites, just as all the carbon and Kevlar components in the car. Max was very

easy to work with.







Once I got my holes drilled in both the frame and the Lexan, I wanted to mask the edges as you see with most auto

glass now. I drew on the protective plastic, then scored the surface, removed the outside, and used black urethane

primer. It worked okay, but took two coats, and the solvent penetrated the plastic in a few places. But hey, it's a

race car!







Then a layer of urethane, lay the Lexan and supports in place, and loosely fasten the screws: I wanted a layer of

urethane about 1/16-1/8" to bring the Lexan out to the glass thickness.







You can buy complete trim around the periphery of the hatch from the dealer using 924 numbers for cars without a

spoiler . That's what I then put on, and it really finished the edges.

Julian Allen

I'll post more as the project continues--but it seems to have a life of its own, and a long one at that!