The Quest for Traction: Wheels, Slicks, and Fender Flares

Since the motor was rebuilt and the interior gutted, the car had become a complete animal to drive.  With over 550ft/lbs torque and no weight to wrestle it down, it would get wheel-spin all the way up to 90mph.  While it was immensely entertaining, smoking the tires at highway speeds wasnt going to break any lap records.  The 275 front and 285 rear tires were as large as the fenders would allow, so once again it was time to start chopping away at Porsche's unique design... but more on this travesty later.

In order to have any chance at getting this monster to hook up, it was going to need a .50 cal size wheels and tires.  A call to Tire Rack and a (once again) empty bank account later, some beautiful OZ Alleggerita HLT wheels arrived at my doorstep.  Tire Rack didnt have an obnoxiously wide rear wheel for a 928 (big surprise there...) so the 18x10 and 18x12 wheels were originally designed for a 996 GT2.  Despite the 200 hours I had worked to pay for these, the car still needed tires... yeah, that was a bitch of a realization.  Thankfully, some lightly used Hoosier A6's were available for a reasonable price.  The fronts are 295mm and the rears 335mm.  I could bore you with why I chose those sizes and the weight reduction of these featherweight wheels minimizing the rotational mass and unsprung weight by 4lbs each, but honestly, who gives a crap?  This was the result:

 

Mounted and Balanced 

 

After some measuring and oddly satisfying chopping of the fenders, the wheels were bolted up.  The new wheels/tires stuck out about 2" past the fenders in the front and back.  This setup would be ready to go at an autocross, but actual race tracks and circuits dont allow this.

 

 
The rear width now measured 78.5"

 

The front width now measured 75"

  

Several hours on the forums and ebay later, I found these Datsun ZG fenders were just large enough to shroud the enormous tires.  The other requirement which these fenders filled was the "bolt on" aspect. Perfectly fiber-glassed and blended fenders look stunning on show cars, but they have no place on a racetrack, especially when they are destined to get obliterated by a competitor or wall of tires.

  

Being fiberglass, they were easily bent to match the contours of the hand bent aluminum front fenders.  Installation was as simple as drilling holes and filling them with rivets.  RTV sealant was used to fill any gaps where air or water might penetrate. 

  

 

  

 

 

 

Final words:   The car is currently barely capable of driveway egress, but it still may need a bit more fender trimming once it's fully lowered.  Regardless, it looks much better with black wheels and it's now as wide as a Lamborghini Countach.  Will the quest for traction be successful? Probably... since F1 cars use the same size rear tires, but it'll be interesting to test once it finally hits the track.

Rainbow Spaghetti: scrapping the stock wiring and installing an 8 circuit race car kit

The lack of headlights, turn signals, and anything that wasn't the starter or ignition system left me with a choice: spend countless hours trying to decipher the hieroglyphics that are the the shop manual of a 1979 Porsche and eliminate all unnecessary wires, or spend $1500 and buy a stand alone race car wiring kit with new gauges.

After seeing this clusterf*ck that is the stock wiring, guess which option I picked...


They say a picture is worth 1000 words, this one is worth 1000 profanities



Using the time traveling power of Evan Williams, the 20lbs of old, crunchy, stock wiring was dispensed with quickly




After sacrificing 2 paychecks to the car gods, I was rewarded with a big brown box of dials, switches, and many wires (also some brake duct hardware but we'll get to that later)



$800 of the $1500 was spent on this Painless Wiring 8 circuit race car kit. Worth every penny.



Switch panel


Mounting all the electrics on one panel makes install and removal simple and fast



New gauge panel made from 3/8" lexan left over from the windshield



Making sure everything fits



A few coats of paint and it's finished.

Gauges are: Oil pressure, Coolant temp, Volts, Fuel, Tach, Speedo, and Fuel pressure (not pictured)



Installed:







Engine bay is much less cluttered with no EFI wires



Start up procedure:




Parting words:

This whole process was time consuming but extremely simple with the included instruction manual from Painless Wiring. If you plan on installing on of their kits, don't be afraid to call and ask for help, they are all super nice and will spend as much time as needed to help you solve whatever conundrum has you stuck. Their tech support line is open on weekends as well!

Adding lightness and downforce: Making a splitter and ditching the headlights

Since this car will probably never be raced at night there was no reason to keep the stock headlights.



~30lb weight loss= headlights, foglights, turn signals, rotation motor, and wiring



Lots of room for brake ducts



Lexan headlight cover



Paint only the back side of the lexan so if the front gets scratched there won't be paint chips



Done: 30lbs lighter and better aero





DIY: Plywood splitter+air dam

Step 1: Get a 4x8 sheet of 3/8" plywood along with the bits seen below in home depot's racing department



Step 2: Cut sheet into 2 pieces so there will be enough wood for a spare splitter.

Step 3: Make template and cut wood accordingly... garbage cans are an acceptable form of sawhorse

Step 4: determine mounting points and drill holes



Step 5: measure distance between splitter and bottom of bumper, cut strips of plywood for air dam.



Mount with 90* steel gate brackets... also from home depot
Then sand and put on a protective waterproof varnish so the wood doesn't rot



Rivet everything in place, screws/bolts are no good as they can blow out your tires if the splitter gets shredded or ripped off



Use an RTV or equivalent sealant around explodes areas to help waterproofing and air flow



Admire snazzy new homemade splitter/ air dam.
Then realize it cost less than $50, and you have a spare in case this one goes tits up when you inevitably crash

Lexan rear window, DIY front crossmember, and the pinaccle of go-faster bits: the spoiler

Lexan is fantastic. Its unbreakable for a kickoff, but its also extremely light and cheaper than dirt... Seriously, its actually cheaper to buy a sheet of lexan than some potting soil, also they are both sold at home depot.

Step 1: Take heavy glass out of insanely tacky german window goop



Step 2: Make template of original window from cardboard so german window goop doesnt get all over the new lexan






Step 3: Trace then cut



Test fit



Step 4: make some supports from angle aluminum or something similar



The steel used for the hatch was too flimsy for my taste, so some 1/4" steel plate left over from the roll cage was used to make a mounting plate for the wing





Step 5: test fit again, then prepare to drill more consecutive holes than you ever have before....and yes, thats what she said



Step 6: Lay down some RTV or black weatherproof sealant before permanently attaching the lexan, it will help keep the lexan in place as well as keep water out of your hatch.



Step 7: Rivet until your wrist is completely destroyed







Drill holes in mounting plate and mount spoiler using heavy duty home depot supports for the back part of the uprights.



I ended up putting a small lip where the gap between the end of the lexan and back of the hatch with some thick tab aluminum and added a small lip which (in theory) should help to produce more down force.







Sidebar: DIY crossmember... If you have more than 500hp in any car, its a good idea to reinforce the front of the car, even with a chassis as Viagra stiff as the 928's

Materials= square steel tube, tab steel

Step 1: Drill 2 holes in tab steel



Step 2: bolt on to lower control arm then place square steel tube on top



Step 3: Weld it up then add paint: