Supercharged Race Car Build

[JohnJL]

I've made enough progress now to pull together things into a coherent thread. I've received a great deal of help from this site, I owe the community here and more directly Wayne a debt of gratitude for providing inspiration, parts and advice.

Thank you.

The car started as a Japan-delivered 1983 SC that had been imported to Australia by a Melbournian for track duty. Unfortunately the previous owner had a serious accident in another car and was forced to retire from racing so put this on the market. I bought the car, road-registered, in 2006.

I stripped the car out, had a cage installed, installed a new suspension and built a new 3.0 twin-plugged, high-compression motor for it and raced it for 2 years. It was a load of fun but I got to the point where my regular instructor (a Cup driver) said "You are driving this car as fast as its capable, you need to do something about the transmission and motor." That was all the excuse I needed!

I signed up for Targa Tasmania Tour this year and as April approached I made a decision to take the race engine out of the 1983 and put it in the 1974 Targa, where it resides now (with Webers.)

After much research, discussion and thought I decided to do something a bit different but which ticked all the boxes that were important to me...an interesting project, a car with a lot of potential/power to keep me occupied for a few years, and easy to drive.

I decided on the following build sheet;

3.0 Case
GT3 oil pump
DR20 cams
Autorotor supercharger
3.0 Crank
98MM JE Pistons, 8:1 CR, Ceramic coated, dry film skirts
98MM Perfectbore Cylinders
3.2 L effective displacement
Twin-plugged wasted spark
Crank-triggered 36-1
1 5/8 headers
Flowmaster 80 2-into-2
Adaptronic ECU
Knock sensor tapped into bridge across 4-5-6 cylinder bank
Mildly ported heads
Raceware rod bolts
Racing valve springs
SC rods
Hydraulic tensioners
Head temp sensors on each head (carryover from earlier installation)
G50 transmission from Patrick Motorsports
Lightened flywheel, sachs racing clutch & pressure plate
Carrera axles
Guard LSD
Hargett shifter
BAT front oil cooler
ATL fuel cell

Lots of other bits I forget, but here are some progress pics

[JohnJL]

Notice Wayne's book's cameo in the pic above!

Here's me gloating and posing with my home-made piston pin spring installer

[JohnJL]

[JohnJL]

"The Office"

[JohnJL]

[JohnJL]

I'm happy to accept criticism, advice, share experience and answer questions...enjoy!

[IROC]

That is extremely cool.

[ChkbookMechanic]

Looks nice.. what displacement supercharger is the Autorotor?

[KeoRS]

John;

That is one intense project you have going! Keep us all updated! It looks like a killer ride.

[euro911sc]

Great build. A couple comments/concerns come to mind:

1) you could lighten the big plates up substantially by making it a laticework instead of a solid plate. Then tie it into the #1 intake at the top for cross plane stability. less weight in this critical area is good as you are well aware of

2) The extension on the shaft of the alternator may prematurely wear out alternator shafts at a rate you are not comfortable with. Not sure how to overcome this... Also, beware your fan blades do not scrap up that nice color job on the fan housing if the belt is too tight or fan strap over tightened... don't ask me how I know

3) I cannot see how you are going to run the belt from the crank-SC-Alt and have enough contact surface on the alternator pulley w/o tons of force... which leads us back to #2. Do you have a pulley tensioner to put in there? Or a free wheel to change the angle of attack for the belt running from SC to Alternator? Or will you have 2 separate belts?

Looks like tons of fun! Any particular reason you chose not to use the already developed supercharger kit for SC's? Availability? You are just a power junkie and that other kit is just to wimpy??

Best regards,

Michael

[JohnJL]

Thanks guys.

Michael, the Autorotor is MX420, 2.0L displacement. Its on this page...http://www.hi-flow.com/HP7Super.htm

Michael, great minds think alike. We put that plate sandwich together first and will lighten it later once we have the tensioner and idler wheels all positioned. We even have some designs the lightening might take...and yes, we are doing exactly that on the second brace. We're working on a brace that comes off the M8 bolts over cyl 2&3 and comes up to attach to the supercharger intake manifold.

have to go to work now, more answers soon....

[Flieger]

I think you could use more reinforcement in your transaxle mounts.

[kodioneill]

wow, bloke!!!

[mjshira]

very interesting, not sure I've seen a supercharger done like that, cool!

[beepbeep]

I'm generally against superchargers and find them inferior to turbos on all points except throttle response but this is a nice build and Lysholm is probably the best supercharger design around.

What others said apply: I would use separate belts for fan and supercharger. If this supercharger is to produce serious power it will need to tap at least 20-30hp just to spin it around. In order to transfer that sort of power trough a belt, you will need decent belt tension and alternator bearings just aren't up to task. Actually, it would be best if you could move alternator itself out of fan and drive it with own down-geared pulley off the crank. That way you can overdrive the fan and underdrive the alternator, giving you better throttle response, longer fan life (no live mass in fan to accelerate/decelerate).

Otherwise, it will be a blast...

I assume you won't be able to pack decent size intercooler into the engine bay but water/air heat exchanger would probably be very good in this application.

Regards,

[JohnJL]

OK, boss isnt looking now...

Yes, we're still working on the bracing and lightening, once we get everything positioned and in place then we'll work out where we can lose some weight.

It became clear yesterday the serpentine design driving everything off one belt isnt going to work, the fan housing has some movement to it when the strap is loosened. We discussed situations like needing to get into the alternator between rally stages/days and the fact it would be very lucky indeed to get the fan positioned exactly back so the belt ran true again. I calculate somewhere around 50hp of force on the belt too, which would deflect it in the 7:00 position. We we've gone to a 2-belt setup, the supercharger inboard and the fan v-belt outboard. It will add some deflection force to the nose of the alternator, but I'm more comfortable with that since the force is significantly less than the supercharger belt. Fitting the 36-1 trigger wheel is now going to be very tight, we're discussing tapping and drilling magnets into the circumference of the crank pulley now as an alternative...The tensioner is a Gates, OEM for Cummins Diesel trucks! The sixe of the pulley on the fan is exaggerated in the pic above as we haven't trimmed it back yet. Its still overly long to accomodate the lathe chuck.

Thanks Goran, yes I know your views on this. I always follow your posts and absorb your advice. You probably didnt know you were unwittingly a major contributor to this project!

I do have space to fit a decent size air-air intercooler we're building the shop. That was a driving factor in the massive tail. I can fit a 3.5 x 21 x 15" intercooler under the wing with the air ducted 90% to force through the core. The other 10% will be ducted to the airbox.

For those of you who havent seen this, Ray Fowler did a similar setup for his street/track car with a slightly smaller Autorotor. Ray's an awesome guy, he shared all his "secrets" along the way including his datalogs, engineering drawings, everything. He let me go over and crawl all over it with a digital camera and answered any question I asked.

[JohnJL]

Here's Ray's site and overview. Ray is the salt of the earth, a truely selfless tinkerer.

www.supercharged911.com

I think he is selling, good fun. I'd buy but cant accomodate a 6th car...

oops his site is down. Will give him a call this weekend.

[Miguel Antonett]

Thank you for sharing, great project; BUT, no air conditioner? :-)

Keep us posted on the progress.

[JohnJL]

Anyone ever get really frustrated by a Previous Owner who has hacked into the wiring harness, in good will, but leaves you no hint how to figure out how to diagnose what happened when something goes wrong?

Well, no more. Having done a few rebuilds now I am resolved to always to a complete wiring diagram. If not for resale value, for my own ability to diagnose in the field.

So here's page 1 of 3 for the race car...

[herman maire]

Nice build. I like your fuel cell idea using the bottom of the oem gas tank and building the fuel cell frame on that. cool.