The Engine Bay……..28 year old and needing a good clean and repaint…..
Turret Detail in Black Satin
Inner wing panels in Alpine Weiss (White)…….
Voila !
Looking good, but then………developments then changed and a decision was made to take this engine out !
If a special one off more powerful New Engine was fitted to match the lightweight chassis the car would not only obtain a higher power to weight ration from all the total weight reductions (Over 250Kg !) but also increase further with more engine power..
Components were sourced, and tuned from across the Altlantic ocean from the Porsche Racing Specialist Lindsey Racing (USA):
– 3.0 944 S2 Litre Block (Lightly Honed)
– 2.5 944 Turbo Crank 2.9kg has been machined off (knife edged) and polished, the original crank design is at the bottom
– 968 3.0 Litre lightweight Forged Conrod’s as opposed to the cars original heavier cast rods
New Lightweight Forged German Manufactured Wossner Pistons & Rings with a higher Compression ratio. (10:9:1)
Orignal cast 2.5 Litre piston on the left…..New Forged on the right…….
You can see how much slimmer the lighter forged Piston is, also the forged rod….
– 2.5 Litre 8 valve Cylinder head before it was sent to Lindsey Racing (USA) for a full rebuild and gas flow work on the Inlets which yields a improvement of 28% more CFM airflow
And after………
Widefire Head Gasket
The capacity of this “Bitzer” configuration is 2707cc
Each piston capacity is just over 675cc x4 cylinders with 2 valves per cylinder…..
The original Steel Flywheel……….@ 7KG
Machined off 1KG to 6KG
But an even lighter Aluminium Spec (USA) item was then decided on….
Which only weighs 2.7 Kg !
New Engine Build
Many parts and components were required to completely build the new engine..
The car’s original engine was stripped……
The oil Pump, And Balance shaft housings were stripped and powder coated……
On the left is a modified cut down & drilled (Lighter) Alternator bracket which will carry a 3kg Alternator and not a 6kG version as the original bracket did on the right!
The original Camshaft was identified as there are 2 versions…….
And a new special profile was selected and made in the USA by Web Camshafts from California.
The Lobes profile of the new Cam (On the left below) are different, with more duration
between the inlet and exhaust valve’s opening…..
Which with mapping will increase engine Torque and BHP,
especially in the mid RPM range….
Adjustable Cam Pulley (Lindsey Racing USA)
Summit Prep (Preston Uk) built the Engine:
Colour
The Engines Colour scheme is Silver block / head and ancillaries… with a vibrant
blue / purple Cambox and Inlet Manifold…
This is a mock up with an experimental cambox, the actual Inlet being used, placed
on to the old engine…..
Another experiment (R&D) is to see what RED “Porsche” letters look like, so this Cambox is the one from the original engine, which has been powder coated in a RED…
All the surfaces have been flattened down by hand to achieve a billard smooth finish,
The next stage is to paint the entire component in the Blue / Purple Colour
with a Special High temp (200 degree) paint blended at thewheelrestorer……
Then when this is dry……I will use a light grade of sanding paper to remove the red
from the top Logo area only, this should reveal a RED Colour, which when Gloss
Powder Lacquered should be looking good!
The bottom and ends have been masked using a special high temp tape…….
After preparation all by hand, flatting down all surfaces……the Cambox was painted
with a High temp Metallic Blue
Once baked and cooled the hardest bit was to remove the blue paint with a palm
sander revealing the red underneath on the Logo….
The finished article…….
Assembly progressing……..
The Engine was installed (Feb 2016)
Modified and lightened original Inlet Manifold
I Cut off the swan neck, and made the throttle body entry more straight…….
Exactly the same Inlet manifolds……
Original on the left,………. modded on the right ( lightened of course!)
Powdercoated in Primer ready for a colour….
This inlet was then sent to the USA to a company called Kennametal
They have a service called “Extrude Honing” which involves an abrasive putty which
is forced under pressure through the inlet manifold, this cleans up the rough casting
walls and vastly improves the airflow by up to 25%
An example of the process………Before with the rough casting surface evident
And After the process
Here’s the Inlet back from the USA………
And a shot of the main throttle inlet looking nice and smooth………
Powdercoated………
Standard Throttle body and Bosch TPS,
An extension tube has been made to give the Inlet a big Plenum volume for the incoming air to “settle” before it’s distributed to the 4 Inlet Tracts
Powdercoated to suit the Blue Inlet and Black Throttle body………….
The Inlet needs some thought and designing, the objective is to create a straight line
of flow for each component : Air Filter, AFM, Throttle body……
Here’s a sketch of what was intended Inlet system with an ITG Filter located behind the front badge panel
But to get the Engine running first a quicker system has been installed.
And before the Rolling road tune, i boxed in the Filter with some Zircotec specific HEat shielding
Modified lighter Balance shafts are were fitted, (with one of the counter balance weights cut off) sourced from Broadfoot Racing USA
Radiator
The original is aluminium & plastic but………….it’s too heavy !
Or rather a lighter version is available……..approx. 1.5kg lighter
Winner Racing (China)
Here coated in a VHT Ceramic Grey
The original fan assembly is very heavy (3.5kg)
I’ve installed a lighter Spal version around 1.5kg
The original Alternator was a lardy 6kg…..!
A Brise lightweight (3kg) has been fitted.
The original Bosch starter motor is not too heavy and will be used…
Starter Motor
The original was used for a few months after the install but was struggling to turn over, either due
to the high compression or it was on it’s way out!
So I replaced it with a GEAR Reduction WOSP Unit.
Transaxle Gearbox
To be checked, rebuild and fitted with a LSD
Wavetrac (USA) unit Supplier By EMC Motorsport (Birmingham)
Summit Preparation stripped the gearbox and are rebuilding it with the new LSD
New Gearshift and rear linkage
Then I found the gearstick was too far away from my low bucket seating position and also
the throw was too long and at a full arm’s stretch, so a Modified “Dog leg” gearshaft
was designed and made which brought it 2″ nearer towards the steering wheel and also
2″ further back.
Also to be used with a Only944 Short shift rear linkage
Dogleg shift rod fitted, and the test drive was a success, the new position is far easier to
get hold of and the knob also better control than the original bulky stem / knob
the original rear linkage came off easy enough but the stay bar sheared it’s bolt
in the top of the gearbox!
So without removing the gearbox to drill it out! I had to design a bracket and put the
stay on the other side.
Revised version II with a Nylon Gearknob and extra gusset for strength
Powdercoated Driveshafts with New CV Joints
Original Engine Tray stripped / coated & fitted:
The car was Running on July 13 2016, and then after several more jobs I collected it on Friday 5th August,
Over that weekend the car & Engine were “Run In” and a Rolling Road session took place 9th August
By Wayne Schofield (Chip Wizards)
![Chipwiz0255[1] (Medium)](http://924SRR27L.co.uk/wp-content/uploads/2015/05/Chipwiz02551-Medium.jpg)
The results were better than anticipated, after 8 hours “Live” mapping a final figure of 205 bhp & 205 Ft Lbs of Torque was achieved…..
Click on the “ChipWiz” & “Tech Spec” underlined links below to view the actual Rolling Road Graph and a specification sheet and the car’s final weight..
which is 1010 Kg ! …………..but this will be reduced further, I want a number beginning with 9…!