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Parts to build a very powerful 944 turbo or 968 turbo S. To be sold to the highest bidder!
In the 1990's Hartech had started out specialising in 924, 924 turbo, 944 and 968 models and inevitably became involved In adjusting the 944 turbos for higher performance – which resulted (like the 924 turbo and Carrera GT) in a very sudden rush of power as the turbo cut in and made the cars difficult to control out of corners and to race and usually slower round a track than less powerful models (like the 944 S2 and 968) as a result.
Years before I had exploited my understanding of torque, power bands and gear ratios to create faster motorcycle racing engines by smoothing the power delivery and these turbos – although fast in a straight line – went against that.
I became involved in some arguments about the importance of torque (not high revs and bhp unless you can then alter the gear ratios to suit) when in 2006 we took in a very high mileage 250bhp 944 turbo in part exchange that we didn't want to sell on and decided to have some fun with it and try and prove my point. We just happened to have a spare 968 block and 2.7 944 head (that fitted) and with 944 S2 pistons (suitably dished to reduce the static C/R) built a 3 litre 944 turbo but unlike many others used the original relatively small turbo (for the new capacity) to see what a difference it made and if it would make the car more controllable.
The results were quite shockingly amazing, compared to a std 2.5 944 turbo, 3.0 S2, and 3.0 968 (graphs available on request).
Although the BHP and torque rose and fell a lot more – to drive - it seemed like it had a very flat torque curve from almost no revs and could be driven round a race track without the tuned 944 turbo problems faster and exit corners as fast as other similar cars but keeping up with them from 2,500 rpm almost whichever gear it was in and not spinning up the back wheels. It was also reported to make no difference to performance if gears were changed up at 5,000 or 6.000 rpm (and the graphs showed why).
The car was tested by a top racing journalist Adam Towler who not only found it fantastic for road driving (and declared it better than a Cayman S) but also recalled it in his published list of top drives when he retired.
However it resulted in a lot of almost abusive responses from others (particularly in the USA) claiming they had created much more powerful 944 engines (not understanding that this was not the prime objective) or that the car produced exactly what was intended - an incredibly fast but easy to drive road and track turbo that was never the less controllable.
Annoyed by this response (because a power competition was not what was planned) I decided to build the most powerful 944 turbo ever to shut them up.
The car was sold while I started to design the replacement and get together the parts for the engine build.
The plan was to buy a 944 turbo or 968 and move the radiators to the side front wing positions (as on a 996 or Boxster) and fit a massive intercooler where the smaller turbo one originally sat in the centre, a much larger turbo and build an engine that would stand the performance resulting.
Knowing that a big problem with highly force charged turbos running with standard camshafts was blow out of the exhaust due to too much valve overlap at high delivery pressures I decided to use a 968 head (that incorporates a variable inlet camshaft adjuster) but reverse the polarity so it closed the overlap as the revs and boost pressure rose.
To accommodate the extra heat the engine was expected to deliver I chose a 2.5 944 turbo block (because it has much deeper coolant depth than the 2.7, 3.0 S2 or 968). The 2.5 also had 2 coolant inlets from the pump (picture available - only one on the others) and the flow in all of them was directed from cyl 1 to 4 (by the head gasket blocking flow upwards) and then up at cyl 4 and back across the head to cyl 1. This resulted in temperature rise front to back in the cylinder block and back to front in the head – not the way to create a very powerful and reliable engine. The coolant exit on the block was altered to suit.
So after machining out the old cylinders I fitted baffles inside the block so that the coolant from the lower inlet passes through the bottom of all the cylinders to the back and up at the rear while the upper coolant inlet flows into the front and upwards at the front into the head. The idea was then to fit a head gasket that was modified to allow flow both at the rear and the centre so the lower flow reached the rear and then up into the head while the front flow only reached the centre before it rose up into the head.
This allows the coolant flows equally front and back. The 968 head has equal sized outlets at the front and rear allowing the coolant to then exit split front to rear and with a thermostat on each exit each connected to a different side wing radiator it would balance the internal bock and head temperatures much more evenly than before and increase the reliable boost that the engine can handle. The cylinders (that come with one spare) are shown in the picture not yet fully fitted but you can see that when they are dropped fully home the mid-way diameter in the ribbed portion of the block aligns with the machined baffle in the block to separate the coolant flows.
All the liners/cylinders are precision machined and in common with all Hartech cylinder replacements are supported at the top (to close the deck) because powerful 944 turbos do flex the otherwise free standing open deck top of the cylinders – improving reliability.
picture available of the cylinders after fitting and before skimming the head level.
The 968 cylinder head has been machined to accept Wills sealing rings (that are also part of the kit) to seal the pressure against a conventional high power turbo cylinder head gasket. The project can also be built with a 2.7 944 head and all the std 944 turbo auxiliaries if preferred.
The original cylinder head studs have been replaced with larger high tensile studs to help contain the planned pressures and the cylinder head stud holes opened out to suit.
Sodium filled valves form part of the kit for the same reason.
Carrillo rods are provided to take the pressures.
Piper camshafts were sourced to increase Volumetric Efficiency at higher revs.
Wossner pistons (12 in all) are also included that were specially created to obtain the right compression ratios at high boost levels.
All the other parts to complete the build are also available and included.
Parts have been dry stored but are dusty after 12 years storge but will be cleaned off and can be securely boxed for International dispatch or local collection.
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With major M96,M97 and 9A1 engine rebuilds being undertaken daily, oversized engines and new developments (due to greenhouse gas issues) none of which were envisaged at the time of the original plan for this engine – it is now reluctantly accepted that also now being in my mid -70's I will never find the time or inclination to complete the project. The whole kit is therefore offered for sale and will be sold to the highest bidder regardless of the price offered and failing interest will then be split with individual components (being sold separately to the highest bidder) and any parts unsold will be scrapped (we need the space).
Interested parties should contact Baz on
[email protected] or 01204 302809 - 9 to 12 am weekdays
