Your engine, as provided by the factory, was built and configured to provide reliable service with reasonable drivability via CIS induction and mechanical ignition timing as its engine management system.
Reliable service is ensured by low static compression ratio, low boost settings and non aggressive ignition timing. Good drivability while meeting emissions with this primitive engine management format is derived by small intake ports, low intake manifold volume and short duration/low lift cams with no overlap. Economics aside, the exhaust system configuration and turbocharger fitted
ensure a reasonably progressive torque curve, at least in post-1986 cars.
With constantly spraying CIS injectors - only volume varies - and an ignition advance relying on a combination of centrifugal advance and boost pressure trimming, timing of fuel or ignition delivery to the "event" - that instant where your fuel/air mixture ignites as combustion - is hit or miss. Mostly the latter as emissions measurements of 3.5% CO will attest to how much you must "pad" the safety margin to ensure no lean spots at any point in the operational range. This configuration will support the post-1991 100bhp per litre factory provided power levels with a decent margin of safety but 145bhp per litre on mechanically modified engine is really the
limit with CIS/mechanical ignition advance if any longevity is to be expected, especially if aggressively driven.
PWR-EFI completely changes this equation. Both fuel and ignition delivery determination are not only dynamically controlled and with more governing parameters (heat, load, rpm, manifold pressure) but changes are made instantaneously resulting in almost ideal timing to the "event." You can now exploit this accuracy by optimizing the engine to take advantage of this capability. higher static compression ratios, larger intake ports, far more aggressive cams and ignition timing as well as related components to making this a better air pump, larger turbo's and larger more efficient intercoolers. Our package motors with PWR-EFI-1 (bank fired injectors) routinely produce 160-170bhp per litre at only .9 bar of boost on pump gas and are absent of the usual exotica assumed necessary to achieve these power levels, utilizing single plug ignition, your original cylinders, intake manifold,
waste gate, C2-type intercooler and off the shelf header system (if already fitted).
Though far more difficult to program successfully, as with factory GT3Rs, your PWR-EFI operates in open loop mode without reliance on an 02 sensor to maintain proper mixture - the failure/degradation of which can destroy your engine. If you are in a location with very stringent emissions standards, we can provide a closed loop /02 sensor format for fine adjustment at idle/low load operation only. Though performance is the priority, this engine configuration consistently returns 18-21mpg at 85mph with standard gearing and no less than 16mpg at the same average speed when utilizing our short geared four speed configuration.
The primary PWR Package engine built to optimize your PWR-EFI-1 or PWR-EFI-2 conversion consists of your 3.0/3.3litre 930/911 Turbo carefully rebuilt with the following:
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 | PWR-EFI-1 or PWR-EFI-2 system |
| PWR design pistons, valves/keepers/collars |
| 38mm Intake system, C2-type intercooler, BOV |
| Headers, PWR mod'd turbo, Borla XR1 based muffler |
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In nearly all cases with individual customers, these conversions/builds are done at our shop - shipping your vehicle is absolutely not a problem - and engines sent to us by other shops are returned with wiring harness/ecu connected/programmed, laying on top of the engine ready for your shop to re-install after a few wiring changes in your engine compartment.
If you are contemplating converting from CIS to EFI on your currently modified 930/911 Turbo, a word of caution if this work was done prior to your ownership, the modifications may/may not be documented
completely and the previous owner's (PO) use is unknown. Even without elevated boost, over 90% of the stock/modified
CIS based 911 turbo engines we rebuild, like this low mileage example, have broken rings/piston lands. These engines are now up to 30 years old and even on low mileage concour
svehicles, besides visible oil leakage, they suffer
from embrittled and now broken cam chain ramps and obstructed piston oilers/cam spray bar
ports. We recommend a full rebuild.
If you are not having a PWR package engine build on your recently rebuilt modified CIS based 930/911 turbo, we will gladly work with your to retain your expensive peripheral
components (headers, turbo's, intercoolers, cams) when doing a PWR-EFI conversion but in many cases we will need to develop a custom ECU map to your application.
Your engine is completely rebuilt from the cases up as is standard for our PWR engine build program. All case plugs and even the oil squirters are removed to ensure your engine is entirely free of any contaminants. Bead blasting - reserved for exterior pieces only on concours restorations of 356/early 911 - is avoided. We clean all parts free of grease and contaminants in our high temp parts washer. This is the right side case fresh from our parts washer completely oil/solvent free and ready for bearing shell fitment.
J&E pistons made to our own design are fitted raising compression ratio to a cc'd 8.19/1 from roughly 6.75-6.95 of listed 7/1 stock. Our package engines make their immense usable power by very strong torque readings under the curve as well as holding that torque curve to well past 7,000rpm (you will note on nearly every dyno chart for a modified 930/911 turbo that they generally peak at only 5,700-5,800rpm). Thus, it is critical that every reciprocating/rotating component be balanced - note weights marked on every piston - to provide reliable longterm operation at higher rpm.
After intake ports have been honed from stock 34.5mm to 38mm, the heads are been prepared with our own valve springs/keepers and then the top half of the engine is assembled with the EFI/your intake manifold honed to match. The cream colored rings in the inset image at the lower right the phenolic blocks that fit between the heads and the EFI manifold to prevent heat soak.
Our PWR-EFI equiped package engines are built/tuned to run just like a very large naturally aspirated motor - but with a
lot more power - therefore there are some operating parameters you need to be aware of when contemplating having one of these built. The combination of rapid throttle response and and high power means your stock/lightly modified chassis will experience far greater weight transfer not only fore/aft but also lateral as you apply - and it responds instantly with - power out of a turn. With weight-to-power ratios dipping
to less than 5lbs/1hp on pre-78 cars, only an 89 inch wheelbase, no ABS or stability control, things happen very quickly. Your stock chassis is absolutely not equipped to handle these engine packages and we list the following as required/recommended.
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PWR-EFI-1 Package Engine Install Requirements |
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| Heavier Torshion Bars. Your rear wheels will foul the tops of your rear fenders under acceleration with stock 26mm bars and boil off your paint, at minimum you'll need to go up 4 sizes on the rear and nominally on the front. |
| Suspension Bushings At a minimum delring bushings need be fitted to the trailing arm and spring plate to prevent dramatic toe-in changes, also under acceleration and preferably on the front for more steering accuracy. |
| Ride Height/Corner Weighted/Aligned As you've seen on various RUF tapes, under hard acceleration with high power, your positraction in action causes your vehicle to track slightly offset to onside at/beyond the traction limit which can cause control problems at higher speeds with improper chassis setup. |
| Brakes: Your 78-later brakes are excellent but on U.S. spec cars you will need to fit the Euro Rest-of-World master cylinder to correct bias orientation rearward. Verify your non-US car has not had the US master cylinder retrofitted over the years. |
| Clutch: Your stock clutch will not hold, especially if you're car is fitted with positraction and/or wider/larger rear wheels/tires. A RUF type will retain factory-like assisted spring clutch pedal action. |
| Oil Cooling: Pre-78 cars need the trombone oil cooler replaced with the radiator type. |
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PWR-EFI-1 Package Engine Install Recommendations |
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| Positraction Though single-traction transaxles can in fact almost hold stock power levels, that power delivery is more gradual and traction enhanced by controlled rearward weight shift under acceleration. With quick throttle response, PWR package engines respond faster than chassis weight bias can shift thus making this open differential totally ineffective in nearly every scenario, we recommend fitting positraction, not only for traction, but handling as well. |
| Gearing: Four speed cars are geared extremely tall and though our package engines can overcome this disadvantage without any problems, we recommend a shorter 2nd, 3rd and 4th to fully exploit this engine's potential. 75% of our customer opt for this change once they've experience our test car so equiped. Part of that balancing process during the engine build to permit higher revs has the direct benefit of reduing vibration. Only the change in exhaust tone will tell you that 4th is shorter on the freeway. |
| Muffler; Your engine as an airpump.....we've found intercoolers and mufflers to be two serious impediments to high speed air pump efficiency. The power numbers we post are based on fitting our own fabricated two-pipe borla based system. No current muffler in the aftermarket will flow the gases of one of these, we recommend fitting one. |
Though the majority of our PWR-EFI package engine builds/conversion customers ship their cars to have the required/recommended modifications done at the same time, we do many complete builds/conversion for both other shops and individuals shipping them in
one of our purpose built crates. Here is one ready to install
in the car down to the clutch/throwout bearing and complete engine wiring harness with ECU sitting on the forklift 
ready to have our crate top fitted and then be shipped.
Though PWR built a complete package engine with our spec cams/pistons/etc.., for now, the customer elected to retain his stock heat exchangers, modified turbo and aftermarket intercooler. It is being dispatched with the ECU custom mapped for this configuration. When he replaces these items at a later date, he'll FedEx his ECU to us for overnight return with the appropriate map re-flashed.
You can expect a time range from receipt of your/your customer's engine/vehicle at our shop of 2 weeks for a CIS to EFI convesion on stock engines to 6 weeks when accompanied with an engine rebuild/modification(s) and the required/recommended chassis/driveline modifications.
