Geoffrey

I just completed my EFI Advanced class this weekend and saved some of the dyno numbers to show you here. The car is a completely stock 1987 924S with 119k that has the ability to run on stock Motronics or aftermarket Autronics. When running Autronics, the fresh air intake is retained, as is the air flow meter which is no longer used so all the restrictions are retained. The only difference is that the Autronic uses an MSD 6A to run the ignition, so it is CDI where the stock Bosch is inductive. However, since the inductive coil is retained, and the MSD products, are not the most powerful, I doubt this has much impact on the final numbers. Here are the final back-to-back runs after the EFI Advanced students tuned the car for proper AFRs and maximum torque. The car gained approximately 14% improvement over the stock system. This was done using 87 octane fuel. I don't know what the drivetrain loss of a 924 setup is, but I would guess somewhere in the 25% range. The car stock is about 140hp, and using the Dynapack peak HP number of 107 computes to about 142hp at the flywheel. If I eliminated the AFM and replaced the stock filter with a K&N style filter, I bet I would have picked up another 5-7hp. Higher octane would also have allowed for additional timing and again, a power increase. Enjoy...

Mighty Shilling

Nice! and I like your name. you rule

Chris_924s

I wonder how much more the 88 has.

Geoffrey

An 88 would have similar power improvements.

M758

The car seems low on power in stock form. 122 rwhp is fine for a box stock 924S with cat in place and zero upgrades.

Here is link to a number of 944-spec car dyno charts. Most cars come in at 130 or so rwhp. These cars have had various mods from pratically nothing to shaved heads. I dynoed my motor at 131 rwhp a couple years ago. It was a 84 block with 87 924S head and cam. Head was cleaned. It was stock except for the test pipe. Car ran with stock paper air filter and muffler. It was not uncommon.

http://members.rennlist.com/m758/944SpecDynoCharts.htm



In the 944-spec car world if you dyno at 120 or below something wrong that needs to be fixed in the car. Simply it is not at stock hp levels, it has a problem. It looks like your change either masked the problem with your motor or the parts you replaced were old and failing. That test does not conclusivly show any real gains from that those aftermarket mods.

Geoffrey

Dyno results vary from dyno-to-dyno and from day-to-day, especially when using a chassis dyno. Dynojet dynos regularly read higher than a Dyno Dynamics or Dynapack, and I'm very comfortable with this testing methodology given the many thousand of hours on all different kinds of dynos. I've gone through this engine mechanically have it has good compression and leakdown numbers, so I'm comfortable that this engine represents a good running 119k 924s engine. As to the condition of the air filter, catalytic converter, or muffler, I don't know, I haven't checked them and they could be good or bad. I believe this accurately represents what is possible going from a Motronics ECU to an aftermarket ECU. Take the 14% gain and apply it to your dyno numbers if you want. There is additional power to be gained by freeing up the exhaust, removing the AFM which is no longer necessary, and using higher octane fuel.

The dyno results were also not corrected to SAE...

MM951

Geoffrey, I live right by you

I'm building up a pretty nice motor for my Conquest (4g64/4g63 hybrid) and I'm gonna need it dyno tuned...Do you only do Porsches or would you work with others?

Looks like you got a great shop