Production and HP

[Marc Woontner]

1. Can anyone tell me how many 1957 1600 super cabriolets we’re built?

2. How much HP is lost in the transmission hooked up to a 62 S90?

[Ron LaDow]

2. How much HP is lost in the transmission hooked up to a 62 S90?

Whatever guess you get is nothing other than a guess, unless the same engine was then put on an engine dyno and the two numbers were compared. Power loss across a transmission is not a constant.
To what are you comparing the engine?

[Marc Woontner]

After a fresh rebuild my S90 dyno’d at 82 hp. I’m trying to see how it compared with a top running stock S90

[C J Murray]

Was the dyno a chassis dyno or an engine dyno? When you ask about transmissions I assume the engine was in a car on a chassis dyno. What brand of dyno is it? They vary. DynoJet is the brand I have worked with and they give results on stock modern cars that are fairly in line with the car company numbers. DynoJet is also very consistent from location to location so they are generally trustworthy. No matter what dyno is used the dyno operator can fake the numbers if they have a profit motive to do so.

When Ron says the answer is a guess he is right but I can tell you a number that has been consistently very close to dead on when testing an engine on a DynoJet chassis dyno, 15%. To get your crankshaft HP take your 82HP/.85 to get 96.5 HP.

[Bruce Smith]

The April '64 issue of Panorama published an article on drag vs. HP for various sports cars of the time. Porsche came out on top. No surprise as the 0.32 drag coefficient of a 356 is just slightly higher that the 0.31 coefficient of a new 911-991. The conversion factor used in the article for engine BHP to the wheels was 0.90, but that was the same assumption used across the board for all cars evaluated. More HP is lost to drag and tires than to the drive train, things that a standard chassis dyno doesn't fully measure. The table below shows the comparisons. I've attached the entire article as well.

[Marc Woontner]

I’m not sure of the name but it was bolted up to the rear wheels using adapters to go from wide 5 to modern 911 bolt pattern.

[C J Murray]

I’m not sure of the name but it was bolted up to the rear wheels using adapters to go from wide 5 to modern 911 bolt pattern.

That is not a DynoJet.