2.7 horsepower?

[haycait911]

I have a '73 t with a 2.7 rebuilt in 1985. build reciept indicates 2.7 pistons and nikasil cylinders, indeterminate cam grind, machine work to case[ inserts I'm assuming]. has webers, k&n's, pertronix, original distributor[ no vaccuum advance ], timing set to 4 degrees btdc. had the car dyno'd yesterday. numbers came in at 155 ft/lbs at 4250 rpm and 145 hp at 5500 rpm, at the rear wheels. both curves fairly flat. compression is 170 psi across all cylinders[ within 3 psi] and leakdown is less than 3 % acrooss the board. my questions are thus;

1] does anyone know approx crankshaft hp and torque based on these #'s. or, what percentage is lost in the drivetrain?

2] are these reasonable numbers for this engine? I'm quite pleased with the results but should I be getting more? am I missing something tuning - wise?

the motor pulls very well from 2000 rpm on up , not peaky at all, very good seat of the pants low-end grunt.

any thoughts / suggestions / input would be much appreciated, thanks, Don.

[GrantG]

Pretty car! Usually, people figure a 15% drivetrain loss with a 911, although dynos are notoriously inaccurate (better for relative measurements than absolute).

[haycait911]

thanks for that Grant ! I was figuring more like 25% power loss but then a 911 HAS to be more efficient than some chunk of american iron. Don.

[450knotOffice]

Yea. 15% seems to be the accepted number for the 911. I'd say you have about 165 HP or so, maybe a couple more.

Beautiful car, btw. I really like it.

[Fishcop]

The 2.7 RS Carrera is rated at 210hp. The engine as from the factory was basically 8.5:1 compression, S cam grind, 38mm ports, specific MFI, and timed at about 36 degrees total. With drive train losses, one can expect between 175hp and 180hp at the rear wheels.

I built my 2.7 CIS engine to RS specs and use webers rather than MFI and get 165hp at the rear wheels which is about right with the carbies. My guess would be that your car has been built to the same specs, but maybe using an E cam (which is what Bruce Anderson recommends and prefers). It has been well documented that there is a great discrepency between dynos, and this might explain differences as well.

Great looking car

[haycait911]

thanks guys! and thanks for the compliments on the car, it's not exactly " correct " but reflects my taste, I like a clean look. Don.