Mark Anderson

$$$$ reward for any information leading to the recovery of my missing HP. Any some of you know I have been in the process of rebuilding my 928 race car engine. After going to the dyno today we are missing 67 flywheel hp. My car ships Monday morning for Road America and I'd love to have it back. I have done the following:
Compression test- all at 215
tested knock sensors
tested hall sensor
tested throttle posiiton switch
I'm running out of ideas.

Giovanni

Maybe one injector is not firing. Cut the harness open and see if you can find any broken wire(s).

shaaark89

are your cams timed correctly?

Richard S

Amsoil?

worf928

Throttle switch WOT activation at LH and EZK?

Other possible culprits according to the LH/EZK diag manual:
final stage ignition amplifiers
MAS
fuel pressure, pump power supply, LH power supply
intake leaks - you're still running the funky CF intake right?
and the most bizarre: the tank vent system (assuming its still there?)
and of course - grounds

AO

WHen was the last time/ever you had the injectors cleaned?

Daniel Dudley

Fuel pressure/volume.

Bill Ball

What was the A/F? If off-target, replace MAF.

Is this a newly rebuilt motor?

Mike Frye

It's still there, I bet it's a dyno correction error.

Black Sea RD

You have access to the best minds in our 928 world right there in your backyard and the engine was rebuilt by the best. I would think your engine is probably doing alright and the statement below may not be that far off.

What does you ***-O-Meter say? It must be a finely tuned instrument by now.

Good luck at the races,
Constantine

Mark Anderson

No flappy in system

Mark Anderson

I did not build the motor but the compression test indicates that they are at least the same left to right.

Mark Anderson

I will swap out the final stages
Yes still Carbon intake
yes it does have some leaks but it alwys did and still made good hp
The tank vent is not hooked up buit never was
I will double check the grounds

Mark Anderson

I have not tried the sharktuner as I lent it out and need to get it back.

Mark Anderson

Motor is brand new and air fuel was reasonable. the missing hp is across the board as well as the missing torque. the air fuel is simialr to previous dynos.