Disapointing Dyno Test
02-08-2008, 12:59 PM
#17
Banned
I think (IIRC) that my S2000 and M3 had ~15% drivetrain loss. I mean the whole thing about dynoing is that it's not a perfect science especially the way us hobbyists are doing it on discounted dyno days at your local dyno shop watering hole.
I would've figured the Carrera 2s had less than 15% on avg. Curious to know what the approximations are between the 2s and the 4s.
I would've figured the Carrera 2s had less than 15% on avg. Curious to know what the approximations are between the 2s and the 4s.
02-08-2008, 01:16 PM
#19
Race Car
02-08-2008, 01:27 PM
#20
Rennlist Member
I'm not trying to pour salt on the wound, but my '95 993 with a chip pulled the same numbers, and I thought at the time it was somewhat low. I would have expected the early 996's to be in the 260s.
02-08-2008, 01:53 PM
#21
Race Car
02-08-2008, 02:00 PM
#22
Race Car
When I had my intake off, if we are talking about the same thing, only had a vacuum hose going to it. I dont remember an electric plug.
The big butterfly valve inside the plenum right?
The one that the vacuum hose comes from the "T" off of the brake booster port?
02-08-2008, 02:34 PM
#23
Rennlist Member
My 964 dyno flattens our at 5500, but just for and instant, then gains again. It does not go down, however. I've never seen one that did that, not normally anyway.
If I knew how to compress the file, I'd show it to you
If I knew how to compress the file, I'd show it to you
02-08-2008, 02:42 PM
#24
Was the rear engine cover open? I got similar results with mine open (although my curve was smoother). I read a few threads suggesting that it's necessary for the cover to be closed in order for the engine to reach full power. Apparently it's some kind of engine management "feature".
02-08-2008, 03:15 PM
#27
Race Car
The butterfly valve (tuning flap) in the back crossover tube is controlled by the electric changeover valve (sits right above alternater) which recieves it's vacuum supply from a reserve canister on top of the engine. There is no interface with the brake booster port.
The tuning flap is normally open and operates as follows:
Open from 700 to 3120 rpm and from 5120 rpm .
Closed from 3120 to 5120 rpm , if the throttle is also more than 30 % open at the same time.
02-08-2008, 04:13 PM
#29
Race Car
The butterfly valve (tuning flap) in the back crossover tube is controlled by the electric changeover valve (sits right above alternater) which recieves it's vacuum supply from a reserve canister on top of the engine. There is no interface with the brake booster port.
The tuning flap is normally open and operates as follows:
Open from 700 to 3120 rpm and from 5120 rpm .
Closed from 3120 to 5120 rpm , if the throttle is also more than 30 % open at the same time.
The tuning flap is normally open and operates as follows:
Open from 700 to 3120 rpm and from 5120 rpm .
Closed from 3120 to 5120 rpm , if the throttle is also more than 30 % open at the same time.
I remember snapping the plastic line that leads to the resonance valve coming from the rear port on the drivers side bank intake plenum where it was "T'ed" to.
02-08-2008, 04:24 PM
#30
Instructor
Good point. Autos have more drivetrain loss, same as awd. You could also have an ailing tq converter perhaps. I'm not a fan of Dynojets. I would try to get it dyno'd on a proper dyno (Mustang) and do at least 3 pulls to have any real idea of your baseline. Where was this done? What were the conditions and how many pulls did you do?
Andrew
Andrew