Joshg

Hi this is my first post here so i'll attach a pic of my car too.

My car is a 98 996 c2. The car has 49k miles and has just had a full service in the last 1000 miles.
I took the car to a dyno dynamics machine to see what power it is, the results were very disappointing. It got 225bhp at the wheels 275bhp at the flywheel
So its basically 25bhp down on a standard car.

The engine is standard apart from a k&n CAI and PSE.

Can anyone suggest anything I could check on my car to work out why its running down on power?

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chsu74

Beautiful car! Because you have an after market CAI, I would suggest cleaning your MAF sensor. I replace mine every 25 to 30K miles because I get oil on my sensors from 1st gen EVO CAI. I notice a big difference before and after. Fuel filter replacement is also recommended every 60K miles. Plugs and coil packs?

Chris996

NICE GT3 LOOK AND THE TITANIUM GT3 RIMS.

nick49

10 different dynos = 10 different results

There are no universal standards for dynos, most results I see are optimistic, some tremendously so!

If you seriously think you have a problem, have your car checked by an Indy or Porsche dealer. A quick test drive by a tech will reveal more than your dyno sheet. GL

ivangene

plugs (old wrong ones)
maf (dirty, oiled)
fuel (bad fuel)
fuel filter (dirty, clogged)
CAI (maybe worse than stock)
Dyno set up wrong?
cats (plugged)
mufflers...missing or altered
full diagnostic on cam possitions (one bank off position to the other - cam solenoid)
steering wheel on the wrong side.....

nice looking car

Optical TDI

How does one clean the MAF?

fpena944

MAF cleaning spray can be found at a local auto parts store. It's real easy to use and helps keep your MAF in best working condition.

Barn996

Your '98 C2 is certainly a looker! Can't add much to what has been suggested, but can you drive a friends C2 so you can make a seat of the pants evaluation to compare the power of each?

Barn996

When I had aCEL last year I cleaned my MAF and it cleared the CEL, but only temporarily. A new replacement solved the problem for me. There is a tamper proof torx tool you'll need, other than that it is very easy to do and might be worth your effort. Do a search and you'll get all the specifics.

jumper5836

A friend of mine with a 3.4 did timed running pulls with ca on and off. He found it was slower with the ca installed.

Divot

There's an easy DIY fix for that.

Joshg

Thanks for the suggestions keep the coming!

Car had major 48k service at Porsche 1000 miles ago.

plugs (old wrong ones) just replaced at 48k major service
maf (dirty, oiled) Has had a new MAF in the last 500 miles !
fuel (bad fuel) Always ran on uk 99 ron fuel basically the best stuff we can get here.
fuel filter (dirty, clogged) just replaced at 48k major service
CAI (maybe worse than stock) Maybe but I thought it was supposed to add power? I will try car with stock setup back on.
Dyno set up wrong? Other cars on that day were getting good results, Ive heard dyno dynamics is the most reliable and accurate dyno around?
cats (plugged) Not sure what how I could check this?
mufflers...missing or altered standard exhaust/headers with PSE mufflers
full diagnostic on cam possitions (one bank off position to the other - cam solenoid) Would I take it to Porsche to check this out?
steering wheel on the wrong side.....

Also coil packs would have been changed at the 48k mile service I think.

Because my car is a 98 it has a cable throttle so I have checked to see if it was stretched and not opening the throttle valve fully but it looked ok.

Quadcammer

not really. Butt dynos are hideously unreliable. A tech might be able to detect a problem with how the car runs, but its rare for someone to notice 10-15 hp missing.

dynos are only are reliable as the information inputted into them. I believe a dyno dynamics is a load bearing dyno, and you need to input the weight of the vehicle. If you get that wrong, it can sway the results. They also tend to show lower results than a dyno jet.

Barn996

You don't think you'd notice a 25hp reduction as stated by the OP? I do.

Flat6 Innovations

How did you attain the flywheel numbers? Were they derived from the RWHP values? Few people have an M96 engine dyno (we do! :-)

A normal 3.4 996 makes 240RWHP on my dynojet over and over again..