New Porsche owner had my car dynoed yesterday and saw a huge drop in power after 4200RPM. What could cause a massive drop in power after 4200RPM, could boost leak or improper gaping cause this to occur?

 

That's actually pretty normal on our cars. Your horsepower still climbs until the end. It does look like a sharper drop than normal though on the torque though, usually it's more of a rounded drop off. Could be boost leak.

 

what mods do you have?

 

K24/18G Turbos, Upgraded Fuel Pump, Upgraded 5 Bar Map Sensor, FPR, Injectors, BMC Air Filter, Motorsport Clutch, LWFW, Diverter Valves, Headers, Modified Exhaust, Short Shifter, RWD conversion, Dyno tune by protomotive @ 550whp (15psi) on pump gas.

 

Those dips is not good at all and that is not normal seems like you have alot of knock and running really rich and timing is being retard.

Datalog it from 3rd gear 3k rpm until redline.

You only made it to 478rwhp which if this was awhp you would be in the 440awhp range.

Heres my old 16g billet dyno sheet this is the way your car should look like under load and afr around 11.8 to 12.0 this was at 1.28bar.

 

That AFR is not good at all, stop driving the car till you get it tuned.
Do a diagnostic scan also, in case some sensors have gone bad.

 

mother of **** that car is running super rich

 

Looks like a boost spike, potentially causing timing to be pulled. Did they log boost pressure on that run?

 

Seriously 5 threads dude ? Lol

 

Did not mean to post so many threads.

Could improper spark plug gapping cause these issues?

I am new to the porsche seen just got the car in oct, went to a dyno day this saturday and put it on the dyno.

Would I able to do some datalogging using a OBD Link MX and tablet?

I did notice some of the boost hoses looked pretty worn out w

Then i replaced the spark plugs and coils specifically the ones going from the turbos to the intercooler.

Will look into the 3.8 Bar Map, not to sure exactly what mods the car has just what i was told by the previous owner prior to purchase.

Thanks for all the help and input.

 

Steve Jarvis i dont think they did pull the boost at all.

 

Who tuned the car with that setup? That would be my first resource to go to.

Also, invest in a Durametric scanner for logging as any tuner will want those logs to look at.

Markski (vendor MarkskiTuning) sells a good boost leak kit as well.

 

Does the car have an aftermarket boost gauge?

If so, do a pull (on the street) in third gear and note what the spikes/peaks at and where it stabilizes.

It may simply be a boost spike, because if you take the big spike out, it looks fairly normal. Keeping in mind that this dyno was on a Mustang dyno, which may be lower than your original numbers if measured on a Dynojet.

550whp seems pretty strong for 15.5psi.

Later, Steve

 

The tune was supposedly done by TODD at protomotive.

Car does not have a boost gauge other then the factory one.

I have notice that some times on WOT it will only get too about .9 bar and some times 1.2 but majority of the time it will be at 1.0/1.1 bar of boost.

 

Planning to pull the sparks plug out this weekend and check to see if the gapping is correct not sure if the gapping would cause this many issues.