Amazing power at first, anemic after ~300miles w/ Dealer installed G6 in 991.1
01-19-2022, 02:47 PM
#1
Amazing power at first, anemic after ~300miles w/ Dealer installed G6 in 991.1
I recently got my 991.1 GT3 back from the dealer with warranty replacement engine after the original engine failed. I am mixing loads and RPM's while keeping it under 7K RPM's to perform a proper break-in procedure. During the first ~200 miles of driving, the car felt insanely strong through the midrange and the torque at 6K was so much of an improvement vs the old motor I was halfway wondering if they accidently stuck a 4.0L in it lol. Every part of the rev range was thick with electric-like torque, and torque modulation at different throttle positions was razor precise and linear at every combination of throttle input and revs (under 7k) the car was so engaging and alive it was like a completely different experience compared to the old motor.
A few days ago I topped off fuel (chevron 91 in SoCal) and the car continued to perform like it had. I am always very careful to limit driving aggression until the engine and oil are fully warmed up. Yesterday, after a very lazy low-throttle drive, I did a 2nd-3rd pull shifting at 7K and the car just felt... weak. Weak enough to where 2nd felt like 3rd, the torque reduction felt like 10-15% or more, and not only at higher revs. Now, when I change throttle positions the response seems less linear, shifts aren't nearly as seamless, and that thick electric torque from 3K-4K is just... gone.
Has anyone experienced similar characteristics and variability in power output? Ambient temperature and humidity have been pretty consistent, I'm using the same brand fuel, this has got me scratching my head.
My running theory is that when I got the car back, ECU adaptations were totally reset and the engine's spark mapping was likely defaulted at a fairly aggressive 93oct spark strategy, hypothetically those adaptations are fairly slow to bake-in learned knock/octane tables.... if so it would make sense that it took ~250 miles before the ECU had fully adapted to a "safer' timing and fueling strategy to accommodate CA 91oct fuel, reducing power across the rev range. What makes me doubt this theory is that the power/response change was abrupt... the prior ignition cycle the car was running with hulk strength, the next drive weaksauce :/
The other theory is that I had also washed the car myself the day before, perhaps got a bit of water down the rear cowl, wetting the air filters temporarily, perhaps trapping dirt in the (new-ish) paper filter media. I've ordered OEM 3RS washable filters to replace the paper and see if this resolves anything.
If anyone has a recommendation for a scan-tool that lets you view and reset ECU adaptations that would be awesome.
A few days ago I topped off fuel (chevron 91 in SoCal) and the car continued to perform like it had. I am always very careful to limit driving aggression until the engine and oil are fully warmed up. Yesterday, after a very lazy low-throttle drive, I did a 2nd-3rd pull shifting at 7K and the car just felt... weak. Weak enough to where 2nd felt like 3rd, the torque reduction felt like 10-15% or more, and not only at higher revs. Now, when I change throttle positions the response seems less linear, shifts aren't nearly as seamless, and that thick electric torque from 3K-4K is just... gone.
Has anyone experienced similar characteristics and variability in power output? Ambient temperature and humidity have been pretty consistent, I'm using the same brand fuel, this has got me scratching my head.
My running theory is that when I got the car back, ECU adaptations were totally reset and the engine's spark mapping was likely defaulted at a fairly aggressive 93oct spark strategy, hypothetically those adaptations are fairly slow to bake-in learned knock/octane tables.... if so it would make sense that it took ~250 miles before the ECU had fully adapted to a "safer' timing and fueling strategy to accommodate CA 91oct fuel, reducing power across the rev range. What makes me doubt this theory is that the power/response change was abrupt... the prior ignition cycle the car was running with hulk strength, the next drive weaksauce :/
The other theory is that I had also washed the car myself the day before, perhaps got a bit of water down the rear cowl, wetting the air filters temporarily, perhaps trapping dirt in the (new-ish) paper filter media. I've ordered OEM 3RS washable filters to replace the paper and see if this resolves anything.
If anyone has a recommendation for a scan-tool that lets you view and reset ECU adaptations that would be awesome.
01-19-2022, 02:54 PM
#2
RL Community Team
Rennlist Member
Rennlist Member
... or maybe you already need another engine?
01-19-2022, 03:05 PM
#3
Banned
Join Date: Jan 2013
Location: Chicagoland Area
Posts: 26,141
Likes: 0
Received 5,413 Likes
on
2,516 Posts
91 octane vs 93 octane should not matter.
Wonder if you got a bad load of fuel?
Where the coil packs re-used or new??
Wonder if you got a bad load of fuel?
Where the coil packs re-used or new??
01-19-2022, 10:39 PM
#5
What has the dealer said?
01-20-2022, 12:47 PM
#6
Rennlist Member
FWIW my car feels a lot more snappy after a trackday, especially if I've mixed a few gallons of race gas in at the track during the sessions. Nothing scientific here though. Cali 91oct is crap though.
01-20-2022, 01:19 PM
#7
SA said the ECU adaptations are most likely culprit; but normally the change is more progressive and not so abrupt. They offered to scan the ECU for any pending codes as well as reset adaptations to compare.
This makes sense, I would love to get a scan tool that would show "learned octane" values or whatever porsche calls the timing adaptations. I remember on my STI there were several coarse + fine learned knock tables that you could evaluate with tactrix cable to see how the ECU had adapted to the fuel as well as identify things like airflow sensor discrepancy etc.
This makes sense, I would love to get a scan tool that would show "learned octane" values or whatever porsche calls the timing adaptations. I remember on my STI there were several coarse + fine learned knock tables that you could evaluate with tactrix cable to see how the ECU had adapted to the fuel as well as identify things like airflow sensor discrepancy etc.
Trending Topics
01-20-2022, 01:56 PM
#8
Rennlist Member
SA said the ECU adaptations are most likely culprit; but normally the change is more progressive and not so abrupt. They offered to scan the ECU for any pending codes as well as reset adaptations to compare.
This makes sense, I would love to get a scan tool that would show "learned octane" values or whatever porsche calls the timing adaptations. I remember on my STI there were several coarse + fine learned knock tables that you could evaluate with tactrix cable to see how the ECU had adapted to the fuel as well as identify things like airflow sensor discrepancy etc.
This makes sense, I would love to get a scan tool that would show "learned octane" values or whatever porsche calls the timing adaptations. I remember on my STI there were several coarse + fine learned knock tables that you could evaluate with tactrix cable to see how the ECU had adapted to the fuel as well as identify things like airflow sensor discrepancy etc.