Question for you 3.4L 911 owners--any OBDll track data?
12-26-2013, 12:08 PM
#1
Question for you 3.4L 911 owners--any OBDll track data?
There was a post on Planet 9--Cayman club--regarding a guy trying trying to mod his 981S intake to gain some additional HP.
http://www.planet-9.com/981-cayman-b...mparisons.html
During the process--which included different intake parts and dyno pulls-- it became clear that the promised HP bump was not happening.
One interesting discovery was that at speeds under 4k the 3.4L in the 981S provides about 90% of FT (full throttle) during an acceleration run. Above 4K, the data shows that the % of FT begins to close as the revs increase to the point at roughly 6K the throttle is at roughly 55% .
To the poster this has raised some questions about the ability of aftermarket parts to add HP without cracking the ECU "code" to change to allow more throttle opening at speed.
I have downloaded engine data via the OBD reader which included throttle position and seen virtually the same data on my car (stock) with the same motor: while in sport mode, giving it full throttle below 4K I get an indicated 90-100% of throttle; above that speed I get less--like 55% going down the back straight at VIR with my foot firmly planted to the floor.
One of the speculations on this data is that this 3.4L motor has been detuned in the 981 platform (vs. the 991) and this is Porsche's way of maintaining the 911 superior HP #'s in the same basic motor.
Pursuing that thought, I'd be interested in knowing if any 991 3.4L owners have collected engine data on the track that might show engine speed and throttle position from an OBD reader?
thanks for any response on this matter in advance.
http://www.planet-9.com/981-cayman-b...mparisons.html
During the process--which included different intake parts and dyno pulls-- it became clear that the promised HP bump was not happening.
One interesting discovery was that at speeds under 4k the 3.4L in the 981S provides about 90% of FT (full throttle) during an acceleration run. Above 4K, the data shows that the % of FT begins to close as the revs increase to the point at roughly 6K the throttle is at roughly 55% .
To the poster this has raised some questions about the ability of aftermarket parts to add HP without cracking the ECU "code" to change to allow more throttle opening at speed.
I have downloaded engine data via the OBD reader which included throttle position and seen virtually the same data on my car (stock) with the same motor: while in sport mode, giving it full throttle below 4K I get an indicated 90-100% of throttle; above that speed I get less--like 55% going down the back straight at VIR with my foot firmly planted to the floor.
One of the speculations on this data is that this 3.4L motor has been detuned in the 981 platform (vs. the 991) and this is Porsche's way of maintaining the 911 superior HP #'s in the same basic motor.
Pursuing that thought, I'd be interested in knowing if any 991 3.4L owners have collected engine data on the track that might show engine speed and throttle position from an OBD reader?
thanks for any response on this matter in advance.
