1/4 Timeslips. Best 10 on the list? --Video
#151
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Originally Posted by lart951
Hold on, you have owned a 944 as in 944 turbo?
There are some guys that own 944 turbos in Az post the challenge on the forum.
There are some guys that own 944 turbos in Az post the challenge on the forum.
#152
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Originally Posted by Andial951
I wish I lived in AZ..............
#154
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Originally Posted by Andial951
awwwww......cmon
#156
It's not that complicated why the 944 turbo is weaker off the line than the NA, however it isn't as simple as the final drive difference.
If you've ever seen a 944 turbo DME ignition map, this will make perfect sense to you, otherwise just try your best to follow. The 944 turbo's ignition advance is based almost entirely on a table with RPM on one axis and throttle position on the other. There is also a separate WOT table that simple gives an advance value every 500 or so RPM starting at around idle.
Now at WOT at 1000 RPM to around 1500 RPM, regardless of throttle position and gear, the car will never see any boost. And at WOT between 3500 RPM and 6500 RPM with the stock turbo, the engine will be close to max boost 90% of the time. Naturally, choosing appropriate advance values for these ends of the table is relatively straight forward.
Things get a bit trickier when you're at WOT between 1800RPM and 3500RPM. If you're accelerating in first gear there may be no boost whatsoever in this area depending on the rpm at which you opened the throttle. On the other hand, if you roll onto the gas in 5th gear at less than 50mph you may see full boost in this zone. The 951's ECU is unable to recognize any difference between these two scenarios. Obviously the optimal advance for the first scenario is greater than for the second. However the consequences of running too much timing on boost are far greater than running detuned off boost.
As far as I know, there is no way to tune around this characteristic of the 951's ecu. You can tweak the exact values in the WOT table, however the low to midrange values will always be a compromise. This was one reason I chose to go standalone. I'll be honest though, the difference is not huge, but having a more versatile timing map makes a noticeable improvement in off-the-line performance. It feels like a genuine 2.5 liter engine off boost whereas it used to feel slower than my 115hp civic. You're a lot less impatient to hit the boost because its gets their faster and its already pulling anyway.
If you've ever seen a 944 turbo DME ignition map, this will make perfect sense to you, otherwise just try your best to follow. The 944 turbo's ignition advance is based almost entirely on a table with RPM on one axis and throttle position on the other. There is also a separate WOT table that simple gives an advance value every 500 or so RPM starting at around idle.
Now at WOT at 1000 RPM to around 1500 RPM, regardless of throttle position and gear, the car will never see any boost. And at WOT between 3500 RPM and 6500 RPM with the stock turbo, the engine will be close to max boost 90% of the time. Naturally, choosing appropriate advance values for these ends of the table is relatively straight forward.
Things get a bit trickier when you're at WOT between 1800RPM and 3500RPM. If you're accelerating in first gear there may be no boost whatsoever in this area depending on the rpm at which you opened the throttle. On the other hand, if you roll onto the gas in 5th gear at less than 50mph you may see full boost in this zone. The 951's ECU is unable to recognize any difference between these two scenarios. Obviously the optimal advance for the first scenario is greater than for the second. However the consequences of running too much timing on boost are far greater than running detuned off boost.
As far as I know, there is no way to tune around this characteristic of the 951's ecu. You can tweak the exact values in the WOT table, however the low to midrange values will always be a compromise. This was one reason I chose to go standalone. I'll be honest though, the difference is not huge, but having a more versatile timing map makes a noticeable improvement in off-the-line performance. It feels like a genuine 2.5 liter engine off boost whereas it used to feel slower than my 115hp civic. You're a lot less impatient to hit the boost because its gets their faster and its already pulling anyway.
#157
To clarify my point, in my actual timing map I see as much as a 10-15 degree difference between two cells on the same RPM column that both see use under WOT depending on if and how much boost is present. An NA would use the greater value whereas the turbo would use the lesser one. That difference combined with the compression difference is why the 944 feels torquey and the 951 feels laggy and sluggish (Jeckell and Hyde as some people call it).
#160
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Originally Posted by Markus951
Hey Guys!
Here is my promised timeslip!
Markus
Here is my promised timeslip!
Markus
It's a fake. it says 1991 944T and we would never take a timeslip from a Trei .
#161
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Originally Posted by RPHARRIS
To clarify my point, in my actual timing map I see as much as a 10-15 degree difference between two cells on the same RPM column that both see use under WOT depending on if and how much boost is present. An NA would use the greater value whereas the turbo would use the lesser one. That difference combined with the compression difference is why the 944 feels torquey and the 951 feels laggy and sluggish (Jeckell and Hyde as some people call it).
#162
Well, it is as fake as my car witch really don't excist but witch is a really good job with photoshop
It's a fake. it says 1991 944T and we would never take a timeslip from a Trei .
#163
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Damn. I can't beleive how close that was. I beat you by 2/1000 of a second. I truly should have had elevens. I can't give more excuses though than that. List is now updated with Markus, Myself, and Tool.
Last edited by 95ONE; 01-31-2008 at 08:13 PM.
#164
Race Car
Very Good job
I will be going up next weds to see where I rank
I am expecting very low 12's as well we'll see. Thsi elevation may pose a problem but I am getting and holding good boost.
I will elaborate on my setup once I turn in a good number, but as of now it is running pretty darn good. I am going to leave it full interior with AC too
I will be going up next weds to see where I rank
I am expecting very low 12's as well we'll see. Thsi elevation may pose a problem but I am getting and holding good boost.
I will elaborate on my setup once I turn in a good number, but as of now it is running pretty darn good. I am going to leave it full interior with AC too