Andial951

I wish I lived in AZ..............

lart951

Your car wont be a fair match for luis's 418rwhp and 275rwtq Gt3 , we need a 2.5L.

Andial951

awwwww......cmon

lart951

Okay, you can race him but you have to be fair and remove one spark plug out of your engine.

Andial951

RPHARRIS

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.

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).

Markus951

Hey Guys!

Here is my promised timeslip!

Markus

LuisGT3

My car makes 372 rwhp.

A.Wayne

It's a fake. it says 1991 944T and we would never take a timeslip from a Trei .

95ONE

Excellent explanation. Makes perfect sense. Clearly FEELs like that's what it is doing.

Markus951

Well, it is as fake as my car witch really don't excist but witch is a really good job with photoshop

95ONE

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.

blown 944

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

eclou

Damn Bruce, that was awesome, especially with the temps in the 90F+ range. A little quicker RT and you would have clipped the 11's