North East SSoM Members!!!

Striped5.0 said:
I saw that black lambo again today while going into windham ( same one that was at the show on sunday) Dayum that thing sounds so good.


I looked up some specs on the Lambo.. MSRP is around $170,000, less than I though. The engine has 500hp and 376tq. Does the 1/4 in 12.2 at 122. So I would bet Mike's car and mine for that matter could give it a run. The car has les power than I thought. The guy driving it, said it had 630HP..LOL ya right.. Still a sweet car.
 
whitehorseupnorth said:
I looked up some specs on the Lambo.. MSRP is around $170,000, less than I though. The engine has 500hp and 376tq. Does the 1/4 in 12.2 at 122. So I would bet Mike's car and mine for that matter could give it a run. The car has les power than I thought. The guy driving it, said it had 630HP..LOL ya right.. Still a sweet car.
and what about me and Bryan??
 
Well, I think I have figured out why my car has been trapping so low in the 1/4. I am gettin a "hesitation" between shifts that has seemingly been a problem for a lot of modded 03/04 Cobra guys. Looks like some of the fuel tables have to be reset, so hopefully James can get that done for me soon. Here is a post from SVT Performance;


James and I have been working together trying to eliminate a lean tip-in condition in my car. This condition results in the same after shift hesitation that is described in this thread. The static Min TP for open loop (MinTPOL) function set to 500 counts is the culprit of the hesitation. The hesitation was caused by an excessive delay going from closed loop to open loop after a shift.

Here is the scenario. After a shift when throttle is applied, the Stabilized Open Loop Fuel (SOLF) table is traced from the bottom of the table upwards and to the right until the MinTPOL for a given RPM is acheived. Until the TP_Rel value exceeded the MinTPOL threshold for a given RPM the car is in closed loop mode trying to remain stoich. With the static MinTPOL function, only when the TP_Rel reached 500 did the PCM go open loop and add the fuel commanded in the SOLF table needed to make power.


During the period after the shift and until the MinTPOL was acheived, my A/F would go lean. This is when the hesitation would occur.

To fix this hesitation, we changed the MinTPOL function from a static function to a sloped function. We used the stock YDH1 MinTPOL function that had 500 counts to start, dropping to 400 counts at 2000 rpom, dropping to 250 counts at 3000 RPM, dropping to 200 counts at 4000 RPM, and dropping to 150 counts above 6000 RPM. This sloped MinTPOL function significanly reduced the latency between post shift throttle application and acheiving open loop. This effectively eliminating the hesitation. My A/F response after a shift is much more crisp now. After the shift my A/F goes right back to power mode (12:1) and doesn't go lean at all.

My belief is that the static MinTPOL function was done by Ford in the 04's to better MPG and avoid the guzzler tax. It was also done in the '03 Stall Flash Calibration (HSF0) and the non-service released (AMZ2). That might be well and good for stock boost cars. But when you add boost, you will be negatively impacted by the static function. I know I was.

JMHO.

Here is a representation of my SOLF table. The light blue is open loop above the MinTPOL. The rose colored area is below MinTPOL and is therfore never referenced for open loop fueling. The Yellow is approximately when open loop will kick in for a given RPM and TP_Rel given my MinTPOL function. (All A/F tuning was done via tweaks to the MAF transfer function).

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A further explanation from James of RWTD;

Actually, fueling in the Cobras does not work off of Load. It works off of TP_Rel (throttle position). The Y-Axis label in your software is correct. On other Ford vehicles it does work off of load (Lightnings, some Mustangs, etc.).

Everyone, the issue in question is actually a few different issues that can be traced back to several areas: the returnless fuel system, PIP parameters (you can do some searches under my username and the term "PIP" to read about what I'm referring to), integral clock windup, TP to enable Open Loop, fuel transition, etc. There's a tip-in hesitation on the Cobra that comes into play above a certain rpm range once airflow is increased drastically due to aftermarket mods, etc., there is the high rpm shifting stumble, and then there is the hesitation after the shift due to throttle position and fueling. So, as you can see, there's a few entirely different situations that some equate to the same thing, when in fact they are not all related (mostly).