Stock boost pressure question

[Brettnrs423]

Hi all,

I already have a thread in the troubleshooting forum but can someone please tell me what the stock boost curve for a 2013 Ford Taurus sho should look like? My car is making about 8 psi to 4000 rpm and then boost increases to roughly 11 psi all the way to redline. If this is correct then I guess my car doesn't have a problem. It just seems odd to me that ford would limit boost more in the midrange and then ramp it up at higher rpm. This implies that there is a lot of power to still be had in the mid rpm range and is atypical for how most turbo cars are tuned. Most cars make the highest boost in the mid rpms and then taper off at high rpms to maximize torque in the midrange and take advantage of peak efficiency for the turbocharger. I am feeling a surge of power around 4k rpms which originally led me to think that there was a problem with the car but othwrwise the car is running great and has thrown no cels. Thanks.

-Brett

 

[FoMoCoSHO]

Hi all,

I already have a thread in the troubleshooting forum but can someone please tell me what the stock boost curve for a 2013 Ford Taurus sho should look like? My car is making about 8 psi to 4000 rpm and then boost increases to roughly 11 psi all the way to redline. If this is correct then I guess my car doesn't have a problem. It just seems odd to me that ford would limit boost more in the midrange and then ramp it up at higher rpm. This implies that there is a lot of power to still be had in the mid rpm range and is atypical for how most turbo cars are tuned. Most cars make the highest boost in the mid rpms and then taper off at high rpms to maximize torque in the midrange and take advantage of peak efficiency for the turbocharger. I am feeling a surge of power around 4k rpms which originally led me to think that there was a problem with the car but othwrwise the car is running great and has thrown no cels. Thanks.

-Brett

Sounds normal, you will never see a flat boost line because these ecm's are torque and load based, so boost will fluctuate depending on operating and environmental conditions.

For example on a really cold day when the air is dense, you may see lower boost because you don't need as much to hit your torque target.

 

[ajpturbo]

Here is a datalog for a dyno pull that is stock except for my downpipes and CAI but commanded boost and everything in tune is stock so you can see the boost curve

In the pic of a datalog the smooth line is rpm, the jagged one is throttle angle you can see it's fully open very little in the pull....ANd the other jagged line is desired TIP or boost..and it peaks at 179 kpa and it does infact taper near redline....Edit, orange line is throttle angle actual, blue is desired boost

Fomo is correct....You don't need the boost in the midrange to hit the desired torque that the ECU is commanding because this engine is most efficient from about 2500-4000....It's a low end and midrange monster if tuned properly

 

[ajpturbo]

By comparison here is what a well tuned AJP boost curve should look like with special boost regulator to be revealed in the near future.

Orange is throttle angle actual, green is boost level and rpm line also shown....A multi gear pull and a 3rd gear sweep.

Notice very little boost spike with throttle 100% open

 

[sholxgt]

with special boost regulator to be revealed in the near future.

Interest peaked!