Jump to content

Boost Spike


Recommended Posts

Hi there,

I have been datalogging my  Nov 06 Territory Ghia turbo (late BF bottom end) which has a HDI front cooler, airbox and battery relocation, hi flow cat, PULSAR GTX3582,PULSAR 50mm External Wastegate along with the Bosch  Bosch EV1 42lb 0280155968 injectors & ZF transmission. At present i can not confirm fuel pump or valve springs, car came with a manual bleed valve. i have removed and reinstalled the factory boost solenoid instead.


I have licensed the car with PCMTEC to allow me to gain access to the tune..i have flashed the PCM with HACH4K6, originally was a HACH3CA. I have copied over variant parameters from the the F6X (HACH4A5) to help with transmission shifting, i have modified the original values as it seemed a SCT flash tuner or Capa tune was loaded prior. This was evident due to torque control features where all turned off. i have adjusted the parameters to what values I'm aware of and re-enabled torque control along with knock sensor to be enabled.

Looking at the log, i noticed there is a spike in boost when the transmission seems to shift. I noticed the total spark drops to 1.3 degree, could this be the cause of the boost spike during gear change? My aim  to have 14- 15 psi at all times to keep the motor safe.

This is one of my concerns, can someone share a pointers on what can cause this erratic boost spike during transmission shift.

i have attached the LOG file and TEC file to assist if anything else stands out

I only have PCMTEC professional so I will not have access to the entire logging value capabilities at this present moment. 


Thanks in advance


3.TT-HACH4K6-4-05-22-4-22.tec 30-04-2022 12-59-59 PM Log.teclog

Link to comment
Share on other sites

Boost spike on gear shift is common due to the extra torque requiring more torque truncation and the 1deg of spark effectively acting like anti lag. 

The fg has a wastegate DC offset during gear shift to help with this. The bf does not. The late model f6 bf may however. 

Look in the fg boost control thread for the parameter name and see if you can find something similar in yours. 

Alternatively you could lower the torque truncation at that load/rpm cell in the ZF trans trunc tables to reduce the spark retard amount. 

When I'm on a pc I'll find you the param names. 

Also a boost spike with only 1deg of timing probably isn't the end of the world as long as it doesn't induce knock when coming out of the shift. 

Link to comment
Share on other sites

  • 3 weeks later...

Hi Roland,

Thanks for the reply, i couldn't locate such values, but looking at log no knock appears when in gear shift and coming out of shift to next gear. i may just be overlooking log's. i will accept this as being a phenomenon 🙂

What I do notice at times; I get  DTC  -Turbocharger Boost Sensor A Circuit Range/Performance error appear randomly, doesn't collate to weather or outdoor temps.

I clear the error and all good, and will appear at times. under heavy throttle or spooling up. Can you run your eye over the tec file to see if anything stands out? If not i may change the boost sensor as that's all i can think being intermittent. ** do note the sensor is not in its factory location and it mounted on a machined block of aluminum which of course has air pressure reference.

Thank you in advance.



Edited by abs351
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Unfortunately, your content contains terms that we do not allow. Please edit your content to remove the highlighted words below.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...