I have my STI tuned for 3" tbe and fmic with ecutek and now the first and 2nd gear hits about 15lb of boost and 3&4&5 gear hits 17.5lb , but my 6th gear is hitting 20lb and it spikes, looks like it wants to stay at 20lb but keep dropping back so i'm wondering if this is normal or am i goign to need a boost controller or something to play with the boost ????

also i have a question about tunning which is that when u are on dyno tunning, usually tune in 4th or 5th which 5th is closer to 1:1 ratio on STI, but since it's only tune in a single gear, so does the setting all the same for first through last gear ?? A/F, timing ..etc??? feels like it's different cuz the boost is hitting at different lvl ?? :confused: :confused: :confused:

I only have mine tuned at 18.5psi and it hold all the way to redline.

Your tuner didn't tune it properly. They are ragging out the boost maps to get you more torque down low. When you do this with the stock VF39 you will run into boost creep. Where are you located? Which tuner did you use? Take it back for a street tune from the same place if you trust them. Boost creep is not easily duplicatable on a dyno. Driveability issues (which is what this is) are corrected with a street tune or by using a much better dyno... i.e. a Dyno Dynamics dyno.

This has nothing to do with boost creep. Boost creep occures when no matter how hard the ECU tries to lower boost using the solenoid, boost continues to rise. This generally happens because of poor wastegate flow.

The problem NewSTI is describing is just a mistake in the wastegate duty cycle maps. The STI ECU has two of these, a high and a low. It sounds like the tuner left a little too much headroom in the high map for heavy loading such as you see in 6th gear. Contact the tuner and he should be able to fix it.

Thanks
-- Ed

but my 6th gear is hitting 20lb and it spikes, looks like it wants to stay at 20lb but keep dropping back

Hummm, looks like boost creep to me. Anytime boost goes beyond the setpoint of max it's boost creep/spiking. Same thing. It's the tune, I had a friend that got tuned at Top Speed and he had this issue on his STI w/APS TBE. Prior to the dyno tune there it was not having issues (was running a Stage 2 map from Dynocomp). He ended up going back and was sold on the whole (the VF39 will always boost creep on any STI with a turboback)<- total BS... now he's the proud owner of an FPGreen. While he did want to upgrade to that anyway, it's just funny to me how they all of a sudden took extra long to make sure this tune was perfect... I would too if someone just bought a new turbo and injectors/pump/install time from me. The first tune took all of 4 pulls. :rolleyes:

Regardless, take it back and point out the issues to the tuner. There is no reason why your car should be doing this... it's a tuning factor.

See this is where you're not getting it. Boost creep is not the same thing as spiking. Spiking occures when the duty cycle map is off. Boost creep occures when the ECU has absolutely no power over boost. As you can see from the original post, the ECU does have power to drop boost since every time it hits 20psi, it'll start to bounce up/down. This is simply spiking and can be fixed by tuning. True boost creep by deffinition cannot be fixed by tuning.

-- Ed

See this is where you're not getting it. Boost creep is not the same thing as spiking. Spiking occures when the duty cycle map is off. Boost creep occures when the ECU has absolutely no power over boost. As you can see from the original post, the ECU does have power to drop boost since every time it hits 20psi, it'll start to bounce up/down. This is simply spiking and can be fixed by tuning. True boost creep by deffinition cannot be fixed by tuning.

-- Ed


yah as you said, i'm pretty sure it's not the boost creep that ppl are talking about on STIs, i hit boost creep b4 i port my wastegate..

anyway, so besides a retune which it's going to lower the boost and less hp, do u guys think it's a good idea to get a boost controller or something ???

This won't require a re-tune, just a minor adjustment to the high wastegate duty cycle map. It should NOT lower overall boost or power but may make boost response slightly slower but nothing significant. A boost controller is not required or recommended. The STI's boost control system is actually very powerful and exceeds most aftermarket boost controllers. It just has to be tuned propperly.

Thanks
-- Ed

excellent question, wonderful lucid info, got this from a google of 'wastegate duty cycle maps'

bravo

can you say max waste gate duty map?
reflash and road check..