Boost leak?

The factory tune is torque targeted and will use as little boost as necessary to make that target.

If you are not setting a p0299 code, then your boost levels are matching desired.

Christopher Estrada said:

when then rpm’s are at 3500-4000, once the engine gets to 45000 i start to lose power! Has anyone else had this issue?

Click to expand...

45000 is about where my boost starts to drop off too. 🤷‍♂️

Is that your peak boost ?

Welcome to the tiny hair dryer masquerading as the stock turbo for the ST. BTW, what is your altitude, what fuel are you using, and what other mods does it have?

rob99rt said:

Welcome to the tiny hair dryer masquerading as the stock turbo for the ST. BTW, what is your altitude, what fuel are you using, and what other mods does it have?

Click to expand...

lmao tiny hair dryer!! my elevation is 550’ i only put in shells premium and it is stock

Well, it is a tiny hair dryer compared to something like a 28 or 30-series turbo, and it's much less efficient at providing a decent volume of air to the motor.

As far as Shell fuel goes, I think it was @TurboGT who stated why Shell gas doesn't typically do as well for the ST crowd... Folks have talked about getting more negative corrections with it than other fuels and I think he said their ethanol content was lower than other fuel suppliers, so if you find you're getting a higher (numerically) octane adjustment ratio (-1 is best to +1 is worst), then you may want to try another fuel supplier. Sure, they're top tier for detergents, but the higher ethanol content of other fuels typically makes for less knock.... I know... 91/93 octane rating should simply be the same for two different suppliers, but for whatever reason it doesn't work out that way for us on the ST... It's goofy...

rob99rt said:

Well, it is a tiny hair dryer compared to something like a 28 or 30-series turbo, and it's much less efficient at providing a decent volume of air to the motor.

As far as Shell fuel goes, I think it was @TurboGT who stated why Shell gas doesn't typically do as well for the ST crowd... Folks have talked about getting more negative corrections with it than other fuels and I think he said their ethanol content was lower than other fuel suppliers, so if you find you're getting a higher (numerically) octane adjustment ratio (-1 is best to +1 is worst), then you may want to try another fuel supplier. Sure, they're top tier for detergents, but the higher ethanol content of other fuels typically makes for less knock.... I know... 91/93 octane rating should simply be the same for two different suppliers, but for whatever reason it doesn't work out that way for us on the ST... It's goofy...

Click to expand...

what gas station would you recommend

I've had good luck with Exxon, and strangely enough, Kroger/King Soopers. At least around here (Denver area), Conoco is garbage, so I stay away from them.. same with Sam's club/Walmart gas... Mileage dropped like 10-15% consistently when I tried their fuel in multiple vehicles to verify the mileage drop.

Costco gas worked well if I could fill it from less than 1/4 tank, but their crazy long filling hoses and small internal holding tank at the pump guarantee you get at least 1.5 gallons of whatever the guy ahead of you filled up with, and around here that's 85 octane... While tuning the car, if I filled up at Costco, even with 8-9 gallons, he could tell on the data logs with how it wouldn't handle as much timing advance.

Well shucks that was the 1st and best example I've read about my employer's gas. Funny thing is, I've noticed different fuel suppliers for Costco gas and although I know "we" use the nation's highest % of fuel additives (well it was told to me by a former reputable Supervisor) I too have noticed that occasionally I was not getting anything more out of the gas than when I was (mostly) getting it from Smith's (Kroger owned). The few times I grabbed Shell my short stormtrooper seemed to light up but in the end I can't say I notice to much difference in power. Car runs good and my mileage is sticking to around 23.5 for city/chitty (hwy) driving. I think my lack of knowledge on defoulers is causing the lower than b4 mileage but Hey! the P0420 light is gone so until I get an AP what do I really know? Nothing!
Oh and yeah the turbo does lean out after 45-4700 rpms but at that point I'm way way over the legal speed limit so best to back off.