Boost Question

[WickedSHO]

Hey all....Today is my learning day I hope.

When it comes to turbo cars, I don't know much, just the basis of how they work and make power. So I need some knowledge from those on here that know better then me.

I was running the Torque app this morning on my way to work, and I noticed that at idle, I hade a negative boost reading, normal I guess since there is no load on the tubros, and they aren't spooling. But when I get on the gas, and I hear the turbos spooling, the number was still negative. It wasn't until I was WOT that I finally saw positive boost mubers. Normal?

Also, I saw a pick boost number of 10.6, is that normal?

 

[ShoBoat]

I am guessing you are not tuned? you should see some boost under load after about 1/2 throttle. Not just at WOT, our cars are setup to make boost when they need it, so yes no boost at idle and at light throttle under load. I can drive around and keep it in vacuum if I try. 10-11 is normal for non tuned.

 

[Brucelinc]

I presume you are still stock.  If so, the maximum boost of 10.6 sounds correct.  The negative boost (vacuum) is dependent upon engine load and RPM.  At idle, you will probably see around 21 in park.  The more load you put on the engine, the lower it will go - until the load is great enough for the turbos to begin showing boost.

Keep in mind the turbos are always spinning - not sure how you would hear them - but they are.  The "boost" is bled off until the engine load is enough for the boost to be needed.  You shouldn't need WOT to have boost show on the gauge, though.  Just a fairly significant load should do it.  Having said that, you should be able to accelerate fairly briskly and never have boost. 

 

[WickedSHO]

Only mod I have so far is a K&N CAI.

 

[Brucelinc]

Like ShoBoat and I said, you shouldn't need WOT for boost - more like 1/2 throttle or maybe even less under load.  Otherwise, what you describe sounds normal.  Also as ShoBoat indicated, it is possible to drive around and maintain vacuum if you keep your foot out of it.  That is the ECO part of Ecoboost. 

 

[WickedSHO]

Thanks guys....I appreciate you taking the time to explain this to me.

Once I get the LMS tunes....What kind of boost numbers can I expect? If you know?

 

[Brucelinc]

Under WOT, I see high 13s beginning at low RPM and continuing to the shift point.  I use an Aeroforce gauge. 

 

[wasinger3000]

Most of the time I barely crest 1-2 psi on normal driving. It's only when you really get after it when you see 15+.

 

[SHOnUup]

Was seeing 13.7 under wot today with 3 bar tune.

 

[Larrylu]

Highest I've recorded so far using Torque with the 3 BAR tune is 13.8.

 

[SHOnUup]

Highest I've recorded so far using Torque with the 3 BAR tune is 13.8.

This statement comforts me, being at 13.7

 

[panther427]

You will see it higher as it gets colder

 

[Larrylu]

I have found that my highest boost numbers come when I've got the most heat soak. I have rationalized that it's because computer knows that more boost will be needed to get the power from the less dense air. Don't know if I'm right.... But seems to make sense to me.

 

[staged_sho]

For what it's worth, I use Dash Command, really prefer their dashboard feature and hit 15psi when taking a reading off my phone and 16 off my tablet on the 4+x tune.  Max readings are recorded as integers on the stats page though (third tab on the dashboard).

 

[Brucelinc]

Highest I've recorded so far using Torque with the 3 BAR tune is 13.8.

This statement comforts me, being at 13.7

Mine is in exactly that range, too.

 

[FoMoCoSHO]

I've seen high 14's in Torque and somewhere along the line, Dash Command recorded a 15.

Larrylu, your gauge setup is looking mighty sweet!

 

[Larrylu]

Thank you sir. I've noticed yours is looking pretty durn good also. Playing with the gauges is a lot of fun for sure!

 

[FoMoCoSHO]

Thank you sir. I've noticed yours is looking pretty durn good also. Playing with the gauges is a lot of fun for sure!

I'm not using obdlink currently, but it makes a cool avatar....

 

[SHOnUup]

Just pulled a reading of 15.8 on torque? That seems awfully high?

 

[ecoboostsho]

I consistently hit 15 psi with the 4X tune.