boost gauge reading?

[rurso01]

Finally my back ordered SPT boost gauge has arrived and its being installed today. Other than the SPT cat back that has been installed, I'm stock and on stock maps (for now). What should my gauge read as "normal". I've never had a boost gauge and never had experience with them before.

What shod it be at idle?

At WOT?

And during normal driving?

Thanks!

[Heide264]

What shod it be at idle?
- In vacuum. This depends on the gauge. I believe mine reads positive pressure in psi, and negative in inHg. I believe it sits around -20. Regardless, should be under zero.

At WOT?
- Whatever your target boost is. This will depend on RPM & Load, and more so your specific car. Stock 08+ I'd expect 14-16psi. I'd be concerned that you have a leak if its under 14 psi at peak torque (3-4k RPM WOT)

And during normal driving?
- Somewhere between idle and zero normally. It tends to "center weight" at zero on my gauge due to the change in labels (psi from inHG)
Thanks!

=)

[rurso01]

Thanks Heide! I have the SPT boost gauge. I'll take a look at the numbers and if they aren't close to those I'll report back

[wrx1234]

My best MPG comes if i stay under -10 PSI.

[Rambo]

Finally my back ordered SPT boost gauge has arrived and its being installed today. Other than the SPT cat back that has been installed, I'm stock and on stock maps (for now). What should my gauge read as "normal". I've never had a boost gauge and never had experience with them before.

What shod it be at idle?

At WOT?

And during normal driving?

Thanks!

At idle and normal cruising, you'll be reading vacuum (I usually read about -10-15mmHg, but YMMV). At full throttle in 3rd gear, Cobb Tuning reported peak boost of 15psi on the stock tune, and it quickly tapers off after that. See the Boost and Air/Fuel Ratio Graph in their map notes here [PDF]: https://static.cobbtuning.com/cobbtu..._WRX_09-13.pdf

So you could expect to see a quick spike around 15psi when you hammer down, then the boost will drop off after that.

[Heide264]

My best MPG comes if i stay under -10 PSI.

It's probably not psi, FWIW. I think idle is around -10psi if you are speaking in relative terms.

[rurso01]

My boost gauge at idle was reading as you stated around -18 or the 18 inHg. Now at idle its -2inHg. Why would this be?

[rurso01]

It shows proper psi at WOT 14ish but every other moment idle or driving normal is 2 inHg.

Anyone have a clue as to why it has started reading this way?! 3rd and 5th gear the turbo psi registers up to14psi and lliterally every other time other than a slight move of the needle, its at 2 inHg

[EJ257]

It shows proper psi at WOT 14ish but every other moment idle or driving normal is 2 inHg.

Anyone have a clue as to why it has started reading this way?! 3rd and 5th gear the turbo psi registers up to14psi and lliterally every other time other than a slight move of the needle, its at 2 inHg

Could be a vacuum leak. What is AF Correction @ idle?

[rurso01]

Would I need an AP to know that? I'm not sure how to obtain that info. I did listen under the hood asmy girlfriend lightly hit the gas and no leaks that I could hear. It was working fine the first 2 days and already on the 3rd day its acting up...

[EJ257]

Would I need an AP to know that? I'm not sure how to obtain that info. I did listen under the hood asmy girlfriend lightly hit the gas and no leaks that I could hear. It was working fine the first 2 days and already on the 3rd day its acting up...

D'oh! For some reason I thought your car was StageI (too many open windows confused me). You would need some form of datalogging. Where about do you live?

[rurso01]

Maryland, Washington County to be exact. Any where near you? Other than a leak, could it be anything else? I guess it might be worthy to take it back to Subaru since they installed it for me. Everytime I take a car into a dealership I always leave with scratches on the interior or paint so I dread taking it back again.

[EJ257]

Maryland, Washington County to be exact. Any where near you? Other than a leak, could it be anything else? I guess it might be worthy to take it back to Subaru since they installed it for me. Everytime I take a car into a dealership I always leave with scratches on the interior or paint so I dread taking it back again.

That's near Baltimore/DC, right?

[rurso01]

Yeah I'm constantly in Gaithersburg. Probably once a week. You from the area?

[Rambo]

D'oh! For some reason I thought your car was StageI (too many open windows confused me). You would need some form of datalogging. Where about do you live?

Considering he has a 2013, I'd let the dealer handle it IMO. It could be a bad gauge. Datalogging would prove that, yes, but the car is brand new...