Boosting 15 psi, with no mbc

[agarc023]

So I just installed my prosport boost gauge and I'm just wondering how it is possible to boost 15 psi on a mostly stock motor, and no mbc (yet) WTF.

On a slightly different note, when I'm driving and boosting the 15 psi, and let off the throttle, my vacuum reading goes past 20 inHg. Is this normal?

 

[LiquidX]

Are you still using the T-25 turbo? The vacuum reading is fine. There are times I would let off the gas at it would get close to 25-30 inHg.

 

[agarc023]

Yep still the stock turbo. Only mods are a dejon tool uicp and a 1g bov

 

[stroked_AWD]

I would get a mbc and turn the boost down the t-25 doesnt like to go much over 16 pounds before it craps out on you. When my t-25 was on my car i would see 12-13 pound with no mbc.

 

[clockworktoy]

## boosting 15psi because your bov doesn't leak anymore and is actually holding pressure. Sounds normal to me, and the vac is also normal.

 

[agarc023]

Thanks for the reply's. I was just thinking that 15 psi was a little high since I've been hearing that it should be 12 psi stock.

 

[Bluefire16]

12-14psi stock...depending on certain variables. (Every car is different IMO, and people argue ALL DAY LONG on here what stock boost is)

 

[TSITurbo95]

Yeah, the 2g bov's are famous for leaking. You fixed a leak in which is why its boosting higher.

 

[jnbracing]

Same thing here... replaced stock BOV and now it boosts to 15 and its solid. The old BOV was junk.

 

[agarc023]

Alright thanks everybody for your input. Looks like I was worrying for nothing. I'll be putting in my mbc next weekend so I can play with the boost (keeping it under 15 psi of course...for now)

Back with another question. After driving for a bit, I have been seeing some boost spikes, to about 20 psi. Just wondering if this is also normal. It only happens when I step on the throttle constantly.

 

[DSMraver]

I would get a mbc and turn the boost down the t-25 doesnt like to go much over 16 pounds before it craps out on you. When my t-25 was on my car i would see 12-13 pound with no mbc.

Adding a boost controller will NOT help you *lower* the boost.

The only thing you can do to *lower* the boost from where it is now, would be to remove the boost control solenoid, and run the vacuum line straight from the compressor outlet nipple to the wastegate.

You could also port the o2 housing/turbine housing wastegate areas, or buy a tubular o2 housing with a wastegate dump.