What are expected boost level on a 2006 GP with 69k miles?

 

Since nobody has replied yet, seems to me numbers suggested should be at sea level as baseline. Images below show mine -2.5 psi at 5k' elev (displayed on Android tablet broadcast from BT OBD2 dongle with engine off) plus a related chart snagged off the web.

 

I'm guess I'm curious to know if you feel yours is off? Does the car feel slow?

I have gauges I need to hook up in my car still, so I can't tell you what my GP currently is at - but my car pulls very strong.

-Andy

 

Using my OEM dealer installed boost gauge, I top out around 11-12 psi under hard acceleration.
My 06 GP with 69k miles is stock with no performance modifications.
It pulls hard but seems sluggish in first.

 

Wouldn't the GP-spec W11 produce same max boost (at given elevation) as the standard JCW Tuning Kit? I ask since the supercharger utilized the same 11% reduction pulley with the only apparent differences which increased from 210hp to 218hp being GP-specific larger intercooler and different ECU parameters? This page from the JCW Register being my point of reference: R53 John Cooper works GP

 

You are correct in your assumptions. What are your typical JCW boost readings?

 

Mine being hybrid non-JCW S-spec with (mostly) known modifications (including 15% or smaller pulley), my boost readings at 5k' home base and higher aren't relevant to the topic question. I can view those in real time but only when monitored via combo of OBD2 dongle and Android app. My comments were meant to be aligned with the topic question pertaining to OEM JCW-spec tuning vs GP-specific on max boost seen on healthy engines, which would then broaden potential responses.

 

FWIW, I get 15 lb. at WOT/7200 rpm with a 15% pulley.

 

That’s impressive! I think that I’m a little down on boost. My peak has been 11-12 on a bone stock 06 GP with 69k miles. No check engine light or code. What could contribute to boost losses?

 

leak someplace? how you checked the boots around the IC?

-Andy

 

To ascertain if there's an unmetered air leak, while the engine's running, try small squirts of starting ether around suspect places. If the idle increases, there's your leak. If that doesn't locate it, try a smoke test. There are a few DIY videos on YouTube that show how to make and perform one.

 

Curious because I don't know the answer. If talking about a boost leak you are talking about a positive pressure leak, correct? So air escaping the system. Starting fluid/ether will not get drawn into the engine in this case and not help find a boost leak. Is this correct? What don't I know I don't know? Thanks

 

You shouldn’t be building boost at idle.

 

Correct but an unmetered air leak at idle will affect boost when boost applied.

 

At idle, the system is under vacuum. If there is an air leak anywhere, it will be drawn in, therefore an inflammable like starting fluid will cause rpm to rise. That same air leak, when under boost will cause boost pressure to be lost.

 

So even though the super charger is spinning, and with a smaller pulley, it's not enough to pressurize the system when at idle?

 

The bypass valve should keep the supercharger from building boost at idle, IIRC how systems with Roots blowers are designed.

 

If you have a boost gauge, you will notice that, at idle, the needle is in negative (vacuum) territory. It is important to remember that an engine is an air pump. It sucks in air, injects atomized fuel, compresses it, and ignites it. At idle, it's sucking in air. Under boost, it's adding pressurized air.

 

Given that the Eaton is a positive pressure blower, it relies on the restriction into the cylinders from the intake to build pressure. The bypass is the reason that the intake isn’t under pressure at idle.