I've tried to do a number of searches to find answers to the following, but had no luck...


When I purchased my current Bonneville in November, I was normally seeing about 6.5-7 psi of boost according to the gauge (and closely mirroring what the ECM was seeing, checked through the scanner).

I've been slowly doing all of the mod's to support a tune and smaller dia. pulley (coming next week...), but am now seeing lower boost (about 5 psi max, maybe 6 at most at higher RPM) all the time.

Is this a situation where the efficiency of the system has been improved to the point, the boost level that can be attained by the stock pulley diameter has dropped?

I ask only because I would think if that were the case, the POWER OUTPUT should remain the same or improve...but it hasn't. Right along with the lower boost readings, the car actually feels slower now than it did before I started ANY of the "improvements".

Any insight from others?

Thanks,
Ken

_________________
2006 Saab 9-7x 5.3i
2005 Pontiac Bonneville GXP / 4.6L Northstar *Sold*
2001 Olds Aurora 4.0 w/GXP Exhaust and High-flow cat (OSV Wannabe) *Sold*

2001 Pontiac Bonneville SSEi, 3.4" MPS, Intense Tune, SD headers, high-flow Cat, GXP exhaust, Modified Air Intake, 180* thermostat, GXP: 18" GXP wheels w/255/45/18 tires, CF Trim, Brakes and Strut Tower Brace. SOON TO HAVE: GXP Swaybars.

1972 Olds Cutlass Convertible / 461ci Olds / TH400 / 3.08 Posi. 13.62 @ 99.7 MPH......Got torque?


Yes, I seem to be drawn to GM's orphaned cars......

Mods like freeing up the exhaust or higher ratio rockers will make the indicated boost go down. With easier flow, there is less "boost stacking" created due to lower end pressure in the cylinder after the exhaust stroke. In actuality, it's still moving more air which *should* mean more power.

Have you tested the fuel pressure?

_________________

WHITE WHINE - 1992 SSE Supercharged 236.26 ci (.040 Over) 15.090 at 90.2 MPH on old engine w/ slipping trans & melted O2 sensor - Gen 3 M62 and matching TB, Gen 2 Pully, Zillamotorsports Ported LIM, YT 1.72 Roller Rockers, SII FPR & Injectors, Hypertech Thermomaster chip w/ 160 Thermo, TransGo Shift Kit, Infinity/Pioneer Speakers and 10" Subs, 1300 watts, 140 amp Alternator, Ricepipe CAI w/ heatshield, Pilot Angel Eye Foglights, Clear Corners, '02 17" Chrome Bent 5's, Magnaflow F-Body Muffler and Hi-flo Cat, Ceramic Coated Ported Exhaust Manifolds, Fan Override
2009 G8 GT - Sport Red Metallic, loaded, SOLO Axlebacks, Rotofab Intake, Tuned, autodim mirror, removed intake manifold cover, HSV GTS triple gauge pod, two tone red-hot shifter and HSV SuperSport steering wheel, GXP rear sway bar and diffuser, 3.45 diff and various Camaro suspension bits, LED Taillights

That's what I was thinking but wanted to confirm.

Thanks.

No, I hadn't checked the fuel pressure as I hadn't seen any symptoms pointing me in that direction (hard starts, loss of top-end, etc.)

I can check it though...

Any idea what pressures I should be expecting (ignition on not running, at idle, and with throttle)?

_________________
2006 Saab 9-7x 5.3i
2005 Pontiac Bonneville GXP / 4.6L Northstar *Sold*
2001 Olds Aurora 4.0 w/GXP Exhaust and High-flow cat (OSV Wannabe) *Sold*

2001 Pontiac Bonneville SSEi, 3.4" MPS, Intense Tune, SD headers, high-flow Cat, GXP exhaust, Modified Air Intake, 180* thermostat, GXP: 18" GXP wheels w/255/45/18 tires, CF Trim, Brakes and Strut Tower Brace. SOON TO HAVE: GXP Swaybars.

1972 Olds Cutlass Convertible / 461ci Olds / TH400 / 3.08 Posi. 13.62 @ 99.7 MPH......Got torque?


Yes, I seem to be drawn to GM's orphaned cars......

It's been a while and I can't remember what it should be. It might be in our techinfo.

_________________

WHITE WHINE - 1992 SSE Supercharged 236.26 ci (.040 Over) 15.090 at 90.2 MPH on old engine w/ slipping trans & melted O2 sensor - Gen 3 M62 and matching TB, Gen 2 Pully, Zillamotorsports Ported LIM, YT 1.72 Roller Rockers, SII FPR & Injectors, Hypertech Thermomaster chip w/ 160 Thermo, TransGo Shift Kit, Infinity/Pioneer Speakers and 10" Subs, 1300 watts, 140 amp Alternator, Ricepipe CAI w/ heatshield, Pilot Angel Eye Foglights, Clear Corners, '02 17" Chrome Bent 5's, Magnaflow F-Body Muffler and Hi-flo Cat, Ceramic Coated Ported Exhaust Manifolds, Fan Override
2009 G8 GT - Sport Red Metallic, loaded, SOLO Axlebacks, Rotofab Intake, Tuned, autodim mirror, removed intake manifold cover, HSV GTS triple gauge pod, two tone red-hot shifter and HSV SuperSport steering wheel, GXP rear sway bar and diffuser, 3.45 diff and various Camaro suspension bits, LED Taillights

I found it, checked it, and found all's A-OK on that front as well.

_________________
2006 Saab 9-7x 5.3i
2005 Pontiac Bonneville GXP / 4.6L Northstar *Sold*
2001 Olds Aurora 4.0 w/GXP Exhaust and High-flow cat (OSV Wannabe) *Sold*

2001 Pontiac Bonneville SSEi, 3.4" MPS, Intense Tune, SD headers, high-flow Cat, GXP exhaust, Modified Air Intake, 180* thermostat, GXP: 18" GXP wheels w/255/45/18 tires, CF Trim, Brakes and Strut Tower Brace. SOON TO HAVE: GXP Swaybars.

1972 Olds Cutlass Convertible / 461ci Olds / TH400 / 3.08 Posi. 13.62 @ 99.7 MPH......Got torque?


Yes, I seem to be drawn to GM's orphaned cars......