boost problems

[Govt issue]

I have 96 vin f 6.5 td. All Stock. I installed guages this weekend. My boost psi is only 4-5 will cruising or wide open throttle. The spike was 8 psi. exhaust temp was 1200 pre turbo at wot threw all gears. is this normal. I tried to get more psi. Made the boost fooler set to 5k Now boost is 6-7 psi with 10 spike. Why can't I get 15 or so out of this thing. Also why can't I cruse at 10?

[markrinker]

From the EGTs, sounds like you have a fair amount of unburned fuel in the exhaust. Are you seeing black smoke during these tests?

Also, are your tests unloaded, or with the boat in tow? If they are unloaded tests, the boost pressure will increase under a loaded test. However, I think your EGTs will be too high...

Two ideas:

1) Is your exhaust restricted? Not just from the stock tubes, but possibly a partially plugged cat?

2) Is your intake restricted? Again, not just the stock intake but a dirty or road salt encrusted OEM filter as well?

Let her breathe on both ends and I bet your boost (and POWER) come up - especially under load.

[GMC Hauler]

Are you sure it's not the wastegate, solenoid, vacuum pump or interconnecting hose? I would try, under a carefully controlled test, to wire the wastegate shut and see if that works. if it does, then it's a problem with the controls.

I've never seen my boost at 10# during steady state crusing. It is ususally 4-6#.

[Govt issue]

Sorry I didn't put all the info down. Sat I completed the guages. Sun Trying to get more boost I Dropped the exhaust. Unbolted it from the 4 bolts in front of the trap. Exhaust temp at wide open throtle decreased a little. 1100 till about 90 then it got to 1200, But it never goes over even with the exhaust hooked up. I havent hooked the boat to it yet. Normal ex temp runs 600 at 75 mph . I have a k/n filter.

[Govt issue]

I almost forgot. I tried to tie the waste gate closed. I closed it then stuck a vacume cap over the vacum port. No matter what I did the truck wouldnt produce but about 2 lbs boost. To me that dosen't seem possible but I tried it twice. Vacum at the wastegat was 20 inches.

[Govt issue]

I almost forgot. I tried to tie the waste gate closed. I closed it then stuck a vacume cap over the vacum port. No matter what I did the truck wouldnt produce but about 2 lbs boost. To me that dosen't seem possible but I tried it twice. Vacum at the wastegat was 20 inches.

[GMC Hauler]

Maybe you have a leak in the intake manifold? you must have some black smoke at full throttle.

Is the air filter relatively clear of debris?

Look at the intake side of the turbo, look at the blades, etc. does it spin freely? are the blades eroded?

What about an exhaust leak?

Could the wastegate be busted?

[charliepeterson]

Boost of 6-7 lbs. with a 10 lb. spike is all you're going to get. How deformed is your down pipe? This is a big restriction. A mechanical waste gate system is better than the vacuum system.
I think the limitations of the GM-4 Turbo is what you might have. The GM-8 is slightly bigger and might give more boost on the top end. It will bolt right up and is slower off the line at building boost but won't run out of air pressure as soon as the smaller GM-4.
On the front of the turbo is a name plate, this is where you'll find out what you have.

[Govt issue]

i,ve got a gm 5 and no black smoke. just a puff, then it stops.

[Govt issue]

I mounted my boost guag in the top of the intake, where the egr valve should be is this ok?

[MTTwister]

Gov't -- I have my boost fooler set to 2K. I 've seen boost up to 13#, EGT @ 900+ going over Homestake and Cottonwood passes ( long hard climbs to 6500 +/- ft) . I backed off when I was hitting 13# ( Not intercooled ya know). I do have the BD downpipe, but don't belive I had gutted the Cat at the time I'm recalling these readings from.

A "Straight" ( should I say clean) downpipe will help a lot, and maybe play with the boost fooler, backing off the ohm-age somewhat.

[Govt issue]

I set my fooler to 2k. I pulled my uncles tractor. It made a huge difference! Now the boost runs 9 10 psi/ 11 spike. Egt came down 100 degress pulling the trailer at wot 1100. Also at 40 mph is 500 100 less.The truck runs much better. Thanks.