boost loss
 

at 60mph my boos gauge would read 7-8psi and now it reads 4-5psi. ive checked my boots, tightened the clamps checkd the line to the gauge and everything was ok. turbo sounds fine and has no play in the shaft. i had 305/70/16 tires on the truck and ended up having to put the 265/75/16 back on that came on the truck when i got it. the tire size difference wouldnt make that big of a difference on the load of the motor to drop the boost would it? this is the only thing i can think of. thanks

have you changed your air and fuel filters lately that would be the first thing i would check if i lost boost :humm: and maybe dropping your tire size has more to do with it then you think instead of going sixty like you think with change in tires you might only be going 54 or 55 miles an hr now and speedo still showing 60 :humm:

both filters were changed about 6k miles ago and i cleaned the air filer out about 300 miles ago. i never would of thought the tires would make that much difference...

well i was just thinking when i lower my speed some going down the road depending on where my boost gauge is sitting it will drop 2 or 3 pds you ought to check your speedo against someone elses to determine if its off by 5 or 6 miles per hour :humm:

it makes sence cuz with the taller tires i would be going faster that what the spedo says with the 265s thats about factory size so i would think the spedo would be closer with those

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about what should i be running for boost at 60mph with my mods?

i dont know for sure but on my 1st gen i am pushing about 10 at 70 mph :yeah:

With my 305s at 70 i was over 10 and now with the 265s at 70 im only about 8psi... idk maybe the tires have more to do with it than we think...

Check with another guage. Or better yet, install a temporary tee and you can compare them side by side.

You can use any kind of pressure guage for this.

i dont think my gauge is bad cuz my turbo really starts to whistle at 5psi and it still does when the gauge hits 5 like it did before

That doesnt tell you anything