Hey there guys just a quick question
I have an old truck with a boosted 4.8.
I am constantly seeing map sensor going all the way to 235kpa
Just wondering that would put me at 19psi right??
I have a 10lb spring on this thing and for some reason can?t get to to stay around that range.
Tried everything
Already drilled and tapped the turbo and installed hard lines.
Wastegate stuck??
How big is the waste gate and where is it mounted?
A wastegate that is too small will give you problems and so will a bad placement.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
44mm it’s mounted on the crossover pipe closer to the driver bank.
This is a single turbo system. Turbo is mounted on passenger side.
So it's really only venting one bank of the engine. To vent both banks equally it should be at the merge, at the turbo inlet. Not just wherever it happened to be easiest to get to.
Make sure you compare with an actual boost gauge. The map is only as good as its configuration and being used properly, maybe you are getting 10psi and the map is just wrong in the computer.
If it really is overboosting you need to test the wastegate because it sounds like it isn't opening at all or opening solely based on exhaust gas pressure
@kingtal0n
Thanks bud I am going to look into that ASAP
Also will install boost gauge here very soon to verify.
Map sensor came with linear offset but you are right.
You just never know. Thank you for the advice here guys.
I?m running a gen5 Turbosmart hypergate 44mm wastegate directly off the merge pipe to t4 flange with a T76 single turbo, angled to flow in same direction as exhaust, with 5psi spring, as it comes off the merge where both banks meet it vents enough to hold 5psi from 3000 to 5500 rpm. Sounds like the wastegate might need to be moved to control boost.
Originally Posted by Lone_mfkn_wolf
Are you running a line to the bottom of the wastegate or top? If at the top it will make about twice what the spring is.
Tuner at PCMofnc.com
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Have the line to the bottom of it
Turbo is a 78/75
I’m thinking of just moving it closer to the turbo
And replacing it with a new one while I’m at it.
go 60mm you wont regret it
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