Losing 5-6 lbs boost on 2-3 shift

[basherbob]

Recently I have been having an issue with losing boost upon 2-3 WOT shift. Noticed it last year but worse this year
From a 30 MPH rolling start, going to WOT I build to about 19 lbs boost with no knock. upon the 2-3 shift at 5200 rpm the boost drops to about 13 lbs and starts to slowly build back up.

I went back to the stock boost hose set up, with the y fitting, dropping the RJC controller. No change. I am running a TA49 with stock adjustable actuator, 42lb injectors, THDP 3 inch with test pipe, dutweiller neck intercooler. Tomkins CAI through a stock MAF (Translator/85mm on the way) and a TT chip.

Thoughts?

 

[we4Mateo]

Is the wastegate hole ported at all?

 

[basherbob]

Is the wastegate hole ported at all?

I dont' think so.

 

[earlbrown]

I'd put the translator on and then resume testing. If your stock MAF is flaky, there's n reason to try and tune around it.

 

[basherbob]

I'd put the translator on and then resume testing. If your stock MAF is flaky, there's n reason to try and tune around it.

I hope to do that tomorrow night.

Could the actuator be getting weak and not holding? What about that solenoid on the valve cover? Could that be bleeding off boost but am not hearing anything like that under the hood.

 

[earlbrown]

If either of those units malfunction, boost goes up, not down.

 

[basherbob]

If either of those units malfunction, boost goes up, not down.

Ok, well lets see what the translator adds tomorrow.
Thanks to all

 

[basherbob]

Ok, well lets see what the translator adds tomorrow.
Thanks to all

Well, I put the 85mm maf / translator in.
Good news.. 20 lbs, little faster spool, and no knock.. thank you Full Throttle.
Bad new.. Still drops 9 lbs to 11 lbs boost upon 2-3 wot shift. Did drop a little more slowly but still drops.
Next?

 

[earlbrown]

drivers side header crack been welded up recently?

and/or did you change anything to try and tune around a bad MAF? Is so, unchange it and see what that does.

 

[basherbob]

No and no..
Thanks for the suggestion.

 

[Bescurred]

Are all the bolts holding the W/G to the turbo? I've seen missing one and it'll do that...

 

[Mr.Spool]

look carefully at the hoses,connectors,and piping for cracks,anything preturbo.

 

[we4Mateo]

look carefully at the hoses,connectors,and piping for cracks,anything preturbo.

What kind of leak pre turbo would cause any issues? Unless it leaks after the maf and takes in a bunch of unmetered air. That still shouldn't affect boost levels though unless the car is shutting down for some reason due to it.

Usually boost control issues result in too much. This is a weird issue.

I can only conjecture that the extra load in 3rd is somehow pushing the gate open regardless of the boost controller.

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[Mr.Spool]

a sheared compressor

 

[we4Mateo]

a sheared compressor

But why does it make boost fine in 1/2 then?

 

[Mr.Spool]

thats how the boost behaved in a buick gn that had a sheared compressor couldn't tell you why.may not be his problem but checking is freecould also be a ripped seam on the intercooler which is why I suggested he check it all.

 

[Chuck Leeper]

What is the rpm drop at the shift? 5200 down to??

 

[we4Mateo]

thats how the boost behaved in a buick gn that had a sheared compressor couldn't tell you why.may not be his problem but checking is freecould also be a ripped seam on the intercooler which is why I suggested he check it all.

How could it be a ripped intercooler seem if it holds pressure in 1/2 and only not in 3rd?

 

[Mr.Spool]

I have ripped an intercooler seam and the car would lose boost in high gear.

 

[SPOOLFOOL2]

How does it spool off the line? Is it quick or slow to spool?

Mike B.