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Won't Make Full Boost


Bellato

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  • Member For: 14y 1m 5d

I've noticed the last couple of weeks my car won't make the full 16.5psi its tuned to but only makes 13.5 when data logging it. It's a constant boost level right through the rev range, like its only making gate pressure (14psi external gate).

I recently went over everything, service, plugs, fuel filter, fresh tank of fuel with injector cleaner run through, new vacuum line to the gate. I think its probably a wastegate or boost solenoid issue but without replacing them im not sure. Anyone have any ideas?

My tuner is in Sydney and Im in Canberra so just trying to check everything before I go up and have them look at it

Cheers

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  • ...JD TUNING ADELAIDE...
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  • Member For: 16y 5m 24d
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Did you ever data log the "tuned" 16.5psi in the same method that you just logged the 13.5psi with ?

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Won't bypassing the solenoid just make it run gate pressure?

Nope never did so I cant compare what the previous tune looked like on my data logger. The only reason I data logged at the moment is cause I raced a car I can mormally keep up with and got chopped big time, plus it barely spins first now and use to be able to roll on in 2nd and just bake tyres

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  • ...JD TUNING ADELAIDE...
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  • Member For: 16y 5m 24d
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For a big variation like that you would typically look for the vac line on the external gate to be damaged but you said you have already checked it

Log wastegate D/C and see if the ECU is still commanding the actual amounts tuned to

You won't know what they are but for gate pressure only tune it will be 0.000 everywhere where as higher than gate pressure will require some DC ( say 0.300's or the like )

If the ecu is commanding it, the vac line is good, then you have an issue starting with the gate and downwards through the exhaust system

It's possible the diaphragm/seal in the gate could be suspect

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  • Member For: 16y 11d
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If it's commanding correctly but only making gate pressure I'd be suss on the solenoid being stuck open. Bypass it and if it still runs 13.5 psi the solenoid ain't doing sh*t. I assume the solenoid should be closed when off? Try blowing through it to check for a leak.

I wouldn't think a damaged gate diaphragm would cause less boost. It'd cause overboosting as now you have a leak so it takes more pressure to overcome the leak + spring pressure. If the spring has gone slack however.... But, IMO, making that close to the advertised 14psi gate pressure, I wouldn't immediately suspect the gate. Though it is possible it's unlikely to have failed just enough to run exactly gate pressure while more is commanded.

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  • Member For: 11y 4d
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Won't bypassing the solenoid just make it run gate pressure?

Exactly, u said it just felt like gate pressure atm...so if its no different bypassed, and was commanding correctly....

If it's commanding correctly but only making gate pressure I'd be suss on the solenoid being stuck open. Bypass it and if it still runs 13.5 psi the solenoid ain't doing sh*t. I assume the solenoid should be closed when off? Try blowing through it to check for a leak.

Edited by barnz
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  • Member For: 14y 1m 5d

Thanks for the help so far guys.

Tried a new solenoid today to no avail. However, put a brand new gate on it and things changed dramatically. Running the new gate bypassing the solenoid made it run perfectly on 14psi gate pressure (I forgot to try the previous wastegate with bypassing the solenoid to see). Then hooked it up properly to the solenoid and it was making over 20psi and so pulled out, this is at about 40% throttle. My mate was thinking that the original gate might not have a 14psi spring so my tuner used the duty cycle to try get 16.5psi out of it.

Pulled apart the gate and found that the outer spring doesn't match any of the outer springs Turbosmart seller so thinking potentially a fake gate or the retailer has put a different brand spring in it. The seal on the diaphragm is also not sealing correct and has crease where it has popped off in the past. The gate has also gone completely bronze (was black) and now sure if its been overheated in its current location or they all do that?

So next step is to ring the retailer in the morning and find out what would be the go with warranty and go from there

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