Hello everyone, havnt been on in a while so hope everyone is well !, and the cars too!!
Right.............
Ive got a few issues with the T-5 recently that are becoming annoying an worrying, i apologise in advance if this subject has been covered a million times before but it would be good to have a "live chat" about it so to speak
The car was all good a few months ago, it made 250bhp and 260lb/sf @ 12.5psi of boost tailing off to rest at around 10.5PSI @ 6000K using a MBC, de-catted 2.5" exhaust and a panel filter but things have changed a little recently.
The boost itself has dropped to around 10.5-11psi and after around 5000RPM the boost drops rapidly down to around 7psi at 6-6200RPM. I Also plumbed back in the stock solenoid and i get a spike to 6PSI the it drops to around 5PSI...
The car has also now become overly sensitive to fuel cut even at 11psi when accelerating from low down or accelerated up hill etc (high load) both on light throttle and full throttle.
Naturally ive been playing to sort the issue out for example ive tried -
1. replacing the diaphragm in the recirculating valve in the turbo
2. checked all the boost hoses for leaks etc
3. checked the T.B and vac tree for leaks
4. checked the PCV system
5. checked the intercooler
6. tried another boost solenoid
7. Changed the MAF sensor
8. checked and changed vac lines
etc etc.....
I would appreciate a few ideas on other things that may be causing the issue, ive heard of cracked turbine housings causing the boost drop and tailing off at high revs......sound familiar??, but then why the increase in fuel cut at lower boost levels??
Also ive heard the actuators can some times become weak leading to the boost drop and tailing off ??, but again you would not imagine this to cause fuel cut more often??
Its worth mentioning a few things such as - even if i wind in the MBC (22psi) i still get no more than around 11PSI of boost and it still tails right off without any evidence of any boost leaks etc :/
And the car still feels fairly rapid aswell !!, i have a boost gauge in the car aswell as the stock rubbish gauge confirming the drop in boost and tailing right off at high RPM's etc so its definitely happening
Anybody suffered this before?, im guessing the flow from the turbo is going somewhere but im stumped as to where as there is no apparent leaks to be found externally on the boost system.....
Any help would be very much appreciated, thank you in advance
Jason
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