Hey everyone, Long time forum stalker here.
A few months back my VF-40 took a dive while I was out and about. Oil analysis came back fantastic showing no bearing material so i decided to risk going ahead and replacing the turbo along with upgrading some other components.
Compression and Leak down test came back good as well.
Cylinder #1 (140 psi) 5% loss at 35 psi.
Cylinder #2 (140 psi) 3% loss at 35 psi.
Cylinder #3 (145 psi) 5% loss at 35 psi.
Cylinder #4 (140 psi) 5% loss at 35 psi.
The motor has 140k on it, it's an 07 LGT 5EAT.
I went ahead and installed the following:
VF-52
Tomei UEL Headers & Up pipe
Catted Cobb DP
Invidia Q300 Catback
Cobb 3-Port BCS
NGK One Step Colder Plugs
Deatschwerks DW65C Fuel Pump
Forced Performance Turbo Oil Line Kit
Cobb V3 Accessport
I've just had the car road tuned and my tuner was having an issue with the boost spiking on the AT shifts.
Right now the tune is only running about 12.5-13.5 PSI throughout most of the powerband until it shifts, and then I see a boost spike to about 17PSI.
When he started tuning it he said he was having an issue pulling back the boost and that he would like to see it peak at 17.5 psi +/- 1.0 psi but it keeps wanting to hit 19 psi. No signs of knock and it only does it on a hard pull when the automatic shifts. The injector duty is around 86% so it is all happy other than he wanted the boost to be a little lower.
He said so far it has resisted letting him back it off.
My question to the group is this.. I know there is more power there with only running 12.5-13.5psi. Has anyone else experienced this phenomenon (im sure some have) and have a recommendation on what I need to look at?
I'd like to have a slightly more aggressive tune while still being safe on the motor and trans. He tuned it pretty conservatively and was very transparent about it.
Just looking for opinions/advice on a path forward. It's my DD and I don't track it but do enjoy the occasional WOT pulls.
Thanks in advance!!
