Turbo spike after exhaust change

[Bad-Trol]

Hi there!
Been browsing the forum for more info on this and I can't find anything.

I just installed a new 2 3/4" exhaust incl. dump. Since then, my turbo has been boosting as high as 22psi while cruising along. It use to max out at around 16psi.
It's a 3l TDDi and I've blocked the EGR, run a larger intercooler and have a larger airbox. I'm installing a Dawes this week so not too concerned, just curious why an exhaust change would cause this to happen.

Thanks in advance!

[97_gq_lwb]

Mine done the same after fitting a 3 inch i guess the original exhaust was so restricting it reduced boost it is maxing out my 15psi gauge now
.

[Ade]

Maybe all you guys need is a boost controller but higher boost suppose to reduce the egt..it didn't have much effect on power unless you tweak the fuel pump up too.

[97_gq_lwb]

Yeah i have an adjustable wastegate just have to turn it back down.

[Bad-Trol]

Installed Dawes now and no more boost spike... Just need to tweak a bit now. If boost stays in low to mid teens, does that use more fuel?

[nissannewby]

You will gain boost sometimes with the fitment of larger exhausts as it removes the restriction and allows the turbo to spin easier.

[Lieney]

I have a GU IV and had the same prob b4, but when it was colder. Due to several reasons I replaced the turbo and had also fitted a 3" pipe. New turbo no spikes at all. Old turbo seemed to be sticking a little. Dawes valve will be added shortly but runs up to 16psi real smooth & no more over-boost. May not e your proble
But somethingg to keep an eye on