Alfa Romeo Forum - View Single Post - 156 2.4 JTD

jasons · 21-01-2008

Originally Posted by aidank

thanks lad.. so ill leave exhaust then. mines 136 year 2000 84000 miles.
ill sort the air intake and remap for now then and manual boost adjustment. wat can this engine model run boost.? and will it go into limp.?

don't know too much about the 136, there are some differences in the turbo and other bits.
Your turbo is a VNT25.
It should still be a vacuum actuator like the 140/150, so a mechanical bleed valve will not work.
It is the ECU that controls boost.
You should be able to map it up, but only to the limit of the prohibitive map sensor at 1.5bar, I think this also includes overboost!

A voltage cap or 3bar/3.5bar map sensor would be much better, then alter the mapping to suit.

21-01-2008	#42 (Post Link)
jasons AO Member Join Date: Sep 2007 Location: Derbyshire Posts: 782 Member car: 156 2.4JTD 200+bhp	Re: 156 2.4 JTD - Project 250+bhp Originally Posted by aidank thanks lad.. so ill leave exhaust then. mines 136 year 2000 84000 miles. ill sort the air intake and remap for now then and manual boost adjustment. wat can this engine model run boost.? and will it go into limp.? don't know too much about the 136, there are some differences in the turbo and other bits. Your turbo is a VNT25. It should still be a vacuum actuator like the 140/150, so a mechanical bleed valve will not work. It is the ECU that controls boost. You should be able to map it up, but only to the limit of the prohibitive map sensor at 1.5bar, I think this also includes overboost! A voltage cap or 3bar/3.5bar map sensor would be much better, then alter the mapping to suit.