Uprated wastegate spring. Worth it?

[Animal Mother]

Hi all

Don't know much about this so excuse any daft Q's.

I know some of you use 1.9 bar wastegate springs, and I've even heard mention of 1.8 bar springs. What benefit do they have, if any?
I thought the wastegate was controlled by the ECU via the N75 not controlled mechanically. Is that right?
If there is a benefit to having a 1.8/1.9 bar spring, is it a straight swap and will it work with a homefries or does it require a remap or removal of the electronic wastegate control?

Cheers

[gedu]

Wastegate spring is what ultimately controls boost level. In our cars there is this N75 that is ECU controlled and can bleed pressure back to turbo intake, so that wastegate doesn't see the full pressure.

Stock spring is around 1.4-1.7bar (absolute) depending on setting. 034 1.9bar (also absolute) spring will get you a bit faster response from turbo, as wastegate wont start to open on as small pressures as with stock spring. In safe mode ECU renders N75 "inoperable" and you get only that base boost.

[Animal Mother]

Wastegate spring is what ultimately controls boost level. In our cars there is this N75 that is ECU controlled and can bleed pressure back to turbo intake, so that wastegate doesn't see the full pressure.

Stock spring is around 1.4-1.7bar (absolute) depending on setting. 034 1.9bar (also absolute) spring will get you a bit faster response from turbo, as wastegate wont start to open on as small pressures as with stock spring. In safe mode ECU renders N75 "inoperable" and you get only that base boost.

So an uprated wastegate spring does not alter the upper boost (overboost) level, it only increases the level at which boost "comes on" giving a more instant surge of boost but at, I estimate, a higher engine speed (i.e. more lag).

So no horsepower increase then?

[A80Avant]

no.the spring will give you more boost on all levels.
for example if you have overboost of 1.8bar and steady 1.4bar with the OEM spring(which is 1.4bar absolute) and you replace it with 1.9bar spring,then you add 0.5bar to your boost levels at any point,meaning you are going to be seeing 2.3bar overboost and 1.9bar steady boost.
If you do that and you dont remap,you can surely kiss your engine goodbye cause you wont have the correct fuelling for that kind of boost.So you always remap along with the spring.
Other thing you can do is modify the wastegate cap to operate the screw which step by step will generally give you an increase in boost levels and while checking the EGT levels not to go too far off.The OEM spring with the right stiffening can reach a nice 1.8bar spring!