[s-cars] 1.8 bar wastegate spring install and impressions

[Sean Douglas]

Just finished installing the 1.8 bar wastegate spring. I did the
diaphragm at the same time, but it's a bit more involved to do.

If you are going to do the diaphragm, its much easier to remove the
wastegate and disassemble it on the bench. If not, the spring can be
easily replaced while the WG is in place.

Wastegate Removal:

1. remove the 3 bolts and nuts where the flex connection attaches to the
downpipe
2. remove the large banjo bolt where the vacuum line attached
3. remove the 4 nuts holding the wastegate to the manifold
4. remove wastegate with flex pipe attached and take to bench and hold
in vice
5. you may need a new downpipe gasket if its original, mine is about 2
years old so I didn't bother. Also if the bolts have never been apart,
it's a good idea to use Rost-off (or the like) and have some new
hardware on hand. The copper nuts are easy to round off.

Cap Removal:

1. remove the six little nuts
2. my wastegate cap was stuck on pretty good, I had to wedge a small
flat blade screwdriver between the diaphragm and the cap and lightly tap
it with a hammer.
3. remove cap
4. remove spring

Diaphragm Replacement:

1. use a allen key wrench on the underside of the piston to prevent the
piston from turning and remove nut
2. remove washer
3. pull out piston with diaphragm attached
4. remove large black backing plate (I had to wedge a small screwdriver
in and tap with a hammer)
5. install in reverse and use blue loc-tite on the nut.

Driving Impressions:

Boost comes on much quicker and at less throttle opening. At half
throttle, boost builds much more quicker - not sure if I like this,
makes it hard to modulate, kinda reminds me of MTM 1+.

It "feels" faster because boost builds faster - not sure if ultimate
power is increased.

Now for the downside - maximum boost is increased, I'm seeing 1.9 bar on
my Greddy electronic gauge with peak memory, with the stock spring I saw
1.6 bar max. This is with Dahlback software. At 1.9 bar boost it pings
pretty bad and I don't think this high level of boost can be good.

I've replaced the stock spring until for now - unless someone has any
suggestions.

Sean D.