P-ssedrightoff

Back in the day , the car was often on rolling roads/dynos but was never interested in what it was putting out,
only wanted to know it was properly set up. Seen screeds of print outs but never a Graph.
Only time AVA went full tilt, head gasket went two weeks later so usually declined full power runs after that.
Only recollect that was 111BHP at 6 PSI on the original standard engine.


Got this yesterday and was happily surprised at the BHP and Torque ones but wondered at the huge spike in the boost
one dropping off rapidly when the formers seemed reasonably smooth.
Not convinced I'll be using 19PSI very often as the engine I've just finished building will be the last time
I go anywhere near a friggin CVH and most definitely don't need the grief on installing it on the car.
No intention of any more mods or searching for more power, just interested why the Boost drops of
so rapidly?

cossie2

How old is turbo actuator?

haz87

Without knowing the entire setup turbo setup/config, the usual causes/areas:
- Actuator not being able to hold/maintain the pressure (cossie2 beat me to it ^^)
- Boost controller leaking or gone bad
- Wastegate not staying shut
- Boost leak somewhere and the turbo just can't "back-fill" what its losing... (shit terminology but you know what I mean )

P-ssedrightoff

Thanks for the replies. The actuator was changed years ago when the Bayjoo chip went in but never saw many miles.
It's not the standard spec one 31/34, never mind which is which but the uprated one.
It's the original standard turbo, done 64K miles.
Should have asked Simon at the time but was so pleased with the first two graphs, never noticed this.
Not actually tried it on high boost and a bit wary of trying 19PSI in spite of Simon saying everything was Healthy.
Used to be set for 8&16 with no problems but I'd just set by the half a hole method when I put it all back together.
Not sure if it's the cam (Piper 285T) or the lightened flywheel but seems way quicker now than I can remember
from 20 odd years ago before these went in.

P-ssedrightoff

Really not keen to run this at 19PSI but assuming if I just lengthen the actuator rod, the low boost will drop accordingly?
Quite happy with the 9 at low but would prefer 15/16 at high. Would I be right in thinking this would mean mucking about with the Amal Valve?