Turbo boost

[gtmatt]

Took the car for a little test tonight ,and running on driveway the turbo is makin no boost , I've got a brass bleed valve ,shut or open makes no difference ???? The act arm does not move a bit ,cold it be the signal from carb or act its a dash 31 any clues :)thanks Matt

[Brigsy]

You need to drive it to make boost with a big turbo lad;) revving the knackers off it might make a little on idle but thats it

[gtmatt]

Well the turbo should start boost at 3000rpm on a t28 I'm sure it didn't start to spool up ,and dont even get compresser surge

[SCHWARTZ]

How much preload do you have on the actuator arm? I get my mountain bike fork pump plumb it to the actuator and my boost gauge and pump until the actuator moves enough to move the wastegate then check the boost gauge and tthat's the boost you will be running.
Depending on cam and timing and other things boost may not come in until 4k

[Lee-H]

New poster! (less than 10 posts)

The engine needs to be under load to for the turbo to make boost. You wont be doing that revving it to 3000 whilst stationary. Certainly not with a large turbo. Rev it alot harder and it should make some positive pressure that you'll see on a gauge.

[SCHWARTZ]

He does say he took the car for a little test so I assume that means it was actually driven.

[Brigsy]

Still 3k rpm wont really wake up a t28. Get a bit of preload on the actuator and give it some revs.

[casper]

If your used to small turbo's that spool up quickly then it can be strange waiting for the boost.It is to me anyway.:laugh:

[gtmatt]

Thanks guys how do u preload the act thanks Matt

[casper]

Preload is basically how much you have to pull the actuator rod to get it on the wastegate so its the gap from the hole on the rod to the wastegate with the penny closed.:agree:

[casper]

Whats the initial lift pressure with a -31?