If you remove the amal valve and just completely remove the hose to the actuator what should happen?

I figured it would just boost as much as it could (until it blew up anyway)?

My amal valve is buggered so I have removed it and it seems that it wont boost over 1 bar in first gear and about 1.5bar in second.

any reason why this would happen?

 

I thought that valve was only a restrictor anyway, Low/Hi changing on whatever RPM and/or pressure it changes at.

I recon it would boost as much as it could too, then if you cant give it enough fuel for whatever pressure it reaches thats gotta be running lean, then it melts. pretty sure thats the order it goes !

 

if theres no connection between the compressor housing and the actuator then yea, it will run unlimited boost and blow up pretty quick!

if you mean you have bypassed the amal and plumbed it straight from compressor > actuator then it will run whatever boost your actuator is set to hold.

 

boost pressure agsinst the wast-gate will open it at the point where the actuator cant hold it any more if you put a pipe direct from comp housing to actuator then it will run what its set at the amal valve bleeds air away from this pipe so more boost pessure is there before the wast gate / acturator opens

 

So what possible reason could there be for my turbo only getting limited boost despite the pipe from actuator to turbo being removed/blocked off?

there cant really be a leak anywhere as you'd hear it if the dump valve or similar was leaking wouldnt you?

It's a T34 btw and used to see around 28psi or just over.

 

what makes you say the amal valve is buggered, and the reason for removing it??

 

amal valve was just clicking randomly at idle and when you wriggled the plug it clicked like mad - loose connection inside or similar.

 

ah.. ok so what was boost doing whilst it was like that? fluctuating I guess..? randomly dropping?
It's hard to see how boost can be LESS with the actuator unconnected.. only thing I can think of is the actuator spring is weak enough that the exhaust pressure is sufficient to open it on it's own.. but then it would have done that with everything connected too..

 

The amal valve is used to INCREASE the boost. If you take it off it will simply run LESS.

 

Stu, my understanding is that the amal valve was removed and the actuator left UNCONNECTED... or have I read it wrong.?

 

Its sort of an odd story but here goes:

When I got the car it had been running the best part of 400bhp through a T34/greys setup, but the owner had sold the turbo and and replaced it with a T3 to sell it. I bought a near new T34 and actuator from Collins and fitted them. i took the car to Stu at motorsport developments to be setup - they checked it over, replaced plugs, phase sensor etc and fitted a new chip and set it all up. I was told it was running 28psi (spiking at around 30psi iirc).

The boost gauge indicated this to be correct but only reads to 2 bar so you couldnt see how far over it went but it didnt seem to be boosting too excessively. It did drive fantastically after the tune though and Kenny got rid of a lot of 'bugs' that made it unpleasant to drive at slow speeds.

About a week after the setup the car was loaded into a container with all my belongings and shipped to Australia where I have emigrated to. Due to all manner of customs issues and difficulty with engineering/compliance work at this end the car has only covered about 150 miles in this country and has just been sitting in a garage most of the time.

Whilst tidying a few things up under the bonnet I noticed the pipe from the turbo to amal valve had been blocked off completely with a steel rod!!!! This must have been like that since before I bought the car but I never noticed it. I can only assume this was done because the amal valve was stuffed.

Now its stood for a while since realising this and a few other bits and pieces have been done to it but when I tried to drive it the other day it just wouldnt boost over 1.5bar no matter what I do, and it makes no difference whether or not a pipe is connected to the actuator.

sorry for the long post....any ideas?

 

Nope, i simply didnt read it at all.. roflol

If you remove the pressure input, your turbo will boost until teh exhaust housing pressure overcomes the spring in the actuator.

 

Im confused now...is it right what its doing, or wrong? lol

 

Depends on the spring.
A good -31 will normally see 2bar + before tailing with no signal.

Are you sure you dont have an air leak that just happens at 1.5bar?

If so, you have 2 options.
1) Actuator is soft. (It will move easy by hand)
2) Turbocharger is FUBAR.

 

your initial post is correct with the pipe off the actuator completely the turbo should boost until it gives up or the engine does.

with the amal valve removed and the pipe connected to the actuator (from the compressor housing or similar) the turbo should boost until the wastegate opens at what even its set to

With an amal/bleed/boost controller valve inline the turbo will boost until the wastegate opens PLUS any bleed off from the amal/bleed/boost controller valve. (So will at higher boost)

sounds a bit strange that yours is not behaving this way, definately no boost leak? have you tried joining the hoses you took off from the amal valve to see if it will boost to the actuator setting?