Some clarification please

[zollaf]

picture it like riding a push bike. in first gear you can peddle like mad but not get anywhere, but once going fast in a high gear you need to peddle hard to keep moving fast, same with a turbo, only needs to do a little work in the lower gears.

[alevuc]

The guys that fitted the turbo checked the arm with vacuum pump and said its all fine.

With the bypass you mentioned, if possible could you explain how i would do that???

Nothing should blow if i tried the bypass right??

Sorry for nagging mate, youve been a great help

[zollaf]

one small pipe comes from the vacuum pump. one goes to the turbo. join them and start engine. lever should move full deflection.

[alevuc]

Jus saw your comment re push bike - i had it the other way around.....thanks for clearing it up for me.

When you say vacum pump r you referring to the tandem pump??

If so i hav a somewhat larger pipe from the tandem pump running to the brake booster n on that pipe a t-piece with a smaller hose running to the solenoid valve block

So if im understanding correctly, disconnect from the solenoid valve block the hose from the tandem pump AND the hose from the actuator and connect them 2??

[zollaf]

yes, spot on. now, dont forget that a turbo has to provide say 1 bar of boost, about 15 psi. so thats over atmospheric which is 1 bar, so it needs to do 2 bar. now on tickover the engine uses very little air. as the boost comes on at 1800 rpm the turbo has to provide all the air plus pressurize it to 2 bar. at 4000 rpm it still has to do the same, so is actually providing an amazing amount of air and spins at upto 200,000 rpm. yes, two hundred thousand. thats fast.

[zollaf]

another test. sit in the car, engine off. pump the brake pedal. how many pumps to extinguish the vacuum and pedal goes hard. now hold foot on pedal and start car. pedal should move down almost instantly as vacuum replenished. now pump pedal rapidly, it shouldnt go hard. (engine still running)

[alevuc]

Yea hell yea, super fast!!!!

Hhhmm, prob there - when i pump my brake (engine off) it doesnt go hard....depresses all the way down

I heard this is a sign that the tandem pump is bad....???

[alevuc]

Sorry mate - made an error

The pedal does go hard when engine off, and when I start the car is does go down (slowly) and when i pump it gets hard but goes down (slowly) again

[zollaf]

if with the engine running, you can pump the pedal and it goes hard, then slowly sinks if you leave you foot on it, it is indicative of a fault either with the tandem pump or a leak in a vacuum pipe. i wouls now fit a vacuum gauge to one of the small pipes, probably where they go into the large servo pipe, and see what reading you get. 20 in mg is what you need, same as a petrol car. then pump the pedal an it shouldnt drop much until going back to 20.

[alevuc]

Thats awsome stuff ill try that - jus need to convince the wife the help and pump the brake haha

Thanks alot mate - il give it a go n let you know.

Could the tandem pump be causing me my underboost issue if its loosing vacuum?