Thread: VNT Turbo Setup??

Originally Posted by the_grubb

Like Rovercare said. You need load to get any boost.

When you rev at stand still the governor kicks in to limit fuel for the desired RPM.

When you are accelerating (ie. load), the governor is yet to limited fuel - as you are still requiring fuel to get to the desired RPM.


Zero Boost + Limited Fuel = Not Much Exhaust Gas = Limited Boost (ie. 3-4psi)


Zero Boost + Not Limited Fuel = More Exhaust Gas = More Boost


More Boost + Not Limited Fuel = Even More Exhaust Gas = Even More Boost


Put her in top gear up a hill and see how you go.

Took rovercare's advice and took her out to the nearest hill earlier, still no joy. Could only get about 5psi out of her no matter what I did. I haven't touched the fuel screw yet as until now I was happy to leave it as it was when it came out of the rangie, but will give her more fuel tomorrow when I can see what I'm doing. Sounds like it's going to be a balancing act of getting the fuelling right, and the VNT vanes set up right, and getting the boost pressure/vacuum balance set up right....

Any progress?

Have you tried wiring the vane lever against the stop (or just hooking it straight to vacuum)and taking it for a drive. That should get some boost happening but choke up as RPM increases.

Will give you a point to start from.

Steve

Originally Posted by mike_ie

Took rovercare's advice and took her out to the nearest hill earlier, still no joy. Could only get about 5psi out of her no matter what I did. I haven't touched the fuel screw yet as until now I was happy to leave it as it was when it came out of the rangie, but will give her more fuel tomorrow when I can see what I'm doing. Sounds like it's going to be a balancing act of getting the fuelling right, and the VNT vanes set up right, and getting the boost pressure/vacuum balance set up right....

Yes sounds like next step is to wind the fuel screw out.

As a guide, I just revved mine at stand still.

Vanes Closed - max boost just under 10psi
Vanes Open - max boost ~0psi

Fuel Screw is wound right out

Originally Posted by steveG

Any progress?

Have you tried wiring the vane lever against the stop (or just hooking it straight to vacuum)and taking it for a drive. That should get some boost happening but choke up as RPM increases.

Will give you a point to start from.

Steve

That's step 2^^^^

You need to ascertain vane direction and actual operation

It will make boost with vanes wired closed, I think about 18-20 psi from memory, but nothing from standstill with vanes wired open

Try both positions, if no extra boost, remove the fuel screw already

Edit: my boost figures were driven, not free revving

Originally Posted by the_grubb

Yes sounds like next step is to wind the fuel screw out.

As a guide, I just revved mine at stand still.

Vanes Closed - max boost just under 10psi
Vanes Open - max boost ~0psi

Fuel Screw is wound right out

The whistle is awesome with vanes open, shame it can't stay that way without more complex actuation control

Yet none deliver enough hp to spin all 4

That thing was slow for an Isuzu, needed more fuel, no need to be scared, it's no tdi300

Agree it needed more fuel, I'll take it for a spin tomorrow as I've driven it/them more than mike and see how it goes, and add fuel as needed

From what I'm told this morning, 900egt's, surging, no power, 5psi boost.
??? Anyone?