compound turbo set up

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Originally Posted by DRanged

The biggest problem is I can't give it enough fuel. So until I decide what to do .

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Originally Posted by rovercare

Is the fuel pump stock? Just that mine has no fuel screw left and can't deliver enough fuel to get past 720* pre turbo with the vnt, so you may need some pump mods

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I guess the answer is stock

This is why I never chased more hp, pump mods are spensive!

Could the vibration be the flywheel just not being heavy enough? The standard problem of doubling the torque and needing to double the inertia to keep the torsional vibrations th same.
If so, welcome to my world.

I'd wastegate it to 20 as a good place to start.

ill hopefully get time this week to weigh my flywheel and get an intertia ring cut and fitted touch wood :angel: ill report back with weights when done...unfortunately im a long way from driving the car so no test drives will be able to be conducted :(

Ok after talking with Eric ( the109) looks like O have used the wrong flywheel. I am 90% sure I used a non turbo truck flywheel.

Any one know the Isuzu p/n for a turbo flywheel???

Justin

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Originally Posted by Dougal

Could the vibration be the flywheel just not being heavy enough? The standard problem of doubling the torque and needing to double the inertia to keep the torsional vibrations th same.
If so, welcome to my world.

I'd wastegate it to 20 as a good place to start.

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Yes, I have this problem with vibration now. Bad for the vibration :( Good because I now have decent torque :D

Well in that case, turbo vs non turbo flywheel isn't going to help you. You need to double the inertia of the flywheel. You can add thickness (Cheif had a line on I think a 6BD1 flywheel) or you can add an inertia ring.

Dougal
The turbo flywheel is approx16kg. Any idea what is a good target. I assume the inertia ring is bolted on around face of the flywheel just clearing the pressure plate then.

J

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Originally Posted by DRanged

Dougal
The turbo flywheel is approx16kg. Any idea what is a good target. I assume the inertia ring is bolted on around face of the flywheel just clearing the pressure plate then.

J

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Yes my 1985 turbo flywheel is also approx 16kg. Same weight as the flywheel on my non turbo 2.2 diesel work car. On the 2.2 it's about right.

Cummins 4BT's (also 3.9L 4 cyl) run flywheels around 50lb, industrial Isuzu's run flywheels which look to have 3x the metal in them. I don't have weights though.

I say double it and then some. I run a 275mm clutch and there is space around that for an inertia ring which could add ~80% to the original flywheel inertia. But I haven't done it yet.
You can add as much weight as you have space. A spacer ring between bellhousings could add as much space as you like.

off topic Q, as this has been a great read.

does incresing the flywheel weight affect engine breaking?

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Originally Posted by weeds

off topic Q, as this has been a great read.

does incresing the flywheel weight affect engine breaking?

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Its a 4bd1 - I doubt its going to break it :p

Steve