All these posts about bigger turbos. How about a smaller turbo that gets to 5psi 500 rpm sooner than the turbo on a 603? For people like me who have no need to get to 100 mph that would be a welcome enhancement. Something cheaper and more easily available/adaptable than VNT please Thoughts?

Sixto
93 300SD

I guess you could, but you would loose power in the higher range, which means slower hill climbing, merging etc. You don't just use max boost when you are going 100 mph. What you need to do is use that smaller turbo to feed the stock turbo, or a larger turbo.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

A VNT is no more difficult to control than a normal turbo and does not take any more effort to mount.

Are there aftermarket VNT controllers that respond to rpm only? Are there VNT turbos for under $500?

I should get one of those Evo afterburner turbos with an injector that fires fuel into the turbine when you step on the clutch

Sixto
93 300SD

I thought that you needed to have the larger turbo first, so that the gasses can go thru it into the smaller one and spool it, and then spool the larger one when theres enough exhaust.

I got my VNT for $125. You don't need anything more than a pressure actuator to control it.

The turbo's don't have an injector in them. The ECM changes the spark timing to fire when the exhaust valve opens so that combustion occurs in the exhaust manifold. Bang bang!