1984 Federal Esprit

[trackmagic]

Hey guys,

Looking for an explanation of the butterfly valve that is directly after the turbo outlet on my Esprit. I don't see a desription in the manual or part catalog. It is operated by a vacuum servo. I have some theory on the function but was hoping someone here would have a idea as to what iti is.

Thanks,

Jeff

[tbeggan]

It's designed to decrease turbo lag by temporarily increasing exhaust backpressure at the beginning of the turbo cycle.

[WayneB]

Its actually designed to close when the engine is shut off to stop heat from the turbo migrating to the carbs via the inlet diffuser and causing hot start problems caused by the fuel getting hot and boiling in the carb float chambers. (vapour lock)

Its not fitted onto any of the UK/ROW Esprits, and was done away with on the Federals when the fuel injection came in .

Edited February 23, 2007 by WayneB

[Jussi]

I have heard someone called it "Arizona valve", like Wayne said it prevents hot start problems.

If you're not living middle of the desert I would suggest to get rid of that valve. We ditched that valve and discovered it never had been fully open on my car. Better check it works properly (opens).

On the other hand you're living in California, so it might be a bit warmer than here Perhaps better not to remove it then...

Edited March 7, 2007 by Jussi

[Esprit Aviation]

Removed mine w/ no problems......= better flow!

[1984_lotus_esprit]

The butterfly valve on the output of the turbo charger is to help the vehicle conform to California

evaporative gas emissions. Excess fuel in the carb float bowls will evaporate and be collected

by the charcoal canister in the right rear quarter panel area when the IGNITION KEY is OFF.

The valve blocks an evaporative emission path. Without this valve, Lotus would have been

forced to go to fuel injection earlier than 1986MY.

I think the best, but not much of a description, is on the emission controls diagram

on the under side of the rear boot lid.

When starting the your car, you have to do a do a few revs to develop a vacuum to open valve

to let air into the engine before the car can start. So with having, the crank times will be longer

than jamming it open or removing it.

I removed this particular section of a European Esprit Turbo's diffuser (the Euro version does not

have this actuator), and have experienced no ill impact for removing this device.

Edited March 8, 2007 by 1984_lotus_esprit