Esprit Dump Valves

**Trigger** Tue Oct 28, 2008 6:26 pm

As per request on the old LDC forum here are a few details and links I have found quickly regarding dump vavles on the Esprit Turbo.

"The Lotus Esprit does not come fitted with a Dump Valve for the
turbo. This is unusual because, especially in high boost applications,
the back pressure caused by lifting off the throttle can cause the
compressor of the turbo to stall. In extreme cases, the compressor can
actually shatter. After a dump valve is fitted, you will notice
an immediate change in feel to the car, especially after changing gear.
This is because the turbo is kept spinning during closed-throttle
conditions and is therefore able to provide full-boost quicker."

www.Andywhittaker.com

Esprit World Engine Modifications Guide

Esprit Dump Valves DumpValveinstall2

**NIJ** Tue Mar 24, 2009 4:26 pm

I have just purchased a dump valve for the non-chargecooled carb turbo. Not fitted it yet, will update with hopefully how easy it was to fit and some pics. or possible the tail of woe if its a git to fit!!!
cheers NIJ

**Trigger** Tue Mar 24, 2009 8:08 pm

NIJ wrote:I have just purchased a dump valve for the non-chargecooled carb turbo. Not fitted it yet, will update with hopefully how easy it was to fit and some pics. or possible the tail of woe if its a git to fit!!!
cheers NIJ

I would be interested in how you get on as although I don't have an Esprit I am looking into getting a blow off valve / dump valve for the turbo on my Elan M100.

The turbo on the Elan gives a chattering sound when the throttle suddenly closes which in my view sounds really cool but is supposedly caused by the turbo stalling on the back pressure. There are those who say that a BOV reduces wear on the turbo main bearing and aids quicker spool up when you put your foot down again. You can either re-circulate this excess pressure back into the air filter or dump it to atmosphere. Dumping it gives a 'whoosh' sound which you may like or may not?!

TopEnd do a kit for the Elan but it ain't cheap so I'm taking time to read through reviews etc incase there are any alternatives available. www.racetep.com/lotus.html

**NIJ** Tue Mar 31, 2009 2:43 pm

Just as an update for anybody interested, I fitted the dump valve which involved removing the flex connection between the turbo and the intake and replacing it with a new flex connection with a T. I then fitted the valve into the T connection and connected the other side of the valve to the Vacuum system. (This took about an hour, given the minimal space I have in a single garage)

Then the test drive which was disapoining as the car was exactly the same as before - so back into the garage for a review.

After concluding the fitting was correct a discussion with Dave from EspritPerformance was necessary (He was extremily helpfull) it was concluded that the carb turbo produces much less boost than the injection (which is the car people normally fit dump valves too) and hence a softer spring within the valve would be required.

The new spring arrived the next day and I removed the valve from the T, took it appart and changed the spring, re-assembled and re-fitted it (about 15 minutes)

Then out for a test drive again - this time working fine!

Will post picture of installation if anybody would like to see

**Trigger** Tue Mar 31, 2009 2:49 pm

Glad to hear you got it fitted. I have also read about the spring similar to what has been sugested to you I see. I think the N/A versions of the Elan require this change in spring also but the standard is designed for those with the turbocharger, same in your situation with the Esprit? I would like to see some photos of how you got on fitting it and its always great for future reference to other Esprit owners ... or owners to be lol.

**rocket63** Tue Mar 31, 2009 9:39 pm

You need to be aware that there are two types of valve. Recirculating and non recirculating.

The recirculating type will need a collector tank for it to breath into and most owners vent it to the airbox on the Esprit.

This is also the choice for owners who do not want the Pissssssssssssttttt noise when it vents. Silent in other words.

If you want the Pissssssssssssssssttt, then you want the non recirculating type which vents to atmosphere. This will cause a fine misting of oil in the engine bay longer term

The purpose of both is to relase the pressure associated to the turbo and thus reduce wear and tear over the long term.

**Trigger** Tue Mar 31, 2009 9:42 pm

Pisssssssssst sound Laughing

Sorry ... yea that is what I'm worried about because I don't want to sound like a chav but I do like the sound of the stalling turbo on the Elan as stock lol. I'm tending to be pushed towards a recirculating setup.

**NIJ** Wed Apr 01, 2009 3:32 pm

If you fit a recirc valve you will have no whoosh noise but you will also loose the turbo stall noise which some people like.

If you fit a non recirc type you will get the whoosh noise - but there are two main generic types.

These are the single piston type which gives a strong whoosh noise (it will sound like a Subaru) or the twin piston type which still gives a small whoosh noise, but it is far more subtle

Guess everybody would have thier own preference!

For those wanting a whoosh noise that have a normally aspirated car you can get a fake dump valve which basically plays an MP3 recording of a whoosh noise when you change gear. This is of course of no benefit other than the noise - pointless you may think - but someone is selling and making money out of it.

**Trigger** Thu Apr 02, 2009 1:52 am

Here is the set-up that I will be going for but with some nice red hoses and chrome pipes. If I decide to recirculate the air from the BOV then I will attach the pipe directly into the trash can set-up for the air filter Very Happy