Boost Guage/dump valve plumbing-late S4

[MGFCrasher]

Hi,

I am helping the guy I sold my S4 to,in getting the car roadworthy again and up to scratch.This wasen't the intention but as I am there quite a lot (he is restoring two other cars for me) I have been helping him out a bit.

Aside from all the normal issues the vacuum plumbing seems a bit strange.

Firstly the dump valve is turned around the other way to normal i.e facing the rear of the car and the vacuum pipe is teed into a black hose that runs to a nipple on the intake manifold as far as I can see.The other end of this hose goes to the front of the car via a thin bore hard plastic tube.This I imagine is the heater vacuum pipe.

Also teed into this vacuum pipe is the boost guage.So effectively both the boost guage and the dump valve are teed into the same vacuum line that goes from the manifold to the heater .

Now this is the later S4 that has the plenum blanking plug where you would connect a boost guage to on an se,so I was wondring if anyone has ideas on whether this set up is right or wrong.

I only drove the car twice and it boosted no more than .5 bar.The dump valve worked but appeared to be dumping on a feathered throttle and not just on gear changes.

I have done searches but all seem be be based on the older SE type 4 cyl vacuum system.

Any help or input appreciated as usual.

Rich

Esprit mechanic ,not owner!

[mr.oogieboogie]

what year is the car, if it helps i can take some pics of my engine (1994) and email them to you at about 16:00 if that would help

[MGFCrasher]

Brilliant,

Its a 1994 ,registered 95 ,so late 94.The one with the vacuum pump only in the boot cubby hole.The vaccuum switches pipework. etc are all in the engine bay.

Thanks for your help,much appreciated. Email is Richsadd@btinternet.com.

Rich

[mr.oogieboogie]

taking them now give me 10mins or so

[MGFCrasher]

Thanks Pete,

This is what makes owning a Lotus so good,peoples help.

I have the emails and will investigate first thing.I know I have the sticker on the engine lid but actually having others input helps so much.Especially when non standard items such as boost guages and Dump valves are fitted.

Cheers

Rich

[MGFCrasher]

Thanks Pete,

You have confirmed that the thin hard plastic hose I am thinking of normally goes straight into the inlet manifold via an elbow.

Have you plumbed in a boost guage or dump valve?

Anyone else done this on an s4 or are Pete and I alone?

I am thinking about changing the dump valve to be teed in at the front of the engine as per the LEW guide,and buying a nipple to replace the blanking plug in the plenum for the boost guage,but I'm interested if anyone else has done it differently.

R