Help please guys

[v8steve007]

just bought this a jon eales plenum


and have this fitted









is the thing on the back a stepper ? it dont have any wires just a hose!
the new plenum dosent have any mounting holes see pic ,
it does have a cold start injector!

cheers

[v8steve007]

OK just found out its a overrun valve can i run without it ? as there is no mounting for it on the new plenum

[rev-erend]

Steve

The plenum top you have is for the flapper system of EFI.

The later system is Hotwire and uses many different components.

What system did you take off ?

[v8steve007]

the bottom 2 pics are whats on the car now i belive its a flapper , but the one in the top pic has no mounting holes for the overrun valve !!

[TVRleigh_BBWR]

Can't you pop the blanking plug out, and then drill and tap the plenum to take the overrun valve.

[v8steve007]

I can but just wondered why it was blocked off in the first place !

[rev-erend]

Agree with Leigh - looks like you cam take out the blanking plate .. but it does seem to leave you with another problem in that there are no mounting holes .. and these would need to be deilled and blind bolts fitter.. I suppose.

Can I ask why you are changing ?

Have you measured the inlet flange - is it 71MM across the butterfly .. that would be the normal reason for changing.

[TVRleigh_BBWR]

v8steve007 said:

I can but just wondered why it was blocked off in the first place !

It must be a converted Land Rover plenum, as they did not have Extra air valve.
I think it was only TVR and SD1 VP engine's etc that had the overrun valve.

I don't think the lower tune engines needed it.

Some just had a 2nd pipe by the throttle body.

[v8steve007]

yes its 71 , ok i will drill out and tap to fit the valve cheers guys

[rev-erend]

Steve

Just a point and you might know this already - it's possible with the bigger plenum 71mm valve - that the engine might now run lean due to the extra air..

It all depends on whether the air flow unit copes with this or not ..

It can measure throttle position and also measures the air flow via the flapper .. and might be able to cope OK .. with just the upper full throttle positions being lean.

Listen out for pinking is the easiest test and possibly a rolling road session to confirm the afr is OK..

[deetes]

I recently spoke to Tim, at ACT, about the overrun valve and he reckons they don't need them.

If and when I ever get my Wedge to run correctly again I shall remove it and blank the hole.

[rev-erend]

It would do no hark to try running without it..

Just seal off any pipes that would have connected to it..

[v8steve007]

I think it has a bigger afm of a jag a lucas 2am and maybe bigger injectors !!