TVR RV8 Plenum Chamber

[Transmitter Man]

Can any engine guru's on the brain trust confirm whether or not there was more than the one model of cast ali plenum chamber used across the different engine range from 350 through to the 5.0L?

If only one type then I need to find a spare if anyone has one for sale - cheap

Phil
420 SEAC

[900T-R]

IIRC all the flapper and hotwire injection plenums were the same casting, however I think the good fellows at NCK/TVR Power bored your SEAC one to 70 mm throttle butterfly size...

[spend]

All the hotwire TVR ones I have seen are stamped with the LR 3.9&4.2 under the cover.

[pwd95]

I've got a spare one you can have Phil. I'll just go & dig it out, it's off my old 400SE Hotwire, has '3.9' cast in to it.

[pwd95]

Ere we go....

[Barkychoc]

Thats a hotwire plenum - the flapper one has a mounting point for a 9th injector/ cold start device whatever you want to call it.

I also assume the flapper version has a different arrangement where the stepper motor goes on the hotwire version.

Later ones have a recess for the plenum badge - but as far as I know its only a cosmetic difference.

Edited by Barkychoc on Saturday 24th October 20:02

[Transmitter Man]

Hi Wyn,

Thanks for the offer.

However after what Chris has stated - me thinks I need a flapper plenum.

If I convert to hotwire I've been told I'd lose all my bangs & pops on the overun and we can't have that can we

Would anyone have photo's of a flapper plenum so I can see the differences.

Eric,

Is there enough meat on the standard plenum to take it out to 70mm or were these 'special' castings?

Many thanks.

Phil

[pwd95]

Here's the back of a flapper...

Edited by pwd95 on Saturday 24th October 22:22

[900T-R]

Transmitter Man said:

Eric,

Is there enough meat on the standard plenum to take it out to 70mm or were these 'special' castings?

Many thanks.

Phil

Eliot @ mez.co.uk takes them out to 72 mm but he inserts a new sleeve for that purpose. John Eales, ACT & V8D do the same (or at least similar) IIRC.

[JR]

900T-R said:

Transmitter Man said:

Eric,

Is there enough meat on the standard plenum to take it out to 70mm or were these 'special' castings?

Many thanks.

Phil

Eliot @ mez.co.uk takes them out to 72 mm but he inserts a new sleeve for that purpose. John Eales, ACT & V8D do the same (or at least similar) IIRC.

The thickness varies from casting to casting so it's pot luck.

[spend]

JR said:

The thickness varies from casting to casting so it's pot luck.

There are also some who swear by cunning (very acute) angles when boring to maximize the size apparently.

You can also do a lot of porting behind the butterfly that will yield similar results. Particularly tricky and labour intensive, so inherently suitable for the DIY-er. A touch of fettling to the butterfly and spindle also helps if sculpting metal is your thing

[Transmitter Man]

Elliot's MEZ site is really a very good read.

Looks like he's come across most every induction system out there.

My reason for wanting a spare plenum is to experiment with various metal finishing techniques including polishing, wet spraying etc. Don't think it's suited to anodising.

Phil

[Transmitter Man]

Elliot's MEZ site is really a very good read.

Looks like he's come across most every induction system out there.

My reason for wanting a spare plenum is to experiment with various metal finishing techniques including polishing, wet spraying etc. Don't think it's suited to anodising.

Phil

[Transmitter Man]

Elliot's MEZ site is really a very good read.

Looks like he's come across most every induction system out there.

My reason for wanting a spare plenum is to experiment with various metal finishing techniques including polishing, wet spraying etc. Don't think it's suited to anodising.

Phil

[Transmitter Man]

Elliot's MEZ site is really a very good read.

Looks like he's come across most every induction system out there.

My reason for wanting a spare plenum is to experiment with various metal finishing techniques including polishing, wet spraying etc. Don't think it's suited to anodising.

Phil

[eliot]

JR said:

900T-R said:

Transmitter Man said:

Eric,

Is there enough meat on the standard plenum to take it out to 70mm or were these 'special' castings?

Many thanks.

Phil

Eliot @ mez.co.uk takes them out to 72 mm but he inserts a new sleeve for that purpose. John Eales, ACT & V8D do the same (or at least similar) IIRC.

The thickness varies from casting to casting so it's pot luck.

My sleeve is only for the attachment of the air hose. It doesn't extend inside the actual throttle. Its the varying quality (thickness) of the castings which makes taking them out to 72 a lottery. Some are decently thick, some break through after taking just a couple of MM out of it.

The two different styles I've seen are the ones in this thead (3.9 logo not enclosed) and this type where the logo is enclosed (and removed):

[Wotland]

71mm is the maximum possible without too much work.

One time I converted one in 73mm but this time the plenum required an complete sleeve.

[url=http://www.servimg.com/image_preview.php?i=335&u=11148396][/url]

[eliot]

Wotland said:

71mm is the maximum possible without too much work.

Indeed. At 72mm you sometimes just start to break through into the Idle air screw - and all this assumes a good casting to start with. I have a couple in the shed that were scrap at 67mm.

[Transmitter Man]

How far in is the rebore?

Do you ever increase the size of that butterfly?

Sorry if this is a dumb question.

Elliot,

Are you up in Milton Keynes?

Maybe you can take a look at my SEAC plenum sometime.

Phil

[eliot]

Transmitter Man said:

How far in is the rebore?

Do you ever increase the size of that butterfly?

Sorry if this is a dumb question.

Elliot,

Are you up in Milton Keynes?

Maybe you can take a look at my SEAC plenum sometime.

Phil

The rebore goes all the way down and a new butterfly is made to suit the new bore.
Yes - I'm in MK (Newport actually) bring it round and I can take a look at it.