Plenum spacer advice please

[Troogly]

Hi

I bought Griffter's superb 4.3 Big Valve Griff recently.

He and I have kept in contact and have got onto the subject of plenum spacers. Has anyone got experience of installing a spacer (eg from SC) and if so how were the results? Would be particularly interested to hear from those with 4.3's as I understand the original plenum design was for the 3.9 - 4.0 configuration?

Thanks

Troogly

[The AJP Griff]

Make one out of Tufnol,and give it a try.Tufnol is a superb insulating material and is easy to work with,and making a spacer would be pretty easy.It's also very cheap,and a peice big enough for what you need would cost less than £10 i suspect.

[eliot]

And also very dodgy for your lungs IRRC, so wear a mask.

[The AJP Griff]

eliot said:

And also very dodgy for your lungs IRRC, so wear a mask.

There was a thread on here not long ago regarding the safety of Tufnol.It USED to contain nasty substances,years ago,apparently.Nowadays it doesnt contain them for legal and safety reasons.Just like wood though,it can create dust whilst working it,so always wise to wear a mask

[Meatball]

Ive been thinking of making one of these myself out of tufnol
This may be of use http://www.tufnol.com/tufnol/default.asp?id=26

[Troogly]

Thanks for the Tufnol suggestions - this is interesting.

Has anyone experience of fitting the plenum spacer, is it a mod worth doing?

Thanks all

Troogly

[Pasco]

Troogly said:

Thanks for the Tufnol suggestions - this is interesting.

Has anyone experience of fitting the plenum spacer, is it a mod worth doing?

Thanks all

Troogly

Yep it is said that you can gain around 5hp........Lets say 3hp.......If you go by the typical rule of the thumb at 1hp = £100.00 then at £50 if you buy the one i did on Flea bay you are quids in

Or make your own you tight Sod

[900T-R]

Are we still talking about the plenum spacer or the insulating plate between intake manifold and trumped base? I can't really imagine how one would make the former from a sheet of Tufnol...

[MoreSteam]

Has anyone gone down the tufnol route for this before? Sounds interesting.

[V8 GRF]

900T-R said:

Are we still talking about the plenum spacer or the insulating plate between intake manifold and trumped base? I can't really imagine how one would make the former from a sheet of Tufnol...

If you make it out of a piece 1mm thick you have a gasket/insulating plate, if it's 12mm thick you have a spacer.

[eliot]

I doubt very much that you will see a power gain at mid/wot with a plenum spacer. More useful for keeping the heat-soak away from the upper manifold IMO. So when you are sat at the lights and you floor it away, your inlet temps will be lower - so less risk of pinking/det.

[Poledriver]

I've fitted a bigger plenum to my MG260, same effect as a spacer. It increases the volume of air contained in the plenum so when you open the throttle hard there is a small reserve of air. This is the only point at which there is any noticeable difference, and I certainly doubt that you would see anything measurable on a rolling road!

HTH

[eliot]

Poledriver said:

I've fitted a bigger plenum to my MG260, same effect as a spacer. It increases the volume of air contained in the plenum so when you open the throttle hard there is a small reserve of air. This is the only point at which there is any noticeable difference, and I certainly doubt that you would see anything measurable on a rolling road!
HTH

you need a pair turbos on it chap

[Poledriver]

eliot said:

Poledriver said:

I've fitted a bigger plenum to my MG260, same effect as a spacer. It increases the volume of air contained in the plenum so when you open the throttle hard there is a small reserve of air. This is the only point at which there is any noticeable difference, and I certainly doubt that you would see anything measurable on a rolling road!
HTH

you need a pair turbos on it chap

Unfortunately There is barely room for the intake manifold, let alone turbos!

Mind you, if I can find £6K I will get a s/c fitted!

[Chimjunkie]

I have the SC Power spacer kit which comes with a plenum spacer and an insulating spacer for under the inlet manifold. Not fitted yet.

[Poledriver]

Thread Hijack, but not off topic!

I'm doing a few engine mods and checks over the winter on my Wedge (puts on flame-proof jacket). I'm going to pay attention to all of those 'small' things which improve power and/or throttle response.
So far I am going to move the air cleaner so that it feeds directly into the AFM and close couple that to the plenum. I will also be heat-shielding the exhaust and putting vents in the bonnet to give a cool air feed to the filter.
Inlet manifold insulator and plenum spacer. RPI Higher pressure regulator. Any other items you guys can think of?

[Chimjunkie]

Thread hijack? You're not even a Griff owner! Says a Chim owner

[Poledriver]

Chimjunkie said:

Thread hijack? You're not even a Griff owner! Says a Chim owner

[spend]

Poledriver said:

So far I am going to move the air cleaner so that it feeds directly into the AFM and close couple that to the plenum.

I don't think its as simple as that, having a short run just enough for the flow to stabilize between each obstruction would seem preferential. For us it implies bends, I'm not sure if you could keep it straight?

I don't see a problem making a plenum spacer out of tufnol if you have trumpets. It does need to be flush with the inner wall, as long as the trumpets orifice has clearance above the spacer IYSWIM.

[rev-erend]

Poledriver said:

Thread Hijack, but not off topic!

I'm doing a few engine mods and checks over the winter on my Wedge (puts on flame-proof jacket). I'm going to pay attention to all of those 'small' things which improve power and/or throttle response.
So far I am going to move the air cleaner so that it feeds directly into the AFM and close couple that to the plenum. I will also be heat-shielding the exhaust and putting vents in the bonnet to give a cool air feed to the filter.
Inlet manifold insulator and plenum spacer. RPI Higher pressure regulator. Any other items you guys can think of?

A straight inlet is easy on a wedge ..

Just swap the water reservoir and the air flow meter.



Also check the front of the car - on the SEAC there are air ducts on the front and this air going into the inner wing - some SEACs were made with drill holes near the bulk head to allow cool air to the air filter.

Every little helps.