Powers plenum spacer

[Meatball]

Has anyone tried this http://www.tvrpower.co.uk/volumetric.efficiency.v8...
Seems good value for £85

[adyw]

Magna para better value for me and should do the same

£25 http://www.magnaparva.com/

will let you know next month if it has made any difference to the power when I stick her on the rollers

[thenick]

Doesn't the magna parva go between the inlet manifold and the trumpet base whereas the power spacer goes between the trumpet base and the plenum top? Also the magna parva is meant to cool inlet charge by isolating the plenum from the engine block whereas the power spacer is meant to increase the volume of air available in the plenum for quicker throttle response etc although there has been a fair bit of debate over its benefits IIRC...

[GreenV8S]

I can't imagine what made them decide to make it from aluminium, they have immediately lost any potential gains from the insulation effect. If they had just made a phenolic version it would have been cheaper and more effective. It just wouldn't have looked as pretty.

[Meatball]

thenick said:

Doesn't the magna parva go between the inlet manifold and the trumpet base whereas the power spacer goes between the trumpet base and the plenum top? Also the magna parva is meant to cool inlet charge by isolating the plenum from the engine block whereas the power spacer is meant to increase the volume of air available in the plenum for quicker throttle response etc although there has been a fair bit of debate over its benefits IIRC...

I spoke to Dom briefly and he said it helps with the shunting, gives about 3-4 bhp and looks nice?
Im not bothered about how it looks but the other two interest me.

[blitzracing]

Meatball said:

thenick said:

Doesn't the magna parva go between the inlet manifold and the trumpet base whereas the power spacer goes between the trumpet base and the plenum top? Also the magna parva is meant to cool inlet charge by isolating the plenum from the engine block whereas the power spacer is meant to increase the volume of air available in the plenum for quicker throttle response etc although there has been a fair bit of debate over its benefits IIRC...

I spoke to Dom briefly and he said it helps with the shunting, gives about 3-4 bhp and looks nice?
Im not bothered about how it looks but the other two interest me.

I cant get my head around about this extra air being available- The Plenum chamber is on the wrong side of the throttle plate to be a reservior of air, and will always be a vaccume, the level of this dependent of how wide open the throttle is and engine RPM. So the first thing you have to do when you snap open the throttle, is refill a bigger chamber with atmospheric pressure, so it takes longer for the pressure to rise. The only way I can see it improving the horse power, is by diluting (persentage wise) the exhaust gas that gets back into the chamber during the valve overlap period. Please someone prove me wrong !!

[350Matt]

Its not as simple as that I'm afraid, the size of the volume above the trumpet goes some way to dictating the strength of the tuning reflection, with 1 to 1.5 x engine capacity being a good balance between power and throttle response.

Also a larger plenum tends to reduce destructive tuning from other cylinders, as the pressure wave migration has more time / room to spread out.
In my F1 airbox testing days I tried all sorts of things and the only hard and fast rule is to make it as big as you can. bear in mind that this was with 1 throttle / cylinder and with a plenum you can't go too big as the throttle response will be rubbish.

So a larger plenum will increase power but will also reduce throttle response, like all things its a compromise.

I think the spacer is a good idea but like Pete says, they missed a trick by not making it out of phenolic resin.

Matt

[hiltonig]

I have spoken to SC who say the spacer has a heat insulating gasket.

[The AJP Griff]

It would be very cheap and easy to make one from tuffnol(carp grade)3mm thick,which is easily available on e-bay.I made a thermal insulator to go between my inlet manifold and trumpet base and it cost me £7 for enough to make two!!To make a spacer to go between the plenum and trumpet base would be much easier still,and that tuffnol is amazing at preventing heat transfer.After a lengthy run on a hot day i could press my hand on the plenum and it would be just luke warm-never hot!

Edited by The AJP Griff on Saturday 1st March 11:10

[anonymous-user]

Does anyone know if this will cause the plenum to touch the underside of the bonnet when fitted?

[That Daddy]

The AJP Griff said:

It would be very cheap and easy to make one from tuffnol(carp grade)3mm thick,which is easily available on e-bay.I made a thermal insulator to go between my inlet manifold and trumpet base and it cost me £7 for enough to make two!!To make a spacer to go between the plenum and trumpet base would be much easier still,and that tuffnol is amazing at preventing heat transfer.After a lengthy run on a hot day i could press my hand on the plenum and it would be just luke warm-never hot!

Edited by The AJP Griff on Saturday 1st March 11:10

Bloody hell!that mod must be worth the trouble even on a regular day that plenum is to hot to touch for more than a second or somay have to look into this come spring.

[adyw]

Yes the Magna pava insulator goes under the trumpet bases and does keep the plenum very cool, After a long run at full temperature the plenum is still cool, enough to put your hand on. As for bonnet closing not a problem, It would be easy to make your own, just get a small piece of insulating material. Does it give bhp increase ? in theory yes but we will see.

[BIGRAH]

Meatball said:

Has anyone tried this http://www.tvrpower.co.uk/volumetric.efficiency.v8...
Seems good value for £85

I have the Magna Parva T Spacer on mine and yes it keeps the Plenium very cool.
I have made a similar Plenium spacer from a £1.50 chopping board.

[The AJP Griff]

That Daddy said:

The AJP Griff said:

It would be very cheap and easy to make one from tuffnol(carp grade)3mm thick,which is easily available on e-bay.I made a thermal insulator to go between my inlet manifold and trumpet base and it cost me £7 for enough to make two!!To make a spacer to go between the plenum and trumpet base would be much easier still,and that tuffnol is amazing at preventing heat transfer.After a lengthy run on a hot day i could press my hand on the plenum and it would be just luke warm-never hot!

Edited by The AJP Griff on Saturday 1st March 11:10

Bloody hell!that mod must be worth the trouble even on a regular day that plenum is to hot to touch for more than a second or somay have to look into this come spring.

I must admit,i was sceptical about just how good it would be,but the results truly are impressive.it was a very satifying little mod to make,i only wished i'd done the plenum spacer as well,and did some dyno tests on both-missed a good oportunity there!

[Pink_Floyd]

How thick is the Magna Parva T Spacer that goes between the trumpet base and inlet manifold.

[adyw]

about 3 or 4 mm

[crackedfinger]

Would both be a good idea? One to space the plenium and the other to reduce heat in the entire setup including the trumpetbase?

[The AJP Griff]

crackedfinger said:

Would both be a good idea? One to space the plenium and the other to reduce heat in the entire set up including the trumpetbase?

Both would be a great idea,one to isolate the heat from the inlet manifold,and one to increase the plenum capacity and reduce plenum temp further.If you need to know just how much bonnet clearance you have,just shut the bonnet with a piece of plastercine on the highest part of the plenum,and you will then find your max clearance.If i were doing it again i would use 3mm thick Tuffnol on the manifold to trumpet base isolator,then as much as i could sensibly get away with for the plenum spacer.
If you go on e-bay and key in Tuffnol,you'll see some 'carp grade' sheets there.If you dont see the size/thickness you want just contact the seller,they were most helpfull when i wanted some,and can provide just about any size you could ask for
Get stuck in,it's great fun

Pinkfloyd-I was told the magna parva was 2mm thick.

Edited by The AJP Griff on Monday 3rd March 12:10

[350Matt]

The Magna Parva spacer is 2mm thick but being as the heat transfer coefficent is 0.7W(m.K) compared to 237W(m.K) of ally so can see you don't need big chunks of it to make a big difference.

Matt

[chrispitman]

Anyone here know what type of Rubber Gasket material would be suitiable for use in the temps in the engine bay.

Was thinking about the Plenum to Trumpet base Insulator could you not make a thick insulator come gasket.

Rubber Gasket (I belive you can by flat gasket sheets to cut to shape)
Tuffnol say 3mm
Rubber Gasket

Bond the lot together then you will have a insulator and it will seal without having to messabout with sealant each time you want to remove the plenum.