Plenum Spacer and Thermal Gasket
Discussion
Im going to remove mine because the top of the plenum now catches the bonnet. I’ve adjusted the bonnet as high as it will go without looking ridiculous! Very frustrating. I have sc engine mounts which should be standard, perhaps the spacer isn’t appropriate for a Griff. I’m going to remove my spacer and see if it makes a difference to low rpm running. My car doesn’t shunt but its just not as smooth below 2k rpm.
I fitted one of these when I did mine as it was.apart, didn't see the point in the spacer.
https://www.actproducts.co.uk/product/ti018a-therm...
https://www.actproducts.co.uk/product/ti018a-therm...
On my old 390SE i fitted a piece of 1/16" birch ply between the manifold and the trumpet base, clamped it in (with the manifold off the engine!!!) position by bolting the two pieces together and ported it with a drill mounted flap wheel. Disassembled, cleaned up, siliconed it in place and then refitted it all to the car using red fibre washers under the trump base bolts to further prevent heat conduction through the bolts. I definitely noticed that the plenum top ran cooler afterwards, and I'd say that to anyone, because it DEFINITELY ran cooler. Horsepower? who knows. possible slight densification of the charge air might have resulted in 0.00000001 BHP...
Personally I wouldn't spend a load of cash on shiny things that add weight and offer benefits based on pseudoscience, but if you are trying to screw every last HP out of it, it probably does make a slight difference, even if its just reducing the likelihood of detting.
Personally I wouldn't spend a load of cash on shiny things that add weight and offer benefits based on pseudoscience, but if you are trying to screw every last HP out of it, it probably does make a slight difference, even if its just reducing the likelihood of detting.
When running in traffic the plenum will get hot, very!
When I come off the track, (or fast roads I guess) due to the huge rush of air through the plenum, it is icy cold.
This is without a spacer.
In traffic, the whole of the engine compartment is like a furnace, no matter if the spacer is made of sheet ice, the plenum will still get hot.
Mind you, I applaud you for making your own and as you say, every little helps, even if it is impossible to measure.
When I come off the track, (or fast roads I guess) due to the huge rush of air through the plenum, it is icy cold.
This is without a spacer.
In traffic, the whole of the engine compartment is like a furnace, no matter if the spacer is made of sheet ice, the plenum will still get hot.
Mind you, I applaud you for making your own and as you say, every little helps, even if it is impossible to measure.
^^ yup whilst I fully understand the people who say if it doesn't add 10 percent power you won't notice the difference, the fact is just 1hp extra makes the car faster than it was.
Add 10 things at 1hp each and you've got 10hp gained.
When the rolling road is at Neil Garner's Open Day and everyone is watching, all of a sudden these 10 things become the most important things in the world!
Add 10 things at 1hp each and you've got 10hp gained.
When the rolling road is at Neil Garner's Open Day and everyone is watching, all of a sudden these 10 things become the most important things in the world!

lancelin said:
Im going to remove mine because the top of the plenum now catches the bonnet. I’ve adjusted the bonnet as high as it will go without looking ridiculous! Very frustrating. I have sc engine mounts which should be standard, perhaps the spacer isn’t appropriate for a Griff..
I've got standard mounts and it still rubs against the bonnet. A waste of money in my opinion.You have missed the point mate, you chop a bit off your dining room table and slide it in....
On a serious note, as well as rover V8's, Mazda MPS's are popular in our house hold. We run versatune software (the equivalent of rover gauge).
On one the MPS's, the PCV failed, which on those is an inlet manifold off job. On the relevant forum at the time they were raving about insulated gaskets and when I checked, the insulated gasket was hardly any more expensive that than an OEM gasket.
So we did a few logs, both wide open throttle and gentle town driving. The insulated gasket made absolutely no measurable difference to any temperature.
Nice idea, and may give 0.0002 HP as well as a nice warm feeling of money well spent, but in the real world a waste of time.
Of course when I came to sell it and the new owner wanted to know about all the modifications, I made a bit thing about the insulated gasket as it was something that others often over looked.....
On a serious note, as well as rover V8's, Mazda MPS's are popular in our house hold. We run versatune software (the equivalent of rover gauge).
On one the MPS's, the PCV failed, which on those is an inlet manifold off job. On the relevant forum at the time they were raving about insulated gaskets and when I checked, the insulated gasket was hardly any more expensive that than an OEM gasket.
So we did a few logs, both wide open throttle and gentle town driving. The insulated gasket made absolutely no measurable difference to any temperature.
Nice idea, and may give 0.0002 HP as well as a nice warm feeling of money well spent, but in the real world a waste of time.
Of course when I came to sell it and the new owner wanted to know about all the modifications, I made a bit thing about the insulated gasket as it was something that others often over looked.....
Fitted a spacer once, took it off and threw it in the bin. Waste of time and money. Any advantages as I see it are Placebo, similar to those who say things like, 'I fitted smooth bore elbow and noticed an improvement' or, ' I removed a spring and improved throttle response', I painted my spark plugs' etc. Yes, any minimal improvement added together will help but as a stand alone? marketing crap imho. Not shouting anyone down honest but really?
peace and love, xx
peace and love, xxEdited by macdeb on Wednesday 30th January 17:29
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Breakdown or something similar I was told when I asked Neil.
