V8 Plenum dimensions
Discussion
V8 GRF said:
dbv8 said:
Just need the width and length of the base.
I need to know wether a 300mm x 200mm piece of tufnol is big enough to make a spacer.
Replied on the TVRCC, It's wide enough but short by about 20mmI need to know wether a 300mm x 200mm piece of tufnol is big enough to make a spacer.
Just popped out to the garage. 300mm covers the base, but the stepper motor housing protrudes a little further at the back.
Looking at that it would appear the base doesn't extend as far as the stepper housing 
You might get away with 300, but the only way to really know is to pop the plenum off and have a look.
Slightly off topic - my apologies to the OP.
Can someone explain the point of the trumpets?
I've been looking at the various base designs in the link above and they vary so much from TVR straight lumps of scaffold tube to flared CF trumpets to flared and blended nylon trumpet base to blended trumpetless base that I'm now confused about the purpose of these trumpets.
How many times can you get trumpet into a sentence
Can someone explain the point of the trumpets?
I've been looking at the various base designs in the link above and they vary so much from TVR straight lumps of scaffold tube to flared CF trumpets to flared and blended nylon trumpet base to blended trumpetless base that I'm now confused about the purpose of these trumpets.
How many times can you get trumpet into a sentence
Barreti said:
Slightly off topic - my apologies to the OP.
Can someone explain the point of the trumpets?
Oh dear you are opening a big brass band full of trumpets on this one.Can someone explain the point of the trumpets?
Original EFI v8s had trumpets to eqaulise the inlet tract i believe.
As the engine has been developed, increased in size and performance then modifications to this area have been made....
see here for more detail.. http://www.mez.co.uk/TuningTheRoverV8-pt5.html
Sorry I thought you were on about the TB... I created greater volume in the plenum a completely different way..
You don't have to stay round, it opens up some interesting possibilities and accomodates airflow around the bends:
You can open the outer ports to @45x50mm and flare the TB (asymmetrically) to account for the extra & more convoluted tracts of 1,2,7&8
You don't have to stay round, it opens up some interesting possibilities and accomodates airflow around the bends:
You can open the outer ports to @45x50mm and flare the TB (asymmetrically) to account for the extra & more convoluted tracts of 1,2,7&8
Something to consider chaps is that aluminium expands at 23 x 10^6 / °C wheras nylon which seems to be used for these blended bases expands at about 8 I think
Consequently when the engine is warmed up your ports won't line up by about 0.5mm for the last one.
Also in my experience a distinct end to a port with a sudden area change ( as provided by a trumpet) provides a stronger tuning pulse and more peak power.
That said the std rover and TVR 'trumpets' leave much to be desired and a blended base to these is probably superior.
Matt
Consequently when the engine is warmed up your ports won't line up by about 0.5mm for the last one.
Also in my experience a distinct end to a port with a sudden area change ( as provided by a trumpet) provides a stronger tuning pulse and more peak power.
That said the std rover and TVR 'trumpets' leave much to be desired and a blended base to these is probably superior.
Matt
interestly enough, we did some dyno testing at Joo`s a while back, and the blended base with a nylon insert, (okay the quality of the base and nylon was a bit naff)! lost 10bhp over the carbon trumpets.
however, the loss in power is more likely down to the fact that without the trumpets the plenum is then to big, reducing the hieght of the plenum over the blended base would probably give much better gains, ...... but have been sidetracked with other projects.
however, the loss in power is more likely down to the fact that without the trumpets the plenum is then to big, reducing the hieght of the plenum over the blended base would probably give much better gains, ...... but have been sidetracked with other projects.
Edited by clive f on Friday 3rd October 05:22
clive f said:
interestly enough, we did some dyno testing at Joo`s a while back, and the blended base with a nylon insert, (okay the quality of the base and nylon was a bit naff)! lost 10bhp over the carbon trumpets.
however, the loss in power is more likely down to the fact that without the trumpets the plenum is then to big, reducing the hieght of the plenum over the blended base would probably give much better gains, ...... but have been sidetracked with other projects.
however, the loss in power is more likely down to the fact that without the trumpets the plenum is then to big, reducing the hieght of the plenum over the blended base would probably give much better gains, ...... but have been sidetracked with other projects.
Edited by clive f on Friday 3rd October 05:22
,much appreciated other projects they are too!
YHM,mate
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