Discussion
How much difference does the fitting of a 72mm inlet plenum make?
I understand it's quite and increase over the 64mm? but how much more air can it flow?
Does it make a difference all the way through the range? or is it just at higher revs/loads?
My engine made 300brake last year without one.....
I understand it's quite and increase over the 64mm? but how much more air can it flow?
Does it make a difference all the way through the range? or is it just at higher revs/loads?
My engine made 300brake last year without one.....
not sure to be honest Ant, I changed mine for a 72mm but had no dyno proof to prove any benefits one way or the other, but I would say it will give you some gains over the 64mm, but bear in mind if you are still on the standard AFM you`ll be restricted by the size of that first.
I`m sure Spendy will be along with an accurate sentence or two shortly.
I`m sure Spendy will be along with an accurate sentence or two shortly.
Edited by clive f on Monday 10th May 19:34
clive f said:
not sure to be honest Ant, I changed mine for a 72mm but had no dyno proof to prove any benefits one way or the other, but I would say it will give you some gains over the 64mm, but bear in mind if you are still on the standard AFM you`ll be restricted by the size of that first.
Come on now Clive, you know I am an Emerald laddie....Ant. said:
clive f said:
not sure to be honest Ant, I changed mine for a 72mm but had no dyno proof to prove any benefits one way or the other, but I would say it will give you some gains over the 64mm, but bear in mind if you are still on the standard AFM you`ll be restricted by the size of that first.
Come on now Clive, you know I am an Emerald laddie.... sorry mate, temporary memory loss due to old age, so I`d get a 72 on there asap mate350Matt said:
Hi
If you've not already got a short trumpet base and large throttle then get it on as you can sort the fuelling out and make the most of it, you'll typically find the engine feels 'uncorked' and will rev more freely
Maybe I should have given more info, the engine has 45mm trumpet base, matched to the inlet which is also matched to V8D Stg3 heads.If you've not already got a short trumpet base and large throttle then get it on as you can sort the fuelling out and make the most of it, you'll typically find the engine feels 'uncorked' and will rev more freely
lwt said:
On my 450 with mapped ECU (KMS) and a 218 cam, the 72mm plenum was worth about 15bhp and a large radius bend feeding into it was worth another 12bhp. These two are probably the best return in bhp per pound. (The general figure, I believe, is typically 100pounds=1bhp)
Ian.
Thats the same cam that I have, what power did you end up making?Ian.
Ant. said:
Well, bit of a thread resurrection, but to update it.....
The 71mm plenum I tried on the car made no difference to the top end, and on the advice of Joo , the car is back on the standard plenum.
Very pleased with the results.
Plenum is in classifieds if anyone is after one.
The 71mm plenum I tried on the car made no difference to the top end, and on the advice of Joo , the car is back on the standard plenum.
Very pleased with the results.
Plenum is in classifieds if anyone is after one.
was the letterbox part of the plenum just after the butterfly throat reworked too or just the bigger butterfly Ant? I am surprised but no doubt someone here will have an explanation 
There's only myself AFIK that has done that work to the internals, Ant was certainly shown all the places to 'hack out'. TBH most of the 72mm plenums I've seen haven't even had the throat to the air pipe chamfered! but have still shown improvements on 5 litre engines at least (maybe its the bigger inlet manifold tracts & valves that the throttle mates well with?).
I hope my linkage isn't being sold with it BTW Ant ~ that was a loaner if you recall
I hope my linkage isn't being sold with it BTW Ant ~ that was a loaner if you recall
spend said:
There's only myself AFIK that has done that work to the internals, Ant was certainly shown all the places to 'hack out'. TBH most of the 72mm plenums I've seen haven't even had the throat to the air pipe chamfered! but have still shown improvements on 5 litre engines at least (maybe its the bigger inlet manifold tracts & valves that the throttle mates well with?).
I hope my linkage isn't being sold with it BTW Ant ~ that was a loaner if you recall
no mate, it is safe!I hope my linkage isn't being sold with it BTW Ant ~ that was a loaner if you recall
spend said:
There's only myself AFIK that has done that work to the internals, Ant was certainly shown all the places to 'hack out'. TBH most of the 72mm plenums I've seen haven't even had the throat to the air pipe chamfered! but have still shown improvements on 5 litre engines at least (maybe its the bigger inlet manifold tracts & valves that the throttle mates well with?).
I hope my linkage isn't being sold with it BTW Ant ~ that was a loaner if you recall
I've opened mine up... and given the pillar thing a wing type shape... Even put a chamfer on the butterfly itself as its about 3mm thick!.... I hope my linkage isn't being sold with it BTW Ant ~ that was a loaner if you recall
Appears to work fine but it was over winter.. so can't comment on it working 'better'...
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