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Sorry i didn't ring today ben, I saw you'd closed for xmas so didn't want to have you chatting about work on your limited time off with family.
They were off a gtr, so yes would be applications for boost, so i'm assuming the throttle body at an angle wont be of any use to a nasp application?
from what i've read 1.5x the displacement is about right in terms of the volume of a plenum.
In terms of the inlet tract lengths, what I was planning on doing is buying some (45mm?) ram-pipes and adjusting the end to suit a 172 inlet port shape. if i were to go with 90mm ones would this be sufficient or should i go as long as physically possible and have them pertruding into the plenum like one of the pictures i posted?
They were off a gtr, so yes would be applications for boost, so i'm assuming the throttle body at an angle wont be of any use to a nasp application?
from what i've read 1.5x the displacement is about right in terms of the volume of a plenum.
In terms of the inlet tract lengths, what I was planning on doing is buying some (45mm?) ram-pipes and adjusting the end to suit a 172 inlet port shape. if i were to go with 90mm ones would this be sufficient or should i go as long as physically possible and have them pertruding into the plenum like one of the pictures i posted?
I dont have reception down here in the sticks anyway lol.
Boosted apps require diff setups, and frankly, a lot (i'd say 95%) of the fabricated manifolds for the states for popular boosted apps, are nowhere near optimal in design and would work terribly as a NASP app. However, boosted cars make power easier with smaller restriction reductions.
Their fantastic fabrication skills though do make them look great!
Angles throttle position isnt such an issue, and the blend into the plenum in those cases is close to what your looking for, however you'll never get away with that particular use of space.
I tend to find most of the issues, personally, with the runner designs, tapers, entries and volumes. Their plenum volumes are small because they are boosted, so I certainly wouldnt stick to the 1.5x rule by any means. When it comes to plenum sizing, unless you run A LOT of engine simulation software that is extremely accurate (you can spend a week just building the stock engine into software to check that it comes up with stock numbers first), then nothing beats experience and the black art of understanding what you are trying to deliver from a plenum.
Running one on a dyno and checking the results is one thing, but on road use and the effects on just how the powercurve is delivered at different throttle angles and rates of opening/closing are far more important considerations. On the dyno you can just end up with excessively large plenums chasing numbers.
Running round entries isnt a bad thing, you'll be fine without manipulating it, just dont sit the entries proud of the plenum base....I hate that. Also the taper and CSA change along the runner will affect things greatly, and this will be dictated by how much runner length you decide to/can fit in......choosing a random length can cause you to hit a nasty point in pressure wave position relative to valve position and generate a huge shift in the torque curve peak/trough.
The smaller the plenum, typically the greater the transient nature of the engine, although cylinder to cylinder interchange becomes more of an issue, and so does the tuning effects of the plenum.
Its tricky, but I guess you gotta start somewhere, then go to the next extreem to see how things swing around on your particular application when your learning.
Boosted apps require diff setups, and frankly, a lot (i'd say 95%) of the fabricated manifolds for the states for popular boosted apps, are nowhere near optimal in design and would work terribly as a NASP app. However, boosted cars make power easier with smaller restriction reductions.
Their fantastic fabrication skills though do make them look great!
Angles throttle position isnt such an issue, and the blend into the plenum in those cases is close to what your looking for, however you'll never get away with that particular use of space.
I tend to find most of the issues, personally, with the runner designs, tapers, entries and volumes. Their plenum volumes are small because they are boosted, so I certainly wouldnt stick to the 1.5x rule by any means. When it comes to plenum sizing, unless you run A LOT of engine simulation software that is extremely accurate (you can spend a week just building the stock engine into software to check that it comes up with stock numbers first), then nothing beats experience and the black art of understanding what you are trying to deliver from a plenum.
Running one on a dyno and checking the results is one thing, but on road use and the effects on just how the powercurve is delivered at different throttle angles and rates of opening/closing are far more important considerations. On the dyno you can just end up with excessively large plenums chasing numbers.
Running round entries isnt a bad thing, you'll be fine without manipulating it, just dont sit the entries proud of the plenum base....I hate that. Also the taper and CSA change along the runner will affect things greatly, and this will be dictated by how much runner length you decide to/can fit in......choosing a random length can cause you to hit a nasty point in pressure wave position relative to valve position and generate a huge shift in the torque curve peak/trough.
The smaller the plenum, typically the greater the transient nature of the engine, although cylinder to cylinder interchange becomes more of an issue, and so does the tuning effects of the plenum.
Its tricky, but I guess you gotta start somewhere, then go to the next extreem to see how things swing around on your particular application when your learning.
If you've got the time, you can build up material with weld and reshape it.
Well, i think i'll run several tract length experiments,with out bell mouth's and it'll all be down to road testing. I've got my reasonably modified lump(larger tb, omex, cat cam 421's, 182 mani, exhaust) and a nigh on stock lump, (exhaust and air filter) so i can experiemt to see how it affects both engines. then once i've found one that suits both, i'll have it made up in ally, add bell mouths, and get mine mapped to suit and post the results.
I'm still pricing up.
The ally sheeting isn't overly expensive, 90-100mm trumpets your looking at about £60, then the pricey bit is getting it all welded together.
but if i were to get it all together and proven gains on a standard/average modifications(air filter/exhaust) then yes i'd look into getting a batch made and sold.
As the prototypes will be made in steel, I can do all the fabrication work myself. that engineering qualification is finally coming together! lol
The ally sheeting isn't overly expensive, 90-100mm trumpets your looking at about £60, then the pricey bit is getting it all welded together.
but if i were to get it all together and proven gains on a standard/average modifications(air filter/exhaust) then yes i'd look into getting a batch made and sold.
As the prototypes will be made in steel, I can do all the fabrication work myself. that engineering qualification is finally coming together! lol
yea, All the sensors and stock throttle body will be able to fit. they'll all go on the side nearest the cambelt, it'll just require taking out of the cvable trunking slightly lower down so go in the end of the plenham.
at the moment the one thing i'm going to have to look at making up is a small plug in extension for those on FBW throttle, as i don't have a ph2 to look at, i dont know how much spare cable is avaliable. but this is a minor thing comapred to what i'm currently doing! lol
at the moment the one thing i'm going to have to look at making up is a small plug in extension for those on FBW throttle, as i don't have a ph2 to look at, i dont know how much spare cable is avaliable. but this is a minor thing comapred to what i'm currently doing! lol
len_beach
ClioSport Club Member
E92 M3,172 track car
little question to ben, stan etc.
Can the plenum extend up over the throttle body to increase volume? or does it have to fall below like it does on mini-valvers? just looking that as i and many people still want to retain a/c, theres little to no room to drop down.
I can kind of see the space issues that you have to get past now... never realised how mucb of a problem it was!
Can the plenum extend up over the throttle body to increase volume? or does it have to fall below like it does on mini-valvers? just looking that as i and many people still want to retain a/c, theres little to no room to drop down.
I can kind of see the space issues that you have to get past now... never realised how mucb of a problem it was!
M
mini-valver
The other problem you'll have is the coolant gallery off the thermo housing. I've had to have the cable lobe on the TB shaped so it misses it as its CLOSE!
M
mini-valver
Pmsl! You may need smaller fans too.... I did!
Utilsing space and keeping even runner flow is especially hard, number 1 is a bugger.
Do what you must!
I dont see the idea behind a throttle body to then 4 ITB's?
Why not just use 4 direct to head bodies as normal.
Enlighten me as im a little dense
Why not just use 4 direct to head bodies as normal.
Enlighten me as im a little dense
???
len_beach
ClioSport Club Member
E92 M3,172 track car
I'm no expert but i'd say it's a halfway house between stock and ITB's.I dont see the idea behind a throttle body to then 4 ITB's?
Why not just use 4 direct to head bodies as normal.
Enlighten me as im a little dense
It has the benefits of 4 individual trumpets, hopefully designed to provide more power/torque but fed from the original throttle body.
This should cost much less than an ITB setup, all being well.
The original setup will be a vast compromise for one reason or another.
Evil Stanley, evil.
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