Intake concept question?
03-19-2015, 07:55 PM
#31
Three Wheelin'
Thanks Bas. Do you have the specs on your stacks? Do you have a pic/s of the stacks sitting inside the plenum before it's sealed up? The reason that I am considering the 'side taper' is only due to size of turbo and heat etc. Seems like you've clearanced yours while retaining a thick plenum all the way across. btw, how thick is your plenum from top to bottom ?
03-20-2015, 10:44 AM
#32
Three Wheelin'
05-10-2015, 11:23 PM
#33
Rennlist Member
Thread Starter
So we're back on this path. Having been in discussion with Michael Mount about one of his beautiful intakes we have decided to still do one ourselves down here. Time and packaging being the primary reasons for not going with the MM version.
As you can see we have had a new flange made up. One of the concerns was the size of the inlet ports and the lack of 'meat' to make a good seal with the flange. (1st pic showing 'before'.) So they machined across the port to make it perfectly flat and then cnc'd the bore of the flange to suit the port shape but brought it back to round with a recess for a neat and easy weld of the runners.
I'm now considering making one of these 'dual plenum' style intakes if we can make it fit. The two constraints being the ducted cooling cores and wanting to keep as far from the turbo as possible for heat.
Another question I'm wondering is how big to make the tapered plenum and also how big to make the opening between this and the main plenum? I anticipate running this motor up to 28psi potentially. Not sure what sort of physics are involved in determining these questions? Any guesses?
As you can see we have had a new flange made up. One of the concerns was the size of the inlet ports and the lack of 'meat' to make a good seal with the flange. (1st pic showing 'before'.) So they machined across the port to make it perfectly flat and then cnc'd the bore of the flange to suit the port shape but brought it back to round with a recess for a neat and easy weld of the runners.
I'm now considering making one of these 'dual plenum' style intakes if we can make it fit. The two constraints being the ducted cooling cores and wanting to keep as far from the turbo as possible for heat.
Another question I'm wondering is how big to make the tapered plenum and also how big to make the opening between this and the main plenum? I anticipate running this motor up to 28psi potentially. Not sure what sort of physics are involved in determining these questions? Any guesses?
05-11-2015, 12:33 AM
#35
Rennlist Member
Thread Starter
Wondering on that logic Rod? I mean you assume that the main benefit for the dual plenum is to get the most even flow possible, no?
05-11-2015, 02:07 AM
#38
Three Wheelin'
Dual-plenum has nothing to do with restrictors. Group B cars did not have any constraints yet they used dual-plenums (Audis).
When you throw air into a plenum at high velocity a lot of times the cylinders will be fed different amounts of air because much of the air tends to push toward the back of the plenum. The dual plenum allows air to be pushed into the first plenum, and then move through a small opening into the second plenum which causes the air to equal out and supply all of the runners with the same amount of air.
When you throw air into a plenum at high velocity a lot of times the cylinders will be fed different amounts of air because much of the air tends to push toward the back of the plenum. The dual plenum allows air to be pushed into the first plenum, and then move through a small opening into the second plenum which causes the air to equal out and supply all of the runners with the same amount of air.
05-11-2015, 02:49 AM
#39
Rennlist Member
Thread Starter
The port size is larger than runners available. Not by a lot but it is what it is. While there may be a little neck where the runners are smaller in diameter I can't see it creating too much of a restriction. May even improve the Ram effect?
We will probably go with the traditional single plenum/throttle setup but I can't help but assume as long as the 'slot' between the two plenums is at least as large as the throttle body then it could work quite well. Speculation of course.
We will probably go with the traditional single plenum/throttle setup but I can't help but assume as long as the 'slot' between the two plenums is at least as large as the throttle body then it could work quite well. Speculation of course.
05-11-2015, 02:51 AM
#40
Rennlist Member
Thread Starter
Dual-plenum has nothing to do with restrictors. Group B cars did not have any constraints yet they used dual-plenums (Audis).
When you throw air into a plenum at high velocity a lot of times the cylinders will be fed different amounts of air because much of the air tends to push toward the back of the plenum. The dual plenum allows air to be pushed into the first plenum, and then move through a small opening into the second plenum which causes the air to equal out and supply all of the runners with the same amount of air.
When you throw air into a plenum at high velocity a lot of times the cylinders will be fed different amounts of air because much of the air tends to push toward the back of the plenum. The dual plenum allows air to be pushed into the first plenum, and then move through a small opening into the second plenum which causes the air to equal out and supply all of the runners with the same amount of air.
05-11-2015, 02:58 AM
#41
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probably higher velocities.
I'm quite surprised you guys haven't played with ITB setups yet. With that you could play with runner lengths if you had different length runners with flanges on either side & o-ring seals. Easily swap one length for another length.
Or make them variable length, by making a tube slipping into another. and holding them in place via silicone hose and clamps.
Nothing out of the way from Paul's fabricating skills.
I'm quite surprised you guys haven't played with ITB setups yet. With that you could play with runner lengths if you had different length runners with flanges on either side & o-ring seals. Easily swap one length for another length.
Or make them variable length, by making a tube slipping into another. and holding them in place via silicone hose and clamps.
Nothing out of the way from Paul's fabricating skills.
05-11-2015, 04:03 AM
#42
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Thread Starter
It wouldn't be so difficult Pauly but it's always a matter of timing and often budget. I have kind of relegated the idea of something really trick to the 16v motor if/when that gets done.
05-11-2015, 05:09 AM
#43
Three Wheelin'
I made the slot 25mm wide, so that the area will be equal or a bit bigger than trumpet inlet areas combined. It does not create any restriction but it allows the cylinders to get equal filling. I verified this by checking each cylinders EGT and examined plugs under a microscope. No need to trim fuel individually.
05-11-2015, 05:16 AM
#44
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But i always wonder about when you say "budget" haha.
There's so much id like to try with an intake. but for me it's time.
05-11-2015, 08:03 AM
#45
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Thread Starter
Ha, well despite appearances, there isn't an unending supply of cash...more's the pity! We are also hoping to 'defend' our state title for what it's worth and there isn't time to make something prettier.