intake manifold design?
04-18-2006, 05:12 AM
#31
0.0 BAR
Join Date: Jan 2005
Posts: 21
Re: intake manifold design?
The champ car engine is ultimately tuned and built as N/A, it only boosts for a max of 60 seconds during a 2 hour race. I don't think the velocity stacks are tuned for boost. If they were then the engine wouldn't be producing maximum power for 99% of the race.
04-18-2006, 06:03 PM
#33
1.0 BAR
Join Date: Nov 2005
Posts: 483
Re: intake manifold design?
Originally Posted by sailman
i believe there is still a suction pulling in air with a n/a engine.... take the head off an engine and put a piston or the piston (if single cylinder) at TDC and put your hand over the top of the cylinder and turn the crankshaft.... there is deffintly a suction proving that a cylinder will pull in air, or put your hand ocer the intake of a running motor...... it sull suck the ---- outta your hand
or better yet where the ---- do you think vaccum comes from for opening your BOV? if a cylinder didnt pull in air then a BOV would never work....... so hence whhy dont ya shuve your dick in your cold air intake and test out jizz injection
yes any empty space is filled by atmospheric pressure, but in terms of a motor, i believe you are wrong
or better yet where the ---- do you think vaccum comes from for opening your BOV? if a cylinder didnt pull in air then a BOV would never work....... so hence whhy dont ya shuve your dick in your cold air intake and test out jizz injection
yes any empty space is filled by atmospheric pressure, but in terms of a motor, i believe you are wrong
04-20-2006, 01:53 PM
#34
1.5 BAR
Join Date: Jan 2003
Posts: 1,037
Re: intake manifold design?
Originally Posted by Joseph Davis
Boost, NA, same thing. Notice the Victor X manifold the big boost guys love is rated as a NA piece for 7000+ rpm powerbands? Think about it.
04-20-2006, 02:32 PM
#35
0.0 BAR
Join Date: Feb 2003
Posts: 0
Re: intake manifold design?
Engineering is ignored by people who think Legos are the pinnacle of fabrication.
We are dealing with airmass. Airmass is power. Flow characeristics mutate subtly as pressure/density changes, but for the most part plenum size dictates efficiency at a given power level. If you know your desired power level you can dictate plenum size for best efficiency. Not that I care about efficiency one whit, but it goes hand in hand with balanced flow between cylinders.
Uhm, this is the first time I've seen this thread on a real computer (instead of my phone) so I can see the pics. A few pointers:
1) the only TBs I've seen cocked to flow along the back of the manifold were modified stockers... the restrictive small plenums in big power boost situations forced most of the air into #3 and #4, this helped them. Flow is still somewhat imbalanced, but it is a BIG improvement.
2) if you look toward the AIR mani, or the Full-Race copy of the AIR manifold, you see a large non-restrictive plenum that tapers as you go back towards cyls #2 and #1. This keeps pressure constant as the air travels deeper into the manifold, so that flow is pretty well balanced across a decent range of power.
3) Look at the manifold below. It has the cocked throttlebody and no taper - but it does have a nice big angle to transition as much airmass as posible exclusively into #1. The engine this was pulled off of had the single most fucked up #1 piston I have ever seen. Ring lands die, even on forgings, whatever. THIS piston had broken *rings*, there were a couple pieces about 1/4" long that ran vertically as everything in that area was shattered and mangled. The Manley rods and the top faces of the pistons were great, though... hell, the other three pistons were ****.
We are dealing with airmass. Airmass is power. Flow characeristics mutate subtly as pressure/density changes, but for the most part plenum size dictates efficiency at a given power level. If you know your desired power level you can dictate plenum size for best efficiency. Not that I care about efficiency one whit, but it goes hand in hand with balanced flow between cylinders.
Uhm, this is the first time I've seen this thread on a real computer (instead of my phone) so I can see the pics. A few pointers:
1) the only TBs I've seen cocked to flow along the back of the manifold were modified stockers... the restrictive small plenums in big power boost situations forced most of the air into #3 and #4, this helped them. Flow is still somewhat imbalanced, but it is a BIG improvement.
2) if you look toward the AIR mani, or the Full-Race copy of the AIR manifold, you see a large non-restrictive plenum that tapers as you go back towards cyls #2 and #1. This keeps pressure constant as the air travels deeper into the manifold, so that flow is pretty well balanced across a decent range of power.
3) Look at the manifold below. It has the cocked throttlebody and no taper - but it does have a nice big angle to transition as much airmass as posible exclusively into #1. The engine this was pulled off of had the single most fucked up #1 piston I have ever seen. Ring lands die, even on forgings, whatever. THIS piston had broken *rings*, there were a couple pieces about 1/4" long that ran vertically as everything in that area was shattered and mangled. The Manley rods and the top faces of the pistons were great, though... hell, the other three pistons were ****.
04-20-2006, 03:55 PM
#36
0.0 BAR
Join Date: Feb 2005
Posts: 0
Re: intake manifold design?
Originally Posted by Joseph Davis
Boost, NA, same thing. Notice the Victor X manifold the big boost guys love is rated as a NA piece for 7000+ rpm powerbands? Think about it.
04-20-2006, 04:09 PM
#37
3.0 BAR
Join Date: May 2004
Posts: 5,042
Re: intake manifold design?
Originally Posted by Snafubmx234
The LS1 uses a plastic intake manifold. I think if you added some velocity stacks, that ---- would be hot.
The "sawy hoarse" style of IM on a V engine doesn't have to handel much at all compared to what is being suggested.
