Turbo intake plumbing, series or parallel?? see pic

[SirAndy]

Originally posted by mike mueller
I like this method instead of the usual "T" which feeds both sides equally and at the same time.

why?
what i mean is "why do you like this system better"? just because it's different? because you have some actual data that tells you that it works better than the "T" setup? because the parts are shiny? because you always wanted to be different than the guy next door?

why?
Andy

[turboman808]

That is a really odd setup. I don't see how you can gt equal pressure on both sides.

[SirAndy]

Originally posted by turboman808
That is a really odd setup. I don't see how you can gt equal pressure on both sides.

maybe he got different displacement and valve sizes side to side ...

Andy

[Brian Mifsud]

Originally posted by SirAndy
maybe he got different displacement and valve sizes side to side ...

Andy

I like that one Andy.. a 1.7 cylinder head on the near side, and a 2.0 on the far side.

Of course, you could also vary the individual valve sizes within a head going stock and one size up each to maximize the assymetry....

While your in there.. what about tweaking the compression ratios of each cylinder???

It couldn't be any weirder than VW's "V-5" whack job engine used in European market only Golfs.....

[mike mueller]

Originally posted by SirAndy
why?
what i mean is "why do you like this system better"? just because it's different? because you have some actual data that tells you that it works better than the "T" setup? because the parts are shiny? because you always wanted to be different than the guy next door?

why?
Andy

Andy needs a beer

I "like" the packaging of it, that is all, currently I don't know or think that it'll work better than the "T"

If I had data, I would not have asked, I have never seen it done this way on a flat motor........

It has nothing to do with being different nor the use of shiney parts.....


Now that I think of it, it should work okay, look at it as just a large common intake plenum, sure there might be some lag for cylinders 3/4, but would it be enough to easily measure??

According to the books I've read on plenum design (for turbos), you want the plenum volume to be eqaul to the engine capacity, that looks like more than 2.0 liters of air volume

[okieflyr]

I give the guy kudo's for the effort he's put into this, it looks nice.

The point that no one has brought up is the potential imbalance of air flow under light load vaccum. I'd agree (not that anyone would care) that a "Y" in the plenum would provide better balance, and a balance tube may provide some help in the intake pulse dept. My $.02 Kevin

[RandyLok]

Normal induction works with vacuum... valve opens, piston goes down, air is sucked in.

Forced induction pushes air in faster than the vacuum would suck it in. This requires pressurized air.

Air is pressurized when a turbo or supercharger pushes it into a closed space. It is compressed into that closed space until the intake valve opens, then it's forced into the cylinder.

It does NOT matter which side the air enters. Only that it is pressurized. Putting the entrance on one side will NOT cause the cylinders on that side to get more air. If the container is closed, the pressure the same at both ends.

There's nothing wrong with this guy's design. In this case it may just be that it was easier to find room running it around the outside than going straight to the middle through the space where the throttle linkage is.

[Acox914]

Originally posted by RandyLok
Ok, if you take a 4 foot piece of pipe, put a balloon on each end, hook an air hose to the middle and inflate... which balloon inflates faster? What if you move the air input closer to one end?

If the first side was "using up" energy from the air as it went by, that's one thing. But if positivie air pressure fills the whole thing and two sides are drawing from it, it doesn't matter where they are positioned.

this example has holes in each baloon, which baloon has more air coming out of it?

[Brando]

The balloon in the higher pressure zone, or rather, the one nearest the pressurizing source.

People here have been saying there's a difference between water and air... I beg to differ. You can still treat gasses like fluids. High pressure and low pressure zones in atmosphere and with water (judged by weight, though). Different gasses will layer as well, heavier gasses sink, as do heavier fluids in water. They can be treated the same way in that respect.

Think of it this way, if fuel pressure across the whole fuel rail was not an issue, why would you need a fuel dampener? As the injectors pulse you will get varying degrees of pressure in the fuel rail all across.

Another example:

In an aquarium where you have air lines running and you have multiple T-fittings run across to those little charcoal blocks, the further you go down the line, less and less air will come out of the blocks. The ones closest to the pressure source will let the most air out.

I don't know **** about physics, though. Just some real-world examples.

[RandyLok]

In an aquarium where you have air lines running and you have multiple T-fittings run across to those little charcoal blocks, the further you go down the line, less and less air will come out of the blocks. The ones closest to the pressure source will let the most air out.

Not the same. You've got to remember that there are valves!

In the aquarium example, if each block had a valve, and only one opened at a time, each would flow the same. The position does NOT matter. The PRESSURE determines the flow volume.

[914/eg33]

Just an idea, provided the frictional losses are so small that they can be easily discraded, what if a splitter was fitted above the first carb, and diverted the air 50/50 across both banks?
or if frictional losses were to be thrown into the equation, one could split the air unevenly, say 55/45 across both banks...
that should solve the problem... or am i missing something?

[Joe Bob]

As I said before....the proof is in the instrumentation. A simple plumbing job and a digital manometer will/would tell the story.

[maf 914]

Originally posted by mike mueller
Andy needs a beer

Now that I think of it, it should work okay, look at it as just a large common intake plenum, sure there might be some lag for cylinders 3/4, but would it be enough to easily measure??

According to the books I've read on plenum design (for turbos), you want the plenum volume to be eqaul to the engine capacity, that looks like more than 2.0 liters of air volume

That's the way I've been thinking about it. When you do this you can see the charge flowing to the 3/4 cylinders has an additional distance to travel through the connecting tube. No matter what you do you can't avoid losses due to friction. The friction loss, or energy loss, will result in a pressure drop. This loss may not be really significant in this case.

The builder has designed a nice looking package. The turbo with intercooler will probably give a very nice "boost" and any imbalances may be hidden by the increased performance.

As I mentioned in my previous post, early turbo systems in various racing categories were relatively crude by todays standards. Early turbo manifolds were typically simple pipe or log type manifolds, a constant diameter tube fed from one end with individual takeoffs along its length. This worked fine in the beginning, but once everyone had this arrangement, designers started looking for the extra horsepower and soon turbo manifolds became more carefully designed and balanced plenum systems with all inlet runners drawing from the same conditions. You won't see a pipe-type turbo manifold on a contemporary turbo racing engine, and there is a reason for that.

[maf 914]

Originally posted by RandyLok
Normal induction works with vacuum... valve opens, piston goes down, air is sucked in.

Forced induction pushes air in faster than the vacuum would suck it in. This requires pressurized air.

Actually, both normal induction and turbo induction work in the same manner. Both require pressure to fill the cylinder. If there was no pressure there would be no flow into the cylinder. Normal induction works with atmospheric pressure, 14.7 psi or 1.0 bar at sea level, while turbo induction works with a pressure boosted above atmospheric. In both cases air flows from an area of higher pressure to lower pressure. The greater the difference in pressure, the greater the flow, usually.

[Thack]

People here have been saying there's a difference between water and air... I beg to differ. You can still treat gasses like fluids.

Actually a gas is a fluid. The difference between air and water is you can't compress a liquid into a smaller volume.

[spoke]

Several years ago in CART racing with turbo engines, Ford found a loop-hole in the rules concerning the dreaded turbo pressure pop-off valve. Ford found that if they put the pop-off valve on the plenum nearest the air inlet, they were able to get more boost since the theory was that moving air would have less pressure.

This indeed was true and Honda and Toyota complained and CART changed the rule to require the pop-off valve to be located in the center of the plenum.

Taking this into account, then the 2 cylinders furthest at the end would get more boost than the 2 cylinders on the T.

Spoke

[So.Cal.914]

When doing air-conditioning the supply starts at the unit (turbo) then it follows the trunk line and to the branch's and out the vents (carbs).
after the install you have to go back and tune the system. This consists
of adjusting the vents down (starting with the one closest to the supply)
until they all blow equally. The first one is closed up the most and they progress until wide open. So there should be a difference between the two, but as close as they are I doubt it would be much.

[zosyn]

Look at the whole system as a single intake manifold. As long as its pressurized by the turbo then there should be no difference in boost between any of the cylinders.

Take a long tube and pressurize it. If you measure the pressure any where along the tube it will be the same.

[914/eg33]

Originally posted by zosyn
Look at the whole system as a single intake manifold. As long as its pressurized by the turbo then there should be no difference in boost between any of the cylinders.

Take a long tube and pressurize it. If you measure the pressure any where along the tube it will be the same.

That would be true if the air was stationary, but once the air starts moving, frictional losses are going to occur, and hydrodynamics 101 teaches us that the greater the frictionnal losses the lower the pressure....

[spoke]

Originally posted by So.Cal.914
When doing air-conditioning the supply starts at the unit (turbo) then it follows the trunk line and to the branch's and out the vents (carbs).
after the install you have to go back and tune the system. This consists
of adjusting the vents down (starting with the one closest to the supply)
until they all blow equally. The first one is closed up the most and they progress until wide open. So there should be a difference between the two, but as close as they are I doubt it would be much.

Can I change my opinion?

This is correct, to get the same pressure and air flow, the pipe from the 1st intake to the 2nd should be of a smaller diameter to keep the same pressure. However, this would change with varying airflow.

Spoke