Idea Tubular intake manifold

[Lofty]

I had a good idea the other night.

How about fabbing up a tubular intake manifold for our cars. The longer and thinner the runners are, the more torque, but we are limited to space in the engine bay. If we made it tubular, we would have more space to extend the runners.

It's just an idea, any input on how this would peform? I know gt40s have these, as well as toyotas...sometimes...

 

[1SloEvo]

I would imagine if it would work well, some of the companies who have built aftermarket manifolds for the DSM would have tried it and would offer it. However, you might be able to find someone to do it. Only problem is something like that will take a lot of time to make...and cost quite a bit of money, especially if only making a couple of them.

 

[knochgoon24]

If you want more low end torque than the 2g IM, you should look into some higher compression pistons.

 

[spoonman]

Having a long tubular intake manifold, with little to no plenum on our cars would be best suited for low RPM gas mileage situations. So for a DD situation it would seem that the stock intake manifold has good dimensions as far as runner size and length, as well as plenum volume. Where it could be improved though is construction and design.





For all you youngsters here is an explanation on "Pulse Tuning"



Torque- Torque can be thought of as the instantaneous force generated at the crankshaft. It is a measurement of the amount of energy being developed in the engine during EACH operating cycle. Or the amount of air/fuel mixture being burned per cycle.

Power, HP-Power should be thought of as the amount of energy being developed by the engine per minute. So power is torque times speed.

It is only possible to get 100% Volumetric Efficiency from an engine, right? You can only fill the cylinders with their exact displacement of air?Wrong What the above statement fails to take into account is the air's density or mass. On a NA engine if you have 100% VE it would be assumed that your cylinder is filled completely with with air at 14.7 PSIA (sea level) or 0 PSI (guage pressure). At 80% VE the engine only has 80% filled with 14.7 PSIA air, the complete cylinder is actually filled but at a lower pressure, because the air is less dense. A forced induction engine can produce 200% VE easily by compressing the air and increasing its mass or density. "Pulse Tuning" is used to maximize torque output by taking advantage of the pressure waves which exist in the intake and exhaust system. These pressure pulses can actually ram air into the cylinder to achieve up to 130% VE on NA cars. To make it function correctly very carefully designed pipe lengths and diameters are used to achieve these pulses and the effect only works over a narrow rpm band. Tuning for maximum torque at a certain RPM though usually has an adverse effect on the higher flowing RPM band of the engine. OEM intake and exhaust systems are usually designed to promote maximum torque/efficiency at low RPM's that would produce the best gas mileage with the throttle plate opened below 20%.

 

[RipperXX]

I know pulse tuning has been around for intake manifolds since the early 80's. Maybe sooner so thats nothing new. But it's also got about jack to do with a turbo engine. I doubt it really wold make any real difference in a forced induction engine. I could be wrong, but really I doubt it would make more than a 3-5hp difference. Now on a NA engine, yes it can help.

Turbo engines can already easily surpass 100% VE anyway. To the OP if you want more low end torque, then increase the displacement of your engine, use higher comp pistons, better fuel and more ignition timing... and a smaller turbo.



Although I have seen a intake manifold that looked like an exhaust header on a crazy setup for a drag car... i'll dig up the picture.

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[EclipticalGS]

4 turbos is enough for me.

 

[RipperXX]

The idea behind that crazy intake manifold if I recall correctly, was to make sure there was an even distribution of air to each cyl.

 

[bjones18]

An air-pressure pulse created by a closing intake-valve:

1. "flys" backwards through the intake runner at the speed of sound,
2. this "back-flying" pulse hits the "infinite mass" of air in the plenum,
3. the pulse bounces off the "infinite mass" back towards the valve,
4. if the valve opens the instant this pulse "returns home..."
5. the correctly timed pulse "pushes" more charge into the cylinder.
6. hence, increasing volumetric efficiency (more charge in cylinder).

For this to work, as previously mentioned, the runner length and rpm (valve timing) must be matched with the air properties at temp. The problem comes in the fact the runner lenght needs to be around a meter for a single "to and fro" pulse to work at "our ideal sweet spot". Packaging leads to designing a shorter runner length to "capture" the 4th, 5th or 6th "bouncing back & forth-round-trip" of the pulse. I'm not sure of the efficiency of this "multi-bounce" effect. Turbo cars can take advantage of this effect, but in our underhood package we may be kidding ourselves. Proper design of air-funnels, airpaths, velocity stacks, and plenum-distribution are probably more important than tuning runner length for pulse pumping (which is similar to scavanging on exhaust side).

 

[paultheninja]

Just do a 2.3 stroker if you want more low end torque.

 

[bostonhatcher]

The idea of pulse tuning is about as ridiculous as global warming.

 

[Boosted98gsx]

Just do a 2.3 stroker if you want more low end torque.

And get some large duration cams with good overlap if you want super high VE.

 

[donniekak]

The idea of pulse tuning is about as ridiculous as global warming.

Yes, they both are true.

 

[delta448]

Some light reading...

The dsmtuners tech article...