your thought's on this?

[Anonymous]

http://www.impulsengine.com/how.htm

i still dont really know if its all for real,

it all still sounds like a lot of smoke and mirrors to me.

cheers.joe.

 

[StrangeRanger]

I smell something too. Their explanation is largely bull, I assume from that that their product is too.

 

[CobraSix]

It's a joke.

This has been around for a few years now. It's just a joke to see how gullable people are. Do you really think Yearone would carry this? But they are listed on the website.

Slade

 

[rbohm]

8) their explanation of the theory is a load of bravo sierra. it is done in a way to seem plausable, but it doesnt hold water.

 

[68coupe200]

I agree with the earlier post that this is a big load of bravo sierra.... it seems plausible, till you use the higher regions of your mental capacity.


total BS! :roll:

 

[80broncoman]

Awful lot of marketing just to sell headers and cams. It will run i am sure, if it worth it I wouldn't think so.

As smoky used to say the internal combustion engine is a 80 year old hag dressed up as a 16 yr old whore! (he said this around the mid 80s) guess shes almost 100 years old now) He was refrering to all the new tricks used to make modern engine run better. he even refered to the piston engine being only about 33% efficent. ( other 33 pecent heat out exh, 33 percent heat out cooling system).
Jim

 

[Lazy JW]

YEEHAA! I'm gonna have to get me one of them thar Stage 7 Ford 302's that makes 600 lb/ft of torque at 1000-3500 rpm. Boy howdy, ain't it sumpin'?
Joe

 

[Anonymous]

Easy, boys, easy ---
at the risk of becoming unpopular here, I'm about to add a bit of truth to this "Negative Supercharging" thing - although I admit to never having heard it called this before...

This is part of the essence of high-RPM engine tuning, a.k.a. bike engines.
Here's how it works (without the 'fluff' in that site):
-As the exhaust gases exit the head, they should pass thru a port that is only about 125% of the exhaust valve's seat diameter. This passage should be about 3 times as long as the diameter of this port. (For example, if the exhaust valve's area was 1 square inch, the port should be 1.25 sq. in., and it should be 3 inches long).
- Next, the port should increase in cross-section (i.e. 'taper') to a larger diameter in proportion to 2 things: a.) temperature drop and b.) RPM range desired. If you're skeptical, take a long look at the famous 1968 Mike Hailwood racing poster, that 6-cylinder 250cc Honda with him leaning all the way over to the footpegs. You'll clearly see what I'm getting at, because the pipes' taper is clearly visible, front-to-end. Which, by the way, upset Honda very much at the time, having that clear picture published worldwide....

The physics involved are: a pulse wave moving down an increasing-diameter funnel creates a very large suction immediately behind it. We're talking here of number like 10 inches Hg, where standard headers create about 3-5 inches Hg by comparison. By timing this suction to hit the exhaust port at just the right time, cylinder scavenging is so dramatic that it makes the oil rings flutter as they start to lose oil past them - oil rings of the 3-piece type suffer short life under these conditions, hence bikes seldom use them. In order to increase the pulse strength, the exhaust valve shuts early, which defines the exhaust pulse very sharply. To "spread" the pulse over a longer (wider) RPM range, the exhaust pipes are frequently wrapped (insulated) to raise the temperature over a longer span. This allows for the piping nearest the exhaust valve to be smaller in diameter while still tapering. In racing circles, this also hides the amount of taper you are running, which speaks directly to the RPM range your bike will have on the track.

Sorry to burst your bubble, but...it's not an urban myth. I've been doing it, with Yoshimura's help, since 1970....

 

[rbohm]

8) exhaust flow tuning of the type they are suggesting does work, but it depends on many variables, and generaly works in a very narrow rpm band, and doesnt produce the gains these guys are suggesting. exhaust gas does have weight, and when things are right you can get about a 10% or so gain, as long as the intake cylinder heads and cam timing are all in synch with each other. i have seen engines supercharge themselves because things were all working together, in fact the ford indy engine of the mid 60's had a volumetric efficiency of 104% at it's peak ve rpm. but the engine worked in a very narrow rpm range, and was only over 100% for a very tiny rpm band. the gains they are suggesting are virtually impossible to get with cam timing and exhaust tuning alone.

 

[MustangSix]

I used something like these on my model airplanes many years ago. They do work. In fact, on a couple of racing engines, the engine would not run without it. But they were tuned for a very narrow operating range, usually no more than a couple of thousand rpms apart, so prop selection was critical.

 

[Lazy JW]

Easy, boys, easy ---
at the risk of becoming unpopular here, I'm about to add a bit of truth to this "Negative Supercharging" thing - although I admit to never having heard it called this before...

Mark,
I am well aware of the benefits of the so-called "Negative Supercharging", but 600 lb/ft of torque out of 302 at 3500rpm Can any of you dyno jockeys tell us how much turbo boost that would require?
Joe

 

[Anonymous]

Jack:
those pipes were often called 'expansion chambers'. 'Stroker' bikes use them a lot. As the exhaust pulse moved into the widening angle portion, it created the needed suction through the open exhaust port. The length of the taper determines the width of the powerband and the height of the suction. Longer taper=wider band, shorter taper=higher suction. The 2-cycle engines REALLY need these when the ports are raised too much and the CR is 'way up there to compensate, because the VE goes to nuthin'...

JW: I don't know how to calc those number to see if V-8 tuned exhausting would provide something that big. I do know from experience that the effect of the piping in the 10,000-14,000 RPM range on the roadracer bikes turned the engine into a 'switch' if you weren't careful. Sometimes you'll see someone in a roadrace pack accidentally wheelie (ESPN stuff), probably because their tuner didn't know to back off the spark advance right at the beginning of the pipe's action. This makes them 'come on' so suddenly that the bike is hard to control. Been there.

Here's an example, though, that makes the piping seem improbable to me (for a car): on a 250cc engine (2-cylinder), the pipes must be 7.75 feet long, with a steady taper of .225"/ft for the whole length, at a minimum bend radius of 3 feet (all straight is much better). But, that's a small volume, for tuning at 11,000-13,000 RPM band. For a 4" bore engine, the pipes would have to be much larger, like 3"-6" diameter, with minimum bends in the 6-ft radius range. I don't see how this could fit under a car !
The other thing is: these pipes are REAL, REAL LOUD! If you add a muffler of any kind, whose job it is to break up these impulses for silencing, the effect goes completely away. That's why you so often see dirt bikers running with detachable mufflers - so it's street legal (sorta) on its way to the track. These slip-on mufflers can detune an expansion chamber by over 30% when they're on.

 

[Anonymous]

[No message]

 

[Anonymous]

Cool, Panic!

This is the 1st time I've seen a 'speed of propagation' number, 240fps.
The roadracer 250 I referred to before used a little over 7 ft. length when it was curved: this 240fps figure yields 6.7 feet length (assuming straight pipe). That's a nice number to keep in mind: it seems to be 'right there'.

 

[Lazy JW]

These guys are claiming 600 lb/ft of torque from 1000 rpm to 3500 rpm (not 15,000) out of a 302 I'm a pretty novice motorhead, but I understand some of the principles involved in making power. In order to double the torque (and horsepower) at a given speed, we need to stuff in roughly twice as much air/fuel mixture, burn it efficiently, and send it out the exhaust. Now I realize this isn't precisely correct, but I'm telling a story, not writing a doctoral thesis. So, can a 302 REALLY make that much torque at 1000 rpm, and how much boost does it require?
Joe

 

[StrangeRanger]

At 95% VE and 75% turbo and intercooler efficiency, about 15 PSI

 

[Lazy JW]

At 95% VE and 75% turbo and intercooler efficiency, about 15 PSI

Thanks, StrangeRanger,
That's what I was looking for. So these jokers are claiming that their "Negative Supercharging" is equal to 15 PSI boost in the real world. :rolflmao: :rolflmao: :rolflmao: :rolflmao: :rolflmao:
Joe

 

[Anonymous]

Hmm... I worked for a while with Detroit Diesel, whose 2-stroke engines have a supercharger (required to make a 2-stroke diesel start) and a turbo on top of that. The resulting pressure in the intake tract was 35 PSI to start and could hit 80 PSI under heavy loads (these are boost gage numbers, not atmospheric).

Of course, these are diesels, but they did get up to 4.8HP per cubic inch on some of these engines with this setup. The wrist pins were as big as my forearm and the rods each weighed more than my I6 exhaust manifold !