vacum on the exhaust?

[chrisj0123]

Can anyone give me thier ideas or objections to the Idea of placing a vacum on the exhaust of my car?!

geting bigger pipes allows more eshaust flow to exit engine... so if you applied a vacum wouldn't that allow you do run smaller pipes and get the same performance as if you where running straigt pipe or something else... 21/4" pipes... It seems to me that you could keep your smaller pipes you would just have to make sure whatever create's your vacum could handle the HEAT!!!

Ok as I think about this more I will add more to this but for now just let me know what you think. any discussion would be appreciated!


Hey also I'm thinking of buying the magnum 360 engine it is supposed to have 380 hp... wow... cost roughly 3500... Do you think its worth it? If you have the summit racing catalog ...its in there.. one of the last few pages!


chris

[gthomas]

Install a larger diameter exhaust system, its less expensive and actually works well!!!! Forget about using a Sears Upright, Shop Vac or an Electrolux Vacuum cleaner, how many cubic feet of exhaust are you gonna vacuum away?

[pishta]

Exhaust pulses travel at something like 600 MPH or FPS or something astronomical. You would need a exhaust fan that could pull your carb CFM multiplied by 5 or so to compensate for the expansion of the combustion stroke. Imagine a turbo sucking exhaust at 100,000 rpm. Forget it..

[road chicken]

Your right Chris,

If you make a negative pressure on the pipes you could keep the smaller diameter pipes. It would still have to flow the same amount- and achieve a higher velocity thru the pipe- that a bigger diameter pipe. However, like these guys have pointed out- it isn't cost effective as just opening up the diameter of the pipes. there is a world of difference in area from a 2.25 to a 2.5 and then to a 3.0" pipe.

[chrisj0123]

Well I sure as hell don't want a shop vac your upright sticking out of the back of my cars exhaust.... lol...

One of the things I was considering is...noise level.... How could I get the power of say 3" pipes without the noise level associated with it...Police seem to object to exceeding the noise level set by the city orrdance.And In my area there might be a few ppl who would object to having there window rattle when I start the car up!... Although it would be fun... used to love goning through a parking lot with my brother... would rev the engine and listen to the sweet sound of 20 car alarms going off......oops sorry off on a tangent

Is there another effective way of reduceing the noise level without sticking with the smaller diameter pipes?

The thought occured to me just now that running a dual intake simalar to that of a ram air... the intakes would be located just behind the doors on either side of the car... forcing a turbine to turn similar to that of a turbo. Creating a suction close to the end of the exhaust..... another thing in one more year my car will be a classic and I won't have to worry about emmissions..yeah....

alright enough rambling for now!

chris

[road chicken]

Oh bud- You got the right idea- but the Vacuum generator would HAVE to be powered. Any time you can lessen the back pressure on the exhaust- it's a good thing,( just not too close the valves- they will overheat),- but the volume your talking about just couldn't be generated,( as far as i can figure), by just a pressure differential intake on the car. its justs way to far away from what you need to drive the turbo fast enough to be effective. You could try the same thing with an on board air tank and a venturi style Vacuum generator too, or even drive the turbo with hi pressure stream of air- but it out weighs the benefit.... I think- I never tried it- Maybe electric motors could be the source of rotation- there is something to be gained- but at what cost?

Screw authority- put a good set of Dynomax's on it and let the windows know there be Mopar here

[rb77413]

Originally posted by road chicken
Oh bud- You got the right idea- but the Vacuum generator would HAVE to be powered. Any time you can lessen the back pressure on the exhaust- it's a good thing,( just not too close the valves- they will overheat),- but the volume your talking about just couldn't be generated,( as far as i can figure), by just a pressure differential intake on the car. its justs way to far away from what you need to drive the turbo fast enough to be effective. You could try the same thing with an on board air tank and a venturi style Vacuum generator too, or even drive the turbo with hi pressure stream of air- but it out weighs the benefit.... I think- I never tried it- Maybe electric motors could be the source of rotation- there is something to be gained- but at what cost?

Screw authority- put a good set of Dynomax's on it and let the windows know there be Mopar here

This is prolly was off topic but why would the vavles overheat? I have always heard that but noone could explain why?

[chrisj0123]

Hey check out my post called perfect Idea... and see if that matches up.... I think It should..... If you still don't think so.. tell me why...before I go off and try it!

[road chicken]

rb77413

I don't know why the valves will over heat- for sure. I would suppose it has to do with the pressure, ( backpressure) and the density and speed of the out going charge. Like an air compressor when you release the compressed air it has a cooling effect - I assume the effect of the compressed air in the cylinder would have the same effect ,(albeit at a much higher temperature). The back pressure/ restriction would have to do with slowing the air down enough to give it time to draw the heat out of the valve. That would be my semi educated guess.


Chris- i will check tonight or tomorrow on that post. I have my hands full here- Broke the snow plow last night and we have more snow on the way today- so that has GOT to get done first . I will check it out asap

[gthomas]

If you have a single exhaust, and its legal, you could go to dual exhaust and a couple of good flowing low toned mufflers with a cross over pipe. I don't know what size pipe you're using now, but with duals using the same size pipes, it should icrease your flow a lot and probably give you better low end torque. As far as buying a 360/380, you'll have to decide what mods you'll need to fit it in your vehicle. Do you already have a V8 or are you converting a V6? Can you transfer some of your existing engine parts to the 360? What vehicle do you have? State smog requirements?

[5thAve]

Why not just start with a bigger exhaust? If it cost a fortuen or wwasn't possible because of emissions or something it would be a different reason, but it's probably just as cheap to use a bigger exhaust.

I've heard good and bad things about the 360 MP engine. Seems to be luck of the draw with them. The only bonus to them is the new parts (which someone pointed out in another post on the subject) but I'd still rather pay less and have an engine built for me then pay more to get that.