Venturi tubes

[Kurobei]

At first when I saw the thread name, the first thing that came to my mind seeing venturi was the famous "whale penis" design where the flow of the chamber goes from big to small to increase air velocity. I'm surprised nobody mentioned LoDollars custom downpipe. The first time I saw pictures of it, it reminded me of a mini-me venturi power chamber because of the design. In a sense his downpipe where it meets his compressor exit should. create a similar effect.

I'm on my cellphone right now but if someone would be nice to post a picture of his enginebay, you'll clearly see what Im talking about.

[bcjammerx]

At first when I saw the thread name, the first thing that came to my mind seeing venturi was the famous "whale penis" design where the flow of the chamber goes from big to small to increase air velocity. I'm surprised nobody mentioned LoDollars custom downpipe. The first time I saw pictures of it, it reminded me of a mini-me venturi power chamber because of the design. In a sense his downpipe where it meets his compressor exit should. create a similar effect.

I'm on my cellphone right now but if someone would be nice to post a picture of his enginebay, you'll clearly see what Im talking about.

I know what you're talking about...and that makes since given what's been said of that intake...the fist pic doesn't.

here's an overhead of lodollars

[Kurobei]

I know what you're talking about...and that makes since given what's been said of that intake...the fist pic doesn't.

here's an overhead of lodollars

Thanks for the post. Yeah there's another pic of his car that really shows the small to big area of his piping.

[d112crzy]

I don't think he did it thinking of the venturi effect. That's just simply going from the size of the flange straight to 4".

[bcjammerx]

I don't think he did it thinking of the venturi effect. That's just simply going from the size of the flange straight to 4".

perhaps and accidental bonus?

[d112crzy]

Well yeah.

[93F22A6]

Most high dollar headers use something like this. They won't exactly go from big to small and back to big, but just one size and then they will cone to a bigger size, usually after the collector.


And whomever mentioned back pressure, quit thinking in the olden days. You don't EVER want back pressure. What you want is an exhaust that has no restriction and has optimal flow for the powerband you want.

That was me, but I thought some backpressure was good. So basically what I'm gathering from using this you can run a larger exh and not loose velocity, correct?

[Kurobei]

perhaps and accidental bonus?

haha really

[mndude07]

In theory yes, you can run a larger exhaust and not lose velocity. Too large and you will have stagnation and you will lose the scavenging effect that you dearly need.

Everyone has been discussing the ideas behind the venturi effect, but what do you all think about one placed into an exhaust setup like i proposed?

Someone said it seemed to them like it would just choke the exhaust, but then someone else said that they gained alot of torque when going from a 3" flowmaster to a stock EX muffler.

A venturi tube will give the same effect, creating more low-rpm torque, yet increasing the air velocity throughout the exhaust system after the venturi tube. Air velocity is less with higher pressure before the venturi...and if the venturi is immediately after the collector, then basically your header is now your choke point? More specifically where it merges 4 down to 2 pipes I think? I'm going in circles with this concept. I wish Bisi or someone like that would chime in.

So for example, what I can gather is that a 2.5" exhaust system with no venturi and a 3" system with a venturi will flow about the same, provided that somewhere between 2.5" and 3" piping is the true perfect piping diameter mathematically?

Who says I should just weld one on with the rest of my new setup and see what happens, and who thinks I shouldn't bother?

[93F22A6]

I was thinking of using it, if it truely works, on my next setup. 3 inch into a cherry bomb extreme(the wing design one) with dual 2.5 exits and then two cherry bomb glasspacks for each exit.

[civic_90_08]

or, you can just run 2.5" exhaust with a Highflow cat, 26" res., and a straight through muffer like the ES Tuning muffler.

thats what i have. its quite, but it breathes like a bitch.

-Jordan

[mndude07]

or, you can just run 2.5" exhaust with a Highflow cat, 26" res., and a straight through muffer like the ES Tuning muffler.

thats what i have. its quite, but it breathes like a bitch.

-Jordan

Thats essentially what my setup is going to be, except a magnaflow muffler...one of the largest ones they make.

I'm trying to figure out if the addition of this venturi tube will give additional gains to a system like yours though.

[93F22A6]

or, you can just run 2.5" exhaust with a Highflow cat, 26" res., and a straight through muffer like the ES Tuning muffler.

thats what i have. its quite, but it breathes like a bitch.

-Jordan

I would have 8" res. I like it loud, after spending time around race cars you think it's quiet. Plus I like scaring people with my car Always funny to see people jump when I go by.

[owequitit]

Some corrections about the venturi.

It runs at a lower pressure/higher velocity IN the restriction.

After the restriction it begins to slow down to its original pressure/speed.

This phenomemon is a component to how wings work as well as how carburetors work.

In order to maintain the flow through the pipe, the velocity must go up, resulting in a corresponding pressure drop.

[civic_90_08]

I would have 8" res. I like it loud, after spending time around race cars you think it's quiet. Plus I like scaring people with my car Always funny to see people jump when I go by.

Then why have a res. at all?...be pointless to even put an 8" one on there.

And if you do find out if that think helps and exhaust system like mine...let me know.

-Jordan