Koreandude

If you're not familiar with this product click this link!
http://www.carchemistry.com/ccinserts.html
I spoke to a technician that makes these and he said it would dramatically improve the "resonnating" sound i get from my 2.25" exhaust (w/ carsound cat/25" glass pack/muffler). He said it will totally out flow my glass pack and suppress the sound better without hurting my hp numbers. As a matter of fact, he says if at all it'll increase my hp and torque numbers!! He recommends that i remove the glass pack and replace it with the 3 disk insert.

I've taken it upon myself to be the guinea pig so i'll update ya on the situation.

Zman

MMMmmmmm......
It sounds too intersting, the truth is I feel suspicious about this, but if they work it would be very good to know.
A question, do they work similar or identical to the "sound dampeners" that fit into the exhaust tips?

BV1

If you talking about the inserts at the end of the muffler, that can be put in or taken out, they will make the car quieter, but they won't give you more HP. The inserts work by increasing backpressure, and increasing the amount of time the exhaust gas and the noise it carries, stay inside the pipe and its resonators. The longer the gas stays inside the glass pack or any resonators the quieter the car will be.

But don't think that you will gain HP by installing a surpresser and removing a glasspack.
Glasspacks aren't great, but they are significantly less restriction then a surpresser, meaning they will give you a better top end or more HP then having no glasspack and a surpresser.

Think about it this way, if you were running water through your exhaust, and not gas, where will it flow better, through a straigh-through 2.25 glasspack and 2.25 exhaust or through a 2.25 exhaust with a 3 holed surpresser on the end.

Hope this helps,

-Steve

Koreandude

no no no... sorry bud but now you're talking about something else. I'm not talking about a surpressor one slaps on the back of a muffler to make things quiet. The item i'm talking about looks like this.

These inserts are placed after the cat, creating a vacuum, which helps excavenge the exhaust better producing better flow characteristics than a glasspack. Yes glasspacks are a straight through design, however, this is the smarter way of quieting the exhaust (using some pretty sneaky physics) without sacraficing hp/tq #'s like glasspacks do. This is much different than the average exhaust plug. As a matter of fact, it isn't an exhaust plug. wink

I'm ordering a 3 or a 2 disk in a couple of days. check out the link i posted earlier.

[ August 21, 2002, 07:49 AM: Message edited by: Koreandude ]

Ego

I'm sorry, I design piping for a living, I'm doing flow calculations pretty much every day--and someone's blowing smoke(or exhaust) up your ass.

There is NOTHING that can stay stationary in a pipe and 'create' vacuum. Simple law of physics: to have a motive force (like suction or vacuum) you have to have energy input. You get scavenging at the headers due to the velocity created by the momentum created as the exhaust is pushed out of the cylinder by the piston--this is energy input. A secondary effect there is the cooling of the exhaust gasses--they contract as they lose heat, 'creating' more suction. The heat from the combustion is the energy input for that. With these things there is no energy input, only interference. Interference creates turbulence, turbulence creates backpressure.

Those things actually look just like the internals of some types of silencers for a gun--silencers reduce your range. They take away from the energy available to the bullet by buffering(slowing down) the gasses that are propelling the bullet--just like these things will do to your exhaust flow.

Koreandude

I've seen certain headers help create vacuum by enlarging the extractor dia. in certain spots down from the main flange. Since it's a permanent fixture of the header (being part of the header and welded in) and 'stationary' and it does create vacuum, i don't find it hard to believe that this insert may do something similar (of course you weld it in when you install it). I'm not discrediting your knowledge or experience and as a matter of fact i like learning as much as i can about everything i can but how do i trust you more than what they say? Not to be rude but i know neither you nor Car Chemistry however they have dyno results and proof of it's effectivness, so i have to give them the benefit of the doubt. smile.gif

***Has anyone checked out their web site before posting on this thred?***

[ August 21, 2002, 08:45 AM: Message edited by: Koreandude ]

Ego

Mmm, yes, but you're still dealing with straight-through pipe. By shaping an enlarging portion properly, you can achieve a venturi effect. When a gas is expanded it draws energy from its surroundings. The expansion is not always very efficient though, due to turbulence. If you shape the expansion to use the venturi effect to acheive a smooth transition, the turbulence losses are reduced if not negated, and the net momentum of the system can actually increase slightly. No energy is actually added--the internal energy of the gas is converted efficiently.

With these inserts there is no free expansion--quite the opposite actually, as higher pressure regions will build up in front of the flat surfaces. Sure, it expands a bit again on the other side but you end up losing energy because both the compression and expansion have an efficiency attached--energy is lost to turbulence twice.

I did glance at the website, the dyno table at the end was on an open pipe engine, and it looks like the engine was not optimized to run with an open pipe. Strange how they compared the sound levels for the open, 2-insert, 3-insert, and muffer systems, yet the muffler seems to have disappeared during the dyno runs. If you haven't tuned the engine to run with an open pipe, the results are meaningless. What was the header configuration? Did it dump right after the header, or was there more piping? What was changed to put the inserts in? There are way too many variables to trust those numbers.

[ August 21, 2002, 09:10 AM: Message edited by: Ego ]

Koreandude

I spoke to the technician and had asked him many questions we threw around here. That dyno was from an open header, no cat just an insert at the end of the collector where all the runners meet. You're probably right about the turbulence and high pressure regions forming from the inserts. It's a very valuable observation and it'll probably of all things effect top end hp. I'm going to get my car dyno'ed this weekend hopefully and in the mean time i'm going to order this insert and then redyno the whole setup. So i guess we'll see what happens. Even if i "loose" a few ponies up north (compared to a completely open exhaust), the net result will be higher than stock and what i have just got done (hi-flow cat, a 25" glasspack as a resonator, 'turbo style' muffler with 2.25" piping). I'll be replacing my glasspack w/ the insert.

The REALLY REALLY important thing here (at least to me) is the fact it'll be much quieter. Lets just say the glass pack does 2 hp better for peak power. Well, if those 2 ponies mean i'll be 18db quieter then, well it'll be well worth it!
You guys are great wink

[ August 21, 2002, 01:26 PM: Message edited by: Koreandude ]

Ego

Ah ha! So it adds low-end power and a bit of mid--basically it creates backpressure. (I don't see the words 'vacuum' or 'vortex' anywhere on their webpage.)

In fact they look identical to the supressor/silencer inserts you linked to in that other thread, except for the additional holes. So I'd say they do exactly the same thing with a bit less backpressure.

The problem with creating backpressure this way is that it is inefficient. What you want to get good scavenging is to have high momentum and smooth flow of the exhaust gasses. At high RPMs, there is enough exhaust gas being created to ensure this. At lower RPMs, the piping plays a large role(it helps higher up too, but is more noticable in the lower range). As you go to a larger pipe the gas expands, so you lose density and velocity, the momentum greatly decreases.

By putting something in there to create backpressure, you are increasing the pressure in the line before that point. This keeps the density up--helping your momentum. The velocity, however, still decreases. Overall, you'd be better off going with a slightly smaller pipe size. This would be quieter, without as much lost efficiency due to flow obstruction.

Cheuk in Seoul

I posted about this product last week, along with the link.

I run it on my RX-7 and we put in a pair into the exhaust pipe on a Ferrari 550.

I don't think you will see any extra power in a street car with an intact exhaust / converter. But I can vouch for its effectiveness as a muffler. It's relatively cheap, easy to install and uninstall and does quiet things down.

It is perfect for someone who needs it to lessen the exhaust tone as a temporary measure. Such as to pass exhaust noise test and in my case... to run on the street... I make more power than I need for the street and I have a 3" cutout in my midpipe that I can open up for drag racing.

But a word of warning, it may make your exhaust too quiet.

[ August 21, 2002, 06:09 PM: Message edited by: Cheuk in Seoul ]