This is hands down the best exhaust system company in the market, I will argue with any one about that, any day any time. I have delt woth many manufacturers exhausts on many different makes. First and formost is because the entire system in stainless steel, not just the muffler (baffle) like most other companies. The flanges are stainless the tubing is stainless. Next is fitment and finish the fitment on the seven different vehicles I have delt with regarding Thermal is just like oem, no sagging exhaust, no tubing banging against the chassis, no required modifications or cutting wheels. In my opinion the CL model I purchased is fairly ugly, I like the tips but the baffle casing just looks cheap. I personally also have a Thermal exhaust on my 1996 Turbo Civic, their 3 inch model, same story. Only downside is they have a decent amount of turn around time, but its worth it, so plan ahead and make sure your prepared when your old exhaust rusts through. I give you this warning because I was running around for a month with open downpipe!

 

Pics will be up later.

 

here are pics

 

Looks good, I have a Thermal on my 4th gen and love it.

 

you guys made my decision, ive been mulling over a few different kinds, but this sounds like a good option for "near" stock look and sound

because i love the way my 5th gen sounds with stock exhaust and dont want to stray too far away from that

 

It is probably second most quiet behind apexi WS2, what i had prior.

 

A little update on the exhaust sound. The muffler is quite noisy for my preference. I was also very depressed by the sound of vtec crossover, the muffler note barely changes if at all past crossover, only way it makes itself known is through the cold air. Drone on the highway annoys me silly so i have been using cruise control to keep noise down. After saying this i should stress I am very reserved and despise fart cans UNLESS they have a pleasing tone (in my opinion). This unit has far from a ricer tone but again the highway drone under high engine load is pretty bad. A plus in the noise department is when drawing full vacuum at high RPM (above 6k) the backfire sounds very neat *** does the engine in high vacuum alone. I can live with all this though knowing the exhaust will last forever (unless physically damaged) and wont rust thus keeping its resale value as its integrity will never diminish.

 

I have discovered if it's a straight-through muffler, it's going to be loud and it will drone. Also, it should go without saying, but the bigger the pipe diameter the louder it is. I've been doing some research on 1/4 wave resonators to alleviate highway drone; might be worth looking into if it gets as old for you as it is for me. I'm also going to try putting some acoustic treatment in the exhaust tunnel to help alleviate the resonance.

 

elaborate on 1/4 wave resonator...
its not exactly a straight through muffler but pretty damn close.

 

youve really changed your opinion about this exhaust since Friday, lol now im torn again

 

haha i have only had a stright through design on a n/a b16 that was fully built and loved the sound of it, one the b16 sounded way different becuase 1 it had larger cams 2 the rod ratio is way different and 3 the final gear didnt have the engine spinning at 4k at 80mph. I am very **** about exhuausts so dont let my view on this change your thoughts, that is unless u want near oem noise levels.

 

Weird, I thought they were straight-through; can't find any actual info on their website though.

1/4 wave resonators (aka branch resonator) use sound reversion to cancel out unwanted noise. You essentially "tee" an appropriate (read: calculated) length pipe into your exhaust pipe; the end of the pipe is capped off so no actual exhaust pulses travel through. However, sound waves from your exhaust can travel down the pipe, they hit the end of it and then reflect back to the exhaust. If the pipe is the right length, when the sound waves return, they will be exactly out of phase with the unwanted noise in the exhaust pipe, canceling them out. The length is based on RPM, and there is a peak RPM you can influence and then a couple hundred RPM on either side where you will still see some benefit as well, so basically you target your drone area to cancel it out. The theory is the same as tuned intakes and exhausts; it's all about calculating wave lengths and using them to your benefit to either increase or decrease the amplitude of the waves. There are a couple aftermarket exhaust companies that actually use these in their catback exhausts. If my new muffler doesn't fix my problem, I'm going to try making one.

 

its not like a stright pass through tubings are off set in different chambers unlike a "straight throuh" design

 

This is a resonator:

The Thermal systems all come with one, like you showed in your first post.



The more resonators you add, the more they will cancel out the waves.

And like what was said above, the bigger the diameter on your piping, the louder your tone will be, its just the way it is.

But the H22 needs to breath to get its power out, so going smaller is not what you want to do.

 

Umm this 1/4 wave resonators he is talking about has nothing to do with the resonators most people are familiar with. Instead it is a pipe that is closed at one end and the open end is welded at a certain angle off of the exhaust (usually perpendicular) and the length is determined by your own engine and exhausts RPM of resonation. You could read a physics book ,but I'm sure that you will find this link more helpful.

http://www.performancetrucks.net/for...-drone-489463/

 

to much work for me i have a project car that is destroying my life as it is, the drone isnt that bad, guess im getting use to it. i dont usually daily the prelude but am currently because my alternator on my ek crapped out and its been in the teens temperature wise where i live so its to cold to be working on it, and also the lude burns about 4 quarts of oil for every tank of gas lol its ridiclous

 

I have learned something new today.

So misunderstood what you ment by 1/4 wave resonators.

It would be hard to do under our chassis due to limited space.

 

I think you're correct, because i have never seen one of these on a Honda.

 

What most people refer to as "resonators" (ie the Vibrant shown above) are not true resonators, they are actually just small mufflers. My plan is still to try a 1/4 wave resonator; for space, I'm going to try and put it in the muffler area with a "u"-bend (mandrel bent) pipe, probably 2.5", but maybe even as small as 2". Ideally the pipe would be straight and the same diameter as the exhaust, but it should still work this way. The OEM muffler sits up into the chassis with the tips coming out the bottom, whereas most mufflers (including the one I'll be using from Vibrant) are center/center, or center/offset, and don't stick up very tall (5" or so) leaving room to tuck a piece of pipe up there (hopefully). I'll take pics when I'm done, assuming it works.

 

When I did the calculation for my exhaust it was a foot and a half, not sure where I'm going to put that. Do you think that directly in front of the muffler is the best place for this?

 

I am completely use to the "drone" doesnt bother me at all anymore.

 

Finally got my branch resonator built and installed. I was targeting a 2900rpm-centered drone, so calculations showed I needed a 38" pipe to cancel out those frequencies (99Hz iirc). Obviously that's too long for a straight pipe, so I did mine with what was basically a "u" pipe, and ended up around 36" I think measured on-center of the pipe. I opted for 2" pipe (mandrel-bent) for my 3" exhaust for two reasons: one being space limitations, and two being that canceling out frequencies in one range will double them in the harmonics above and below (ie in my case it will make 50Hz and 198Hz louder, the 1/2 wave frequencies); the larger the pipe diameter, the greater the effect. Here it is built and installed:





It definitely works; it did exactly what I needed it to do, which was kill cabin drone around 2700-3300rpm. Remember that this is not actually targeting an RPM range, but a frequency range which happens to be over-emphasized at certain rpm's, so it will change the overall sound of your exhaust as it lowers the target frequency all the time.

For those interested, that's a Vibrant 3" in/dual 3.5" out that I painted the canister on but left the tips polished, installed on a BB6.

 

s2000's come with a small one from the factory