Review of high flow cat, resonator, and Borla exhaust
 

Welp, got my "CZMid-4" installed today. For those of you who haven't been following this, the unit is a high-flow, high-temp catalytic convertor by Random Technologies with a resonator. It's a legal replacement and CARB & EPA certified, as long as you have a good reason for replacing your stock cat - like damage or plugging. I figure if I need to, I'll pull it off when my car starts getting emissions test in 3 more years.

This unit replaces the stock cat, and while CanZoomer also sells just the HF/HT cat and midpipe, I wanted the unit with the resonator because the cat alone reputedly greatly increases the noise, especially with an aftermarket exhaust. I was concerned about this because I also have the Borla cat-back exhaust, which sounds beeeyoootiful :D by itself.

So is it louder? Most definitely. Is it too loud? Dunno, jury is still out on that. I've only put about 20 miles on the car since I got it on, and it is definitely louder when accelerating - but interestingly enough, not when at interstate-level speeds. Anyway, I'm hoping it will "mellow" with a few miles on it just like my Borla did. Time will tell if it does, and if not, whether the additional noise is enough to bug me.

How's it feel? MUCH better. The car feels smoother throughout the rev range, and seems to pull stronger. My butt-dyno tells me it's good for at least another 10 HP.

So there's the update, campers. :D

Does the Borla by itself with the stock cat and resonator sound good???

Is it loud enough to set off car alarms if you rev it in a crowded parking lot? My old flowmastered 57 chevy used to do that. If not, then it's not too loud. ;)

Also, have you replaced your flywheel/clutch yet? Personally, I'm thinking I might go with Borla/Random cat/ECU mod/flywheel.

Yep... really, really good. :D

Dunno, I'll have to try it. Probably. ;)

Not yet on the clutch/flywheel. Probably down the road a piece.

I was wondering how you would like it Omicron. It is definitely louder isn't it! I think it does mellow a little -- I have about 300 miles on it now including a full day at the track. It felt really nice at the track with all the very high reving -- really does smooth it out. For me it is right on the edge of being too loud -- the younger crowd seems to really enjoy the sound -- getting lots of approving looks and at the track the feedback I got was awesome. I think I may put some of the sound dampening material under the carpet in the trunk -- that will probably reduce the sound just enough for me.

Encouraging words about the mellowing... I hope you're right. And the sound deadener is a good idea too. Hmmm...

BYW, please drop me a PM with your email, I've got a lot of info for ya about the upcoming meet. Also posted in the Mountain forum, and on our website.

Are either of you guys considering going back to the stock exhaust with the Canzoomer midpipe?

That might tone things done enough for you. (plus you can sell your Borla for extra spending money.)

-Mr. Wigggles

That's a thought actually... that's what CanZoomer himself did. He had the MidP-4 and the Greddy cat back, and decided it was too loud.

If I were going to do this though, I'd have to replace the tips on the stock exhaust with something along the size of the Borla. I've really grown to like the way they look, and at this point think the stock tips look too small.

The other thing is that I don't know that I'd want to give up the deep, beautiful tone of the Borla. I'd have to hear the stock exhaust + MidP-4 first before I could make that call. I was also wondering (if I decide it's too loud still after ~500 miles or so) if I could put another resonator in place, somewhere along the length of the Borla's pipe before it gets to the muffler.

But I dunno. The car definitely runs and pulls more strongly, and the sound already seems to be mellowing a bit. Plus it got the Mrs. Omi stamp of approval this morning. :

Omi: So, how's it sound? Is it too loud?
Mrs. Omi: Sounds the same to me honey, it was a bit too loud before with just the Borla, and I don't notice any difference with the new cat. And that's ok because it sounds hot-sports car loud, and that's a good thing.
Omi: :D

Omicron,

Go to NOPI.com, you'll find plenty of tips there. I don't know if you'll find any less than 5" wide though. :)

-Mr. Wigggles

Actually, they've got 2.5" OEM style and up. Quite a bit of clicking but quite a selection too. Thanks!

what size ARE the 8's stock pipes inlets?

I don't think I'm gonna' rework an already good exhaust,but I really want some larger tips,imo the stock ARE too small in proportion.....

Great to hear! I can't wait to get mine. I'm keeping the stock exhaust though. I also really have to work on getting the Mrs. approval:D

hey Omicron, if you ever decide to sell your borla. I will be interested

You will have to pry my Borla out of my cold dead fingers :D

Dunno about inlets, but I think the tips are 2 inch or possibly 2.5 inch. Actually, I believe the cat back pipe is 2.5 inch stock.

The NOPI site listed above does indeed have some pretty nice tips that could be welded onto the stock exhaust in lieu of the stock tips, like this 3.5 inch one:

Or this one:

Or even this Borla one:

That's about how I feel about it. :D

From MIB "your offer is acceptable" ;) .

Maurice's car is nice and quiet now. Pretty much back to stock noise levels. The way he drives that's a good thing :) . The highflow/resonator and Greddy combination shouted "Look at me!" It's also a lot easier for me to test the CZ units. I can hear the injectors again.

where can i get the cz-mid pipe??

http://www.canzoomer.com

I too just installed the CZ Mid-pipe with resonator along with the high flow cat. Personally I do think it’s too loud. If you’re not looking for attention stick with the stock exhaust with the mid-pipe and high flow cat.

FYI, I’ve only had it on a few days and it does seem to be toning down a little. However that may just be me getting used to the sound. Time will tell, but usually mufflers get a little louder—hopefully this one just gets deeper.

Ben

Ben,
What cat-back system do you have? Borla?

Yes, I have the borla. I'm very happy with their design. It light, the tips are big, but not too big. The tips also have a little whole at the bottom so stuff can drip out and they have a little lip on the inside to keep the soot from moving to the outside of the tip.

BTW if you are married it does not have a good WAF (wife acceptance factor). Luckily mine puts up with my shenanigans, but then again I kept her happy by getting her a Land Cruiser.

so it's that much louder huh... May keep people from getting it.

How about at 70 mph in 6th gear or cruising speeds in general?

Or did everything get louder.

I have the same setup -- CZ4 with Borla. I had the CZ4 and the Borla installed at the same time (and same day as Husker), so can't compare to the Borla alone. Verdict: WOW, IT'S TOO LOUD. I agonized for a while that I could get used to it, but Friday afternoon / evening drove from the D.C. area to vacation where in W. Pennsylvania. I think my hearing is now the worse for it. The buzzsaw sound (worse under acceleration) starts around 3000 RPM and peaks around 4000. By 4200 it's starting to sound sweet and at 5K it's really much quieter and lovely. The problem, of course, is that Interstate cruising at 72 mph = almost 4000 RPM, just in the sweet spot of the buzz saw. (You can, of course, do the interstate in 4th or 5th gear, but not practical from a mileage or, perhaps, engine life standpoint.)

It is good for practicing heel-and-toe'ng, as you can hear the revs precisely all the time (a help to Husker in his great track day?) but otherwise too loud for my sedate blood. And, against advice but due to other WAF factors, I gave away my stock exhaust. So I will be looking to make a deal to dispose of the beloved Borla in exchange for a stock exhaust plus draft choices, cash, and/or a mod to be named later. Or any other bright ideas.

The car does feel absolutely super at 5K and above, is breathing free and easy and even sounds great. If I didn't have to go through the other revs to get there I'd be fine.

Interested in the sound deadening idea, AND there was an issue re tight mating of the pipe to the Borla that Husker's and Omi's installers flagged, but mine didn't (and I checked back with him). So MAYBE there's a leak there that my guy didn't anticipate or see, making mine worse than the others? A straw grasp, I'm afraid.

At least nobody tailgated me on the way up to Pennsylvania! :)

Some lovely mountain roads up here. But this far we gotta bomb around in the wife's 325 wagon. Oh well.

Can anyone report what this mod with the RB exhaust sounds like? I was waiting for the RB exhaust and understand it to be mellower than the Borla. I'd really like to try the CZ-P4 and the RB cat back but it'll have to wait. I just put exhaust on my wifes car so I'm now clear to put one on mine but I've got to save a few more nickles first.

Ordered a Dynamat Extreme kit for my trunk yesterday. This should dramatically reduce the interior sound (and increase heat deflection as a side benefit). I won't give up my Borla and really like the feel of the midpipe and cat. Actually -- nobody has even mentioned that the car is louder (my wife didn't even notice that I made a change) -- I'm wondering if most of the sound increase is interior -- putting the sound dampening material inside should solve the problem while letting me keep my mods :D

As you know, I'll be VERY interested in how the Dynamat works out.

Shebam, I wouldn't give up your Borla just yet, we may well come up with a solution.

I've been thinkin on this, and wonder if muffling exhaust tips might just do the trick. Problem is, they need to be no longer than 10 inches, and no bigger around than 5 inch diameter for the muffler cans. I've hunted around a bit (including on the NOPI site) and have yet to find anything fitting these specs. Anyone have any suggestions?

I've also decided that if anything has to go, it won't be the Borla... mostly because (a) I love the sound (b) it's light (c) million mile warranty (d) it won't cause me problems with emissions testing visual inspections and (e) it won't cause me problems with the car's warranty.

I'm hoping I can keep the current setup with just some additional muffling and maybe the dynamat insulation. For now I'm just in a holding pattern to see if it mellows, and to see how the Dynamat works.

Isnt a lot of the noise going to come from the hi-flow cat and mid pipe area which is directly underneath the passangers?

By putting this material in the trunk, will it really reduce noise levels that much?

If you do a Google search on Dynamat, there's a paid link to Quietcar, which is a liquid that sprays or is brushed on. Claims to work differently and more effectively. I inquired, via their web site, whether it might have an application for this problem, and if so where it should be applied. Thus far no answer. Web site indicates they have an industrial division with all sorts of sophisticated applications. But not much info about them elsewhere on the web.

Trust me, most of the additional noise comes from the muffler area.

Omnicron,

Are you getting the same buzzsaw sound from 3000 RPM to 4000RPM that Shebam is getting?

-Mr. Wigggles

Yep. Or, I was. I've pulled the high flow/temp cat + resonator off for now.

Ahhhhhh! Sounds so much better - not too loud, not too quiet, deep and beautiful. Mature. Powerful. Not at all raspy or ricey.

Agree. Just had a lovely run through the mountain roads with the window and sunroof open. The music is coming from the pipe area.

Sounds like you're getting to like it. :D

Hey, if I could do all my driving in 3rd gear, 4500 - 7000 RPM on winding mountain roads in SOMEBODY ELSE'S neck of the woods, with the windows and roof open creating lots of air noise anyway, I would LOVE it. :) It won't be as much fun at a steady 72, or in stop-go traffic, on the way home tomorrow.

This is my day to take the lemons and make lemonade, so might as well look at the bright (er, tangy) side.

i notice almost everyone has hi-flow cats instead of a straight pipe, is there a reason for this?

Worries about vehicle inspections, or they care about the environment while still wanting more power... or both.

NOTE: The environment comment was not a shot at people with straight pipes... just the honest reasons given in the CZ thread a long time ago.

Straight pipe doesn't really add any power to an otherwise stock car. If you tuned the PCM for it, perhaps you could get more. Sure makes it much noisier though. I doubt you could drive past a cop and not get stopped!

Butt Dyno says Borla w/ mid-pipe / high flow cat = slower
 

I installed the CZ-MidP-4 (Random technology mid-pipe and high flow cat) and the Borla exhaust. This setup removes all stock exhaust pieces up to and including the catalytic converter.

1st as, previously discussed, its way too loud.

2nd: My butt dyno says the car is slower. I used to be able to chirp the tires in the 2nd to 3rd shift (shifting at 9000+ or so). Can't seem to any more. Even 1st to 2nd doesn't seem as strong.

I don't have any real numbers this is just my feeling of the car. I also had the "M" flash done around the same time.

Can anyone share their performance results w/ similar setup?

Must be your M flash -- my MidP4 (with Borla) certainly didn't decrease power.

sorry how much is the czmid-4? i cant find the price on the website gave me messed up letters..,

can anyone pls. give a sound clip or video i really need to know an idle how it sounds like?

Hey RXHusker, did you install the dynamat? If so, how do you like it?

I did install the Dynamat Extreme (trunk and trunk lid). I estimate that it reduced the sound level by 25% to 30%.

Install was very easy -- took about 2.5 hours total -- just need a screwdriver (for the carpet fasteners), utility knife and a roller. Sound level is probably about the same as just the Borla (before the midpide/cat install). There isn't much stock sound insulation so adding the Dynamat made a noticeable difference. I think it was worth the $100 plus 2.5 hours. It took 5 of the 9 pieces that are included with the bulk kit. I may use the rest under the front footwells and behind the rear seats (I think most of the remaining sound entering the cabin comes from behind the rear seatback -- just a piece of black plastic between them and the trunk)

My wife (she didn't know I did anything) commented that the car seemed quieter -- I guess that is the real test ;)

Actually in the thread on just changing the tips on stock exhaust, I seem to recall someone commenting that they had more torque with the stock muffler (and mid-pipe) than with a aftermarket muffler (and mid-pipe).

Re: Review of high flow cat, resonator, and Borla exhaust
 

Got a printout? :D

Sorry, just "HAD TO"

Hey Oni... Can you clue us in on any more information you may have about the Borla development?

I cant find the thread where you stated that so I decided to post it here...

Thankx!