Well, I went to the mechanic today and used his lift and installed my RX7Store resonated midpipe..

My previous setup was

Pettit DP
Racing Beat Dual Tip Catback.

Most of you are familiar with the RB and know it's really quiet...With the DP & CB is was slightly louder than stock. I figured that putting the resonated MP on it would wake up my neighbours...Well, as soon as I fired her I though "Hmmm, that's weird, it sounds the same " I was expecting it to be hella loud and stinky....it was neither. I even reved it up a bit in neutral and it was a little bit louder but almost not noticable.

After the install I plugged the O2 pump hose that ran into the stock cat and disconnected the O2 pump. Then I turned off the Profec-B just incase. Prior to the MP with the Profec off I would get 6-7psi...With the MP on and the Profec off I got 7-8...So I turned down the low setting on the profec and then turned it on...went WOT and never went past 10psi...I put it on the high setting on the profec and then turned it down a tad....Hit 13psi and goddamn it pulled like a maahhhfakka!...At 13psi my Inj-duty hit 85%...think I will leave it at that and not push it anymore until I get the rebuild...

The only time you really notice a differencen in sound is when the secondary comes on. It is LOUD...cruzing around town is the same as usual...

There I did what I was afraid to do all along...This forum sure makes you paranoid.

I am like mad quick yo!

 

Awesome review. I plan on running the same MP as well. I already have the RB CB, and the neighbors always comment about how silent it is. I was thinking about getting a MP with the borla muffler welded on, but if the resonated MP is tolerable, I'll just get that. Would it be possible for you to get some sound clips?

 

Wow, thats awesome. I wish MA didn't have an emissions test (or at least I didn't have to pass it ) so I could get one now!

Is it unbearable at WOT? I would think, and from others descriptions, that it's drastically louder all the way through the rev range. But you really just changed my opinion of a midpipe.

 

Nice to hear from you guys. I have the HKS downpipe, N1 cat back and a stock mid. I'm installing the Pettit mid with resonator tomorrow. I hope I'm as lucky with the volume. Otherwise I'm selling the N1. Does the RB make as much power?

Late,

 

Dude,

You are right. I have an HKS catback, a MP and DP. My car is so quiet until over 4500 rpm. and it doesn't smell like gas at IDLE.

If you wanna hear something funny, I hooked my highflow cat up and put my straight through catback and guess what? My car was so freaking loud. Its more the catback that affects the sound than the MP. MP is only loud after 4500 or so.

 

Thats awesome news. I want my car loud after 4500 rpm, cus if it's in that rev range, I'm driving it hard.

How about non-seq? Would it be loud any time in boost? (i.e. is it definitely related to the second turbo?)

 

I dont know cause my car is not non sequential, I would guess it would be loud a little bit sooner, not much. again its just a guess.

 

Your's will be loud all the time. The sequential set-up acts as a muffler below 4500 rpm.

 

i too have no cats and a RB muffler. My car is extremely quiet. Makes decent power too.

 

I need to get a res pipe. My straight exhaust with Trust J-spec cat-back is way to loud. And I am thinking about going non-sequential

 

Nice review, Apneablue. I have the RB cat-back as well, so good to know what I could expect.

I suppose eventually I will give in to all the pressure and run a midpipe but I am too busy finally enjoying the world of above stock boost levels right now....

Fdeeznutz: Like Zerobanger pointed out, the noise level is mostly determined by your cat-back. In your case, it will be VERY loud with a midpipe, I'm guessing, resonated or not.

 

The resonated pipe would not quiet it down at all? Without sounding stupid, what is the point of a resonated mp if not to make it quite?

 

The resonator only works over a limited range of frequencies (or rpm range). It is designed to make the car quieter at "cruising" rpm. It would probably make a noticeable difference in your situation in around town driving, but one of the midpipe guys would have to chime in here. I was merely reiterating that the cat-back is the most important component to how loud your exhaust is.

 

Good point Rynberg.

 

The RB CB is not as restricitive as most people think. If you need X amount of power, it can be done with the RB CB.

 

I read somewhere that by putting in a MP you get less power in the lower RPM's but more in the higher, is/was this true for you?

 

if any of you have seen pictures of the stock twins manifold and how large that door is in it, you will understand fully the large increase in noise after it is opened ~4500 rpm.

and ya, most mufflers will only help out up to a certain exhaust speed as you all know.

good mod - but i always recommend porting your wastegate when running a midpipe. it might be ok now, but when the weather gets colder, you run a higher chance of it creeping/spiking. just my suggestion - others will likely disagree

 

What kinda change would you say, hmmm 40°F temp have on boost?

 

Hey, how much low end torque do you feel you lost?

I'm considering doing the same and have the RB CB and HF Cat now. Getting rid of my air pump would make a few things fit better undre my hood as well. I've been owrried about the noise, smell, and most of all low end torque.

A friend has a MP on his and he seems to regret it which is why I've held off.

 

Egads...you guys wanna talk about loud? DP, non res. mid pipe, n1 dual, with no silencers, running non-seq. Its insanely loud. I love going under underpasses, WOT, at about 6k+!

I just ordered my silencers, and am probably going to make my own resonated section on the mid pipe. Just need to find some SS wool, for the packing.

Could anyone who's ran a mid pipe then a resonated mid pipe tell a difference at idle? I don't drive my car very often, but I'm trying to be kind to my neighbors.

Thanks, CJ

 

Honestly, butt dyno doesn't notice any loss. I am completely happy with this mod.

Speaking of getting rid of the airpump, I disconnected mine and have it plugged at the cat.

I know we need a 4 or 5 rib 29.5" belt when we take off the O2pump...However, I have no clue how the belt is going to be routed...Is it going around the crank, WP, and Alternator? or is it going around the crank, alternator, and then has the outside of the belt rubbing on the WP?

can someone shine some light please?

 

I take it then that you do not want to get the greddy pully kit which removes the airpump.

 

With my DP,mid pipe and Greddy Power Extreem exhaust, my car is loud and stinky all the time. I love it

 

apneablue,
would you like to upload the sound for your MP?
So, you are working on your project

 

You know, I never even thought about using the Greddy kit to eliminate the 02pump...If I remember right it comes with a belt and everything needed. Installation is supposed to be easier than the Unorthodox Racing kit. Why would you choose the Greddy kit over the UR kit?

I recorded some with my portable MP3 player. However, when I listened to it over the headphones it sounded liks distortion. I will transfer them to the PC and see if it sounds better and worth posting.

Edit: Just downloaded the sound files and they sound like **** so I am not even going to bother posting them...Will work on it later.