Jesuscookies

iTrader: (1)

I have seen many, including myself, ask this question but no one has really had any supporting data. So, I did a little informal anaysis on sound and power suppression when adding a resonated midpipe. Again nothing scientific, but I am think it will help for those trying to decide if this is a worthwhile investment.

I initially had a riced out fart canister on my 7. Straight thru, with DP and MP. Got popped by the police within 1 day, 1 hour, of driving it on the street (welcome to California). I measured the sound at 105Db at idle (A weighted)

Based on forum suggestions, I decided I would switch out to the RB Catback to quiet her down. Sound dropped about 10DB, @ 94-98Db (A weighting). Good, but still loud enough to attract attention.
(95DB is the legal limit but I think it is measured with a C weighting )

I then installed the RX 7 Store Resonated Midpipe last night. Quite a noticable noise drop, 20Db to be exact. I was at 74DB (A weighting) and 94Db (C weighting)

I wanted to test power loss if any. The only thing I had to try and measure possible exhaust restrictions was my boost controller. My car is dialed in for 1.07 bar of boost max, 15.72PSI for the geeks . It has rarely if ever deviated from this max. (Blitz single turbo conversion).

After installing the Resonated midpipe, my max boost held constant at 1.06 bar, or 15.58PSI. Again this is not scientific, but I did see this deviation, and the exhaust would explain it. The loss is very small in my opinion. (15.72 as opposed to 15.58).

So there you have it......

oppressor666

1.06 pounds, or 15.58PSI


You mean 1.06 BAR right?

And did you really measure 105Db at Idle, that is insanely loud...How loud is it a WOT at 6000RPM.

Marc

Jesuscookies

iTrader: (1)

Doh!!!! Yes I meant bar. I went back and edited my post.

And yes the initial exhaust I had on there was very aggressive.

vosko

iTrader: (4)

my car with open wastegate had to be 130+ on boost at high rpm.........that was great

Jesuscookies

iTrader: (1)

Yah, if your 7 is highly modifed, forget about trying to quiet down the upper RPM range.

vosko

iTrader: (4)

my FD idling with exhaust leak after accident........

http://vosko.net/photos/fd/fdafteraccident/DSCF0023.AVI

SNracing

jesuscookies, i bet you had the apexi gt spec exhaust, or something similar to it. it is by far the loudest exhaust i have ever heard.

Jesuscookies

iTrader: (1)

Yep, pretty loud indeed

vosko

iTrader: (4)

actually this is more like it

http://www.vosko.net/media/burnout/voskoburnoutdgta.wmv

cmartinp28

racing beat exhaust and midpipe sounds great..... not disturbing, yet screams at WOT

Jesuscookies

iTrader: (1)

I think you are talking about Vosko's. The one I had before the RB Catback was made by Topspeed.

Jesuscookies

iTrader: (1)

So Puuurity

vosko

iTrader: (4)

i got tons more but i'll stop whoring

Jesuscookies

iTrader: (1)

Back to the topic at hand

badass7

Any Fitment issues with the Rx-7 Store Resonated MP and Racing Beat CB ?

I'm also looking to just quiet down idle and crusing noise levels. When I go WOT, I still expect her to reach 200 db's

Jesuscookies

iTrader: (1)

Wow back from the dead


I had no fitment issues with the VRS/RX 7 store midpipe, and the RB catback. This setup will keep attention away from your car at idle. But it roars once you open it up.