View Single Post
#1: 06-06-2011, 09:40 PM
Electric exhaust cutout installed w/pics. Best of both worlds?
TRSCobra's Avatar
Title: Burning Monkey
Rank: Donating Member
Location: Olalla, WA
Car: '12 Mazda 3, '12 C300 4matic, '06 Z06
Posts: 2,304
iTrader: (8)
Send a private message to TRSCobra Find all posts by TRSCobra Reply With Quote
**Edit: Now with dyno results and videos!**
Due to excessive noise, I sold my HKS catback and reinstalled a stock system. While my neighbors and passengers loved the sound (or lack thereof) I really felt the loss of performance with my 20g turbo. My car had the spool of a 20g with the top end of a 16g. Less than ideal,but since every aftermarket exhaust that I've heard is louder than I'd like, I'm stuck with the stock catback.

A few weeks ago, I had a 3" electric cutout installed on my downpipe to give me the power I spent so much money on when I want it. Turbos love to breathe, and what better way than an open dump a few inches after the bellmouth? This bypasses every restriction in the exhaust system and keeps it nice and quiet when it's closed.

Yes, I've read the stories on the internet of these things failing, and talked to people (none with personal experience) who also said they're garbage and won't last. So I did some research and found most of these complaints were with QTP and Badlandz cutouts. The other two major brands, DHM and Race Ready, seemed to have better reviews in terms of longevity. Since Race Ready has a lifetime warranty, I went with their 3" cutout.

I saw two guys running the cutout right after the bellmouth in a cutout thread on NASIOC, both reporting great results. (I PM'ed them and the one with the Race Ready cutout hadn't had any issues in over a year of use.) This position puts it up high enough to avoid the ground clearance issues that many have with these, at the expense of subjecting the electric motor to more heat--another reason I like the lifetime warranty. I spoke with a representative from Race Ready Performance who suggested that I shield it from heat, but he made no mention of it voiding the warranty. Also, it turns out that it's about a foot away from the biggest hole in the firewall, making wiring this thing a breeze.

Since their 12" stainless Y-pipe would need to be cut down to about 7" to fit between the cast bellmouth and the first bend in the DP, I had a local shop that makes stainless headers and custom exhausts cut an oval hole and use their own 304 pipe and flange. Top notch work.

The notched holes on the cutout flange allows a decent amount of options for mounting. I had them clock the flange so the motor would sit where it wouldn't make contact with the control arm or the chassis and allowed for engine movement.

Here it sits, well out of the way of hitting anything I might drive over:

I know that the placement of the Y-pipe is close to the axle, but there is plenty of clearance for turning and suspension movement. I'm going to keep an eye on the inner boot, since it's exposed to more heat than before. If I run into issues, I'll just wrap the DP.

I don't have any sound clips, but it actually sounds quieter than when I ran my catted DP with no catback. This is possibly due to the exhaust pulses reflecting off of the ground. Still super loud, and the turbo whistle really turns heads at the track.

My first 1/4 mile run with the cutout closed was a 13.8 @ 106mph. I had a crappy launch, but I know I could've had a better time. I doubt the trap speed would have changed by much, though. My next run (cutout open) was also a bad launch, but I hit 13.1 at 112mph. Eventually I hit 12.6, but my trap speed stayed at 112mph. 6 mph isn't bad for flipping a switch. This is with ZERO tuning changes.

The car is tuned for the HKS catback, which flows better than the stock system, but nowhere near as well as the open cutout.

I'm in the process of getting an Infamous tune, and I'm going to try to get some dyno results later this month of the car with the cutout closed and open. More track time to follow, too.

Thanks to:
Race Ready Performance
Clear Image Automotive

Last edited by TRSCobra; 06-11-2011 at 06:11 PM..
The Following User Says Thank You to TRSCobra For This Useful Post:
jmatijas_gt (11-28-2011)
Sponsored links