2650R, 2" LTs & off-road just WAY too loud for me, solution.
 

(Scroll to the bottom for pics)

Recently had a set of Kooks 2" long tubes headers installed to complement the Magnuson 2650R to build a reliable/safe track-focused power band. The results were exactly what I wanted, the car makes ~700 rwhp through the automatic and the power delivery is super smooth. Nothing tricky about the setup, just a 2650R on an all-stock motor with LTs, 93 octane, through the A10.

All of that was great, but it was just too damn loud for me, my neighbors, likely any track with any type of noise restriction, etc. To maximize my enjoyment out of the car, I needed to make a change. After some careful research, I settled in on adding a Magnaflow X-pipe muffler where the factory X-pipe was, replacing it with the Magnaflow X. I kept reading people trying to resonators to remove the high pitch rifle shot sound when mixing NPP and LTs but the effect being minimum on DBs and tone.

https://www.magnaflow.com/products/1...rmance-muffler

The end results are FANTASTIC and exactly what I wanted. The car has a mild startup, the ear-piercing BARK when the car roars to life is completely gone. That sound was okay I guess when the car was 100% stock, but after the LTs it was really difficult to live with for me and my 3 year old.

The car now has a much more mellow note and until you add in a lot of throttle, the car is actually really reasonable. Once the exhaust gas picks up speed, the X-Muffler can do less to lower the DBs but the tone is still deeper. So the exhaust, under load still gets VERY loud, louder than stock. However, now you can take a drive in the car and have a regular conversation with a passenger, listening to music or talk on the phone no problem, actually better than stock in that regard.

I realize some of you WANT your cars to be very loud and you enjoy that part of your car. Coming from an 1100 rwhp TT ZL1 and a Buick Grand National before that, loud and fast don't go together for me like it does for some of you, that's a personal thing.

In addition, now that I'm a total track ratt, listening to an ULTRA loud car @ 100% throttle for 20 minutes a day, 6 times a day, isn't fun, even with my helmet on.

(Some may ask, why to keep the stock NPP muffler and I'll give you my 2 reasons. #1 the aerodynamics of the car is affected slightly by removing the suitcase muffler and adding aftermarket mufflers. A void is created where the muffler once sit, disrupting airflow. This may not be an issue for you on your track, but COTA is a high-speed track and after 130mph to about 160mph the rear bumper shakes violently as air pressure catches the bumper cover and tries to pull it off, buffeting it and making it shake, causing lift and slowing the car down. Once you go away from that muffler, you end up adding a diffuser to cover the gap it left, that was a bunch of steps I didn't want to take to make my car even loud. #2 "weight savings isn't there" the stock NPP muffler by itself actually doesn't weigh that much, weight savings is typically negated w/a stainless system, unless you're going to a FULL race setup, which means no muffler and as you could guess, that isn't going to work for me, most tracks, my wife, child or my neighborhood. :) )

I hope this helps some of you who, like me, thought the exhaust note was TOO loud for Track use or just wanted it to be quieter but still enjoyable.


Start-up videos:

Outside

https://www.youtube.com/watch?v=8Sjv1W3VAUw

Inside

https://www.youtube.com/watch?v=O9AoQvxnPiA

Partial throttle, higher RPM, light pulls:

https://www.youtube.com/watch?v=SAOHLPaIqBg

I was pretty surprised at the wicked cold start bark and my neighbors definitely know when the car starts. I now keep the garage door closed until it's running in respect to my neighbors. You sir have a sweet setup.

Might want to check the muffler you used just fyi. Some of the Maggie X Mufflers go down to a single 3" pipe inside (double Y) instead of a normal X merge.

SUPER-COOL!!! Awesome thread.

I'm eager to see how it tracks with that blower. I like the heat-sleeving you've done, too.

KUDOS

Nice option for those that want to quiet their car down. I myself would move before I put a muzzle on my car. As long as the car sounds like its got power under the hood the louder the better for me as long as there isn't a drone present. My z06 is 113db at idle and it only gets better from there. My ss 1le is louder but I have not officially checked it and the zl1 1le is the "quiet" one of the bunch. I live in the country and can't see my neighbors though so I don't have to worry about pissing them off.

Awesome car there and good work for getting it quieter.

How did you fit the seats? Is there a premade console? and what did you do with the airbag light?

cheers
cirpower

I did check it with a boroscope actually, I was worried about the exact same thing!!! It is an X-pipe in there, same size as stock essentially. Thanks for bringing that up as others may wonder. Also, I updated the link because I used the 3" dual inlet / 3" dual outlet, not sure about the 2.5" inlet/outlet muffler although it would probably be the same design.

How did you fit the seats? With BK seat mounts

Is there a premade console? Yes, GM offers it.

and what did you do with the airbag light? Ignore it, very tiny on the dash.

Me too! Hopefully super great, that was the whole point of this investment. My home track is COTA and while I am a fairly accomplished AM driver, it is frustrating getting pulled a bit on the back straight by GT3RS's, AMG-GTRs, etc. The idea was cool, reliable boost with a blower that has better cooling and can run all day on 93 octane. The shop that did the work, actually LISTENED to my request and did a great job on the install AND the tune. The power comes on smoother than the stock blower, the tires don't get shocked, feels more like an N/A car than it did with the baby 1700. Lots of different ways to get around the track with a ZL1 1LE faster than stock, this is the way I thought I could do it. The future may hold a baby road race cam with more fuel and a smaller pulley to get the boost over 14psi, but for now power is great and fuel is ample.

Thank you! I sent you a PM for more info on the seats.

After hearing your cold start, I’m seriously considering this as my next mod. My cold start hit 117db (on my iPhone app) and is too loud when I go back to commuting to work. Neighbors would not enjoy it at 6:30am. I’ve got the kooks 2” with green cats, borla 3” stype, and a 2650.

Sakudog, who build your exhaust system? If you'd prefer to take it to PM please message me!

I can't watch the videos on my work computer, but those are some nice pics !!!!


How did you go about doing that back seat delete?
any more photos of it?

looks good.

SchraderPerformance seat delete kit for 2016+ Camaro

https://www.shraderperformance.com/s...r-seat-delete/