[JonDaddy82]

Fresh cold start clip with the updates:

https://youtu.be/DsA4EIn4x8w

[jjgi5150]

Hi all,

Sorry for a late follow up, been busy with lots of other issues at home. I had my installer put in the Kooks Axle back system, will all other exhaust factory stock. When it first started, I was very impressed. Deep, throaty sound like an American muscle car should have, with no higher pitched raspy sounds.

Then I drove it out onto the roadway. At every single RPM point where I drive the car, other than full throttle or idle, the drone...well not really just a drone, a gigantic vibration better describes it, occurred. Between 1900-2500 RPMs, inside my beautiful car it sounded like a muted coffee can with ball bearings being shaken on a paint can shaker. The side windows hummed, the rear glass vibrated, and the entire trunk area, mostly from the thin metal factory suitcase heat shield, resonated almost beyond description. It was completely unbearable. On a deceleration in 2nd or 3rd gear, another surprise...A gigantic humming sound that almost sounded like a giant electric motor slowing down.

Having heard this system on many videos, and on a local persons Gen 6, I really didn't expect what I got. It was so bad, I only drove the car from the shop to my house, then back to the shop to have my stock suitcase reinstalled at the installers next open appointment. None of the above noted problems existed before or after with the factory suitcase.

I believe this system is just not going to work with (Most) M-6 and ZLE cars. It may be that it's just my individual car's own harmonics. Mine was, without any doubt, the worst sounding exhaust (Internally) I've ever added to a car.

Reading about some folks more recent efforts to tame similar issues, it is apparent that the Kooks system can be fixed, but that would end up costing as much as the more expensive systems out there, and most of which the sounds I didn't care for.

I am now extremely happy to be back with the stock system with the #51 fuse pulled. It should be a touch louder, but I wasn't that unhappy with it to start, and for the cost of the Kooks, it was worth a try for me. I'll sell off the very slightly used Kooks here locally to recoup some of the cost.

As a side, with the Kooks installed, the car certainly did feel like it had a bit more punch...but that trade off was more than not worth it.

Sorry I didn't make any videos of the horrific sound show it made, but I just didn't feel like setting up the GoPro...but I think you can all get the basic idea, though.

Good luck with everyone's exhaust system hunting...Gonna stay stock for mine.

JJ

[Can'tHave2MuchHP]

Originally Posted by jjgi5150

Hi all,

Sorry for a late follow up, been busy with lots of other issues at home. I had my installer put in the Kooks Axle back system, will all other exhaust factory stock. When it first started, I was very impressed. Deep, throaty sound like an American muscle car should have, with no higher pitched raspy sounds.

Then I drove it out onto the roadway. At every single RPM point where I drive the car, other than full throttle or idle, the drone...well not really just a drone, a gigantic vibration better describes it, occurred. Between 1900-2500 RPMs, inside my beautiful car it sounded like a muted coffee can with ball bearings being shaken on a paint can shaker. The side windows hummed, the rear glass vibrated, and the entire trunk area, mostly from the thin metal factory suitcase heat shield, resonated almost beyond description. It was completely unbearable. On a deceleration in 2nd or 3rd gear, another surprise...A gigantic humming sound that almost sounded like a giant electric motor slowing down.

Having heard this system on many videos, and on a local persons Gen 6, I really didn't expect what I got. It was so bad, I only drove the car from the shop to my house, then back to the shop to have my stock suitcase reinstalled at the installers next open appointment. None of the above noted problems existed before or after with the factory suitcase.

I believe this system is just not going to work with (Most) M-6 and ZLE cars. It may be that it's just my individual car's own harmonics. Mine was, without any doubt, the worst sounding exhaust (Internally) I've ever added to a car.

Reading about some folks more recent efforts to tame similar issues, it is apparent that the Kooks system can be fixed, but that would end up costing as much as the more expensive systems out there, and most of which the sounds I didn't care for.

I am now extremely happy to be back with the stock system with the #51 fuse pulled. It should be a touch louder, but I wasn't that unhappy with it to start, and for the cost of the Kooks, it was worth a try for me. I'll sell off the very slightly used Kooks here locally to recoup some of the cost.

As a side, with the Kooks installed, the car certainly did feel like it had a bit more punch...but that trade off was more than not worth it.

Sorry I didn't make any videos of the horrific sound show it made, but I just didn't feel like setting up the GoPro...but I think you can all get the basic idea, though.

Good luck with everyone's exhaust system hunting...Gonna stay stock for mine.

JJ

Oof.

[JonDaddy82]

Sorry you threw in the towel on the Kooks so soon. Just in case you wanted to give it another whirl, just have some J-pipes fabbed up to go with them. Still ends up being cheaper than most anything else out there.

[mdmoore23]

Originally Posted by JonDaddy82

Sorry you threw in the towel on the Kooks so soon. Just in case you wanted to give it another whirl, just have some J-pipes fabbed up to go with them. Still ends up being cheaper than most anything else out there.

I spoke with him also. Don't know if he just gave up too soon or the system on the ZL1 1LE may be absolutely too much for some. It has slightly different trans gearing, lacks some insulation, and has some less dampened suspension contact points that could've all made his situation worse than a standard M6 ZL1. But with all the rattles and noises he mentioned, I'd almost question whether there was a clearance issue going on with the install. Seems like the system could've possibly been contacting something under the car. Hard to see how, but I've seen it happen before on exhaust installs.

[mlee]

Originally Posted by mdmoore23

I spoke with him also. Don't know if he just gave up too soon or the system on the ZL1 1LE may be absolutely too much for some. It has slightly different trans gearing, lacks some insulation, and has some less dampened suspension contact points that could've all made his situation worse than a standard M6 ZL1. But with all the rattles and noises he mentioned, I'd almost question whether there was a clearance issue going on with the install. Seems like the system could've possibly been contacting something under the car. Hard to see how, but I've seen it happen before on exhaust installs.

Gave up too soon... I would have done exactly the same thing.

Your comments are quite the stretch.

[jjgi5150]

Originally Posted by JonDaddy82

Sorry you threw in the towel on the Kooks so soon. Just in case you wanted to give it another whirl, just have some J-pipes fabbed up to go with them. Still ends up being cheaper than most anything else out there.

I'm going to just stay with the stock system. I like it well enough to just leave it as is. There are so many thngs I enjoy about the car stock it's just not worth the extra effort to take away from car driving time, Harley riding time, shooting and a ton of other retirement things I get to enjoy.

The fitment of the Kooks was not the issue. There was no contact vibration from the system, all the rubber busings were perfect, and everything was properly torqued. My installer is a true pro, and treated the car like it was his own. I watched the entire install.

I really believe it was just a matter of the harmonics in MY car. Possibly a loose panel or shield or ???? that did not get affected by the stock system but was by the Kooks. The solid suspension bushings in the ZLE could have added to the cause as well. I could have messed with it a lot more, Dynamated everything, added another resonator and on and on...but it's just not worth my time now for a stock setup that I'm not that unhappy with.

JJ

[mdmoore23]

Originally Posted by mlee

Gave up too soon... I would have done exactly the same thing.

Your comments are quite the stretch.

I'm not declaring he gave up too soon, just said that in reference to the previous post where "threw in the towel so soon" was used. I personally spoke with both of these guys. Dont get how these comments are a "stretch". The things I listed are obviously differences between the base zl1 and ZLE that could contribute to what he described.

[mlee]

Originally Posted by mdmoore23

I'm not declaring he gave up too soon just said that in reference to the previous post. I personally spoke with both of these guys. Dont get how these comments are a "stretch". The things I listed are obviously differences between the base zl1 and ZLE that could contribute to what he described.

...and they are all a stretch when it comes to drone, even with the back seat down on a ZLE. We've mentioned since the beginning of this thread "buyer beware". It's not the way a ZL1 should sound.

[mdmoore23]

Originally Posted by mlee

...and they are all a stretch when it comes to drone, even with the back seat down on a ZLE. We've mentioned since the beginning of this thread "buyer beware". It's not the way a ZL1 should sound.

Well, these aren't the only cases I'm aware of where people have purchased Kooks axlebacks based on my recommendation. One person I know of so far has removed his system, and that's the gentleman in this thread with the ZLE. I drive my car every single chance I get and have never once thought about taking my exhaust back to stock. I'm not deaf, so obviously there are some key differences between a10s, m6's, and 1LE's as far as harmonics are concerned. I still stand by my opinion of this being the best sounding option out there for these cars. I know people's drone tolerances are different, but what the gentleman in the 1LE describes sounds like more than just that. I was disappointed to hear that these two people had issues with their systems, based somewhat on my video, that cost them additional time and money, so I reached out to them and spoke with them weeks ago. Still dont get how you're saying it's a stretch that a car with less insulation, solid body to suspension mounting points, and different trans gears wouldn't have an affect on drone. Plus, all it takes is a slightly twist the wrong way of those mufflers at install and they will contact the rear subframe. If his back window was rattling, this could've surely been a possibility also. I said from the beginning for people that wanted this system to be ready for more drone than stock, but nothing extreme.

[jjgi5150]

Hey all,

No upset here with me. It was worth a try as far as I was concerned after hearing the Kooks system. I still believe the cost of many of the other popular axle back systems is way over what they should be, any many are not the sound that I like.

If I was to ever try anything else, I might consider a custom fabricated set of mufflers from a '15 Z/28, fitted onto my stock system. Those were about the best sounding stock mufflers I've heard from an America car in ages. But I'm not sure if the fitment might not be too much of an issue.

Anyway, for now, and likely forever, I'm glad to be back to stock...it works for me.

[mdmoore23]

Originally Posted by jjgi5150

Hey all,

No upset here with me. It was worth a try as far as I was concerned after hearing the Kooks system. I still believe the cost of many of the other popular axle back systems is way over what they should be, any many are not the sound that I like.

If I was to ever try anything else, I might consider a custom fabricated set of mufflers from a '15 Z/28, fitted onto my stock system. Those were about the best sounding stock mufflers I've heard from an America car in ages. But I'm not sure if the fitment might not be too much of an issue.

Anyway, for now, and likely forever, I'm glad to be back to stock...it works for me.

No harm done my way. Like I said I was disappointed to hear it didn't work out for you. Just speaking with several other people that have gotten it installed with no issues and love it, makes me think the ZLE's harmonics are weird like we talked about or the exhaust was possibly touching your rear subframe. Glad you got it resolved though.

[JonDaddy82]

Originally Posted by jjgi5150

I'm going to just stay with the stock system. I like it well enough to just leave it as is. There are so many thngs I enjoy about the car stock it's just not worth the extra effort to take away from car driving time, Harley riding time, shooting and a ton of other retirement things I get to enjoy.

The fitment of the Kooks was not the issue. There was no contact vibration from the system, all the rubber busings were perfect, and everything was properly torqued. My installer is a true pro, and treated the car like it was his own. I watched the entire install.

I really believe it was just a matter of the harmonics in MY car. Possibly a loose panel or shield or ???? that did not get affected by the stock system but was by the Kooks. The solid suspension bushings in the ZLE could have added to the cause as well. I could have messed with it a lot more, Dynamated everything, added another resonator and on and on...but it's just not worth my time now for a stock setup that I'm not that unhappy with.

JJ

Totally understand my friend, makes perfect sense. I didn’t have this insane drone on any exhaust system I’ve ever had on my 3rd Gen, 4th Gen, trucks, imports, you name it. I guess I just target fixated on making this work, otherwise it would have ended up on Craigslist and an AWE or Borla in it’s place.

[joe944]

Just to add to the discussion, I haven't had any issues with drone with the AWE Touring non-resonated catback on my A10.

Seems like a good middle of the road solution with regard to deep muscle car sound and the higher pitched Corsa. Seems like it has a similar right foot controlled sound level.