Finished the Dad Wagon but fighting with exhaust

[Racie]

Almost done with all my tuning etc on my Escalade after I bought it from previous owner. Problem is I have the Kooks long tubes and Y-pipe. I have a slight exhaust leak or header tick that’s driving me nuts. I’ve even smoked the system for an hour and found no leaks, still replaced flange gaskets and not it seems to be coming from the header collector area. Also I’m thinking of going to the large 22” Magnaflow because the blowmaster is way to vicious and obnoxious sounding. I’m not 18 anymore lol.... anybody running the large magnaflow with longtubes?

 

[iamdub]

Almost done with all my tuning etc on my Escalade after I bought it from previous owner. Problem is I have the Kooks long tubes and Y-pipe. I have a slight exhaust leak or header tick that’s driving me nuts. I’ve even smoked the system for an hour and found no leaks, still replaced flange gaskets and not it seems to be coming from the header collector area. Also I’m thinking of going to the large 22” Magnaflow because the blowmaster is way to vicious and obnoxious sounding. I’m not 18 anymore lol.... anybody running the large magnaflow with longtubes?

View attachment 279087

Catted Y-pipe? I gave up my cats when I got headers and it took 40" of muffler to get the exhaust back to a reasonable level. It's actually quite nice again- very mild hum when cruising but roars when you mash it. I have 18" and 22" Magnaflow knock-offs, made by AP Exhaust, from their Xlerator line.

 

[Racie]

Catted Y-pipe? I gave up my cats when I got headers and it took 40" of muffler to get the exhaust back to a reasonable level. It's actually quite nice again- very mild hum when cruising but roars when you mash it. I have 18" and 22" Magnaflow knock-offs, made by AP Exhaust, from their Xlerator line.

Yea it’s a catted kooks setup...cammed, stage III heads, ported 2.9 Whipple and 102mm TB with 1 7/8” longtubes. I put a 70 series FM on it and it still sucks ass and I’m not liking it at all. Not for daily business anyway....and I feel like it’s choking it.

 

[Philpug]

Pffft...you are never finished.

 

[CMoore711]

Yea it’s a catted kooks setup...cammed, stage III heads, ported 2.9 Whipple and 102mm TB with 1 7/8” longtubes. I put a 70 series FM on it and it still sucks ass and I’m not liking it at all. Not for daily business anyway....and I feel like it’s choking it.

Just so I'm understanding the exhaust right; 1-7/8" Kooks LT's to Kooks catted Y pipe to stock exhaust system with a FM 70 series muffler welded in where the stock muffler was?
Do you still have the exhaust flap?
Do you still have the OEM resonator in the back over the rear axle before the tip in the exhaust system?

On another note...
Sounds like a sweet build.
What kind of power did you put down with that combo? WHP/WTQ?
Standard Whipple Pulley or did you pulley down?
Are you still running the stock transmission and converter?

 

[Racie]

Just so I'm understanding the exhaust right; 1-7/8" Kooks LT's to Kooks catted Y pipe to stock exhaust system with a FM 70 series muffler welded in where the stock muffler was?
Do you still have the exhaust flap?
Do you still have the OEM resonator in the back over the rear axle before the tip in the exhaust system?

On another note...
Sounds like a sweet build.
What kind of power did you put down with that combo? WHP/WTQ?
Standard Whipple Pulley or did you pulley down?
Are you still running the stock transmission and converter?

Correct and Exhaust flap is gone....OEM resonator is still in place. Transmission is tuned and running a small converter and cooler. Running a tad over 10lbs of boost putting down 750 on a mustang Dyno. Honestly I could care less at this point to loose a few HP to have it quieter. It’s hella fun to drive and the shock on people’s faces is priceless. But I have other big HP toys so this one doesn’t have to be so extreme for daily duty I’m sure it will still be fun with a little less I just don’t want it feeling like it’s choking to death.

 

[CMoore711]

Nice set-up. I bet that is fun. If you've smoked the system with no leaks there probably aren't any. If it's a header tick you're hearing that kind of stuff comes with the territory of running headers. Sometimes that stuff is hit or miss if it's an issue or not. Only thing I think you could try is ceramic coating them or wrapping them in hopes that it provides additional sound deadening from the headers? I guess there is an offset chance there's a porous weld or small weld bit of steel bouncing around or causing a noise, but those type of QC issues are slim with Kooks from my experience.

I'm a bit surprised it's still loud and obnoxious with the OEM resonator still place. I don't have headers or anything; But I got my hands on a Corsa 3.5" in/out muffler from their #14866 kit for the 6.2 Silverado/Sierra's and had that welded in, flapper removed, left OEM resonator in place and the sound/tone level is perfect. Not too obnoxious on cold start, but you know somethings there, great sound at WOT, and zero drone ever.

I think the Corsa Sport exhaust kits by themselves installed on the Tahoe/Yukon/Escalade are almost too loud on the cold start and at WOT. I never wanted to go that route anyway because their kit for the K2XX SUV's is still 3" and the OEM piping is 3.5" on the 6.2L L86 models.

Always got my eye out for a lightly used Corsa #14866 kit for 6.2 Silverado/Sierra's due to it still being a 3.5" system. I'm confident it would take minimal modifications from a muffler shop to fit our K2XX SUV's easily and add a 3.5" Vibrant resonator in the back around where the OEM one is located and it'd be perfect sound/tone, wouldn't sacrifice performance with the mandrel bent 3.5" system, and it'd all be stainless.

 

[Racie]

Nice set-up. I bet that is fun. If you've smoked the system with no leaks there probably aren't any. If it's a header tick you're hearing that kind of stuff comes with the territory of running headers. Sometimes that stuff is hit or miss if it's an issue or not. Only thing I think you could try is ceramic coating them or wrapping them in hopes that it provides additional sound deadening from the headers? I guess there is an offset chance there's a porous weld or small weld bit of steel bouncing around or causing a noise, but those type of QC issues are slim with Kooks from my experience.

I'm a bit surprised it's still loud and obnoxious with the OEM resonator still place. I don't have headers or anything; But I got my hands on a Corsa 3.5" in/out muffler from their #14866 kit for the 6.2 Silverado/Sierra's and had that welded in, flapper removed, left OEM resonator in place and the sound/tone level is perfect. Not too obnoxious on cold start, but you know somethings there, great sound at WOT, and zero drone ever.

I think the Corsa Sport exhaust kits by themselves installed on the Tahoe/Yukon/Escalade are almost too loud on the cold start and at WOT. I never wanted to go that route anyway because their kit for the K2XX SUV's is still 3" and the OEM piping is 3.5" on the 6.2L L86 models.

Always got my eye out for a lightly used Corsa #14866 kit for 6.2 Silverado/Sierra's due to it still being a 3.5" system. I'm confident it would take minimal modifications from a muffler shop to fit our K2XX SUV's easily and add a 3.5" Vibrant resonator in the back around where the OEM one is located and it'd be perfect sound/tone, wouldn't sacrifice performance with the mandrel bent 3.5" system, and it'd all be stainless.

Yea I’m going to be wrapping the headers next when I take the flowmaster off and I’ll probably do the Y-pipe also. Never had an issue with Kooks or American racing but I had the Kooks on the bench and we actually welded all the way around the flanges where the primaries connect. I’m going to re-inspect the collector area also and yes I did an hour or more smoke test and found nada . Thinking I can get lucky and find a corsa set up or do a magnaflow and vibrant resonators and hopefully that’ll get me where I wanna be.

 

[RThomasII]

I ran the Magnaflow 12909 with the same headers/catted y pipe on my 2019 Denali (rest of the exhaust was stock) and it didn't really sound too much different than stock.

I've got the full Magnaflow Catback exhaust (no other mods) on my Escalade now and its got a nice mellow tone to it. Cold start is a little loud but overall it gives the truck a nice growl without sounding like a muscle car. Sounds about right for a luxury SUV imho.

That said... I'm getting rid of the catback and going with a custom built exhaust.

 

[iamdub]

Yea it’s a catted kooks setup...cammed, stage III heads, ported 2.9 Whipple and 102mm TB with 1 7/8” longtubes. I put a 70 series FM on it and it still sucks ass and I’m not liking it at all. Not for daily business anyway....and I feel like it’s choking it.

Ugh- Blowmaster. With all of that you need a straight-through style muffler(s).