Exhaust removal

psk256 · January 3, 2021

I have a new exhaust on the way and wondering what's the best way to removes the factory one? I'm not against using a saw. Whatever is the easiest. from what I've read and watched, taking it our in one piece can be a pain in the A**. Thanks!

AJMBLAZER · January 3, 2021

If you can get the truck up in the air with the rear axle drooped down then you might be able to get the exhaust out as one piece. Then you could possibly sell it.

If not, try to cut it around the axle somewhere that someone else could put a band clamp on it or easily weld it back together.

If you’re just trashing it unbolt it at the front and chop away. Sawzalls are fun!

NorCal2020 · January 3, 2021

I tried lifting mine up in the driveway on the passenger side but I didn't trust getting under the truck. (maybe I was doing something wrong but with parking brake engaged, threw it in 4WD) Initially forgot to throw the tire chocks in and it rolled forward a few inches before I slammed the jack back down, then I put wheel chocks in and I just didn't quite trust it to not roll with me underneath. So even then, I tried to wiggle in and get the exhaust out but I knew it was gonna be a ******.

I started using my sawzall to get it out, but it had an older used blade in it and it snapped about halfway through, busted out the angle grinder with a cutting wheel and got it the rest of the way out.

Honestly hardest part was getting the rubber hangars off everything lol.

AJMBLAZER · January 3, 2021

They make fancy pliers for the rubber hangars but I've had good luck with some kind of lube and regular pliers.

bshort · January 3, 2021

Probably not going to get it high enough in the driveway. It's just too damn long. Sawsall at the transition up to go over the axle.

Vmax08 · January 3, 2021

Got mine off my 2020 crew cab in one piece by disconnecting the shocks and raising the truck high enough that the rear wheels were just off the ground & supported by jack stands. If I remember I had move it to the rear to drop the front past the crossmember then twist the exhaust as I got it over the axle going towards the front of the truck. I had the duel exhaust so I unbolted it at the joint by the spare. It can be done!

BluegrassMotorsport · January 3, 2021

Following this thread. My catback system ships Monday and I was hoping to be able to do this in the garage on jack stands.

psk256 · January 3, 2021

Thanks for the replies. I'll let you know how it goes!

Jay P · January 3, 2021

I cut mine just behind the muffler/valve where I could weld it back together if needed. You need to support the muffler with a floor or tranny jack.

Take out the spare tire and the spare shield. This makes it a lot easier to remove the old and install the new.

I did this on ramps & jack stands. Took about 2 hours to remove the old and install the Borla cat back.

Jay

Edited January 3, 2021 by Jay P

BluegrassMotorsport · January 3, 2021

59 minutes ago, Jay P said:

I cut mine just behind the muffler/valve where I could weld it back together if needed. You need to support the muffler with a floor or tranny jack.

Take out the spare tire and the spare shield. This makes it a lot easier to remove the old and install the new.

I did this on ramps & jack stands. Took about 2 hours to remove the old and install the Borla cat back.

Jay

My muffler is already gone since I did the muffler delete before deciding on a catback. In theory, that should make it easier (hopefully).

HistoryTeacher2020 · January 4, 2021

I had a Magnaflow installed on my Lt 5.3. The shop used a power saw then welded up the joints. I originally had a flowmaster 40 but it was way too loud. So, I went with the Magnaflow.

kodiakdenali · January 4, 2021

I thought I would try my hand at making some videos of some modifications to my truck, the first one actually is installing a catback exhaust. I went with the Borla ATAK and I really like the sound. I know there is another video up of doing a catback install on a T1, I think gm-trucks.com itself did the video. I showed a couple of things in mine that theirs didn't mention, and also my exhaust replaced the factory tips which the other video didn't cover. So in case it would be helpful to you, check it out! Skip to about 2:50 to see the start of the stock exhaust removal. At the end of the video are a bunch of after clips with sound recorded on high end audio equipment so you can hear what it sounds like.

Edited January 13, 2021 by kodiakdenali

psk256 · January 5, 2021

20 hours ago, kodiakdenali said:

I thought I would try my hand at making some videos of some modifications to my truck, the first one actually is installing a catback exhaust. I went with the Borla ATAK and I really like the sound. I know there is another video up of doing a catback install on a T1, I think gm-trucks.com itself did the video. I showed a couple of things in mine that theirs didn't mention, and also my exhaust replaced the factory tips which the other video didn't cover. So in case it would be helpful to you, check it out! Skip to about 2:50 to see the start of the stock exhaust removal. At the end of the video are a bunch of after clips with sound recorded on high end audio equipment so you can hear what it sounds like.

Awesome video, thanks!!!

snork · January 8, 2021

thanks for the video, was the video recorded post sc install? like to know more about your sc6.2 and your brakes upgrade

kodiakdenali · January 8, 2021

3 hours ago, snork said:

thanks for the video, was the video recorded post sc install? like to know more about your sc6.2 and your brakes upgrade

Glad you liked it! I enjoy photography and videography. I wasn't really planning to make how to's on my truck mods, but I think maybe I'll make some more. they're fun to make and maybe they can help inspire someone to make some fun mods of their own.

most of it was shot before the supercharger, actually the dyno pull was after...a little bit of movie magic there those are Borla only power numbers, but I didn't get to video the baseline pulls. (and the blower is so quiet, you can't hear it over the exhaust, even with the hood up)

the brakes are actually the GMC accessories Brembo brake kit, I had the brakes refinished to remove the GMC logo and make them simply say Brembo. the kit as GMC sells it has Brembo in a small font and a big GMC in the center of the caliper. nothing wrong with that, but I like this look better! they're 6 piston, advertised as 80% bigger than the stock brakes, which is saying something because the stock ones are actually pretty big already. in the rear unfortunately the brakes are basically stock GMC, just colored in Brembo red. but they do look good. Very happy with them, quiet and lots of braking power. They are going to look even better on my 22" summer wheels, the ones in the video are the smaller 20's with snow tires I run for winter.

The blower is the new 3.0L positive displacement twin screw Whipple unit. I'm loving it so far! major power increase yet when you aren't on the throttle the truck drives just like stock. It made 481whp and 482wtq which it somewhere in the vicinity of 570bhp. Although that isn't the whole picture as twin screws are particularly good at making boost at lower rpm so typically you see a much bigger gain over stock numbers in the mid RPM range while the gains over stock at the peak are big, but not nearly as big. I don't have a good copy of the whole chart so its really hard to tell exactly how much. when American Trucks did their 2.9L Whipple on a 6.2L k2 (its on youtube) they saw about 100hp/100lb-ft peak, but saw over 200hp and 300lb-ft gains over stock numbers in the middle, 3500rpm. who knows. I can't read the chart well enough to see what mine did, but that apparently is typical of Whipple blowers, that the peak numbers are only half the story.

Very pleased with that, although those numbers are a good chunk less than what Whipple advertises for this setup (525whp, 513wtq). that made me curious and i dove into the complicated world of correction factors and all that. everyone knows atmospheric condition affect power output, so there are corrections that take that into account and try to even out the effects of the atmosphere and make dyno results comparable to one another. the issue there is that there are multiple different standards for how to do this. the dyno I was on used SAE J1349, but if you look in the corner of the Whipple dyno graphs it says its using STD, STD produces higher numbers than SAE due to differences in how the correction factor is calculated. although even so I couldn't get the numbers to even out perfectly, and you can consider that my truck made 354/393 wheel on the SAE (but with the catback) and Whipple shows a baseline of 364/394 using STD on a stock truck. depending on what post you read online the typical difference between SAE and STD is 2.3 or 4.3% and I'm sure there are plenty of other results out there...at the end of the day, I don't really care, I step on the pedal and this thing flies, so that's all that matters. If you quibble about all the numbers you'll just give yourself a headache .

Edited January 8, 2021 by kodiakdenali