Exhaust single to dual on a tight budget - Then we get into some after issues

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Grit dog

Full Access Member
Joined
May 18, 2020
Posts
5,976
Reaction score
9,923
Location
Washington
First Name
Todd
Truck Year
1986
Truck Model
K20
Engine Size
454
Yea, and just one seemingly simple thing has lead to this rabbit hole.... But I'm getting closer to being out of it, and certainly when I can afford the cats I'll be all the way out of it.
At this point I may have just engaged a local tweaker to procure ya a couple cats for the truck! Lol.
Someone is gonna get those stolen cats, may as well be you than the sketchy scrap yard guy! Hahaha
Couple questions?
Why not just get a longer hydraulic hose or a fitting and a short hose to make it longer and get it out of the way?
PS. Chrome side pipes would have been out of the way of everything!!
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
At this point I may have just engaged a local tweaker to procure ya a couple cats for the truck! Lol.
Someone is gonna get those stolen cats, may as well be you than the sketchy scrap yard guy! Hahaha
Couple questions?
Why not just get a longer hydraulic hose or a fitting and a short hose to make it longer and get it out of the way?
PS. Chrome side pipes would have been out of the way of everything!!
Gee thanks but I've already got a pair of cats. I just need to find the time to install them!

Your right about those chrome side pipes, but I'd have to pull the running boards and then what do I use to get my fat ass in the truck? (Don't worry I still have a couple inches between my belly and the steering wheel lol.) Last week we had an older range rover at the shop with round tube running boards, I stepped up on that went to swing my body in, my foot slipped of that stupid round tube and ran my shin down it!!! I hate those things!!! Love traditional running boards!

So on the hose, it attaches to the bottom of the hydraulic cylinder and the cylinder is mounted in the hinge, so when you raise the bed the distance between the cylinder and the pump effectively becomes shorter. So the hose has to be able to move. I added a zip tie and a spring to frame to keep it from dangling, so it does not lay on the tailpipe, but I just want to be cautious. I do have a spare hose, and the pump just has ATF in it, so it's not the end of the world if heat kills the hose.

Honestly if I could go back in time I would have kept the single exhaust. All of this work just to make it work has been a bit frustrating, add this stupid oil leak in as well. I may very well feel different once all the kinks are worked out. I suppose if I had a crystal ball I would have know what to do from the very beginning.
 

HotWheelsBurban

Full Access Member
Joined
Mar 31, 2023
Posts
1,777
Reaction score
3,929
Location
Houston, Texas
First Name
Carol
Truck Year
1990
Truck Model
R2500 Suburban
Engine Size
350
Gee thanks but I've already got a pair of cats. I just need to find the time to install them!

Your right about those chrome side pipes, but I'd have to pull the running boards and then what do I use to get my fat ass in the truck? (Don't worry I still have a couple inches between my belly and the steering wheel lol.) Last week we had an older range rover at the shop with round tube running boards, I stepped up on that went to swing my body in, my foot slipped of that stupid round tube and ran my shin down it!!! I hate those things!!! Love traditional running boards!

So on the hose, it attaches to the bottom of the hydraulic cylinder and the cylinder is mounted in the hinge, so when you raise the bed the distance between the cylinder and the pump effectively becomes shorter. So the hose has to be able to move. I added a zip tie and a spring to frame to keep it from dangling, so it does not lay on the tailpipe, but I just want to be cautious. I do have a spare hose, and the pump just has ATF in it, so it's not the end of the world if heat kills the hose.

Honestly if I could go back in time I would have kept the single exhaust. All of this work just to make it work has been a bit frustrating, add this stupid oil leak in as well. I may very well feel different once all the kinks are worked out. I suppose if I had a crystal ball I would have know what to do from the very beginning.
Tube running boards/steps are something that you have to learn how to stand on, and how to pivot off them. My crew cab came to me with tube boards and since it's a one ton, they are needed to get in and out of it. Best to step on the rubber platform, but if you have to step on the tube, there is a way to do this in hiking/work boots. But I understand in a shop situation with a customer vehicle, that's not necessarily a thing you have time to figure out.
 

Attachments

  • IMG_20230921_173731633_HDR.jpg
    IMG_20230921_173731633_HDR.jpg
    210.3 KB · Views: 20

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
Tube running boards/steps are something that you have to learn how to stand on, and how to pivot off them. My crew cab came to me with tube boards and since it's a one ton, they are needed to get in and out of it. Best to step on the rubber platform, but if you have to step on the tube, there is a way to do this in hiking/work boots. But I understand in a shop situation with a customer vehicle, that's not necessarily a thing you have time to figure out.
I'm sure you are right, and given that I have traditional running boards on my truck where I can pivot my foot sideways where as on a tube I fall off lol.
 

HotWheelsBurban

Full Access Member
Joined
Mar 31, 2023
Posts
1,777
Reaction score
3,929
Location
Houston, Texas
First Name
Carol
Truck Year
1990
Truck Model
R2500 Suburban
Engine Size
350
I'm sure you are right, and given that I have traditional running boards on my truck where I can pivot my foot sideways where as on a tube I fall off lol.
I had to learn just how to plant my boot on the tube, if I have to step there and not on the pad. I don't like falling out of my truck either!
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
Finally the catalytic converters went on today. I told the everyone in the shop that I was going to end my day today at 2:30pm, so at 3PM I clocked off.

For the drivers side cat the installation location was the factory location, immediately behind the cross member.
Because of the shape of the cross member the pipe on the drivers side goes above it, so getting the cat tucked up in that factory location was no problem. The hardest part was welding the front part of the cat to the pipe because the down pipe ends right at the back of the cross member so there was a lot of blind welding, I added a clamp just to make sure it would be a leak free connection.

On the passenger side, because of the shape of the cross member the pipe goes under it. So my choices were to install the cat roughly the same distance from manifold as the drivers side cat, but lower it would have to be the height of the pipe at the cross member, or I could go back about a foot and tuck it up, but then it would be right under and close to the tank switching valve. Obviously that wasn't going to work so I went for the lower, but closer to the manifold location. The good thing about this is that it should be plenty far enough from the fuel lines and the switching valve that I don't think the heat will be an issue even on the hottest of days. But It's going to HAVE to get a lower shield on it before I take it into hay fields this summer. Definitely don't want to light one of those up!

Some pictures of the cats installed, then some of the over all exhaust while I had it on the hoist then I'll get to my driving experience with them. Probably total of three posts.

Driver side cat:
You must be registered for see images attach


Passenger side:
You must be registered for see images attach
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
More exhaust pics: Looking back after cats.
You must be registered for see images attach


Looking forward at cats, notice height differences. And yes that's a huge exhaust fan in front of the truck
You must be registered for see images attach


Looking back from under the engine:
You must be registered for see images attach
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
I was told years ago by a walker rep that it is very important for new cats to get up to temp as quickly as possible after installation to ensure that the substrate (honey comb) expands and sticks in place properly. On a modern car they heat up fast enough it's just get in and drive normally, but on a carbureted engine he recommended that as soon as you feel comfortable after starting the engine to rev it to 2K and hold it there for 5 minutes, then let it idle and check inlet and outlet temps of the cat looking for at minimum 50F higher at the outlet than the inlet, but closer to 100F is more ideal. Can go up to 15 minutes checking every 5 minutes. If they aren't lit in 15 minutes the cats are to far from the manifold, or the system needs an air pump.

I have a working air pump, so my only concern is that I have 2 cats now instead of 1 so that's 1/2 as much volume of exhaust, will that affect temp??? So I fired the truck up let the engine run for a few to get the oil circulated and ran it up to 2K. I immediately thought to myself it's going to get stinky in here I forgot to open the shop door. Much to my delight after 5 minutes of running I got out of the truck and noticed the lack of odor in the air and a little condensation dripping out of the tailpipe. A quick check with an IR heat gun confirmed what I suspected, both cats were already up to temp and working quite well.

As for the drive after work, I had to run the truck for 2 hours a little traffic leaving the city, then a short bit on the freeway with most of the drive on country roads. I'm happy to report that I was not assaulted with with any stinky exhaust or oil smell (In the midst of this I had a valve cover gasket start leaking). It was just a nice and plain, pleasant drive home, no exhaust sucked in the heater and none even with the window open sitting in traffic. So far it seems like these cats are actually working better than my old single cat did, but how knows how old that one was.

Also the addition of the cats mellowed the tone of the turbo muffler, which is not unexpected but it puts them right around the volume and tone I'd wanted in the first place so I'm VERY happy to get new cats back on.

I'd say that if someone is looking to add cats to their truck even a dual exhaust truck where two are required it'll work just fine with a modern universal honey comb type cat, mounted behind the transmission cross member, but I should also mention that my truck has a functioning air pump, pumping air into the exhaust manifold, which helps the catalytic converter (s) get up to temp faster and start working quicker and stay at temperature.

I have to put about 200 miles on the truck tomorrow to haul feed back to the farm, so we'll see how it goes and I'll report back, but I'm thinking this will be the end of the BS and me fiddling around with the exhaust.

@DoubleDingo tagging you since you have expressed some interest in putting cats on our truck, pic of the install in the above two posts.
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
This will likely be my last exhaust update unless something happens. 200 miles of blissful driving today without even so much as a hint of exhaust in the cab, and better than that, no asthma flair from exhaust either! Woo hoo on that!
 

DoubleDingo

Full Access Member
Joined
Jul 3, 2012
Posts
10,188
Reaction score
14,497
Location
Right where I am
First Name
Bagoomba
Truck Year
1981, 1965
Truck Model
81-C20 Silverado Camper Special-TH400-4.10s; 65-C20 with 4:57 gears and Borg Warner Overdrive
Engine Size
Carb'ed Vortec 350; 1972 L48 350
Thanks, mine is single, so it would be mounted where yours was before you switched to duals
 

Forum statistics

Threads
42,137
Posts
909,904
Members
33,635
Latest member
85sqbod
Top