Replacement Catalytic Convertor Q's

[QUICK STORM]

need to replace cat as exhaust smells super rich and is probably shot.
i replaced cap/rotor, plugs(cr42ts), wires, fuel filter, fuel pump and fpr with all new ac delco parts so i know that the truck is running clean. will replace the iac soon as the truck idles funny especially with the ac turned on. has a brand new battery-ac delco and a remaned altenator.

i have the whole stock setup turbo/wastegate/downpipe/cat with a muffler delete due to a flowmaster-junk already installed when i bought the truck. had to get rid of it and noticed better spool-up.

i am looking to go with the atr 3in. exhaust, ty being mufflerless sounds cool at wot but i don't like the sound of it the rest of the time. i would like to know what is the best convertor high flow or not for our trucks so i can stay away from overboosting.

i used the search and could not find a clear answer. thanks for all the help guys!

 

[scottKP]

converter

converter

I ran a Catco universal (I think 12") SS from Summit for like $55 and had no problem with boost control. It also sounded very good.

 

[Syclone#1992]

If there is any less restriction than stock muffler and cat, 95% of the time you are going to have boost control issues.

 

[Baja Resident]

If there is any less restriction than stock muffler and cat, 95% of the time you are going to have boost control issues.

Can you explain this in more detail? I have no cat, 3" and would like to know what to look out for.

 

[SeattleSy#1255]

If there is any less restriction than stock muffler and cat, 95% of the time you are going to have boost control issues.

Can you explain this in more detail? I have no cat, 3" and would like to know what to look out for.

Well this is primarly on a stock vehicle in the context he means i'm assuming. The stock wastegate is inadequate to control boost on many stock trucks and lessening backpressure of the exhaust by opening it up can make things worse. I'm assuming you have a general idea how a turbo spools up, and if you do then you'll likely understand this concept, if not, no problem just ask and I or someone else can explain it more to you. What to look for: we'll have a boost gauge that works or a scan tool that tells you your boost level (stock boost gauge is likely incorrect) and it it boost over the desired level then you have overboost...if it slowly climbs over the desired level, you have boost creep which is usually less dangerous. To much boost can blow your motor worse case senereo.

Your signature says "highly modified" so i'm assuming you don't have the stock turbo/WG setup so if you are having problems there could be many thing it could be.


HTH

 

[Syclone#1992]

If there is any less restriction than stock muffler and cat, 95% of the time you are going to have boost control issues.

Can you explain this in more detail? I have no cat, 3" and would like to know what to look out for.

Baja, if you don't have a stock wastegate, I remember you saying you didn't. you are safe. Stock wastegate is very small and poorly controls boost. Poor boost control leads to spikes, ect, that can cause you to loose a motor rather quickly.

 

[QUICK STORM]

no one is really giving me a clear cut answer, i'm going to stay with the stock setup for now as funds don't call for any high priced mods, just bolt ons.

a clear answer with an explanation would be most helpful!

 

[turbodog]

I'm running a 3 inch inlet/outlet Catco, with ATR exhaust (modified to mate with the cat outlet). K&N air filter. Rest of system is bone stock. No overboost. However, these trucks vary, so TIFWIW

 

[dgoodhue]

On my Sy, I have a random Technology Cat and Borla Exhaust. I can hit 15-16 psi with my solenoid disconnected (stock suposedly is 8-9 psi) My boost control is still fine with the ultimate (ie its a roller coaster like stock), but its on the edge. I can see why a catless exhaust would easily overboost.

 

[Six-is-Enough]

On my truck we used a cat from a 95 Chevy Tahoe. They are 3 inch inlet and outlet. We (jeff scott & myself) mated it to an JSM 3"dp and a 3"AtR cat back.It was pretty cheap from autozone, but I don't recall the price.sorry.

We did experince some overboosting issues though that had to be resolved through chipping and waste gate modification.