Removed cats, now too poppy, need advice...

[randymbtech]

Hey guys, my '98 K-1500 has Edelbrock ceramic coated shorty headers, Magnaflow dual cat pipe, custom 2 1/4" cat back with H-pipe and Thrush welded mufflers with 2 1/4" tailpipes out the back. I wanted it louder, so I removed the Magnaflow cat pipe and installed the off-road 2 1/4" pipe from Jegs. It is a lot louder, but has a loud popping sound at certain RPM's under a load. It's a dirty sound, and I don't like it. Should I weld in some 2 1/4" Thunderbolt cats, or change the mufflers? I love the chambered, hollow sound of a Flowmaster type muffler. My Thrush welded mufflers are similar to the old Flowmaster 2 chamber mufflers, so I am thinking I may need to get some three chamber 50 series delta flows or something like that. I like the loud, but I am not lovin the poppy sound.

My old 88 chevy had shortys, custom y-pipe, 3 inch Flowmaster single in, dual out with 2 1/2" tails, and it wasn't poppy at all.

Any suggestions???

[Collector]

add another muffler or a resonator.

[1988 GMC 355]

Do you have tips on there??
I run a thunderbolt cat and love it, I have LT's, 2.5" y pipe, single 3" cat, and had a SI/SO 3" thrush, and it was great.

for you I would either put some cats in, or run some long 2.5" tips

[randymbtech]

I do have 3" polished stainless steel tips. Thinking about adding the thunderbolt cats to mellow it out a little. It will also shut off the check engine light.

[southcarolina12]

mines the same why. im going to and 2 glass packs where the cats use to be

[1988 GMC 355]

I do have 3" polished stainless steel tips. Thinking about adding the thunderbolt cats to mellow it out a little. It will also shut off the check engine light.

cats will mellow it out for sure

[GarnetRed4.3]

Get yourself a good high flow catalytic converter (like the one you mentioned, or a Magnaflow) and have it welded in. The lack of a cat is the cause of that popping noise you don't like. A high flow cat will flow way better than the factory cats, and the power difference between a high flow cat and off-road (catless) exhaust is negligible. You will keep the sound volume, but will smooth out that popping noise. Additionally, like you said your check engine light will turn off.

Welding in another muffler or resonator will decrease your sound volume, and most likely the popping noise will still exist.

[randymbtech]

Thanks guys, great info. I had this Magnaflow pipe:

http://www.summitracing.com/parts/MPE-23453/

But the truck was a little too quiet for me. The pipes are small and the cats are huge, so I figured the 2 1/4" off road pipe would open it up a little. If I weld in thunderbolt cats, i hope it's louder than the Magnaflow pipe. It should be, the pipes are bigger and the cats will be smaller...lol.

[BHB]

...Or bypass your air pump.

[1988 GMC 355]

Thanks guys, great info. I had this Magnaflow pipe:

http://www.summitracing.com/parts/MPE-23453/

But the truck was a little too quiet for me. The pipes are small and the cats are huge, so I figured the 2 1/4" off road pipe would open it up a little. If I weld in thunderbolt cats, i hope it's louder than the Magnaflow pipe. It should be, the pipes are bigger and the cats will be smaller...lol.

It should be alot louder then what you had before and probably exactly what your looking for.

[southcarolina12]

...Or bypass your air pump.
would unpluging it be the same as bypassing it? or am i thinking of a different part?