I Have been running with long tubes hi flow cats and stock cat back for about a year now. It sounds better than stock but not to loud.

 

A couple words of advice.................

Believe half of what you read on the internet

And nothing of what Rob writes

 

Maybe it would be good to define just how fast or how much power the truck still needs to make once you re-do the exhaust?

l-menace says good-bye to high HP. Well, let's define high HP.

I agree that opening up the exhaust can really help with this type of application, and with all the toys Twinturbo Ranger has, he understands this better than most.

But I also understand the reasoning behind leaving the stock exhaust on.

I am going to try and hit ~450rwhp with the stock manifolds, stock cat H-pipe, and my "one muffler" (read: quiet) Magnaflow cat-back. I think it can be done. That probably isn't considered "high HP" by a lot of you guys, though.

 

Thanks for the reply. My system now is just TOO raspy. No cats and a straight thru muffler. I am hoping if I go to a baffled muffler I can fix that. -Mat-

 

"TwinturboRanger" and the desire for a Lexus sound levels on a performance truck simply does not compute.

 

Sounds like I have a very similar setup as you do... built motor, cams, ported heads, KB, etc...530.90 hp/592.60 tq on 15# of boost.
For emissions reasons (California), I'm stuck with the stock manifolds and cats. I also have a Bassani cat-back exhaust.
I'm guessing I'm loosing about 25-30hp due to having a choked off exhaust.
Its not very loud in my opinion. Since I haul my kids around in my beast on occassion, I'm not too upset that the exhaust wasn't too loud. Highway driving has minimal drone. Plus there's some security about being able to nail it without every cop in a 5 mile radius hearing you. Of course, you lose the cool rich sound when you do want to hear every burble of your exhaust note.

I would try to keep the long tubes and try to go with a quieter muffler like the stock catback as I don't think there's much power loss in the muffler setup from the factory. Maybe that might fix your problem.

 

Your quite welcome

 

I have a completely stock exhaust. I ran a best of 11.86@116 with a KB and bolt ons on Nitto's. I am making around 470hp at the wheels. I also don't want a loud exhaust but was wondering about high flow cats with everything else stock. Does any one make a Hi flow cat that bolts right in the stock exhaust?

 

I believe **** had a setup that replaced the factory 4-cat setup with a 2-cat when you were keeping the factory exhaust manifolds.

Jody