Which would be a better aftermarket exhaus--- Cat back or Turbo back??? Would the truck still pass inspection with the cat removed?? I live in Waco,Texas and do not have to deal with the smog test at inspec. time yet. I dont want it to be too loud on the inside of the cab.. Want a good deep tone on the outside. any answers???

 

your best bet is to just go with a full turbo back.

MBRP, and bully dog have some good set-ups

 

On my '05 I just did a 4" straight pipe to the 30" magnaflow, not too loud, sounds good under load. the system is already mandrel bent and is 4" in diameter so there is no benefit to swapping the whole exhaust out (IMO).

 

and before it gets asked, a 5 inch exhaust will not help you at all. the stock 4 inch exhaust sans the cat and muffler will support around 550-600hp. after that a 5 inch is mandatory.

the only thing is the stock 4 inch exhaust is measured by the outside diameter, the aftermarket is measured by inside diameter, so your gunna get a slightly larger pipe.

 

I just did the magnaflow 4" turbo back with a muffler. It works well is not real loud it actually made my truck quieter at idle and lower rpms. It gave me about 1mpg improvement but we all know that depends on your driving habits.

 

that would also depend on which truck your talking about...my milage dropped about .5 with my exhaust swap. the plus side is it's easy to get higher boost levels.

 

Drew,

You just saved me a boatload of cash I don't have as I was told these CDT need the 5 inch exhaust to run good. I'm still debating if a CAI is worth the money and would worry being I do drive on dusty gravel roads.

 

DBLR,
Some people have a TRUE 5" exhaust and some don't. What do I mean? OK....The majority of 5" turbo back systems have a taper in the first tube section anywhere up to 24" or so away from the turbo elbow. Some taper IMMEDIATELY upon entering the First section. The latter type will result in slower spool up, and less low end torque as a result. The EGT benefit is better with a replacement 5" over 4". Both gave me a mileage increase of 1+ mpg across the board. Both gave me 1-200 DEG lower EGT's across the board. But the fact that my CTD is only slightly modified showed me that the Hp numbers Drew is talkin' to need a 5" is true! The ANSA 4" system I have now spools up at least as fast as stock, and gives me slightly lower egt's.


The guys that say the 5" system on their lightly modified CTD gives them quick spool up have 5" systems that taper 12+ inches down the tube, hence giving them the same backpressure as the stock system, but better flow than stock. IMHO

Does this make any sense?
Cheers
Mike
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