TD vs. Cat back numbers.

Does anybody have actual dyno proof that true duals make a usefull hp gain over a 3 inch cat back? I know they flow better and will make more power and all, but I want to know how much. I've never found any post that has head to head dyno results- catback vs. duals... it's always catback vs duals+headers+cam or something useless like that.

It really depends how much power one is making. In all honesty, for a bolt on car, it probably won't make a noticeable difference.

But a car with an aggressive heads/cam package or one that is supercharged, there will probably be a significant difference.

i have been wanting to know this too, is there really THAT much of a difference? what is the best!!

the gains are going to come at a high rpm, if the motor is being held back by the exhaust. Like stated, if you have a need for the TD's they will be provide benefit. If not they will make the engine sound a hell of a lot better.

The x pipe also helps out with scavenging(sp) which does a whole lot of complicated things that i am not too good at explaining. So i'll let someone else chime in for that.

There is another TB vs. catbach thread going on, check it out. Also search, you will find endless info on TD's.

95zwannabe or something like that had a post from back in 2003 where he put TDs on his stock exhaust MANIFOLDS over a ORY and cat back and he picked up like 10rwhp and 5-10rwtq. Depends on the car I would assume.

95zwannabe or something like that had a post from back in 2003 where he put TDs on his stock exhaust MANIFOLDS over a ORY and cat back and he picked up like 10rwhp and 5-10rwtq. Depends on the car I would assume.

Thankyou. This is the kind of information I've been looking for.

maybe do some searching for dual cutouts....since that's not much different from true duals.

but as stated, the existing mods will determine the power gains.

TDs on a bolt on lt1 may not get anything over a 3" catback

TDs on a h/c LS1 could get you 20hp

A long long time ago i saw a guy post up his gains from stock manifolds to a TD setup, 2.5 after the x pipe into bullets or glasspacks.
He gained 35rwtq and 41rwhp. Hooker lt's(no pacesetters at this time), a sumit racing TD pack( mainly just an x pipe) and the bullet mufflers.
All the power was after 3k rpms(well mainly) and the tq was across the borad.

I know your all saying "wow" but you have to think about the differences there is. hooker lt's, ory, and borla or something else with a very good flowing muffler would produce similar gains to the TD setup.