I haven't really made a big deal about it but after about a week of having the Magnaflow catback on, it still feels like it lost a noticeable amount of torque....especially down low. It doesn't spin the tires like it used to from a dead stop AND the boost gauge seems a little slow to rise now. The only thing that I think I feel is a slight gain in top end power from 3rd-4th gear at higher rpm's. Will this make me slower at the track of is the loss of TQ making it feel like it lost more power? Any of you with the same experience? The truck is stock except for an intake. I have a pulley waiting to go on now because of this feeling of lost power.

 

With a little less back pressure you may notice a slight drop in torque, but should'nt notice to much.

 

A friend of mine lost a pound of boost gutting his cats, but says his quarter time MPH/ET remained the same.

Less low end tire spin is a blessing on the street if you get into a scuffle with someone.

 

It's normal ... you just traded torque for noise ...

 

The day that you chip/tune and add a pulley you will never again have problems with not spinning your tires from a dead stop.
On that day you enter a whole new ballgame.
You will be forced to develop a whole new set of skills.
Add a FTVB to the mix and...Katey bar the doors!!!!

 

There have been several documented cases of power loss with cat backs.

 

None here.

 

Weren't there dynosheets floating around of gains seen with some aftermarket catbacks?

 

I agree 100%. I actually have a hard time keeping my tires from spinning from a roll. From a dead stop, forget about it. The Magnaflow was the first mod I made, and I didn't feel any loss of power. But sometimes louder = faster (I think you know what I mean). I then added the FTVB and a Single blade TB, and things got exciting. After the 4#, Denso plugs, and Predator tune were added, holly sheep ***** Batman, it didn't even seem like the same truck. There was a HUGE difference in power. In fact the power was so good, I haven't modified a thing since.

Put your pulley on and get a good tune and you won't be singing the blues any more.

 

By my observation and many others, it appears that a reduction in back pressure is followed by a richening of the fuel mixture by the computer which translates in less power. On BMW's the computer reacts exactly the opposite way and goes leaner. Tuners lean out the A/F. That's how most of the power gains are achieved.

But with just a cat back, the difference really can't be that much because most of the restriction is in the 4 cats.

TB

 

This is why I very carefully researched the cat back I bought. (A spintech)

Trackbeast, Just do a 4# lower and a applicable tune. You'll soon forget all about this moment in time.

Rich