OK so I installed a Dynomax 3" IPipe and a 2002 Camaro SS Stainless Steel Muffler.

Without IPipe/SS Muffler I ran a best of 14.779@93.729 MPH 2.147 60 ft. (not bad for a stock full load GTA!)

With IPipe/SS Muffler I ran a best of 14.646@96.086 MPH 2.326 60 ft. (lousy traction)

As you can see I picked up nearly 25HP from a Cat back exhaust on on otherwise stock L98!!!

To date I have picked up .5 second and 7 MPH from removing the CAT, installing the IPipe and SS muffler and my custom prom(ARAP)!!!

My 60ft are consistently getting worse as I am putting more power out. Next I will be returing with a set of sticky tires!! I also might consider moving a torque convertor swap up the timeline to get this car in the 13s without touching the engine compartment!!! My vortec heads might be sitting on the bench awhile longer untill I max out this combination.

 

Without knowing the specifics of the atmospheric and track conditions, you can't claim any power gain at all. I've seen that much variation in a single day (even more just this last Saturday).

As for more power making for slower 60' times - bunk. I did the porting work on the 396 induction, heads, and headers after last season; this season I've seen consistent 2-tenths across-the-board improvement, 1 mph improvement, and a good .05 improvement in 60' times.

I'm not saying your changes didn't improve power, rather that you aren't providing conclusive proof that this change specifically improved power.

 

Actually my overall gain is over 6 MPH...First time I ran the car on a cool fall day I ran 89-90 MPH over 5 runs with 2.04-2.18 60ft(2002 bone stock).

Then on a cool sping day ran 92-93 MPH with no cat and ARAP bin. with 2.14-2.2660ft(2003). A 3 MPH gain

2 weeks later on a warmer sunny day with the IPipe and muffler I ran 95-96 MPH with 2.27-2.3560 ft. Another 3 MPH gain

I would say that I am conclusively making more power now than before the exhaust work. That's what I was trying to demostrate with this post. Now did removing the cat have a greater impact than the catback? Maybe. But I did demonstrate that there is plenty of room for improvement in a stock Fbody exhaust.

My short times are directly affected by the fact that I am making more power and spinning all through first gear versus last year I wasn't spinning all that much. (Same track, same tires, same driving technique, different day)

I also did some suspension work to help traction, but I need better tires that what I am currently are running to really help me.(BFG Drags or Nittos, still debating)

While I agree the impact of weather conditions can be dramatic, I am also a bracket racer of many years experience and do believe that the conditions on both days at the track were pretty decent. I might go back next time and run slower like before, but unlikely because along with the actual track times, my SOTP dyno tells me the car is pulling stronger.

I find it funny that you were so quick to dismiss this progress, I was just trying to post actual results to help guys make informed decisions. I am pretty tired of bench racers on this board(not calling you one), because it's hard to come by good proven results so I just wanted to contribute a little.

As for a 7 mph variation in a single day...on a 14 sec car I'd be worried something is wrong. Variations should be within 1-2 MPH tops on the same day unless you went from Hot humid weather to cool dense air in the same day. I have over 8 years of bracket racing experience and have never seen such a dramatic change in 1 day.

 

I didn't say it wasn't progress, I said it wasn't conclusive proof.

I've been bracket racing for 25 years. I've seen all sorts of data scatter caused by all sorts of conditions. And, I wasn't referring to your 7 mph improvement, rather your 2.357 mph change, which I've seen in a single day starting with cool morning tail wind going to hot afternoon headwind with no changes to the car. I've also seen big differences between runs made 2 hours apart (typical for time trials and 1st round elimination) and the round-robin of later rounds.

It's long-term, overall improvement that's indicative of positive changes, not single data points. My first runs after my winter work were rather disappointing, but a simple jet change made a big difference the next time I went out. Saturday, I had one run that was no better than most made late last year, but another that was better than any last year. Overall, it is running quicker and faster. You appear to also have overall improvement, which wasn't evident in your original post.

The way you first stated you 60' issue is completely different than your second explaination as well. And, that's more likely a torque improvement than a power improvement. Semantics, perhaps.

Look, I'm not trying to put you down. I am trying to keep others from misinterpreting what you're saying. I agree that you're moving in the right direction, and as you get the whole "package" together (traction seems to be the issue now), you'll be able to show even better results. I've been working a long time to get the "package" together, limited mostly by funds; so, I can appreciate the joys and frustrations alike.

Sorry if I came off as a wet blanket. Wasn't my intent.

 

Didn't mean to be so defensive either...I guess I could have provided a little more info on my original post...I was just impressed with the exhaust work.


Yeah I feel I am moving in the right direction...