This is a reprint of a post that Tony from AFR heads made considering the effectiveness of the factory Titanium System :cheers:
Z06 Ti Exhaust Info & Dyno Results
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Hello Everyone,
I've been extremely busy or I would have already posted this information, but I have your back to back results on how good (or bad) a factory Ti exhaust system actually is. I have spent the last month or so fabricating a custom exhaust with "Y" pipes and electric cut-outs that when open allows the exhaust gas to "by pass" the muffler and go straight out the tailpipe exits. In reality, some of the exhaust gas will still go thru the muffler as well, but it will take the path of least resistance and the bulk of the flow will take the path off the "Y" pipe that exits directly to the rear. A picture is worth 1000 words, but I hope you get the "gist" of what I built. Bottom line, when the electric cutout is closed, all gases are routed thru the muffler and its business as usual, when I open the cut-out electronically, it essentially completely eliminates the muffler as a "restriction" in the system, not to mention sounds awesome at WOT.
First off, after I cut off both exits and inlet from the factory muffler, I was shocked to see that a 2.5" inlet pipe necks down immediate to a 2" pipe (1.875" ID) YIKES!!! I'm thinking sure it sounds "stealthy" at idle and cruise RPM's, but I would have bet you anything I was going to be down 10 plus RWHP minimum on a car putting down 475 or so at the tire. Good thing I didn't have anyone taking me up on that wager....the results were surprising to say the least.
First off, my last trip to the dyno netted me 477 HP....not quite the 480 I have seen on one or two of my previous best pulls, but right in line with the better of my "average" runs. This was achieved thru LG long tubes and the 3" metal matrix Cats and X-pipe. My former "cat-back" was a Magnaflow system that came with 2.5" pipes that go up and over the rear driveline. By the way, the weight difference between the two is exactly 25 lbs total....not too shabby a savings for guys trying to put their car on a diet.
On to the results....After spending a little time with LS1 edit adjusting the fuel curve (THANKS CHARLIE!), with my cut-outs in the open position, our two best power runs were 481 and 480 back to back with peak torque output on both of them peaking at 439 ft/lbs (huge # for stock displacement). We then proceeded to let the car cool for 10-15 minutes and with no other changes except for closing the cut-outs, running thru the "corked up" factory TI system, the car still put down two back to back runs of 476 HP and 475 HP, with peak torque output at 435 and 432 respectively!! I was shocked to say the least. Obviously necking down to a mere 2" pipe that far back in the system is less of a problem than MANY people would have ever thought. Looks like the GM engineers certainly did their homework....in a car with 100 less HP to the tires, I bet that system would barely cost you 3 HP....Very impressive indeed.
For you guys looking for the ultimate in "stealth" with your current headers/heads/cam cars....you can't beat the factory Ti system, BUT some of you might find it TOO conservative. I like the fact that with my new exhaust configuration you can "have your cake and eat it too" by having the best of both worlds depending on the mood your in.
Anyway....interesting info for all to read!!
Regards,
Tony Mamo
Z06 Ti Exhaust Info & Dyno Results
--------------------------------------------------------------------------------
Hello Everyone,
I've been extremely busy or I would have already posted this information, but I have your back to back results on how good (or bad) a factory Ti exhaust system actually is. I have spent the last month or so fabricating a custom exhaust with "Y" pipes and electric cut-outs that when open allows the exhaust gas to "by pass" the muffler and go straight out the tailpipe exits. In reality, some of the exhaust gas will still go thru the muffler as well, but it will take the path of least resistance and the bulk of the flow will take the path off the "Y" pipe that exits directly to the rear. A picture is worth 1000 words, but I hope you get the "gist" of what I built. Bottom line, when the electric cutout is closed, all gases are routed thru the muffler and its business as usual, when I open the cut-out electronically, it essentially completely eliminates the muffler as a "restriction" in the system, not to mention sounds awesome at WOT.
First off, after I cut off both exits and inlet from the factory muffler, I was shocked to see that a 2.5" inlet pipe necks down immediate to a 2" pipe (1.875" ID) YIKES!!! I'm thinking sure it sounds "stealthy" at idle and cruise RPM's, but I would have bet you anything I was going to be down 10 plus RWHP minimum on a car putting down 475 or so at the tire. Good thing I didn't have anyone taking me up on that wager....the results were surprising to say the least.
First off, my last trip to the dyno netted me 477 HP....not quite the 480 I have seen on one or two of my previous best pulls, but right in line with the better of my "average" runs. This was achieved thru LG long tubes and the 3" metal matrix Cats and X-pipe. My former "cat-back" was a Magnaflow system that came with 2.5" pipes that go up and over the rear driveline. By the way, the weight difference between the two is exactly 25 lbs total....not too shabby a savings for guys trying to put their car on a diet.
On to the results....After spending a little time with LS1 edit adjusting the fuel curve (THANKS CHARLIE!), with my cut-outs in the open position, our two best power runs were 481 and 480 back to back with peak torque output on both of them peaking at 439 ft/lbs (huge # for stock displacement). We then proceeded to let the car cool for 10-15 minutes and with no other changes except for closing the cut-outs, running thru the "corked up" factory TI system, the car still put down two back to back runs of 476 HP and 475 HP, with peak torque output at 435 and 432 respectively!! I was shocked to say the least. Obviously necking down to a mere 2" pipe that far back in the system is less of a problem than MANY people would have ever thought. Looks like the GM engineers certainly did their homework....in a car with 100 less HP to the tires, I bet that system would barely cost you 3 HP....Very impressive indeed.
For you guys looking for the ultimate in "stealth" with your current headers/heads/cam cars....you can't beat the factory Ti system, BUT some of you might find it TOO conservative. I like the fact that with my new exhaust configuration you can "have your cake and eat it too" by having the best of both worlds depending on the mood your in.
Anyway....interesting info for all to read!!
Regards,
Tony Mamo