: new exhaust with #s



stbtt
08-27-07, 12:23 PM
well new pipes at least i used the stock mufflers and put a bullet cat on each side to keep it quiet and you cant hardly tell the exhaust tone is about the same as stock the dyno runs were in all the same conditions other than it was 10 degs hotter than all my other runs still got 13 hp and 11 ftlb at the wheels.i have a 2 1/2 inch pipe on each side going as far back as i could then put a y in to a 3 inch then y back out to 2 1/2.i would of had daul all the way back but i figured they might get to close to the floor pan and radle over bumps
http://i149.photobucket.com/albums/s77/stbtt/08-27-07_1047.jpg
http://i149.photobucket.com/albums/s77/stbtt/08-13-07_0941.jpg
http://i149.photobucket.com/albums/s77/stbtt/cai-ex.jpg

fubar569
08-27-07, 12:56 PM
very good numbers! :thumbsup:

on my 97 i hollowed out the stock cat (for now), took it off the back of the stock cat with a 3" into 2.5" Y and ran dual 2.5" all the way out the tips with cutdown and repacked 10" cherrybomb glasspacks. with you still having bullet cats but eliminating the front Y i would say i should have gained at least that much. my ultimate plan is to make it duals with an X section by eliminating the stock crossover pipe. true 2.5" diameter the entire way through the system...should be sweet when finished...

but you are right. our floorpans are vastly different but it wont fit in the tunnel if you run dual 2.5" the entire way. mine sits wedged in there so it doesnt squeak or rattle too badly. the front Y once it's gone should provide the room i need for the X section and i dont count on having to modify things too much more with the exception of remaking the 2 underbody braces that go across the tunnel on my car. i will need to make new ones that hug the floorpan so i can make regular exhaust hangers...

codewize
08-28-07, 08:17 AM
Nice, good job. What car is that? Are there any other mods?

airfuel2001
09-27-07, 11:30 PM
very nice...and clean install-Im in the middle of doing my Y as well. Im going to replace the factory Y with a aftermarket Y. duel 2.5 pipes going into a 3in collector and using the same bullet conveter with bung, 3in downstream of the Y. I hope I will get similar gains...

cadillac8686
10-03-07, 11:32 AM
I was just wondering why you would use the stock mufflers? I would like to replace my cats to highflow ones, remove the resonater and have a 3" from cat into a 3" inlet/dual 2.5" outlet Y pipe into a set of 2.5" inlet/outlet Dynomax's. I want it to be quiet though. Also when I put in a high flow filter it robbed me of MPG, low end torque and no increase in upper rpm either? Maybe because of the restricted exhaust? Coming in good but leaving bad? Any suggestions? I have an 02" STS

Submariner409
10-03-07, 04:04 PM
The upper RPM is permanently redlined by the PCM. 6250 is IT. Period. After the larger intake work, a lower restriction (there isn't much, stock) exhaust much larger than 2.75" will further decrease low end torque and slightly increase WOT redline power, but see above for electronically limited redlines, or would you like to see one of three timing chains break and go snaking around inside the timing case?????? (And this is an interference engine: a timing chain breaks, the valves hit the pistons, and instant junk.) I am a fan of CORSA, because I own one of their systems (Disclaimer.....), it's pricey, but when you can lift the car, remove the stock system, and install an entire cat-back in less than 45 minutes, and it's guaranteed for life and does have some top-end power gains while not droning you out of the car, what's the drawback??? The OEM cat is not a significant restriction problem, either.

stbtt
10-04-07, 09:48 AM
i wanted to keep it quite is why i still have stock mufflers as for the redline my car will shift at 6450 at wot i have run it to revlimiter it was at around 6600 and the power gains are across the rpm range not just at high rpm

msta293412
10-04-07, 10:31 AM
Take it from me...I had a high-flo cat with 3" piping into 2 1/2 Y...and not only was it to loud IN the car...it robbed low end....even though I have a HIGHLY modded intake.....I put the stock cat back on with the same set up and car runs like a raped ape!....0-60 6.01...ran a 14.97 1/4 mile with 2 people in the car in 85 degree weather....but I digress.....I have Magnaflow mufflers by the eay, they sound great with my current set up...

Submariner409
10-04-07, 12:09 PM
stbtt......, If your engine (what car, what year, what VIN?) will shift at ~6450 and wind to ~6600, why do your dyno pulls indicate a radical power/torque drop at 6,300 ? It looks like the gains realized really begin around 3,200 rpm and extend up to the mid-5's. Best shift point around 5,450 ??? Nice documentation of exhaust changes for the better. A 4.5% power gain at the top of the power curve is proof that a N* will respond to some exhaust tweaking.

stbtt
10-04-07, 12:41 PM
computer controled trans cars dont shift at peak power they will shift going off of 2 factors set in the pcm mph or rpm they will shift at witch ever comes first the rpm set point or the mph if it were up to me i would like this car to shift at a lower rpm but thats the way the car has been since the day i got it oh the car is a 03 sts

cadillac8686
10-08-07, 05:29 PM
You used the stock muffler? And if so, what reason? How much did this run you Cash wise? And how is the low end? Nice set - up!

Submariner409
10-08-07, 09:10 PM
The original and the replacement. Judge for yourself. (In the "top view", the inlet pipes from the Y to the mufflers are nominally 1 3/4" OD.)

stbtt
10-09-07, 09:27 AM
You used the stock muffler? And if so, what reason? How much did this run you Cash wise? And how is the low end? Nice set - up!
yes i did use stock mufflers so the car is still stock in sound it did not cost me anything i did the work at my shop

cadillac8686
10-09-07, 10:46 AM
"Stbtt" did you run 2.5" into the mufflers, doesn't it have 1 3/4" inlets. Did you go back down to the stock size before the muffler or did you finagle it into a 2.5". You got that much WHP just from making the pipes bigger? NIce! It has to be a little louder since you got rid of the resonator. How is the low end with high flow cats?

Submariner, you are making me want that Corsa real bad, know of anywhere I can get a used one at? Those stock pipes are so DAMN SMALL!

Corsa with bullet cats? Enough back pressure. If i can get a cheap Corsa I would still change the cats into the Bullets like STBTT. Where do you get those Bullets?

Submariner409
10-09-07, 01:15 PM
8686.....Thought you had a link to 2 1/2 honeycomb s/s bullet cats here a day or so ago. "Bullet" as in "sorta looks like a little glasspack...." The OEM mufflers have a welded inlet pipe slightly larger than 2" OD. The pipe bender necks the bends down to 1 3/4". The tip outlets are also smaller. If need be, I guess I can lay a ruler on the old system....the pic shows it laid up against a new target board on my pistol range.

cadillac8686
10-09-07, 02:14 PM
Nice target, def something to aim at! Is that your car in the pic, the Crimson Pearl with the Corsa? I want a Corsa just really hate droaning!!!

AlBundy
10-09-07, 03:12 PM
Good lookin exhaust guys.

fubar569
10-09-07, 05:30 PM
my thread with pics of mine should still be around somewhere...if not, i did save them and can post them up if you guys would like...

with the exhaust to date mine has run a best of 14.7x at 9x??? mph...gotta find the timeslip to verify exactly what time and mph...however i think that was with the gutted stock system..and not my dual 2.5" catback...

Submariner409
10-09-07, 06:23 PM
Yes, that's my Red Rocket, and a CORSA does not drone. It's dead quiet at cruise, from 20 to 80. Low, rumbly idle. Punch it, and there's no question it ain't stock. Ricers with fart cans hate me.

cadillac8686
10-09-07, 07:33 PM
I know 50 series Flowmaster are pretty quiet, hoe would that go with a Northstar?

airfuel2001
10-10-07, 10:45 PM
I dont know what you guys are talking about...the first thing I did was put a 3in pipe from the cat back to the OEM muffs, and gained-throttle reponse was better...and drivability was improved. Next I had my Bassani mufflers-3in as well as a 3in Y put on. Wide open was enhanced, but response was lackluster. In an attempt to get back lowend, I plugged one of the duel 3in pipes and increased backpressure. It worked-its snappy down low, and I have peace of mind up top about restriction. the next thing on the list is the OEM cat... its a factory 2.5in which is smaller than reg. 2.5 at the muffler shop. 3in high flow in the original place should do the trick...well see

dmgranger
10-11-07, 07:21 PM
I just picked up a 2004 CTS-V and was thinking about upgrading to Corsa. I put a Corsa cat back on my 1991 Corvette ZR-1 and not only does it sound amazing but it was more responsive as well! Love it!! Easy to install too! :thumbsup:

AlBundy
10-13-07, 08:06 PM
Has anyone ever fabricated their own exaust and added Corsa mufflers?

fubar569
10-13-07, 11:01 PM
Has anyone ever fabricated their own exaust and added Corsa mufflers?

if anyone wants to donate 2.5" in/out corsa mufflers i will be happy to provide clips ;)

cadillac8686
10-15-07, 10:26 AM
How much r the muffs?

Submariner409
10-15-07, 01:25 PM
A landline call to CORSA in Ohio is your best bet for the straight scoop........

cadillac8686
10-15-07, 02:07 PM
Yeah I have my exhaust set up already done, I am good. I was just wondering how much they ran?