Custom exhaust: guy told me not to try 3" center pipe? What do you guy have?

JAFO

Registered User
Went out to see what this is going to run. I'm looking for 2.25"-3"-2.5" which is what seems to be the consensus for the SC's, max flow and no drone (correct me if I'm wrong, please!). Not swapping the gas tank, and this is a '91.
He said that if he put in a 3" center pipe that it would crimp it down so much that he'd feel that he wasn't doing me a good job. I see where he's coming from, like most places he can't do mandrel bends.
Are you guys living with the crimp or are you all ordering aftermarket kits? Good lord those things are big $$$$$$. Am I missing something here?
 
xhaust

2/12 is plenty for the mid pipe.Most people go to big and loose velocity and then wonder where their torque went.I'm 260hp 348tq at the wheels and have 2 1/4 ,high flow cats,2 1/2 half center w/ a Magnaflow resonator into a y pipe w/ 2 1/4 into Dynomax Super Turbos.That's the same torque a 03 Cobra has.Sounds good,not too loud and no clearance issues.
 
I have the SCP catback exhaust and it is 2.5-3-2.5 and it is not too big at all. I would recommend going with the 3 inch center pipe. Trust me I did not loose any low end tourqe. If you have or are going to be further modding your car there should be no question, 3 INCH CENTER SECTION! it only makes sense if you are going from two 2.5 inch pipes why would you want to go down to one 2.5 inch pipe.

Nick
 
well

teh SCP kit has mandrel bends..I hav eit on my 94...I can see how using the older gas tank and non mandrel 3 inch would definately crimp it down a bit
 
It would be a good time to go to a junk yard and get a gas tank from a newer Bird, then use a 2 1/2
3 2 1/2 system.
 
Nah, don't want to swap the gas tank. I like the larger tank and I think that would just complicate everything. I just don't want to cough up $750 for the SCP system. I'll check a few more shops and see if they can offer more hope for the 3", or if they feel good aboiut the 2.5".

Somewhere I've seen something that helps you deal with the computer code that you'd get if you delete the cat's, due to the O2 sensors. Where does that thing hook up? Any opinions on that too?
 
Just an idea, get some "pre-made" mandrel bend pipe "angles" and have them joined to the shop provided straight pipe. That should eliminate the crimping issue.
 
That's a good idea. You'd think that a good shop would have access to pre-bent pipes like that, even if it had to be ordered. I'm wondering what difference the bend will really make in the diameter of the pipe at the bend. I'd expect it to crimp down, but how much?

Still, anyone use that wiring setup for deleting the cat's?
 
According to your signature file, you have a 1991. This does not have the sensors before and after the cats like the 94, and newer ones that require the fix when you remove the cats. Yours, like all others with EFI, needs the sensors to control the fuel injectors. You will need another O2 bung installed in the new pipe, if its removed with the cat. The newer cars use a sensor before and after the cats to monitor cat funtion. The 2nd one has no effect on fule injector control, only emmision monitorong.
 
94/5 SC's are don't have 02 sensors after the cat's...in fact they are set up just like the early model's...two 02 sensor's, one on each side.
 
Like Jimmy correctly stated.

The 94/95 SC's had EEC-IV diagnostics, essentially "OBD-I".

Only the 94+ Tbirds with the "new" 4.6L had "OBD-II" and the dual O2 sensor set up.
 
Deep6 is correct. No downstream O2 sensor to know if there's cats or not. I have 2 1/4 duals the whole way on my 1995 with NO cats. I did however notice a drop in low end power...That is until I installed my pulley. All my power came back and then some. This year at World Ford Challenge 5 in St. Louie, I had a talk with the reps in the Flowmaster booth. They recommended that I do away with the true dual setup and go to 2.25 into 3 into 2.25-2.5. Why bigger to the mufflers? Got me? But since that's what they do for a living I guess I will have to trust 'em. BTW, you can order pre bent mandrel sections from just about any mail order parts company. They said that the 3 down the middle will flow better due to a "scavenge" and also the sound will mellow out a bit. No, I haven't changed mine yet. Flowmaster also said that a single 3 flows as much as dual 2 1/4. Mine sounds like a fart in a coffee can, and I,ve found myself saying "HUH" for a few hours after I drive it. Good luck and please keep me posted as to what ya do!
 
I hit a performance shop today for my '94, after I got done dealing with the guy telling me that I really didn't NEED Z-rated tires, he told me they could hook me up with a cat back 3 inch into (I'm assuming 2 1/2") mandrel bent with twin flowmasters for between $425-$475 or if I want the quiet ones (the 50 series I think) $475-$525. I'm leaning towards the quieter ones as I would rather have the car be more of a sleeper.

Paul
 
(Casey punches Slowpoke in the gut)
But he agrees. DRONEmasters on a V6. My buddies 5.0 suonded soooo good with 'em.
EXcelerator?? (spelling) is a brand of muffler a local shop here uses and they swear by it. To tell you the truth.....I bought Flomasters so when people ask me what kinda exhaust I have I can say "Flowmaster".......true story. I have Dynomax on my 87 Monte SS and they sound great. But it is a SBC. They sound good with just about anything.
 
There's another shop around here that can get Magnaflow. Another prefers "Bullit"(sp?) mufflers for a V6. Or Dynomax? I haven't heard any of these on an SC so I don't know which I should go for. I'd want the deepest sound possible with the 6, not too worried about being quiet or loud as long as it isn't like Cherry Bombs or something.
 
What kind of....

Exhaust set up should I get (cats/resonator/mufflers) if I want my car to sound docile at idle and cruise but also to scream like an Italian Banshee above 3000rpm?????
 
I'm getting my exhaust done at a small custom shop here in the Phoenix area on Monday, dumping the middle cat and the resonator, going to 3" to dual ... might be dynomaxs... I'm not sure what he is planning on using. I asked hmm to get me the most flow with the least sound... the cops here are vicious and I want my bird to be a sleeper... I'll let you guys know what happens and maybe take some digital pics on monday when it is on the rack :)

Paul
 
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