: The NEW Cat-Back is DONE! (kinda)



fubar569
05-22-07, 10:04 PM
Well, the unit is fully welded, fits within the stock heatshields (the heatshields were modified for fit), just kisses within 1/4" of the heatshield around the gas tank (plenty of room, plus there is space between shield and tank)...i am going to cut the nub off the bottom of the lower A arm on the passenger side so it will not contact the suspension under load...

i will not lie...it is a DAMN TIGHT FIT!!!!!! so tight that in one spot it spans the width of the tunnel and actually pushes the heatshield out a bit...however in this location there is plenty of room to spare between the shield and body...

i had to make a new hanger...cut some 1/2" rod, suspended in rear subframe holes and welded in place, used old hanger rubber, and welded to new pipe...

it fits rather well considering only ONE 2.5" pipe was meant to fit in there...and i have 2! - i estimate i lost under an inch of ground clearance in certain areas (some close to zero, others closer to 1 inch)...

i miscalculated the angles on the tailpipes and the exit location however...need to cut off and reweld them with a different angle...basically tucking them up as much as possible. pipes are exiting at angles toward the corners of the car but in the stock exit location. i have single 2.5" polished tips (but they have lost the polish...lol)...


i need to wend in additional bracing between the pipes (to pull them in together), finish up 2 more hangers, and rework those tips...

otherwise IM DONE!

it sounds marginally louder than the stock piping, and i have no idea what the gain is (if any)...prolly not much till i redo the front half and tie it in and make it a true dual system...

pics will come upon completion

AlBundy
05-22-07, 10:24 PM
Can't wait to see pics.:thumbsup:

fubar569
05-22-07, 10:41 PM
oh i wont disappoint...or rather i try not to...

the stock system on my deville is UNDER 2.5" (about 2.3" outer diameter) at the front of the cat...and exits the cat as a single 2.5" and runs that way till it hits the rear Y at the back and splits into dual 2" to the mufflers...

as of now:

still stock front, stock (but hollowed out) cat...stock cat exits immediately into a custom single 3" to dual 2.5" Y pipe (necked down to 2.5" to fit stock cat)...and from there runs dual 2.5" all the way back to the tips that exit in the stock locations...

i think this is much better! will get pics while the car is in the air tomorrow for all you guys!

fubar569
05-23-07, 07:34 PM
car is 100% done...and got a new fuel filter today too!

pics as promised:

http://mysite.verizon.net/fubar569/IMG_0023.JPG
http://mysite.verizon.net/fubar569/IMG_0024.JPG
http://mysite.verizon.net/fubar569/IMG_0025.JPG

http://mysite.verizon.net/fubar569/IMG_0026.JPG
http://mysite.verizon.net/fubar569/IMG_0027.JPG
http://mysite.verizon.net/fubar569/IMG_0028.JPG
http://mysite.verizon.net/fubar569/IMG_0029.JPG
http://mysite.verizon.net/fubar569/IMG_0030.JPG
http://mysite.verizon.net/fubar569/IMG_0031.JPG
http://mysite.verizon.net/fubar569/IMG_0032.JPG

chazglenn3
05-23-07, 10:06 PM
Nice! But no mufflers?

AlBundy
05-23-07, 10:18 PM
I like, I like.:D Good luck at the track.:thumbsup:

EcSTSatic
05-23-07, 10:39 PM
Nice! But no mufflers?
Also no cat. Illegal in most states.
And the tips don't extend beyond the body. I hope he doesn't suck fumes into the interior.

AlBundy
05-23-07, 11:09 PM
Also no cat. Illegal in most states.
And the tips don't extend beyond the body. I hope he doesn't suck fumes into the interior.

I wondered the same thing. You might want to extend them further unless you have something else in mind.

CadillacSTS42005
05-23-07, 11:33 PM
damn....
i am impressed to say the least...
however im not one for bypassing mufflers...

CadillacGurl
05-23-07, 11:37 PM
damn! you better post a vid on how that baby sounds!

fubar569
05-23-07, 11:54 PM
Also no cat. Illegal in most states.
And the tips don't extend beyond the body. I hope he doesn't suck fumes into the interior.

the cat is still there! at least in the picture it is...i dunno whats inside of it...

the stock tips did not exit outside the body either...those ones are angled so as to be pointing right out of the stock holes in the bumper, and actually are tackwelded in place...i have plans to add dynomax bullets and will revisit the tips issue later...fumes do not get into the cab...

eldorado1
05-24-07, 12:13 AM
And the tips don't extend beyond the body. I hope he doesn't suck fumes into the interior.

Oh brother.... like the 5" would make a difference.....

At least he won't have to worry about wiping soot off his bumper....

fubar569
05-24-07, 12:44 AM
Oh brother.... like the 5" would make a difference.....

At least he won't have to worry about wiping soot off his bumper ....

actually, i do...the only reason is i dont have turndowns...these point straight out...IF i had tucked these pipes upmore toward the trunk floor i'd have the room for that...but i didnt have enough mandrel bends to pull it off...if i had 4 more bends or so i would have done things quite a bit different...

also, those tips came off the old exhaust on my 84 corvette and have been through 3 exhaust systems now...so they will work for the time being...lol

i think if and when i add the dynomax bullets i might take the contour more toweard the trunk floor and will prolly add a set of polished twin tips per side. it would look really nice...also make them come straight out the back instead of an angle...but hey...work with what ya got!

i will try to shoot a vid tomorrow for everyone...think of a LT equipped LS1 with a nasty bark...thats what i think of when i rev mine up...getting close to 6k and it sounds killer...obviously plenty loud enough to let everyone know you're coming...strange thing though is going from stock exhaust to the new dual 2.5" catback i got rid of that really annoying resonation about 2k rpm...car is smooth through the band and is actually a bit quieter in the car as a result...

Tommy Deville
05-24-07, 03:13 AM
DAmn that sucker is gonna be loud! 4inch pipes I love it!

EcSTSatic
05-24-07, 08:35 AM
Oh brother.... like the 5" would make a difference.....

At least he won't have to worry about wiping soot off his bumper....

You obviously don't understand how air flows. Why do you think every factory designed system extends outside the body? If there was a smoke generator you would see the difference. Soot is the least concern. CO is deadly.

Raze
05-24-07, 08:50 AM
You obviously don't understand how air flows. Why do you think every factory designed system extends outside the body? If there was a smoke generator you would see the difference. Soot is the least concern. CO is deadly.

Wow, dude seriously I have a degree in how air flows and burns but I'm w/Eldorado on this one, beyond the soot it don't matter. If you understood how air flows you'd know that sitting at idle with a tail wind will push CO into your cabin even with the tips extended out past the body of the car...

EcSTSatic
05-24-07, 08:59 AM
Wow, dude seriously I have a degree in how air flows and burns but I'm w/Eldorado on this one, beyond the soot it don't matter. If you understood how air flows you'd know that sitting at idle with a tail wind will push CO into your cabin even with the tips extended out past the body of the car...

Well that's a no-brainer. The danger that every exhaust system designer/regulator understands is that CO that is not ported out from underneath the car runs the risk of seeping into the cab.

codewize
05-24-07, 09:32 AM
That's insane. It's probably going to sound great. Hot rod loud at all throttle positions but that's one crazy ass configuration. Who designed that?

I would also think you're going to fill the car with fumes for a couple reasons. One is that fact that the tips stop under the car, as mentioned, probably illegal AND you will get fumes inside. The other is the pointing sideways rather than straight back. Not a good idea. Think about the air flow around that while you're driving. There will be lots of turbulence against the exiting exhaust making it both more difficult for the exhaust to escape AND swirling it around all over the place causing even more fumes into the interior.

That whole thing is just a flat out bad design. Oh and you'll probably get loud exhaust tickets continually.

EcSTSatic
05-24-07, 10:05 AM
the cat is still there! at least in the picture it is...i dunno whats inside of it...

Sure you do. You said earlier that it was hollowed out.
I'm all for a well designed, responsible system but I think you've missed the mark. It's your car to do with what you want (the feds may disagree) but we're all here to learn from one another and take the best away with us.

fubar569
05-24-07, 10:58 AM
That's insane. It's probably going to sound great. Hot rod loud at all throttle positions but that's one crazy ass configuration. Who designed that?

I would also think you're going to fill the car with fumes for a couple reasons. One is that fact that the tips stop under the car, as mentioned, probably illegal AND you will get fumes inside. The other is the pointing sideways rather than straight back. Not a good idea. Think about the air flow around that while you're driving. There will be lots of turbulence against the exiting exhaust making it both more difficult for the exhaust to escape AND swirling it around all over the place causing even more fumes into the interior.

That whole thing is just a flat out bad design. Oh and you'll probably get loud exhaust tickets continually.

it is loud...plenty loud...

i designed it on the go...rather once i had the Y made i just got under the car and measured pieces to make the first bend and welded that section up...then once i got the stock exhaust cut out from under the car i used that as a template to follow...

big reason the tips exit like they do is sheer simplicity...i ran out of mandrel bends and couldnt route them towards the center and make them exit straight out. however this can be fixed rather easily when my next shipment of pipe arrives...gotta figure out what i need for the corvette and i can slip in the bends i need to finish up the cadillac right...

as far as the tips stopping underneath the car...each tip is only an inch (or less...didnt measure) away from the edge of the cutout in the plastic trim...there is 2" of pipe inside each tip so i could really pull them out if i wanted but then they'd eat into that plastic trim...not only that, but no fumes are being pulled in...i can see the vapor spots and soot on the bumper so i can assume if that is happening they must be making it past that point or it would be collecting on the inside of the trim which isnt happening.

loud exhaust tickets? till they start ticketing all the trucks with stacks, no mufflers, ricers with fartcans and all the harleys with straight pipes in PA i am not worried one bit...plus i seem to get complimented alot...they really leave you alone if you're not being a complete idiot like most ricers, etc...

and as for the cat comment...it was a bit of sarcasm...i did that pretty much because again, no emissions for me and i didnt have the cash for the set of highflows i'd need to complete the system.

will i likely re-do this in the near future? probably...i know there's alot i could have done better and/or different...but how many people do you know that would go through the expense of 3 days of measuring, cutting, welding, grinding, etc...just for a custom catback to try to cut some time off the 1/4mi on a car never meant to ever see more than 60mph by virtue of the crowd it was marketed to? plus i know of no company that makes a catback for the 96-99 devilles and if they did, i'm sure it would be over a grand like the corsa system for 2000+

everything that is "wrong" with the tips can be fixed with about 30 dollars in parts...i'd wait till i did the front half of the exhaust if i replaced the cat with working ones as i'd need 2 anyway (one on each bank)...the mufflers...well depending on what i go with could be anywhere from 70 a pair to 150 plus a pair...i'd need something with a short overall length however...

the foundation is there for a terrific system...for a first attempt i think i did rather well...everyone has thier own tastes however...

EcSTSatic
05-24-07, 11:19 AM
the foundation is there for a terrific system..

I agree :thumbsup:.
Did you have to have a signon name like "Fubar" :)

fubar569
05-24-07, 11:47 AM
I agree :thumbsup:.
Did you have to have a signon name like "Fubar" :)

i didnt get it from the military...i got it from the movie "Tango & Cash" - i thought it sounded pretty awesome...keep in mind i've had a signon with the word "fubar" in it since about age 12 and i'm 23 now...first fubar7, then fubar69, then fubar569 and 569 has stuck with me forever

fubar569
05-24-07, 12:38 PM
VIDEOTIME!!!!!

http://videos.streetfire.net/video/b84e53d8-cb1c-43a5-ad68-993800ca6945.htm

eldorado1
05-24-07, 12:40 PM
Well that's a no-brainer. The danger that every exhaust system designer/regulator understands is that CO that is not ported out from underneath the car runs the risk of seeping into the cab.

The cab is a sealed system. The only entrance is the vent at the base of the windshield. In fact, the blower motor draws in air and pressurizes the cabin so that any leaks will leak OUT instead of drawing air in.

As long as you don't have an exhaust leak in the engine compartment, you're fine.

eldorado1
05-24-07, 12:43 PM
VIDEOTIME!!!!!

http://videos.streetfire.net/video/b84e53d8-cb1c-43a5-ad68-993800ca6945.htm

Yeah, it's a little loud!

Just a little. :alchi:

urbanski
05-24-07, 12:57 PM
hilarious

EcSTSatic
05-24-07, 01:41 PM
The cab is a sealed system. The only entrance is the vent at the base of the windshield. In fact, the blower motor draws in air and pressurizes the cabin so that any leaks will leak OUT instead of drawing air in.

As long as you don't have an exhaust leak in the engine compartment, you're fine.

True or not, all I'm going to say is "tell it to the judge". Then "your fine" will take on a new meaning. Excuse the pun. :)

weister42
05-24-07, 02:27 PM
Yeah, it's a little loud!

Just a little. :alchi:

Wow that is ver loud like a truck with straight pipes :thumbsup: How's the noise in the cabin during normal highway cruise?

fubar569
06-10-07, 02:03 PM
sorry i kinda forgot to reply...been busy with a move to pittsburgh...

it's supprisingly not bad now with the new catback...with the stock exhaust was on and gutted it was BAD...

i had to make a modification to the front brace that bolts across the exhaust tunnel today...

seems the clamp i used was rubbing under certain conditions and causing alot of issues...

so i notched the brace about 5" wide and 3/8" deep...and butted a piece of 1" square 11ga steel against the uncut side and re-welded everything together. the 1" square runs from 1" from the inside hole to 1" from the hole on the other side, is welded the entire way down the notched side, on both ends, and in 4 places 1" long on the opposite side. this brace is not going anywhere and will not flex ever again.

the rear brace...lets just say i need to totally re-do it and then when i do that i need to engineer some exhaust hangers at the same time...

this is an ongoingproject it seems...i had to rush to get it done befor ei moved and now im tidying up what i can when im home...

P.S. anyone in the pittsburgh area? im living (for now) on butler street in the lawrenceville area...

Submariner409
06-10-07, 07:19 PM
Disregard.......sorry....

thu
06-11-07, 10:53 PM
Wow, dude seriously I have a degree in how air flows and burns

What degree is that?

EcSTSatic
06-12-07, 03:34 PM
What degree is that?

I sometimes wonder why folks don't just say; Mechanical Engr, Electrical Engr, MBA etc instead? :confused:

airfuel2001
06-24-07, 09:43 PM
I will have to get pictures of mine and post them...

tpis15
06-25-07, 10:04 AM
Thats too loud for a cadillac! And this is coming from a kid with electronic cutouts on a V8 powered S10.

jadcock
06-25-07, 11:50 AM
This is the first time I've read this thread.

I think you did excellent work on the pipes. I'm impressed with how clean you welded them and how straight they run, where they can. Codewise, if you're talking about the "curly q" routing, that's there because that's the stock location. The fuel tank is right in the middle of the car, and the exhaust has to route around it on the E/K cars. On the G cars like 98+ Seville and 00+ DeVille, that configuration was modified for a straight-through route.

Having no working converter is, obviously, illegal in all states. It's not a state law, but a federal law (part of the Clean Air Act). No state can impose a regulation less strict than a federal regulation. I probably wouldn't advertise on your video page that you don't have a converter...I would simply state that you did a custom exhaust with no mufflers. But that would be just me...

Again, I like your work. I would absolutely add a set of mufflers if it were me, but you're not (me), and you're right that everyone has their own taste.

jadcock
06-25-07, 11:54 AM
What degree is that?

C'mon man, keep up. That's the HAFAB degree (How Air Flows And Burns), taught by the School of AAA (All About Air), which is under the University of AA (which has nothing to do with air). :alchi:

EcSTSatic
06-25-07, 12:05 PM
C'mon man, keep up. That's the HAFAB degree (How Air Flows And Burns), taught by the School of AAA (All About Air), which is under the University of AA (which has nothing to do with air). :alchi:

:highfive:

fubar569
06-25-07, 12:18 PM
This is the first time I've read this thread.

I think you did excellent work on the pipes. I'm impressed with how clean you welded them and how straight they run, where they can. Codewise, if you're talking about the "curly q" routing, that's there because that's the stock location. The fuel tank is right in the middle of the car, and the exhaust has to route around it on the E/K cars. On the G cars like 98+ Seville and 00+ DeVille, that configuration was modified for a straight-through route.

Having no working converter is, obviously, illegal in all states. It's not a state law, but a federal law (part of the Clean Air Act). No state can impose a regulation less strict than a federal regulation. I probably wouldn't advertise on your video page that you don't have a converter...I would simply state that you did a custom exhaust with no mufflers. But that would be just me...

Again, I like your work. I would absolutely add a set of mufflers if it were me, but you're not (me), and you're right that everyone has their own taste.

Thanks for the props on the pipes. that was my first full run through welding pipes on my own. i did some small practice stuff but i basically cut and hacked up some old corvette pipes and put them back together only a few days before doing this...i took the tubing, eyeballed and cut...then welded everything on a whim and piece by piece for both sides...once i got around the first bend i used the stock as a template and it worked out extremely well. the welding like i said...only started welding pipe about 3 days before doing the exhaust - did everything with our lincoln 135 gas/flux MIG (brilliant welder - highly recommended) - for cutting all i had was a mikita reciprocating saw...also had a bench grinder and wheel...thats it...

It has no converter now as stated, however i will probably be adding bullet cats within the year as i have moved to an emissions area...however i could keep my address at my parents home and avoid the headache...if i go with bullet cats i will be re-adding provisions for my rear O2 sensor as it's currently not even in the pipes, but rather tucked up and tied away...if i do not add the cats i will have an O2 Simulator from a LS1 camaro installed in its place (the rear O2 sensors are the same between a LS1 Camaro and a 97 Deville and others)...

regardless, i am on the hunt however for a set of mufflers that offer a truly unique sound. i love borlas but do not want to pay the premium for that sound. I also had Flowbastards w/ Offroad X on my 02 Mustang GT when i had it and LOVED the sound the flows gave over my friends SLP and Magnaflows...i had a dynomax straight through on my 93 Talon TSi AWD and that was a badass sounding 4 cylinder...

the holdup with mufflers is that i need a short canister. one pipe is only 17" i believe which limits my selections greatly. most mufflers have an overall length in excess of 20+ inches...

and another holdup is i dont want to do anything i dont have to do until i install my custom underpan crossover pipe and go duals with the X pipe. I will also be retaining EGR with this and i have a way envisioned to equal the length of the banks (front and rear) prior to the X so as to obtain maximum benefit. I dont want to have to cut and re-weld 3 or 4 times...i will obtain the pieces, and do it all at once...it's just easier...

it is loud...really loud...though windows up cruising it isnt all that intrusive. after clearancing the heatshields for the exhaust the best i could and redoing the front crossbrace there is little vibration and resonance. i still need to redo the rear crossbrace and fab new hangers for the entire exhaust. right now it is resting on a heat resistant cushion on that crossbrace and it holds it TIGHT in the tunnel...i want to redo that brace, make new hangers, and isolate it from the body as much as possible. this should help to eliminate any vibrations...with mufflers this should keep interior noise and resonance/vibration to a minimum and really ruffle the feathers of those on the other side...quiet and refined at idle yet loud and nasty under load :thumbsup:

jadcock
06-25-07, 02:27 PM
I've had Edelbrock mufflers before, though long ago, and they're not the same (I don't think) as their current lineup. They called them their RPM Series mufflers (similar to the rest of their performance line at the time). I had a set on my old Cutlass and they sounded great. I always said I was going to put them on the Cadillac if it ever needed them (it never did). They're also on the expensive side (stainless), but you do get what you pay for. We've also had Borla before and they were excellent. Personally, I like the aluminized Dynomax Ultra Flows. Simple, easy to get, easy to afford, etc. Will easily outflow "Flowmaster", which is known to not be the best design out there, performance-wise.

http://www.dynomax.com/products/ufw.asp

Or, get creative and use one of Dynomax's Ultra Flow X and put it right inline with your dual-pipe run:

http://www.dynomax.com/products/ufx.asp