Exhaust fabrication questions....

[jlsparky7]

For all you welders out there that know anything about exhaust fabrication where do I start?

I have a 1996 explorer and it has several exhaust leaks. 2 in each front catalytic converter 1 huge hole in the muffer and one in the resignator.

My plan is to trash everything but the headers and get a flowmaster muffler and a high flow cat. I know the exhaust has to move seperately and have flex in some spots so I cant just weld the whole thing together.

Just mimic the stock exhaust?
Where should I put the welds?
How do I go about piecing it all together?
How do I mount the o2 sensor? do they sell mid pipes that are taped for them?
Do I go with a 2.5 or 3 inch pipe?
Advantages and disadvantages to running duals vrs single?

My cousin just bought a 120amp 230volt mig/flux core welder from the china store (harbor freight) and putting an exhaust on will be part of our summer project.

 

[djack12]

it may not even be worth your time. you may just want to take it to a muffler shop and ask them for all new piping when you do it. my brother got all new piping put under his acura for $200. its hard to get the bends you need and all that.

 

[jlsparky7]

it may not even be worth your time. you may just want to take it to a muffler shop and ask them for all new piping when you do it. my brother got all new piping put under his acura for $200. its hard to get the bends you need and all that.

Its a project vehicle so if it takes me a long time its no big deal. Im doing it just for the experience and to be able to say I built the exhaust. Its pretty much a straight shot back from the cats.

It will be expensive to have a shop do it. Prolly close to a grand.

 

[4cfed]

well you have a few options... easyest and so you can hear it also.. shot out the sides, yes you can get mid pipes that have o2 ports in them, 3 inch is completely un needed. 2.5 is good to 500 hp, and your not running a turbo so 3 inchwill do nothing for you.. go 2.5 with a flow master mufflerrs, run a h or x pipe ... look up mustang h pipe or x pipe.. x will give you the most power, but is harder to make,

you want ah or x pipe cuz it will help with torque and horse power, you want the mufflers right before the rear axle if you end up running it outt he back, if you run it out the sides run the mufflers as back as far as you can than put the 90 degree right on the muffler and out the side, the headers to the rear axle are the easy part,

for going over the axle you want your pipes to go up, than over than down, than to the back, as for fit ment your gonna want fit everything before welding, and probbly clamp it lighty, and work the rear suepnsion to make sure the exhaust dont hit the rear axle. and most importinat dont want it rubbing on the floor or suspension cuz thats annoying

but yet you also dont want it to hang to low..... as for hanging the exhausst you stock style hangers, normally a rubber type hanger from the pipe to the truck, this will slow the exhaust to move with the motor, but yet there isnt much movement in the motor but there is some, so just use hangers simmaler to whats on it now,


single is a option, and wont hurt the power none.. again 2.5 threw a flow master,

what ever you do stay away from ' turbo mufflers' they give a tinny sound and the quality sucks,

muffler options for agood sound are flowmasters, mac, spintec and pypes, dyno max straight threw weld mufflers are also decent

 

[Country Blaster]

Ok, I see you already have a welder but do you have access to a pipe bender? I fully agree with 2.5 being plenty for what you are trying to do, as for the O2 sensor just drill a hole where they need to be and weld a O2 sensor bung and your set.

Now its time to decide where you want your exhaust to exit, in front of rear tires, behind rear tires, strait back etc. Spend some time under the vehicle and find a clear rout that will result in the fewest bends, decide where you want your mufflers and cat. Finish it off with a set of 4" chrome tips and your custom exhaust is complete.

 

[jlsparky7]

well you have a few options... easyest and so you can hear it also.. shot out the sides, yes you can get mid pipes that have o2 ports in them, 3 inch is completely un needed. 2.5 is good to 500 hp, and your not running a turbo so 3 inchwill do nothing for you.. go 2.5 with a flow master mufflerrs, run a h or x pipe ... look up mustang h pipe or x pipe.. x will give you the most power, but is harder to make,

you want ah or x pipe cuz it will help with torque and horse power, you want the mufflers right before the rear axle if you end up running it outt he back, if you run it out the sides run the mufflers as back as far as you can than put the 90 degree right on the muffler and out the side, the headers to the rear axle are the easy part,

for going over the axle you want your pipes to go up, than over than down, than to the back, as for fit ment your gonna want fit everything before welding, and probbly clamp it lighty, and work the rear suepnsion to make sure the exhaust dont hit the rear axle. and most importinat dont want it rubbing on the floor or suspension cuz thats annoying

but yet you also dont want it to hang to low..... as for hanging the exhausst you stock style hangers, normally a rubber type hanger from the pipe to the truck, this will slow the exhaust to move with the motor, but yet there isnt much movement in the motor but there is some, so just use hangers simmaler to whats on it now,


single is a option, and wont hurt the power none.. again 2.5 threw a flow master,

what ever you do stay away from ' turbo mufflers' they give a tinny sound and the quality sucks,

muffler options for agood sound are flowmasters, mac, spintec and pypes, dyno max straight threw weld mufflers are also decent

Perfect. Thanks a lot.

Ok, I see you already have a welder but do you have access to a pipe bender? I fully agree with 2.5 being plenty for what you are trying to do, as for the O2 sensor just drill a hole where they need to be and weld a O2 sensor bung and your set.

Now its time to decide where you want your exhaust to exit, in front of rear tires, behind rear tires, strait back etc. Spend some time under the vehicle and find a clear rout that will result in the fewest bends, decide where you want your mufflers and cat. Finish it off with a set of 4" chrome tips and your custom exhaust is complete.

I do not have access to a bender however the parts store near me has TONS of exhaust piping, I would imagine I could just mix and match until I get what I need.

Thanks for the reply.

 

[4cfed]

you dont want your exhaust completely straight though, the bends are what changes the tone,

 

[92blaster]

what kind of steel will you be using some welder cannont weld stainless steel, if your using just regular steel you should be fine with a regular mig..

 

[jlsparky7]

you dont want your exhaust completely straight though, the bends are what changes the tone,

I wont be running straight pipes. Only way I would do that is if I had a race cam. Which I would never do to an explorer....

what kind of steel will you be using some welder cannont weld stainless steel, if your using just regular steel you should be fine with a regular mig..

I have a 120 amp 230 volt mig/flux core welder. Can be run with or without gas. Heres the link.

- Harbor Freight Tools - Quality Tools at the Lowest Prices

Think it could do stainless and regular steel? I think so, its a step below the best mig they sell.

We just got the welder the other day and havnt even ran the 220 line yet. Im going to be doing lots of practice welding before I tackle the exhaust. Ive never welded anything before.

 

[4cfed]

i didnt m,ean like straight pipes .. and a cam WONT effect anything with the exhaust nor will the exhaust mess with the same.. i mean straight like.. straght back to the mufflers, you want some curves and bends in the exhaust, trust me.. running bends up and over the axle will make the exhaust tone sound much nicer

and regular mild steel exhaust pipe will work just fine... JUST remmeber to get some high temp exhaust paint, and after you weld the pipes and it cool paint over the welded, it wil help protect the welds from rusting since the welding will burn off the protective coating

 

[Cochise]

Buy a flowmaster u-fit dual kit and fab yourself a single side exit (behind the rear wheel) and tuck it up as tight as possible if you plan to off road.

 

[jlsparky7]

i didnt m,ean like straight pipes .. and a cam WONT effect anything with the exhaust nor will the exhaust mess with the same.. i mean straight like.. straght back to the mufflers, you want some curves and bends in the exhaust, trust me.. running bends up and over the axle will make the exhaust tone sound much nicer

and regular mild steel exhaust pipe will work just fine... JUST remmeber to get some high temp exhaust paint, and after you weld the pipes and it cool paint over the welded, it wil help protect the welds from rusting since the welding will burn off the protective coating

How could a cam not effect the exhaust? The cam controls the exhaust valve and the exhaust controls the back pressure. Doesnt make sense to me how one couldnt effect the other.

Ill definitely paint it with high temp black paint.

Buy a flowmaster u-fit dual kit and fab yourself a single side exit (behind the rear wheel) and tuck it up as tight as possible if you plan to off road.

Thats the route im planning on going so far. No reason to run duals.

 

[4cfed]

iv been in the drag racing scene for almost 10 years now.... friend has a mustang with a 600+ lift cam, trick flow r heads, sheet metal intake, long tube headers 13:1 compression and he ran 4 mufflers ( true dual) ran pullits about 8 inches behind the headers than a set of flow masters right after them ( cops kept fkn with him for the sound) finnay started to leave him alone once they stopped him and seen he has 4 mufflers.. car ran the same time with the flowmasters behind the bullits as it did with just the bullits

 

[Cochise]

Also I dont recommend Flow Master mufflers. They are cheap as f*ck and dont last very long. And I'm talking about REAL FM's. Cherry Bomb Chambered, Thrush Welded, Force Pro's, and Summit Welded are damn good mufflers for a damn good price. Stay away from flowmasters, they arent worth it.

 

[4cfed]

i beg to differ... normally the thrush and cherry bomb mufflers are junk...... i bought a flow master cat back for a mustang i had, guy bought it new 8 years before i bought it from him and it still looked and sounded great

 

[Cochise]

I've gone through just about every damn muffler you can think of. I'm VERY picky on exhaust notes. Of all the ones I've used, the ones I mentioned above were the best built/designed and sounded great. The flowmaster 40 I had was very cheaply made in comparison and the damn ends were more crooked than a dogs hind leg. Flow Master is just like K&N. Overhyped Junk.

 

[4cfed]

lol.. thats why my next street machine is gettin super 44s of original flowmasters.. ill pay a lil more for the added quality

 

[Cochise]

I've seen almost every FM muffler made in person ( decisions, decisions) They were all the same. Cheap thing guage metal and very shady manufacturing processes. I have a set of welded chambered mufflers on my car now. They are white box, no-name mufflers and not only do they sound good they are 12ga. cold rolled steel, tig welded, and PERFECT! And only $50 a piece from the local speed shop.

 

[Cochise]

However I will add that the tubing they use in their exhaust kits is VERY nice. But still never fits quite right. No catback ever really does.

 

[4cfed]

iv bought one cat back that fit perfect.. that was a obx 2.5 mirror polished stainless steel cat back for my old 95 eclipse, bought the exhaust new off ebay ( didnt pass quality control cuz the tip was dented slightly so the silencer wouldnt come out) straightened it with a plyers and looks perfect! exhaust fit excelent