Hello,

During the summer I put a cheap cat-back on my truck to get rid of my rusty pipes.

It had a flowmaster and fake duals, now it is a 2.5 inch single system. The exhaust guy did the pipes for me for 100 bux, and my muffler was 75, pretty cheap.

Well, I can see why the job was so cheap, the bends he made are horrible!! They were not made using a mandrel pipe bender, obviously. there are probably 4 bends after my muffler that look like they were bent on the corner of a bench.

I got this system because I was looking for a different (louder) sound, and more torque by ditching the fake duals. I definetely got the sound I wanted, but the performance actually might have seemed to decrease.

I have a magnaflow mandrel bent y pipe, into a magnaflow high flow cat, and so I was wondering if these bends were significantly hurting my performance?? Would it be worth it to hack off the tailpipe, and either, weld on a prefabbed one, or put on a turndown?


Thanks!
Brian

 

I would just put a turndown on it or get a pipe made to exit in front of your rear wheel -Scot-

 

yes those bends are probably hurting performance. I would cut them off and clamp on a turndown until you figure out what you really want done.

 

The 4 bends are probably over the axle right? They don't have to be mandrel bent to be ok but if bent too far they could hurt performance a bit. Also depends on how tight of a bend too. We do not have a mandrel bender at work, but they way we bend pipes for custom exhaust has never been a problem or hurt performance as far as I know. They don't look like they were bent on the edge of a bench anyway. I would venture to say most places do not have a mandrel bender at least around here. If tailpipe is clamped on you could take it off and see if you notice a difference. If you have a 2.5" tailpipe the bend probably is reduced to like 2.25" which won't cause a problem unless all the bends are done a weird way.

 

there is one bend before the axle, and the other 3 are after it. I could take some pictures of it if needed, or I could measure the circumference and figure out the average diameter of those bends. They seem to be pretty small, my understanding is that a 302 needs atleast 2.25 to breathe well, that is why the 2.5 seemed like a good choice for me. It actually felt slower when i was messing with it on the highway, compared to what it used to be, and i've done other mods to increase the breathing, with what seems to be a pretty minimal gain...maybe the exhaust is restricting it quite a bit.

I think i might end up getting a cheap hanger and turndown at kragen, and clamp it up. then i can reclamp the tailpipe later on if need be.

anybody know the "law" for exit locations in california?

 

Dont by any means quote me but i wanna say 16" past cab is standard, i know in texas you must have 16" of pipe past your cat and atleast a turndown.

 

mine will end up right before the rear axle, so i guess that will be alright?

 

I would think so. But just to be safe or legal, i would check state laws, but again honestly, how many cops check to see if your exhaust is of legal lenght, ive been pulled over for speeding with open headers before and not a word about the exhaust noise. Yes i was speeding, but i was stumped on how you could miss the noise?

 

Here in PA the exhaust has to exit anywhere behind the cab. You will be fine with turn downs right before the rear axle.

I know what your saying about bad bends. I got a pipe the local exhaust shop bent for me thats collapsed pretty bad from their bender. Turns a 3" pipe to 2.25" pipe at the bend. I ordered some magnaflow mandrel bends and am custom making my own pipe.

 

yea ive seen this all to many times, if i choose a shop i ask around from people that have new exhausts done. See how well there hung, if there clamped or welded and if bends are good. Only real way to tell how good a shop is, in my opinion anyways!

 

3" pipe is pretty hard to bend at least on bender at work. We dread doing 3" pipe. If I was to do a 3" system for myself I would do the same thing ordering the mandrel bends. 3" is a bit of a pain to work with even though our bender is capable of doing it. Just a hassle.

Also for a stock 302 2.25" pipe is fine I would say. 2.5" might be a little too big. Although on my 73 I have headers with 2.5" pipes into mufflers then 2.25" tailpipes. I wouldn't mind seeing a picture of your exhaust. Maybe they just put extra bends because they were having a problem lining it up??

 

How does being well hung make the shop good??

I like welding exhaust, but welding aluminized pipe burns some coating off making the welded part rust if you use MIG, so clamping is technically better for it lasting longer. We probably weld more custom exhausts though because it looks better. No clamps. My personal exhaust is half welded half clamped because I got tired of staying to finish it. One day I will redo it properly when I decide on what I want for tailpipes. They are before rear wheels right now.

Also everyone's idea of good work is different. I found a picture of someone's exhaust of a truck similiar in year to mine. The bends look good and I'm sure the exhaust functions well. I personally would never route it under the crossmember. I almost did turndowns the same way as this truck though, but opted for chrome tips out the side.

 

I agree dual 2.5" is oversized for a 302. I got it put on about 8 years ago when I wasn't as keen on exhaust size as I am today. I got my headers installed, true duals with glasspacks and chrome tips for $240 8 years ago, not much to complain about there. I'm going to put a new exhaust on my 74' eventually, but I am going to go with dual 2.25" pipes. I was thinking of just buying a Flowmaster universal pipe kit and fabbing up my own exhaust. My 74' F-100 is still bundled up for the winter.

I'll post some pics of my 74' up in the 73'-79' section eventually. I got to scan some of my 35mm pics. I only recently got a good digital cam, I've had a good 35mm for years so thats what I used last time.

 

Looking forward to seeing the pics over there! I might drop my exhaust down to 2.25" all the way through one day. I'm not sure I see any benefits to the headers or 2.5" exhaust except waking up the neighbors . I'm glad I did 2.25" tailpipes though over 2.5" There isn't much 2.5 from headers to the mufflers. If I were do to it over I'd drop down to 2.25". There is no gain with the bigger pipe on a stock engine. I'm assuming mine is a stock 71 mustang engine. Before I did the headers it had 2.5" exhaust all the way back. I did not notice a decrease in power between before and after I did my exhaust. I hope the original poster posts some pics of the exhaust. Curious to see if the bends are bad enough to cause a problem or if it could just be the 2.5" exhaust.

 

I think I'm going to stick a set of Dynomax bullets on my 74' with the 2.25" piping and maybe dump it in front of the rear wheels. It will be loud as hell. The next door neghbors will hate it for shure. I put a quieter muffler on my 04' so I have to make the 74' louder to make up for it.

The 74' has been feeling a little left out. Since I got my my 04' it has been getting all of the money for mods.