Marc's Exhaust overhaul

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Marc's Exhaust overhaul

Postby broncomarc » Wed Apr 08, 2009 7:37 am

I'm on to the next project. I'm re-doing my exhaust in order to clear my long arms. I also want to set it up to clear a future 4 link in the back. I've got some shiny new WH headers here and a box full of mandrel bends on the way.

The headers are 2.25 out, so I'm using 2.25" tubing. I'm probably going to do a 2 into 1 exhaust. I'm going to try to fit the crossover between the torque converter dust plate and the oil pan to keep good clearance and keep it out of the way.

Right now I'm debating if I should make a Y pipe or use a 2 into 1 muffler. I don't really want to do the 2 into 1 muffler because I would need to need to run the 2nd pipe back to the muffler and that would take up space. It would also require a different size output and I'd have to buy more tubing.

But, If I do a Y pipe and use all 2.25" tubing, is that going to be way too restrictive for my 351w? Is a restrictive exhaust better for torque? I'm more interested in low end torque than high end HP. I don't rev it that high very often.
- Marc Reiter
1973 Bronco - http://www.broncomarc.com/bronco/
1969 Bronco uncut halfcab
1969 Mach 1 - http://www.broncomarc.com/mach1/

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Postby broncomarc » Sat Apr 11, 2009 12:23 am

No opinions?? I was waiting to get blasted for wanting to do a 2 into 1 into 2.25" tube.

I've almost convinced myself to just take both tubes into the muffler and 3" out of the muffler and just do a turndown coming out of the muffler. I'm looking at this muffler:
http://www.jegs.com/i/Edelbrock/350/55770/10002/-1

Still looking for opinions though...
- Marc Reiter
1973 Bronco - http://www.broncomarc.com/bronco/
1969 Bronco uncut halfcab
1969 Mach 1 - http://www.broncomarc.com/mach1/

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Postby Bill Weaver » Sat Apr 11, 2009 6:37 am

I wouldn't do the turn down in the rear......gona blow dust in your face.
Bill Weaver
1966 Bronco 302,3 speed
2007 F-150 FX2 Sport
2001 Honda Recon

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Postby broncomarc » Sat Apr 11, 2009 11:58 am

I'm just going to do the turndown for now. It'll be band clamped to the muffler so I can change it later if I don't like it. Also, If I do a 4 link later I may need to change it, so I don't want to go too far yet.

I found another option. I found a y pipe that goes from dual 2.25" to a single 3" :
http://www.jegs.com/i/Flowmaster/389/Y214300/10002/-1

With that I could just use a single in/out muffler and give myself the option of a space saving round muffler.
- Marc Reiter
1973 Bronco - http://www.broncomarc.com/bronco/
1969 Bronco uncut halfcab
1969 Mach 1 - http://www.broncomarc.com/mach1/

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Postby j howell » Sat Apr 11, 2009 5:54 pm

post pics of the headers.
do a 2.25 into a 3 and it will flow enough.

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Postby EJ » Sat Apr 11, 2009 8:06 pm

I think you can look at the cross sectional area of the tube to compare....

The 2.25" tubing CS is about 15.9 sq in. if it goes into 3" tubing CS is about 28.3 sq in.... to have no restriction, it calculates out to 3.18" tubing. So going to 3" looks very doable....

I run the same size tubing before the y as I do after:eek: I should maybe rethink that......


ej

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Postby Bill Weaver » Sat Apr 11, 2009 9:50 pm

I like the look of collector pipe. I'm still trying to figure out your clearance to be able to make a single exhaust work. The crossover seems like it will be crowding your trans/transfer case space.
I know that off my headers the dual exhaust pipe coming down the right side is very close to trans/transfer.
Not trying to tell you not to do just trying to think how it will work and get you all the area you are expecting....

.02 worth could be just babbling!
Bill Weaver
1966 Bronco 302,3 speed
2007 F-150 FX2 Sport
2001 Honda Recon

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Postby broncomarc » Sat Apr 11, 2009 10:32 pm

I'll check the clearance for where I want to run the crossover pipe tomorrow. Hopefully there is room there.

Would the heat from the exhaust be bad for the torque converter or oil pan if I run it between there?
- Marc Reiter
1973 Bronco - http://www.broncomarc.com/bronco/
1969 Bronco uncut halfcab
1969 Mach 1 - http://www.broncomarc.com/mach1/

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Postby Bill Weaver » Sun Apr 12, 2009 9:03 am

Would the heat from the exhaust be bad for the torque converter or oil pan if I run it between there?


Yes I would be concerned about that. I'm going to crawl under mine and see if I can help you on this. I think I have a good idea where you want to route exhaust.
Bill Weaver
1966 Bronco 302,3 speed
2007 F-150 FX2 Sport
2001 Honda Recon

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Postby broncomarc » Sun Apr 12, 2009 11:18 am

I think I found where I got the idea to put the crossover pipe there. Check out this post. It looks like he dumps both sides into a single 2.25" pipe.

http://www.classicbroncos.com/forums/sh ... p?t=115614
- Marc Reiter
1973 Bronco - http://www.broncomarc.com/bronco/
1969 Bronco uncut halfcab
1969 Mach 1 - http://www.broncomarc.com/mach1/

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Postby broncomarc » Sun Apr 12, 2009 11:24 am

Here's the pic Jim wanted. Man these could stand to be ported. That's pretty rough!
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- Marc Reiter
1973 Bronco - http://www.broncomarc.com/bronco/
1969 Bronco uncut halfcab
1969 Mach 1 - http://www.broncomarc.com/mach1/

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Postby j howell » Sun Apr 12, 2009 12:02 pm

imo. the heat will not be a problem there. if i'm wrong you can rap the tube in that area with some heat tape.
i think it was Karl Bradley and Drew that have a nice 2 into 1 exhaust. they dropped the driver side just as you plan to do and cross to the pass side in the area between the oil pan and bell housing the same as you but then they drop the pass side down to the area ABOVE the transfer case and the driver side stays below the same cross member. then they come together with a 2.25 into a single 3 inch Y pipe behind the crossmember. then into the muffler. then run it out the pass side in front of the rear tire. looks clean. and simple.

i would be bitching about the flash inside those headers. if they came from Wild Horses i know you paid enough not to be accepting ANY compromising.

a die grinder on a short arbor works good on the headers. i did the same to my SVO shorties a few years ago.
also sense your at it take your exhaust gasket and tape it to your heads. trace the ID of the exhaust port from the gasket on your heads exhaust port. especially at the top of the port. i removed about 3/16 to a 1/4 inch of metal st the surface of the port. then blend it back about 3/4 of an inch in the port. this in effect raises the exhaust port that is said to be the best bang for the time spent on the cast heads. this is the number 1 reason the "P" heads out flow the gt-40's. and the higher port is why the normal headers won't fit. it only takes a 1/2 hour of your time.

jim

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Postby broncomarc » Sun Apr 12, 2009 1:14 pm

These headers came with a felt gasket with a metal core. These any good?
- Marc Reiter
1973 Bronco - http://www.broncomarc.com/bronco/
1969 Bronco uncut halfcab
1969 Mach 1 - http://www.broncomarc.com/mach1/

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Postby broncomarc » Sun Apr 12, 2009 7:34 pm

Well... I was kidding myself. There's 3/4" between the bell housing and the oil pan. I don't think I can squeeze the 2 1/4" tubing in there. I can fit it between the bell housing and the tranny pan, but then the driveshaft may hit it. Especially when I go high pinion in the front. Maybe I should stick with dual exhaust!
- Marc Reiter
1973 Bronco - http://www.broncomarc.com/bronco/
1969 Bronco uncut halfcab
1969 Mach 1 - http://www.broncomarc.com/mach1/

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Postby Bill Weaver » Mon Apr 13, 2009 6:08 pm

I just looked under mine and I have a little more room with the manual tranny. My headers come back further than yours will be. I'm guessing they dump midway down by transmission. If you didn't run a high pinion you could possibly drop down and cross over under oil pan. I also thought you could cross over back of the transfer case "under" the drive shaft. Maybe?
It looks like any way you go it's going to be real tight if you don't go straight back with dual exhaust.
Bill Weaver
1966 Bronco 302,3 speed
2007 F-150 FX2 Sport
2001 Honda Recon

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