Mandrel vs crush bend; Worth it?

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Brandon Weaver

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I had true duals for my slant welded up by my local mom and pop shop a couple of years ago, and for the combination (170-180 horse) I never gave it a second thought. Now I'm going back through and building a better engine (more cam, carb, comp, headwork) and some of these bend stick out like a sore thumb to me.

So... Is there really that much to be gained by going from a crush bent exhaust to mandrel? If I do, I probably won't bother worrying about the tailpipes. I figure they are after the muffler, and most people neck down in size after the muffler anyways to keep velocity up when the gasses cool.

So what's everyone's thoughts on this?

Oh, and the nice thing about having 2" exhaust is THIS would make a fine and economical source of bends...
 
I was looking at the costs of mandrel bent pipes for my 65 273 cuda, and I checked out the cost of a pipe for a slant early dart, just for info. I forget which co. , but the headpipe ( engine back to muffler. was like $180 if I remember, the mom and pop shop cost me $120 for the complete pipes they did on a 65 slant dart...., ( I had muffler and flange). the shipping would add to that $180 no doubt.
I would say, if you are spending the $$ for a higher HP engine, the small extra costs of a single headpipe is worth it???
 
Good question. With a fire breathing 415 stroker it might make a few HP difference at the rear wheels but nothing you'd notice with a nicely built engine in a street car.
 
Gotta remember that to a certain point the ID of the pipe remains the same weather it oval or round.
 
I believe the marginal gain of 1 or 2 hp is not really an issue on a daily driver or street car .

If all out race car and looking for that tenth then collectively may make a difference but in real world nobody will notice the difference
 
Wouldn't be easier and cheaper to simply get 2 1/2" pipe all the way back at the local shop...this way even if you lose a little on the muffler shop bends you'll still get at least 2 1/4" bends which are more than enough for 6 cylinder. JMO

Treblig
 
Brandon Weaver said:
I had true duals for my slant welded up by my local mom and pop shop a couple of years ago, and for the combination (170-180 horse) I never gave it a second thought. Now I'm going back through and building a better engine (more cam, carb, comp, headwork) and some of these bend stick out like a sore thumb to me.

So... Is there really that much to be gained by going from a crush bent exhaust to mandrel? If I do, I probably won't bother worrying about the tailpipes. I figure they are after the muffler, and most people neck down in size after the muffler anyways to keep velocity up when the gasses cool.

So what's everyone's thoughts on this?

Oh, and the nice thing about having 2" exhaust is THIS would make a fine and economical source of bends...
Click to expand...
Looks better , gain in HP not sure it will be noticeable . all my pipes have been mandrel bent , never noticed any gain when I switched from crush pipes .
 
On over 90% of cars built it doesn't make a hill of beans difference. Don't waste your money.
 
On a mild motor, I don't think there is gonna be much gain. I do like the way the mandrel bends look though.
 
I would have to think that the guys that buy the mandrel bent exhaust systems off venders like tti, etc..... are wanting a OEM system, or that pretty look of the mandrel system, or just don' t have a local shop that can do it. on these A bodies, the bends can be pretty tight and hard to do. I had to look for a different guy to do my exh on the 273 65 cuda. the guy that usually does it didn't want to fool with it. can't blame him, he;s 70, the weather if hot, he doesn't need the $$, and it is tight bending!
 
Alright guys, thanks for the input! The more I think about it, to go through the work of replacing the bend would be troublesome. And I can think of one spot in particular where the crush comes in handy (with dual dutra manifolds, the rear pipe is extremely close to even a mini starter. The crush type bend gave me a little more clearance here)

Thanks again!
 
I build my exhaust systems from pre-made mandrel bends. Crimp bends offend my visual sense of what's right, but I doubt that there's much difference in performance. I build my systems because I usually want a very specific fit that I usually couldn't afford to have a muffler shop build even if they were willing to do it. I only buy 180° bends, usually from Columbia River Mandrel Bending. I also make the systems with stepped flanges so that I can easily take sections of it out as needed. Valiant exhaust pics start a little down from the top here.
 
Treblig said:
Wouldn't be easier and cheaper to simply get 2 1/2" pipe all the way back at the local shop...this way even if you lose a little on the muffler shop bends you'll still get at least 2 1/4" bends which are more than enough for 6 cylinder. JMO

Treblig
Click to expand...

This......

And if they're not the crinkle type of bend..........
 
With the availability of cheap mandrel bends in various sizes these days from many vendors including summit etc I can't see why you wouldn't? Unless your desperate for something in a time crunch and just want it quick and dirty from Muffler Man or something. I bought a Summit universal mandrel X- pipe kit from and mufflers and had a buddy fab it up and weld it all together and it turned out awesome! Better than anything a crush bend muffler shop can do and $ was comparable.....just took a little more time.
 
There are some pretty tight bends going around the rear end on A-bodies, and muffler shops can do some bad crush bends. Mandrel is better; however, if you are not putting anything on after the mufflers then then bends don't matter much.
 
Beatnik said:
With the availability of cheap mandrel bends in various sizes these days from many vendors including summit etc I can't see why you wouldn't? Unless your desperate for something in a time crunch and just want it quick and dirty from Muffler Man or something. I bought a Summit universal mandrel X- pipe kit from and mufflers and had a buddy fab it up and weld it all together and it turned out awesome! Better than anything a crush bend muffler shop can do and $ was comparable.....just took a little more time.
Click to expand...

I was just looking at the Summit bends and straight pipe on line over the weekend and that is exactly what I am going to do. I can drive by the Summit store on the way home from work and pick everything up. Have MIG, will travel.
 
67Dart273 said:
What are some of your sources for bends?
Click to expand...
Occasionally bits & pieces from Summit (the SST bend that became the Valiant's exhaust tip for example), earlier systems were sourced from SPD Exhaust, last set of bends & Marmon joints came from Columbia River Mandrel Bends. There's another vendor, whose name is currently escaping me, that I plan to use for the Sched 10 weld elbows to build an exhaust manifold for the Valiant. I *think* they're marked at home. If they are, I'll edit this post.

EDIT: Source for weld elbows as used by some to build turbo exhaust manifolds: http://www.sharpeproducts.com/store/bent-180-pipe-tube-elbows-with-tangents
 
My exhaust guy said, he couldn't make a 3 inch>"S"
and look nice, (bender is crush type)plus the time to cut, shape and fit, would be costly.

went with pipes from Columbia River Mandrel Bends.
dragged out the band saw and mig,
and used the left over 45*
for tail pipe extensions

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017_zpsj8rb1b4r.jpg


009_zpsmc1khn59.jpg
 
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