The gain in performance between your compression bent exhaust is not a smoothness issue since both are smooth bends, it is a matter of physical size. The old school wrinkle bends and the compression bends reduce the pipes size and this is where the difference in performance is, it is not an issue so much as to how smooth but more to how big or small. The old benders simply would grab the pipe before and after the bend point and then bend it like Superman would a bar of steel, this causes the pipe to wrinkle at the inside of the bend as well as reducing it's size. The compression bender adds a wheel that is used to create a far better bend by bending the pipe against the wheel eliminating the wrinkles, thus increasing the flow by eliminating the turbulences created by the wrinkles, but it still reduces the pipes size at the bend. A mandrel bender creates the perfect bend by slowly bending the pipe around a wheel, this creates the smooth bend while retaining the pipes size all the way through the bend maximizing flow. As I have said, it has been proven not only on paper with a dyno, but also at the track in real world use that it increases power by a noticeable difference.[sm=smiley23.gif][sm=exactly.gif]

The reason your R/T's exhaust sounds good is because or your muffler, the pipes bends have nothing to do with the sound of the exhaust. If you set up two R/T's with the same muffler and size exhaust pipe, but one has compression bends and the other has mandrel bends, they will both sound the same.

How is it that you can believe that the bends make a difference on the intake side and not on the exhaust side? If the bends on the exhaust side don't matter, then why have all headers always had mandrel bends instead of compression bends? One is just as important as the other. Remember, an engine is nothing more than an air pump, the more and faster it can get the air in as well as out, the more power it can and will produce.[sm=exactly.gif]

As far as the open headers go, the open headers provide maximum horsepower, but they reduce maximum torque. Since you have plenty of torque to get you going the added horsepower is making you turn better times. If you were running just the 1/8 mile then you would probably be better off with header extensions to increase your torque.[sm=goodidea.gif]

 

You ever seen that bumper sticker that says, "Arguing with me is like mud wrestling a pig, the longer you go the more you're going to realize I enjoy it." I

I just thought it was funny.[sm=lol.gif][sm=exactly.gif]

 

we tried extensions this year..did the whole wax marking thing, and it slowed me down across the boards..i was actually hoping it would help...[:@]

and while i understand the whole issue of non mandrel bends crimping to some extent, i cant see it making any noticable difference on any regular street car, as compared to the cost...and for that matter...i dont even know where to get pipes mandrel bent. what i DO know is that the people i hear talk the most about mandrel bend are ricers..because it "looks" nicer...

also, say you have 1 compression bend, about 30 degrees, then another 30 degree bend into a muffler, something cheap, say, gibson...you are telling me that with the backpressure provided by that cheap muffler, that you would notice gains on a dyno over the same system with mandrel bends? for the same of arguement, assume a 14 second 3500lb street car.

 

Measurable, yes. That's what 71RR was talking about in a previous post. How often too would you run into a situation where a car exhaust only has 60* of bends in the system.

 

i know its "only the mirada", but it only has 2 bends in the exhaust...it comes off the collector for about a foot and makes an estimated 30degree bend inward, then about 10 inches, and another 30 bend which straightens it back to the mufflers. actually, there are no bends, just angled welds. i would have to see dyno proof showing that the subtle crimp of the compression bend makles any difference with the distrbance caused by most lower end mufflers.

 

Since when is the Mirada a street car?[sm=noooo.gif] Not a good arguement. Even the Coronet has more than 60* in it, all mandrel though.

You can believe what you like obviously, I'm just trying to help you out.[sm=imsorry.gif]

 

youre not helping anyone out..youre arguing simply for the sake of arguing. and how is it not a street car? because it doesnt have exhaust on it?? the only thing preventing me from driving it all the time is finding a way around the emissions testing. which isnt far off.if i get a classic or CV plate, i am exempt, and the inspection isnt a problem,....one of my buddies inspected the RT, and the truck...and it only takes 10 minutes to bolt the exhuast up.

 

[sm=sorry.gif], but I'm not. Your absolutely right and everyone else is wrong. Thanks for straightening me out.

 

youre welcome.[sm=smiley31.gif]

 

http://www.quickhonda.net/exhaust.htm

They talk about mandrel vs. compression bending. Interesting reading if you're not up to speed. This was the first choice that can up during the search.