I know mandrel bending like about 33% more efficient than the crush bending....but what about this bend? (attachment) I'm not asking because of an intake, I'm just using it as an example. The pipe isn't crushed together like a stock exhaust bend, but it also isn't the same diameter the whole way through, which if I'm correct, a mandrel bend is.

The space inside the pipe should still be the same, right? Except oval?

It might not flow as efficiently as if it were a perfect circle all the way through, but this change seems pretty small to decrease flow by a whole lot.

So if I used 3" piping and had it bent like the attached intake picture, it would probably flow well enough for an exhaust on a 2.8 V6, right? Just thought it might be a cheaper alternative to consider. The engine isn't HEAVILY modified, but I do want to have a little fun with it.

 

It is what it is, mandrel bent intake parts have a more unchanged path.

 

A 3" exhaust is extreme overkill for a 2.8L. I suggest that unless you plan on swapping some kind of V8, or turboing your 6, stay around 2 1/4" -2 1/2". it will give you some back pressure and help you immensly on the low end torque. Also you will maintain good exhaust velocity and that will help you make a few more ponies due to the effects of exhaust scavenging. So what I'm saying is if you must make it sound better get a replacement muffler such as flowmaster or dynamax in the stock exhaust diameter.

-Kevin

 

Yeah. I'm thinkin about gettin the 2.5" Dynomax catback from Summit. Only $170, and if I really don't like the sound (it says it sounds somewhat stock) I can just use the muffler I allready put on my car. Its a Flowtech...probably not the best flow, but I like the sound even with the stock pipes.


So that bend in the picture is not a mandrel bend? Thats what I thought, but it still doesn't look too bad as far as flow for an exhaust.

 

It should sound better than the flowtech IMHO. Keep in mind that if this is a project car with V8 aspirations then you might just want to hold off and get something that will look sound and flow best with the larger displacement motor. I'm a big "Do it Once" kind of guy. I don't see a reason to go through 3 different exhausts on 2 different engines before getting what you want in the end. May as well just save the $$ towards the end result.

-Kevin

 

That's true. But I'm just goin into my senior year in highschool. If this car even makes it with me through college, and the beginning of a family and all that, only then would I consider dropping in a V8.

So for now, I really do think this would be a one time deal. If it does happen though, I know it'll be years and years and years later.

Hope I still have my car then.

 

Bazookajoe, think positive!! I bought my first 3rd gen 2yrs after HS @ 19 yr's old. I turned that 42k mile 84Z H.O. into a 375 horse screamer only to flip it on it's roof 4 yrs later (don't ask how), bought 2 more during a 3 yr span only to buy my 4th and last 3rd gen, the one I have now which I've been buying parts for and building....all the time supporting mortages and a 6 person family!!!! Best of luck

 

That's actually how my exhaust is bent. I bought the car from a self proclaimed "mechanic" and one of the horribly done mods to the car was the exhaust. I noticed it and thought, "How cheap can you get?" but if cheap is what you're going for, then sure, it would probably work better than crush bending.

 

That intake tube in the first pic isnt mandrel bent, its press bent. Thats how all the exhaust shops around here do it, but they call it mandrel bending.

 

You see... that is the funny thing about the types of benders. Most shops that even produce bends aren't necessarily Mandrel benders. They are simply CNC Pipe Benders (Radius Benders). What defines a Mandrel Bender is the attachment to feed pipe. Usually is 5' additions. A mandrel will cost far more due to the fact you can design a pipe in the system. Insert the proper length of pipe for the job and hit start. Come back a few minutes later and you have a completed exhaust pipe.

What you have on your intake is in fact a traditional press bend. It is caused by two arms bending the pipe over an anvil or radius. Mandrel draws in the pipe to a Radius Bender and since it wraps around the entire pipe there is no where to flex but where the mandrel is pressing it.

As far as efficiency... that "bulge" caused by the press bend can cause turbulence and tumbling in your air stream... and the answer is YES... it potentially can cause a loss in power similar to a crush bend... but not as drastic.

 

take a look at the Burns Stainless catalog to see what pieces of mandrel bent tubing look like.

I had my head stuck under the hood of the car from my teens through my 40's. completely missed the "beginning of a family" part, missed the boat. oh well. good to see you're thinking ahead.