2 90* bends in exhaust

[David K]

I dont like how the 79 exhaust is routed. I have an MSA rear bumper on the 79 now. It exits on the passenger side. On my previous 79, i was running the exhaust out of the back of the drivers side. I cant do this on the current 79 because the MSA bumper comes out the passenger side. After the muffler, there is one 90* bend, and then right before the tip, there is another 90* bend.

 

After the stock system is done, i want to put together a few peices of pipe i have in the garage. The best i can come up with is running a 2.5 outlet muffler, and a 2.5 mandrel to the tip.

 

How much are those 90* bends going to hurt flow?

[David K]

I could run 2.5 exhaust into a 2.5 inlet/2.5 outlet muffler with a 3" pipe from the muffler to the tip. Itll be like there is nothing there after the muffler.

 

Or I could cut out the 90* bends all together and weld 2 45* bends in place of 1 90* bend.

[blueovalz]

I can't imagine you will even notice the two 90's as far as performance is concerned.

[labrat]

An old heating/AC worker friend told me once that adding a 90* turn to ducting was just like adding 10 feet of straight pipe as far as resistance to flow is concerned.

 

For what it's worth....

Bill

[jeffp]

I have 2 90 degree bends in my DP and the car is running 500hp. The back pressure at the inlet of the turbo is 1:1 so 25psi of boost gets me 25psi of back pressure at the turbo inlet.

I dont thing the bends make that much difference in a mandrel system, in fact if you look at the bend radious and picture the air moving over the inner and outer radious, you wil find that it makes the air swirl around the radious, then into the second bend the swirl addes to the flow through the bend.

anyway, I have 500hp and very low back pressure in my system and that works for me.