i need dynos of na rx7s with the only mod being the exhuast, a need a couple with single exhaust and a couple with dual, my dad does not believe me when i say it doesnt make a difference

 

I actually think it does make a difference to have dual vs single as their is less restriction for the exhaust on a dual setup.

Though you would be able to see it better on a turbo setup, their is a hp difference in single and dual exhaust setups...

I think...

 

There actually is a difference between dual and single exhaust setups.

Think about it like this...

You have a car with a single 2.5 inch exhaust from header to muffler tip...
It is only 2.5 inches in diameter the whole way out and keeps whatever velocity it started out with and may even slow down along the way.

Now you have another car with a 2.5 inch pipe that splits off into dual 2 inch pipes. You now have a 2.5 inch pipe opening up into a 4 inch exhaust...

And since the exhaust becomes 2 inches on each pipe that speeds up the exhaust gas velocity because it is being squeezed into a smaller diameter pipe.


Which do you think is better, a single 1 size pipe that can lose exhaust gas velocity as it travels down the pipe, or a pipe that goes from 2.5 inches to dual 2 inch pipes which helps speed up the exhaust gas for better flow?



Racing Beat has even proven that a dual exhaust is better than a single which is why they sell dual exhausts that they have tested instead of single exhausts.

 

It doesn't.


-Ted

 

my thoughts being that a more freely flowing exhaust is going to help whether single or dual, and there might be a difference but it's probably negligible, like 1 or two a hp on the same car. That being said you really can't compare two different cars because it's not the same for the control variable. Because no two cars are the same

My .02 just go with the exhaust you like to look at and hear

 

ya but im looking at getting a 2.75 cuz eventualy im gunna put a turbo on it and i need a new exhaust system to pass inspection.

 

I say go single.
1. Dual or single make NO diff.
2. Its a start to having a lighter/faster car.

ANd Im pretty sure mazda used a dual exhaust system; more for it being quiet rather than it being for the performance.

 

I think it depends on size of piping, if both single and dual have the same diameter, i think the dual setup would have better top end and the single would have better bottom end, simply due to back pressure, however, the different in power would not be that noticeable, Also, design of exhaust has a lot to do with it too

I wouldn't worry too much about it though, if you ever plan on going turbo, just run a electronic cut out at the bottom of the downpipe, to me, this is where you will unleash power the most, it might make a little difference on stock na though unless it's modified

 

^^ I like your idea. Put a 3in downpie/dump valve/stockcat/stock exhaust.

You can get cheap manual cut outs. ANd its supper sleeper.!

Cheaper than a full exhaust. If you have good sources. i LIKE IT.