Anyone tested the Drag caused by swapping exhaust?
 

Notice how the Z's exhaust is designed, it's engineered so that the air passing underneath the car curves through the bends of the exhaust through the rear diffuser in a smooth way. This causes less drag at high speed.

By changing the exhaust to a two piece set up, i.e: Fast Intentions, Berk, etc. you are are creating essentially a parachute on the rear of the car. I would think drag is significantly increased by this design.

When you remove the CAN design, the rear bumper gets exposed and creates a huge gap which traps air underneath the car just as its exiting through the rear.

The better designs would be exhausts similar to the stock setup and/or the nismo setup. Stillen, Greddy have similar designs which leave less of a gap in the rear bumper.

Your thoughts?

You are absolutely correct... much like the square back of a VW golf creates a vacuum. However unless you are looking for absolute top speed of the vehicle, this may be just an academic observation.

:tiphat:

Interesting point, never really thought of that. Significant to affect necessary performance, not really.

Well just imagine how much drag you are creating at higher speeds? The higher the MPH the higher the drag your car is creating. I would think that any significant HP gain from these two piece setups systems would be offset by the increase in drag they create?

I know the two piece setup sound nice and looks cool from the back but not much engineering thought is put into these systems IMHO.

But the car goes much faster while standing still with the HKS style exhaust setup ;)

:icon18:

I've noticed that too. It's such a huge gap, and the back is mostly solid. There are several aftermarket exhausts that still use a setup similar to OEM though, like Invidia, Akrapovic, Ark DTS Type 1 (did that ever go into production?), and probably a couple more I can't recall.

One could probably just put a flat piece over the entire area to cover it up if the drag really is significant.

I haven't noticed any issues at speeds around 240km/h....

I see the difference being extremely minimal..

I'm going to sell my exhaust now and revert to stock. I need to make sure I'm as aerodynamic as possible.

:roflpuke2:

LOL funny but hypocritical and sarcastic at the same time! lol think about it aerodynamics and drag coefficient should be equally considered and are equally as important as HP gains, back pressure, etc when considering an exhaust setup! Otherwise, why get one at all! :p

Sounds like an opportunity for someone to develop a fireproof foam insert to fill the gap. Only way to find out is to line up a stock Z and a Z with upgraded exhaust and wind sail for a 1 mile race. :eekdance:

Blocking it with something would just make things worse IMO... At least the canisters are round and they are pretty slick.. A straight wall would make it even harder for the air to go around

The large majority of people who buy an aftermarket exhaust system are more concerned with sound and looks.