Newb from the north, with a stinky Z
 

Hey guys, I just bought my first 300 and it has a bad exhaust leak somewhere. I'll probably just replace the whole exhaust but I was thinking of picking up one of the cat backs on here: http://www.importconcern.ca/parts/exhaust/ to save some work, but is there any down side to going single? I would think there would be a benifit in weight reduction.
I would like to make this car alot lighter by summer so I can track it a bit. Which brings me to my next point, on the same site they have FRP fenders on sale pretty cheap. Would they be a worth while investment?

Thanks -T

Newb from the north, with a stinky Z
 

Hey guys, I just bought my first 300 and it has a bad exhaust leak somewhere. I'll probably just replace the whole exhaust but I was thinking of picking up one of the cat backs on here: http://www.importconcern.ca/parts/exhaust/ to save some work, but is there any down side to going single? I would think there would be a benifit in weight reduction.
I would like to make this car alot lighter by summer so I can track it a bit. Which brings me to my next point, on the same site they have FRP fenders on sale pretty cheap. Would they be a worth while investment?

Thanks -T

Yeah, I hope you didn't get that. Your mass flow rate is directly related to the cross sectional area of your pipe. I believe the stock exhaust is 2.5 inches. Might want to double check that. That gives you:

Area = pi*((2.5/2)^2) = 4.90 x 2 pipes = 9.8 in^2 for the dual exhaust


For the single:

Area = pi*((3.5/2)^2) = 4.90 x 2 pipes = 9.6 in^2


So you're missing out on .2 in^2 in that section of pipe by going with the single and that's if the exhaust isn't 3" stock. This honestly isn't that big a deal but it gets to be a much bigger deal when you get to the section with the catback. The HKS cans on the back of mine are at least 4.5" but you're looking at two instead of one so you're looking at a reduction in your flow rate because you have to send the exhaust out through one instead of two. Granted, the catback isn't a very large portion of the exhaust and it probably isn't a big deal. What concerns me the most is that section where the two pipes join. Looks like a great spot for all sorts of turbulence or just general messed up flow. You want it to be as free-flowing as possible to make more power and be better on gas so obviously this isn't a great idea. I just found this with a quick google search. I have no idea if it is any good or not but I know it is better than what you were looking at and at not much of a higher cost. Point being, shop around and see what you can find.
http://www.dashzracing.com/90-96-nis...FSM0QgodwzoajQ

Gotta love the description on the exhaust I posted.

"These Nissan 300ZX Turbo catback does not come with any installation guide; therefore, professional installation is highly recommended."

Yes, because bolting together two flanges and hanging the exhaust from the rubber hangers is so hard...