Straight Pipes 72 Datsun 521 ?????

[RatVonDude]

Hi All,

Was looking under my 521 pick-up and noticed that the pipes are way rusted, however there are no holes or anything, probably still some life in them.

It seems to me that straight, or straighter pipes with a cherry bomb or glass pack  would give it better back pressure other than the stock muffler and angled exhaust pipes. ???????

Any recommendations,??????? Do not have a tig welder.

I wanna keep the stock header only because there is a list of things I want to do over time.

 

Truck hauls ass with weber 32/36,  stock L 16,  four speed manual. It just feels that the stock exhaust is not helping it off the line.

 

 

 

[Ratwagon1600]

Erhem.

 

Welcome.

 

Pictures and then magically the answers will follow.

[RatVonDude]

 

[Jayden71]

 

 

 

 

Nice oics! :rofl:

 

I have a glass pack on my 71 521. Its been on there since I have had the truck.....9 years. Yeah its rusted, no there is no holes in it. It gets the job done I guess. Kinda loud when I stomp on it. I too have L16 weber, offenhauser intake but I have dogleg 5 spd :thumbup:  :thumbup: .

 

I am looking at getting something a little better. I guess I am just getting old in my old age and want something nice and smooth. Its only 1 3/4" now. I am going to go up to 2"

[HRH]

Point of clarification:  You NEVER want backpressure.  You WANT good flow.  Too big of a pipe and the exhaust pulses will tumble around and you will lose performance.  Too small of a pipe and you create a restriction.

[metalmonkey47]

You NEVER want backpressure.

 

Wouldn't backpressure be good for low end power/torque??

[HRH]

No, but the exact right amount of flow would!  If you have "back" pressure, that means the engine is fighting to breath.  If your pipe is exactly the right size for 1500-2500 rpm, then you have the ideal torque lets say.  If you have bigger pipe that flows well at 7000 rpm, that means you likely won't have enough flow at low rpm, so your low end torque will suffer as the exhaust is not scavenging out of the cylinders effectively.  A small pipe is great for making it easy to get exhaust out at low rpm.  As soon as you get up high though, it starts to suffer.  Regardless, "flow" vs. "backpressure" is the issue.  There was a really good article about this in Sport Compact Car quite a while back, damn if I know where it is now.