What's the difference between old an modern exhaust headers?

Question

in old cars like renault 5, the fresh air arrives in ad the smoke goes out in 2 pipes which are combined in 1 bigger pipe, But in newer cars like kia pride, the pipes are not combined, they are in two opposite ways. why?

Answer 1

Those differences have been around for a long time. The one on the Renault is what's known as a Tri-Y or 4-2-1, while the Kia one you mentioned is a four into one or 4-1 design.

The Tri-Y performs better at low RPM and sometimes fits more easily into cramped engine comparments, while four into one designs often work better at high RPM. Which one to use depends on how the designer wants the engine to perform.

Answer 2

Hello,

as Mad Scientist said there are different kinds of exhaust designs to meet performance and emission and cost expectations. The Renault 5 is an older construction, and it has not been designed for performance, but for fuel consumption. For driveability, bottom-end power is preferred at the sake of peak powers in higher RPMs (long and small diameter pipes have high flow restriction, which limits gas flow at higher RPMs, but supports combustion at lower engine speeds). Another design factor is that it must fit into the engine compartment and should be cheap :D. 4-2-1 exhausts are common constructions in this vehicle class, but it's a trade-off. Another solution is the 'siamese' exhaust, where only one exhaust pipe get out of 2 cylinders next to each other and joining after a while. even cheaper, but even less strong.

Novadays, emissions and performance are more important, engines are big and strong enough to support exhaust systems that are 'working' in the upper RPM area, maximizing power in the high-end. With variable valve control systems and 4-valve cylinders, it's possible to maintain good bottom-end power and peak power. And they can ask more money for it :D That's why they can use 4-1 systems.

Regards

Answer 3

Depends how strict exhaust emissions are in your country. Some car have to have two different fuel systems for a four cyl engine. Refered to in diagnostic as bank one and bank two that way converters can clean up the exhaust better. USA Califorina Smog rules ZLEV and SLULEV AND "LLEV" in the rest of america on the under hood sticker. Zero emissions and Super low emissions and Low emissions...

Answer 4

Rust?!?! Seriously, you already have had some good information, but I now have another 2 points. IT'S FRIDAY!!!! A Good Weekend to all!