If these are going on a pretty much stock C5?

If these are going on a pretty much stock C5?

You probably won't notice any unless you use forced induction or replace the heads, etc.

What I noticed (going to headers) was that the cabin quieted down and the exhaust sounded better.

You probably won't notice any unless you use forced induction or replace the heads, etc.

What I noticed (going to headers) was that the cabin quieted down and the exhaust sounded better.

I agree. If your car is stock you might as well get the 1 3/4, if you are planning on going FI or a head/cam swap then I would go ahead and get the 1 7/8. :cheers:

For a stock engine, I'd go with the 1 3/4" diameter hedders. So the exhaust gas velocity remains high as it passes through the tubes..........

Id go with the 1-3/4" unless you have a big stroker motor or a supercharger.

If these are going on a pretty much stock C5?

Great timing on this thread!! :thumbsup:
I was just wondering the exact same thing this morning! :thumbsup3:

Mahalo!!!! :cheers:


:patriot:

Well I would go 1 7/8 route just incase you decide to go bigger in the future with mods.:thumbsup:

I agree with 1 7/8 two years ago I ordered the 1 3/4 for my c5 and the place sent headers that were for a c6 by mistake. It's a long story but the garage putting them on, didn't see the c6 written on the box or else didn't know they were working on a c5, they managed to get um on after they customized them, only problem was one side hung down about two inches below the bottom of the car. The car ran great. But I didn't like the wrong headers on the car. They sent the rite ones and they were put on. The car didn't run as strong, I called the shipper back and asked what could possibly be different, he said other than the C6 headers being 1 7/8..... Nothing. I'd definitely go with 1 7/8.

The larger primaries will actually hurt your bottom end on a stock cubes n/a car. Reason being the wider the piping, the slower the exhaust moves through the pipes. Slower moving exhaust kills both torque and pending the length of the primaries will also decrease the scavenging effect headers were intended to produce.

Exhaust size is a science:
Too small pipging = too much much gas pressure (engine has to work harder to push out the exhaust gases)

Too large = not enough exhaust velocity (most exhaust gas is in the system at any given time and the engine has to push it all out)

Ideal pipe size = exhaust gases flow easily and quickly through the plumbing. Minimal effort for the engine and some scavenging effect will aid in "sucking" the exhuast out of the combustion chamber

I agree. If your car is stock you might as well get the 1 3/4, if you are planning on going FI or a head/cam swap then I would go ahead and get the 1 7/8. :cheers:

For a stock engine, I'd go with the 1 3/4" diameter hedders. So the exhaust gas velocity remains high as it passes through the tubes..........

Id go with the 1-3/4" unless you have a big stroker motor or a supercharger.:goodpost: :2ni19wj:

The larger primaries will actually hurt your bottom end on a stock cubes n/a car. Reason being the wider the piping, the slower the exhaust moves through the pipes. Slower moving exhaust kills both torque and pending the length of the primaries will also decrease the scavenging effect headers were intended to produce.

Exhaust size is a science:
Too small pipging = too much much gas pressure (engine has to work harder to push out the exhaust gases)

Too large = not enough exhaust velocity (most exhaust gas is in the system at any given time and the engine has to push it all out)

Ideal pipe size = exhaust gases flow easily and quickly through the plumbing. Minimal effort for the engine and some scavenging effect will aid in "sucking" the exhuast out of the combustion chamber

Great answer
If you go with 1 7/8s, you will probably wind up regretting it. The larger tubes will KILL your torque, especially at low RPM. Larger diameter tubes are more for high hp drag racers than a street car. In the old "how to build a small block Chevy" book (doesn't cover LSx) they devote an entire section to header design.
But don't think they will not make hp; I'm well over 600rwhp (FI) and there are guys well over 700 with "street friendly" 1 3/4 tube headers:thumbsup:

I am making 449/423 with a H/C 6 speed and I use LG Streets with no CATS.

Chris

440 rwhp na and then a 125 shot on top of that. You thing there will be a waste of money to go form my 1 3/4 to 1 7/8th?