HC Mechanic

I’m curious to see if anyone has a comparison graph on the 1 7/8 vs. 2” American Racing Headers

redbird555

http://www.camaro5.com/forums/showthread.php?t=63640

here ya go. 2" is always the better choice

HC Mechanic

Pretty crazy to see that type of response with only 400 or so horsepower.

cbrtrx

One thing to take into consideration is that the 2 inch don't fit as well and hang a little lower, they are pretty close to everything.

redbird555

Well my 2” arh clear better than my 1-7/8 looks did so I’m going to have to disagree there. Besides 1/8” here or there isn’t going to make any noticeable difference

xBoostx

I removed my ARH 1 7/8 and sold them over how hard it is to remove and install them compared to the Kooks which if you loose a handle on them from the top you have to go under the car to pick em up that's also how easy they are to install.

Also worth mention is the ARH leaked from all 4 in both collectors so I had to cut collectors weld/seal and weld them back on not wanting to ship to the NY and keep car two or more weeks on jack stands got zero for it from manufacturer.

The ARH did fit flush not so the Kooks which hang one full inch below.

All in all I prefer to adjust the Kooks.

CMY SIX

LS2's prefer the 1 3/4 so there goes that argument, I wonder why the OP just didn't ask ARH of
r Kooks?

HOXXOH

The brand vs tube size vs tube length vs collector size vs other mods vs the RPM desired vs the wallet, will all be factors in the best choice.

There are lots of ways to get more power, but the combination of parts and tune to match your desired result is the most important consideration.

Since you're in CA, the 2012-13 Z06 manifold, cats, X-pipe, with any decent muffler will get you through the smog check and give about a 12-15 hp boost.

Boomer111

True although I saw the low end HP wise. The big lose is in the torque dept. The long tubes really help the torque.

redbird555

WideVette

Not necessarily. From the same post (#20):


"I don't understand how the 1 7/8 is "best all around header" in your opinion if the 2" headers had better average and peak numbers. Could you please explain? Thanks.

A few Reasons, the additional cost does not justify the gains.
They are a Tighter fit.
They are Heavier
Most manufacturers offer a 1 7/8 headers so they are easier to get.
The biggest gains from headers are in the middle of the curve where you drive most and you can't tell the difference between 1 7/8 and 2 inch, on the dyno graph or in the car.

Unless your Racing you won't miss the 5 HP at 6300 RPM, your not there enough to use it on the street.

Hope this Helps"

redbird555

WideVette

Sorry! My bad! I forgot you have the bigger d!ck so only your opinion matters! Forgive me, Master!

redbird555

WideVette

As I said, my bad, your good. Happy New Year!

HOXXOH

Still kinda hard to explain the quickest LS2 and LS3 bolton cars both running 1.75" headers, isn't it?

redbird555

Dano523

Yep, tube id size plays second fiddle to actual collect design and how well the header is scavenging the tubes in the first place.

Hence we take something like the below collector with its velocity spike, which will create a great bernoulli effect to scavenge the other tubes,


While a collector like this could be a ***** show instead,


Hence it boils down to the bernoulli effect of the headers, so it stems all the way back to collect and how well it going to do its job firstly creating the needed vacuum effect in the other tubes as one tube fires through it too draw the exhaust out of the other tubes, , then how well it will scavenge the volume of the header pipes from there next (at what exhaust speeds/volumes as well).



So if you use the graph listed in the other link, then there is something wrong with the torque curves, since if the tube lengths are all the same for all the header tubes, then the smaller diameter of the tubes should have the exhaust gasses traveling through the collector faster at the lower RPM's, and will create more HP and torque lower in the RPM range instead.

Hence this is the trade off with tube sizes, being the wider more volume of the tubes, the slower your going to have the exhaust flow through the collect to start with, and it will have more power upper end instead. With smaller tube headers of the same length, its the lower rpms that the headers come on line faster, and depending on the tube size if too small, will be paying the price in the upper end isntead.

As for max HP, it just that, being only used for a brief second before you shift, and what matter more, is the entire power you are making through the working power band of the RPMs you going to running instead.

HOXXOH

Thanks for that Dano. I think we both know there are several more factors to be considered when choosing exhaust systems than just primary tube size. The only thing that dyno test did, was to show differences by the same manufacturer on a car with no supporting mods. Dynos are only a stationary tuning tool anyway. Timeslips tell a more accurate story of real performance.

Dcasole

Now that was funny ....

Dave