ARH Catted Extension Pipes

[CountingZs]

Picked up a Z/28 about a month ago and still have a learning curve (last 5th Gen was a 2010 SS when they were first released). Knew the car had ARH longtubes, but just now realized the "high-flow" cats are welded into a 3" X-pipe instead of separate extensions.

Have a Corsa 14971 system arriving tomorrow, and hoping to avoid cutting the cats off of the existing X-pipe. Has anyone found a way to order just the 3" catted extensions (part of their "short system") from AR or any other vendor?



https://americanracingheaders.com/co...market-catback

[CountingZs]

Quick update: Nick (ARH owner) just reached out and is getting me squared away on Monday. Talk about customer service!

[1JEWLDSSRS]

Originally Posted by CountingZs

Quick update: Nick (ARH owner) just reached out and is getting me squared away on Monday. Talk about customer service!

That's cool!! And you are going to love that Corsa catback! It's the one I have on my Camaro.

[void_kp]

Interesting thread, I am also new to the z/28 but more than that I am new to the US so some of the tuning "jargon" is unfamiliar to me so I am unsure about the various components I am browsing on the web. I wonder if you can help me out.

After the summer ends in the pacific northwest I plan to fix the heads of my LS7, just to put some pace to my heart. For very strange reasons I find myself with a TSP cam and everything that is needed to install it (gaskets, pushrods, etc).
I have 3 problems:

1/ I don't understand (yet) which "fix" is needed to prevent the valve drop. What needs to be done to the heads?

2/ Once I install the cam I think it will make sense to install headers and tune everything up, I am looking for drivability more than power, I don't care if I lose 10hp to make car drivable. I will use the car on track only but I need to drive there, in traffic. I'd like to keep my cats on to avoid the hassle of putting them back on for inspections, which headers/exhaust combo would you suggest?
2.1/ to tune the car, do I need to replace ECU or is the stock one re-programmable and "good enough" ?

3/ I don't plan to fix heads or install everything myself so I am looking for some trusted/trustable shop to do it at a reasonable distance from Seattle (WA). Any recommendation?

[CountingZs]

Sorry for the delayed reply, just getting caught up on hobbies after several work trips.

Nick and the ARH team entered an order for 3" catted extensions within minutes of me reaching out. Corsa 14971 and MGW short shifter are patiently waiting for them to arrive...

1JEWLDSSRS, if the sound is half as good as those tips look I won't be disappointed! If only this car had the same TSP Stage 3 yours does...

void_kp, I'm still trying to get back into an LSx frame of mind having been on the LTx platform for several years now. Others on this forum will absolutely have better insight than me, but my .02 cents below:

1) Valve guide tolerance is the main culprit with LS7 heads, even new-in-box from GM today. You will want to ensure those are sleeved, and also dial-check the valve stems depending on mileage/hours on your engine. Most throw in a cam and look at an MSD or Fast intake since having the heads off make those jobs much easier. If I didn't have a crazy protection plan (in writing!?) for 10yrs/100K, I would consider the same.

2) This car came with America Racing 1-7/8" longtubes and a catted AR 3" x-pipe mated up to the factory NPP mufflers. That is more than enough for a mild NA build, but if you are considering forced induction or E85, I would look a bit larger for enough overhead. Tuning can be done by any reputable LSx shop with the existing ECU. I'm running cats simply to keep my wife from passing out at stoplights.

3) Used to live in Renton 15 years ago and used Carb Connection (https://carbconn.com) in Kirkland for tuning my race cars (2008 C6, 2010 Camaro SS...both non-catted). Am sure a lot has changed, and plenty more vendors available, since then. But I was pleased with the outcomes on both cars.

[1JEWLDSSRS]

Originally Posted by CountingZs

Sorry for the delayed reply, just getting caught up on hobbies after several work trips.

Nick and the ARH team entered an order for 3" catted extensions within minutes of me reaching out. Corsa 14971 and MGW short shifter are patiently waiting for them to arrive...

1JEWLDSSRS, if the sound is half as good as those tips look I won't be disappointed! If only this car had the same TSP Stage 3 yours does...

void_kp, I'm still trying to get back into an LSx frame of mind having been on the LTx platform for several years now. Others on this forum will absolutely have better insight than me, but my .02 cents below:

1) Valve guide tolerance is the main culprit with LS7 heads, even new-in-box from GM today. You will want to ensure those are sleeved, and also dial-check the valve stems depending on mileage/hours on your engine. Most throw in a cam and look at an MSD or Fast intake since having the heads off make those jobs much easier. If I didn't have a crazy protection plan (in writing!?) for 10yrs/100K, I would consider the same.

2) This car came with America Racing 1-7/8" longtubes and a catted AR 3" x-pipe mated up to the factory NPP mufflers. That is more than enough for a mild NA build, but if you are considering forced induction or E85, I would look a bit larger for enough overhead. Tuning can be done by any reputable LSx shop with the existing ECU. I'm running cats simply to keep my wife from passing out at stoplights.

3) Used to live in Renton 15 years ago and used Carb Connection (https://carbconn.com) in Kirkland for tuning my race cars (2008 C6, 2010 Camaro SS...both non-catted). Am sure a lot has changed, and plenty more vendors available, since then. But I was pleased with the outcomes on both cars.

Thanks! When you do get your Corsa system and open the box and unwrap it all, you will be REALLY amazed at the quality of the system! I was, and couldn't wait to get it installed! It is by far the best system I have had on my Camaro. Been through about 8 different configurations and ended up here! Here is a short video clip of it, the second video. Turn up the volume!! lol.

https://www.facebook.com/groups/cama...8562174322335/

[CountingZs]

Sorry for the delayed update. While it's unlikely this thread will see much traffic, figured some may wish to see how things turned out if any Z/28s end up changing hands over the years.

The extensions pictured above were not what I received from ARH, despite articulating this over the phone and via email. I ended up with another set of the angled pipes already on the car, but being MAO, I was stuck with them.



To complicate things a bit more, the Corsa 14971 system has a reduced inlet on the elbows. I called their customer service team and they do not offer a 3" female end option.

So, with 304 being near impossible to flare out once formed, and a set of incompatible extensions, ended up working with a local shop to cut the catted ARH extensions already on the car, as well as the inlet adapter on the Corsa elbows, and weld those up.


Note: I have no idea why some of these pics are rotated?

Having had a few of these clamps loosen on other builds due to temp swings (and midwestern weather), went ahead and welded the elbows, X-pipe and outlet extensions into one piece. Mufflers are still banded, as are the catted extensions at the collectors.



I know some are not fans of black tips, but for those who are (like me), they really complete the look. Apologize for some of the "wet" shots, as ran into a thunderstorm on the way home. Just some perspective on how well you can tuck these; plenty of runout if you want the tips to protrude instead.







Sound is incredible, exactly the open/throaty tone I had hoped for...plus more decel burble/pops. Zero drone cruising (even with LTs), which blew me away. Idle is a tad quieter than the Z06 (secondary cat delete, BBE X-pipe and Corsa Xtreme), but WOT is a dead heat. Will try to update this thread with coldstart/idle/rev videos next burst of spare time.


1JEWLDSSRS, spot on with Corsa's quality. This is my sixth system (C6 vert, C6 GS, C6 ZR1, 2017 Sierra, C7 Z06, Z/28), and the attention to detail is impeccable every time. I wish I had your TSP stage 3!

[NoDakZ/28]

Looks great, can't wait to hear it! I'm ordering ARH 2" LT, high flow cats and their 3" exhaust for my Z soon.

[1JEWLDSSRS]

Very awesome my friend!! Sad that you had to do all THAT extra work on the connector pipes! But all in all looks like it turned out very well!! And yep, it is an awesome system with the sound AND in fact that there is absolutely NO drone at cruising, is why I purchased mine. And I too like the lack tips, almost went with them at first, was a toss up on them and the polished, so I went polished since my Camaro was asking for them. lol. But yeah, yours with the white and black just looks right. And as for the cam. she does get a LOT of attention when I pull up to the shows and cruises!! Who knows, maybe one day you will want to cam yours! Nice job sir, and awesome looking Z28...

[void_kp]

void_kp, I'm still trying to get back into an LSx frame of mind having been on the LTx platform for several years now. Others on this forum will absolutely have better insight than me, but my .02 cents below:

never thanked you for your answer. I really appreciated it.

[CountingZs]

Not the best videos, but they give you an idea of how much more open/throaty the Corsa 14971 is, especially once the camera angle comes up a bit in the second one:

American Racing 1-7/8" to 3" longtube headers, high-flow cats, 3" American Racing X-pipe to stock NPP mufflers: https://youtu.be/_9_-JYugmXg


American Racing 1-7/8" to 3" longtube headers, high-flow cats, Corsa 3" X-pipe and Sport mufflers (14971): https://youtu.be/X5PyvFd7eOg

Once warmed up, volume iis about the same for both while the Corsa has a notably lower tone. Makes the stock cam sound much more aggressive...can only imagine more lope with this setup.

Will try to get some quality driving video, as the decel burble/pops are great and WOT is insane. Inside the car, probably 20% louder...but closer to 50% louder outside.

[CountingZs]

Originally Posted by void_kp

never thanked you for your answer. I really appreciated it.

I probably raised more questions than answers, but you are absolutely welcome. Camaro5 and CorvetteForum have incredible folks who really do care about helping each other out. So much experience to pull from, and it really makes this hobby more enjoyable.

[1JEWLDSSRS]

Originally Posted by CountingZs

Not the best videos, but they give you an idea of how much more open/throaty the Corsa 14971 is, especially once the camera angle comes up a bit in the second one:

American Racing 1-7/8" to 3" longtube headers, high-flow cats, 3" American Racing X-pipe to stock NPP mufflers: https://youtu.be/_9_-JYugmXg


American Racing 1-7/8" to 3" longtube headers, high-flow cats, Corsa 3" X-pipe and Sport mufflers (14971): https://youtu.be/X5PyvFd7eOg

Once warmed up, volume iis about the same for both while the Corsa has a notably lower tone. Makes the stock cam sound much more aggressive...can only imagine more lope with this setup.

Will try to get some quality driving video, as the decel burble/pops are great and WOT is insane. Inside the car, probably 20% louder...but closer to 50% louder outside.

Man that Corsa sounds really great!! Kinda sounds like it has an aftermarket cam in it already!! Very cool.

[1JEWLDSSRS]

Originally Posted by CountingZs

I probably raised more questions than answers, but you are absolutely welcome. Camaro5 and CorvetteForum have incredible folks who really do care about helping each other out. So much experience to pull from, and it really makes this hobby more enjoyable.

Amen to that!! I have learned soo much on here in the 12 years I have been a member, and have helped countless folks out as well with all I have been through, and learned. Really cool!!