I would venture to say the ones that were on your car are toast, and fall into the "single use" category.

You can throw the stock pipes back on if things go wrong, technically, the less restriction is easier on a motor. So for GM to say it hurt your motor, will be a farce anyway.

you have a z06 too correct? Not saying your data is irrelevant, just trying to keep info categorized in my brain.

you have the big daddy sims, correct?

if so, I will continue on out theory of what your light is and why it is generated.

short story is, car does not just use 02 sensors to calculate cat temp, they also use algorithms that monitor engine temps and wot duration times.

if those don't match the 02 readings, it assumes there is a problem still.

Oh, well then yes, if you have cats on downpipes, car is mad because you are melting them.

1/2 miles of wot and they are molten.

your car is in COT mode by the quarter mile

I was out driving with Mike 2 nights ago.

first of all, he is fast as hell.

second, you should see what he has done to his stock cats on his z06... he has photos like poorsha of the first time his pipes ruptured/melted around 6k miles.. he runs wot for miles at a time sometimes, and his car is totally stock.

However, he has not had them fail since, so...

we think he melted out his cats as his car is louder than a stock z06 with the baffles open or closed, apples to apples...

and his car is also about as fast as my zr1, and his car is a stock z06.

once the restriction is removed, the pipes no longer rupture we believe.

his stock car screams with the baffles open. But he wishes it were silent he says. We like it, he hates it.

You ABSOLUTELY want headers with 2" primaries at that. The reason long tube headers make more power for a variety of reasons. I'm going to keep this at the 1000' level for simplicity and not delve into the sub layers of complicated physics and thermodynamics. To keep it simple, you have a top mounted PD blower that can jump to peak boost in a second and you NEED to remove those exhaust gases as expediently as possible for a few reasons - cylinder sleeve, piston face, ring, and valves.

LT header benefits:

• Primaries
• Collector
• Secondary Diameter
• Cats (if necessary)
• X Pipe placement
• Weight

Primaries - The reason header companies keep making larger primaries is simple, in this case, if designed properly BIGGER IS BETTER. ARH now has a 2-1/8" primary! A 2" primary moves approx 280cfm. Longer primaries result in more low and mid length torque as well, which a PD blower doesn't necessarily need; however, why would you pass that up if you have the tire to hook it? I'll take it, thanks! :)

Collector - Very few companies make stepped headers or tri-y headers, so what we see here is a merge collector which merges all 4 primaries on each side into 1 taking advantage of the Venturi effect, which coupled with the primaries increase power and torque at all RPMs. The magic inside the merge collector is the scavenger spike! This is a long spike in between all of the primary merge pipes which helps to channel not only the exhaust gas scavenging, but also the sounds as it reduces the turbulence, since there are usually "hot" cylinders (leaner AFR) on each head that channel more air due to the flow from above. This was why you saw the Eaton 1740 supercharger redesign with the taller bricks to change the airflow to the back cylinders.

Cats - Aside from the legality issue of removing cats, OEM cats are NOT rated to higher boost pressures and as road racing guys find out, the OEM cats can blow out as they get hot. This is EXTREMELY dangerous if the cat collapses internally because the air has no where to go and thus the heat cannot escape the engine and you will usually melt a piston or worse. Most header companies high flow cats are NOT up to more than 10 psi of boost pressure either and you guys buying headers with cats need to do your research. I have seen SW, AR, and Kooks regular cats start to push out. The ONLY ones that I have seen hold up to high HP and boost is Kooks Green cats. We cut these into a Whipple LT1 Escalade we did that was making 760whp and it lost NO HP afterwards. The guy "bought his wife" a new truck and modded it for her and she hated the smell. After that, he brought it back in for service a year later, it had 25,000 mi on it already and it didn't skip a beat! Laid down nearly the identical number it left with (despite the engine bay and inside looking like they spent some time in Desert Storm LOL). I am running these same cats on my ZR1 with NO whp loss at 794whp!

X Pipe - OEM mfgrs usually put their x pipe towards the middle of the car for emissions, whereas the best placement for the x pipe is as far forward as possible so you get exhaust gas cross over as hot as possible. This is a reason the Corsa x pipe makes better power than the Borla as well.

Weight - self explanatory, the OEM flanges, piping, cats, resonators, etc are all heavier than the aftermarket metal

Coating - not on the list, but I always coat them because you want the exhaust gases as hot as possible inside to keep it flowing as fast as possible.

All of these are simply irrefutable and despite the debate having been weighed over and over, it has been proven over and over as well. Show me a car with OEM manifolds and cat delete pipes and you're showing me a car that's leaving power on the table. Some guys have their reasons and that's fine, but if you're out for power, it's headers... period. Don't believe me? Go try to run a mile breathing through a straw :)

;)

yep... you don't see headers with cats blowing like that :)

I am not more confused than when I started reading this thread. Ben, what are you recommending for a ZR1 that is going to hold up to heavy track use, is warranty friendly, and a reasonably easy install? Ideally I'd like to keep the cats and clearly a tune is out of the question. I'm not worried about capturing the last 10 HP.

NA vs FI
 

Here's another (kiss) perspective for your consideration.

* Four exhaust holes on each head that are a certain size.
* Four exhaust manifolds or header 'tubes' that are the same size or larger.
* At the end of the 'short' exhaust manifold tube you have the collector which is plenty large for each of the 'individual' pulses coming into that large open area (not all four cylinders fire at the same time). You have about the same thing with headers but the straws :D are longer.
* I have read from many sources/experts over time that Naturally aspirated (NA) engines require a 'tuned' exhaust (to produce the most HP taking everything into consideration) which is accomplished by adjusting primary tube size and length for the best power. Header tuning also entails pulse/venturi, etc. to help pull extra air into an engine by hopefully pulling a vacuum for the cylinder that is filling. Well a NA engine and a Forced Induction (FI) engine are two different animals because the air is being force under pressure (not vacuum) into and out of the FI engine so all that tuning of the exhaust system is not 'much' of a factor if the exhaust system is sufficient (large enough) to handle the exhaust flow.
* Like another 'vendor' on here has said, they 'found' on their 9 second set-up that adding headers to their package did little if anything to increase power so they do not recommend headers unless the customer wants them. :cheers:

PS: Cats can and do restrict flow once you reach a certain level (or melt them) and some cats evidently like the 'Green' cats have a higher level which is a good thing to know if you use aftermarket cats. :thumbs:

Poor-sha was the converter core itself fine or did the core of the converter have any melting or disfigurement.

Ben posted the real story! 2 inch ARH header vs stock exhaust only someone with NO clue what so ever on our supercharged Z's They have no idea or experience just a guess "what they heard" would think the stock exhaust manifold does anything as good as the header! I guess it flows about 60 percent of the CFM of the uncorked header!
The ARH cat is better and flows more than the Kooks regular cat never tried the green cats. You can see the difference. I do know the answer you want to run the cats.? If you 1/4 or street race your fine not going to hurt the ARH cat from street use.
use Track use? I have no Idea guys say you can I believe them! Run the car real hard extended use on the track? swap the xpipe to no cats
Thanks for playing!

Makes sense! ZR1 vs stock Z06 with melted out cats the Z06 is about just as fast? Sure it is!

Was out with him the other night. Made me realize it's true that money and a fast car does not mean one will win the race. I've known a lot of fast drivers in my life, and I can drive... but he is on another level.

One might think they have a fast car, but when he turns on the jets, he just loses everyone, never before in my life have I been going my fastest, and completely lost sight of someone... when they are in the slower car. The guy can drive, and curves and traffic are his friend. He is in his element. How he has never gone to jail, is a paradox all in itself.

you might think a straight line, you can beat him... but I hope you are prepared to drive 180mph for 30 miles, because he does. Sane humans give up every time.

I bought a manual trans, and while I am glad I did, he makes me realize I will never be as fast as he is while driving an automatic 95% of the time.
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Oil change 500 miles, supervising in case they messed up

While I respect Ben and their shop does great work, I respectfully disagree, and especially when he talks in absolutes and starts his comment with the word "absolutely"

in fact, I have read no threads where Ben has tested the catless downpipes on his zr1, so to use a word like "absolutely" and favor one so much over the other... without a fair test between the 2 style pipes, does not bode well with me personally, at all.

Frankly, you could not pay me to put LT headers on this car... everything that Mike and Hess say checks out... factual data and evidence are behind everything they have taught me.

check engine lights, and it's a no brainer... I want nothing to do with LT headers. They see the big picture, and I know for a fact the crew members at weapon x have told Mike on the phone that their computer on their zr1 locks up at times, and they don't know why it happens and they have to reset the car. That means it could be the headers it is mad about. They did not seem to know at the time of the convo. Maybe Ben can shed some light on why their zr1 did this and how they have solved it.

I am glad I met Hess and Mike. I will be reducing my Underhood and engine temps with the wrapped catless downpipes. Those that add long tube headers will be increasing temps. They showed me enough data on real apples to apples cars, from the track and on the street.

they share a small percentage of their data here on the forum.

these guys are mad scientists. Most of the time they laugh at the stuff they read here and don't argue.

keep in mind, while all shops and members are still doubting Mike will lemon his car, I have seen video of him put other random strangers z06 into limp mode at high speed. He can do it to any car on command. He's milking the miles as he know he gets a brand new one as soon as he files with BBB.

He is going to see what my zr1 does once it gets colder out down south here. He says if the zr1 does not go into limp mode in the cold... then, I should be fine with a ported blower on the stock tune when it is hot or at higher altitude. He crunches numbers in his head with pressures etc, I have to get out a paper and internet calculator to follow what he calculates in his head in a matter of seconds... and every time that I double checked his math, he has been right, and it takes me 2 minutes or more to fully grasp what he understands in the blink of an eye.

he respects certain vendors on this forum a lot. He and Crawford racing have some stuff brewing.

if big shops were smart, they would be having people like Mike and Poorsha testing their stuff... These guys put cars through a hell most of the rest of us can't.

If i were you, I would stop doubting Mike so much and instead try to meet the guy... and try to keep up. Literally.

he loses people quickly in more ways than one. He has an extremely low tolerance for bs or false info or unwarranted arrogance.

I'll likely end up in jail of I keep tagging along with him :steering::_dupe:

or maybe I'll stay out... somehow he rides in the police chopper at least once per year. I've seen his videos on his cell phone of him inside, flying around and talking back and forth with the pilot.

he knows how to get his way and thinks life is a video game he says. It's foolish to be his enemy, when being his friend is a blast. I come home, reflect on the things we did, and I laugh to myself.

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but, according to very intelligent members of this forum, Mike and I are the same person, and I just drive 2 corvettes around at once.

I've taken split personality to another level apparently. I should start a reality tv show. Put David Copperfield and David Blaine out of business.

Ever have a moment where you wish people understood how little you think of them and their opinions of you? Some of the members of our team are at that point with a couple people on this forum.

Who's Mike?

That really doesn't have anything to do with anything, since not all stock exhaust manifolds are created equal. The stock Z06 manifolds are supposed to be pretty good. And they have much less heat radiating surface area than headers, as well as heat shielding.

exactly.

especially a catted LT header.

the power comes from less restriction. A catted header vs an open downpipe... It's no contest in my eyes. The catted header loses in every category... and especially heat under the hood.

we live in south florida. The guy arguing lives in a state where it's been below freezing already this week.

I'm tried of people thinking they know all, who keep arguing with the people who drive their cars hard, and those arguing with us provide no scientific logic or data to justify their claims.

hess took the time to explain what Mike knew for years.

if you go back through this forum, and the older threads, you'll see that someone has countered Mike every step of the way on the downpipe vs header debate.

that person says "WRONG" an awful lot to members of our team and other people on this forum, who we, and the real data, both agree with.

I would venture to say if we ran around the forum typing "WRONG!" After every other posts people make, we would be banned.

LT headers radiate more heat than an apples to apples coated catless norcal or AFE. It's a fact.

if any shop wants to do a fair apples to apples comparison and put up the data, we will happily observe and compare notes, and have healthy discussion.

but so far, no one has. We think it might have something to do with the profit margins on the LT headers for shops, vs the more direct sales business model of the norcal and AFE, where the shops lose out on profit.

it gets old being countered by people, who we believe are wrong, but we just keep tollerating it, without writing WRONG (followed by no convincing logic) after every other post they make, as they do to us. If I were a forum moderator, I would try to shake hands with Chris Crawford and Mike, and whatever behind the scene loyalty you have to the members who cross either of them, will quickly evaporate. They are 2 guys you want to know and want to listen to.

hopefully those reading understand, I have zero skin in the game. I have no reason to lie. Norcal are going on my car, i have seen their performance logged on other z06, i am impressed, and I'll let you know how it goes on my zr1

good question. Hess and I are still trying to figure it out ourselves.

There is more to him than meets the eye. The best way to put it, he plays possum.

and then once you are convinced he is normal and lame... he does something you can't even tell your friends about because they will think you are lying.