Headers vs Cat delete pipe

[3 Z06ZR1]

Lots of noise on the web about the cat delete pipe being as good of a performance mod vs Headers... Anyone with experience with both mods know better . The 2 inch Jethot Coated ARH with these are about a 37-45 rwhp hp mod in the times I had installed them on the Corvette's then dyno tuned.
Some are off base and say the cat delete pipe is as just as good.
Anyone with real car experience from about 40 plus years of modding know this is absolutely untrue.

They also change the factory xpipe with cats and add an aftermarket x-pipe.
Then call the two mods the together as a gain for the cat delete pipe. When even though it is two mods they call it as one. I personally have also seen the cat delete aftermarket x-pipe mod on Corvettes on the dyno they do not keep up with headers nor do they sound as good.
The coated headers also enjoy a cooler temps under the hood. In concert with the cooler running 2300. I drive around temps about 10-15 degree' cooler than stock.

[SheepDog]

It's to early to know cost and mod options for the C8. That said and acknowledged, it OK to guesstimate. How much cost will get increase HP in the C8? 50HP. 60HP.? Easy gain. harder gain? Increased overall performance?

First, a guesstimate on exhaust mods: what likely options and cost.
Second: turbo or supercharge?
Third: engine internals.
4th: suspension.
5th: Wheels and tires
6th: Other mods
7th: what or which is [and is not} a void of warranties?

What loose predictions off the top of the head and experience serves, anybody?

[ZORA 69]

One thing I do know if GM incorporates this New Electrical Architecture into the C8 that they have announced will definitely be in some of the Cadillac's for 2020 and rumored to be in the C8. Altering anything as far as performance with aftermarket performance products may and most likely will be ECU unfriendly.

[SheepDog]

Motor Authority says the C8 is reportedly untunable, maybe.

Sean Szymkowski May 29, 2019


The aftermarket may have a tough go with the mid-engine 2020 Chevrolet C8 Corvette.

The mid-engine sports car has a "unique encrypted ECU system," according to a Tuesday report from Muscle Cars & Trucks. Per the report, any changes in the pursuit of more horsepower to the ECU will be a difficult task, if not impossible.



2020 Chevrolet Corvette (C8) spy shots - Image via S. Baldauf/SB-Medien

It's worth noting the 2020 Corvette will likely be one of the many new cars from General Motors to use the automaker's new electrical architecture, which has been floated as one of many reasons why the car was subject to delays. The "digital architecture" not only boosts output for future in-car technologies but also puts a major focus on cybersecurity. The latter is reportedly one of the major roadblocks to ECU tuning.

In the event re-programming fails, the mid-engine Corvette will enter a "recovery mode." Like a rolling computer, the car will need to be rebooted. Those who don't have the resources to restore the car's ECU will be left with a "bricked" sports car, sources said.



2020 Chevrolet Corvette

ECU tuning is often an essential means of squeezing more power from a car. It can be as simple as unlocking more power from the parts that are already there or retuning to match new parts, including new or larger turbochargers or superchargers. Yet, where there's a will, there's a way. That way may involve a few bricked mid-engine Corvettes along the way. The Corvette has always been a prized car for aftermarket companies to tinker with. This time, they may not be able to crack into the ECU and if they can they will have to be careful not to brick the C8.

The 2020 Corvette will—finally—debut on July 18 in California. The common thought has been that the car will come with an upgraded version of the Corvette's current pushrod 6.2-liter V-8 making about 500 horsepower. However, the Muscle Cars & Trucks story expects the engine at launch to be a dual-overhead cam V-8 called LT-2. It was previously speculated that a DOHC V-8 with a flat-plane crank would come later and make about 600 hp. Rumors also suggest a twin-turbocharged V-8 and even a hybrid powertrain are on the table. The latter could sport all-wheel drive with its electrified running gear.

[John]

It's to early to know cost and mod options for the C8. That said and acknowledged, it OK to guesstimate. How much cost will get increase HP in the C8? 50HP. 60HP.? Easy gain. harder gain? Increased overall performance?

First, a guesstimate on exhaust mods: what likely options and cost.
Second: turbo or supercharge?
Third: engine internals.
4th: suspension.
5th: Wheels and tires
6th: Other mods
7th: what or which is [and is not} a void of warranties?

What loose predictions off the top of the head and experience serves, anybody?

Used to be sizable gains with headers, but just like intake systems, the OEMs are now smartly stock engineering every morsel of power they can out of them. Of course OEMs do have some things that work against them, such durability and emissions and fuel economy, but even then, there is IMO very little to be gained from either unless one is going to also tune the motor.

However over time, GM’s engineers also learned more, e.g., the 2018 announced, factory-warranty-compatible new performance intake system which developed between 0 HP more in the Stingray all the way up to 17 more HP in the ZR1.

Since we are allowed to guess, I believe that we will only have one 2020 one performance option, option code NPP, “performance exhaust,” and that it too would be worth another 5 HP for the LT2. Cost will not be separately identified nor purchasable IMO, as it would be part of the $5,000 Z-51 package (with suspension, eLSD, and many other upgrades).

Also guessing, I am thinking the LT2 will produce, 507 HP, 503 TQ (not even a scientific but a wild ___ guess).

No internal engine mods available from GM, nor anyone else the first year unless someone finds a way to hack into the ECU — and then bye, bye warranty.

There will however be the typical claims of greater HP though lower restrictive air intake systems. Maybe even dyno results on those.

Guessing that there will be about six months after the car starts to get into exhaust company hands, that there will be dyno results of 5-10 more HP from their less restrictive cat back mufflers. (But those pulling cats, not just emissions issues but also warranty issues come into play.

Tires and wheels I expect to see about two/three months after the cars arrive in customer hands, but unless we are talking about all carbon fiber wheels, the consequences of improving performance are minuscule IMO>

And lastly, the typical smaller crank pulleys will become available roughly the same three months later.

[meyerweb]

The manufacturers of catless x-pipes for the C7 only claim about 5 - 10 HP gains. A good set of headers and matching exhaust, and a tune that takes advantage of them, will get you far more than that. The C8 exhaust is going to be more interesting. There's not much distance between the heads and the mufflers, so I doubt there's any sort of x-pipe there, and I wonder if there's room for 4 cats like on the C7. There may be only one per side, and if so removing it would definitely throw a code (on the C7 you can remove the smaller secondary cats without a code, but not the main ones). I think playing with the exhaust and keeping it streetable is going to be harder on the C8, especially if what we're hearing about the encrypted ECU is true.

Catback systems seem to work fine on the C7 without changing the ECU. Probably not ideal, but acceptable. The same may be true for the C8.

Any aftermarket headers will likely need to include, or retain compatibility with, catalytic converters. A cat back system might be the most cost effective solution to getting more sound, but probably not a lot more HP.

Of course, I'm neither an automotive engineer nor an exhaust specialist, so I'm waiting just like everyone else to see what the reality is.

Regarding NPP, that option is available as a standalone on "base" model C7s, and I would expect it to be the same on the C8. It seems to be a very popular option. Almost everyone I know who has bought a Corvette in the last few years has the NPP, even if they don't have a Z51. GS, or Z06.

[John]

Thank you meyerweb.

[3 Z06ZR1]

It's to early to know cost and mod options for the C8. That said and acknowledged, it OK to guesstimate. How much cost will get increase HP in the C8? 50HP. 60HP.? Easy gain. harder gain? Increased overall performance?

First, a guesstimate on exhaust mods: what likely options and cost.
Second: turbo or supercharge?
Third: engine internals.
4th: suspension.
5th: Wheels and tires
6th: Other mods
7th: what or which is [and is not} a void of warranties?

What loose predictions off the top of the head and experience serves, anybody?

Just a guess because it is wait and see but my thoughts are.
The C8 will be held back from much mods at all. Like the lt1 the lt2 with cast parts it will not be not real mod friendly like the Lt4/lt5 which are the same less different blowers. Current Lt1 is and the lt2 will be and are fragile to large power increases. Then the likely lack of tuning.

Where the Lt4 is the greatest GM engine ever and a power producing brute many hitting over 1000 rwhp. Hate to say the C8 will be power handi capped. Those wanting more power more should wait to see what the C8 Z06 brings. Unless the C8 comes in lighter weight than the C7 which I think it will be heavier.

[John]

I respectfully disagree that the LT1 has been fragile to large power increases. I have friends who have put on super chargers, getting HP over 600 on their LT1’s — without an issue, and some many tens of thousands of miles since they did so. Many LT1’s have been expertly tuned by Lingenfelter, by Callaway and other top notch engineering firms.

I also disagree with your predicting the LT2 would be fragile. We get it, that you are Z06 ga-ga, and we are excited you are that enthusiastic about the Z06, especially its motor (I love my Z06 too); however, there is no need to run down the C7’s LT1 motor, nor the C8’s LT2 motor.

[3 Z06ZR1]

I respectfully disagree that the LT1 has been fragile to large power increases. I have friends who have put on super chargers, getting HP over 600 on their LT1’s — without an issue, and some many tens of thousands of miles since they did so. Many LT1’s have been expertly tuned by Lingenfelter, by Callaway and other top notch engineering firms.

I also disagree with your predicting the LT2 would be fragile. We get it, that you are Z06 ga-ga, and we are excited you are that enthusiastic about the Z06, especially its motor (I love my Z06 too); however, there is no need to run down the C7’s LT1 motor, nor the C8’s LT2 motor.

The Z06 is finest Corvette made no reason not to go gaga!
Noted not running down anything just shedding light on the truth the lt1-2 compared to the Lt 4/5 are less robust since they use cast pistons not forged plus the crank and heads not as robust . The lt4/5 is over 2-4 times the cost.

I say that with experience with the lt1 and good knowledge of Superchargers and Corvette V8's . My 2014 Z51 had a supercharger installed at the Company owners shop, installed and tuned by the owner. Only supercharger kit ever I didn't install myself.

The car rolled out with 600 rwhp that afternoon I drove it normal and with in 25 miles it failed to barely make it home with oil coming out the hood seams about a quart every minute it ran. My tuner said tune was a few degree's too much timing to be safe probably a broken ring. I sold the car with fewer than 10k miles on it.

Normal max output for boost with the lt1 is 570 rwhp proven more that is trouble Nothing was offered to help they knew they blew my motor. . I no longer do any business with them. IMO After a lot of C7 experience Most good shops will not recommend boosting them anyway with out at least a piston change.

Not boosted I would agree and say they are very good engines and plenty robust but not when it comes to adding boost/high power increases they are simply not designed for it with the high compression they run. I don't see anyone boosting the Lt2 but I could be wrong.

[meyerweb]

^^^
A sample size of one proves nothing.

The owner's shop or not, What you describe is an assembly error, and more than just a timing misadjustment. An engine driven "normally" does eat a ring or blow oil out in less than 25 miles. They probably didn't torque the heads correctly, distorting the castings or something similar.

As John says, there are a great many modified LT1s on the road with zero problems. Callaway warrants it's supercharge installation on the LT1 for 3 years / 36,000 miles.

[JB]

I prefer catalytic convertors on the cars these days...they really dont hold back exhaust flow or hp..might as well be conscious of our responsibility to the environment...

here in nj its a ten thousand dollar fine to the shop who removes a catalytic convertor...

better to buy headers if you feel you need more flow...

jmo

of course Im pretty much done with tuners after my debacle of unreliable ls6 motor in my c5 z06.. at 65k of daily driving it blew...

i dont need that nonsense and I hated the tuners keeping the car forever...didnt matter how much money I threw at that shop thats now closed....

they couldnt get my god dam car out of the shop and it ****ed me off...

after that nonsense i swore off modding into the engine...just pain in my butt...

want more power do a few bolt ons if you must...or just buy the factory higher performance version...

bolting on the bigger supercharger seems like a smart move too...

but i do have to say since gm is warrantying track time on the stock setup...

thats my personal favorite...

best mod in my opinion is driver skill

just my two cents although i do understand the allure

your two z06 s are awesome and I always enjoy your informative threads.

[meyerweb]

best mod in my opinion is driver skill.

And for some of us, a driver diet.

[3 Z06ZR1]

Back on topic! I sold my 2015 Z06 to a friend and now we have a direct comparison and the result is similar to what I saw before.
This pretty telling when it is the same car, same dyno, same tuner ( improved 2017) stock blower as well. Apples to Apples
The Header car with cats produces a more power than the cats delete pipe with no rear cats. Car also had the Halltech intake, smaller upper pulley, cat delete pipe
and deleted x pipe cats and after market radiator cooling tank.

Same car w/ Halltech intake, ARH headers, stock pully tune made 42 rwhp over and 7 rwtq less the vs Halltech/ cat delete mod/pulley route w/ tune.
Headers are the number 1 mod!

[meyerweb]

Agree. A cat delete pipe probably adds a few hp at peak, but mostly it's about adding a little more sound. Which is what a lot of people really want.