2020 C8 Corvette These Headers Lost Power Over Factory Ones... UGH!

[@completestreetperformance]

I wanted to give everyone an important follow up, Kooks called me about these disappointing results. In our discussion, they let me know that the downsize to a 2.5" flange was intentional because the factory cat flange is apparently the same 2.5" inlet and they wanted to avoid a rough transition. I will verify that size in the near future when we do our follow up tests. The box was mislabeled. Additionally, we will run the car again before replacing the cats with the kooks cats to see if we get different results. And finally, and most importantly, kooks is happy to work with us to make sure their product does perform. So we may even test a revision to the product after all the tests are done. They seem committed to making sure the right product gets in all of our hands!

[@dirtysouthtv2209]

The stock header still has a larger exit hole. There is literally no excuse for under-performance. Kooks made a mistake at some point, and their best move now is to rewind, fix the mistake and send everyone out the new proper design THAT THEY TEST BEFORE THEY SEND ANYTHING ELSE OUT. There is nothing else to talk about.

[@jodadej]

Wow crazy it lost. I'd be so sad.

[@joobaggs6886]

you should try porting and polishing the factory headers. might gain a few hp!

[@CaptainNero]

Very sad... I would not be sending them nice emails or phone calls.

[@001dmike]

See what makes more power with proper tuning done. Looks gonna come out on top

[@patricksmith19716]

im glad that your calling these people out and not giving anybody free passes to make questionable products and try to pass it on to the public to make a fast buck ....love your integrity and honesty and keep up the good work

[@BenHayat]

That's because he paid for them. I wonder what he would say if the were "FREE".

[@lawyers9]

It’s great to see and hear someone telling it like it really is and not pushing a defective product!

[@stevenreynolds2327]

Maybe....GM engineers actually know what there doing.....hmmm

[@BarnfindGT]

Ik It’s not like they have millions upon millions invested in research and development 😂

[@completestreetperformance]

True, but even with that previous generations have been able to be improved upon...

[@GMbusa1]

Ok Karen

[@shannonsisk]

Gm engineers for sure know what’s up 🤙

[@BarnfindGT]

Complete Street Performance true I’m sure a properly designed header would pick up some power, like you said in the video the power loss is probably from the neck down in the collector. I think LTH makes a header for the c8 wonder if they actually pick up power vs the stock ones and kooks

[@DailyDownshift]

Glad you're being honest and transparent, saves people A LOT of money.

[@stevec9077]

I love the unbiased videos posted! Great comparison and thank you for the honesty.

[@julionavascues6642]

This also happened to CorvettesDirect

[@nickmoore4212]

Those stock headers look beefy lol

[@digital_art_froth874]

So glad we have people like you willing to burn your money in a trashcan so the rest of us don't have to, thank you

[@zioo3117]

Talk about timely! I just thought about or ordered the Kooks headers with their 20 horsepower gain. Kooks, was a bit foggy about the set up of their headers with regards to: factory cats; factory exhausts, etc. So the claim appears to be a 20 hoursepower and a torque increase with a straight Kook's swap without any other changes. I'm hoping that this presentation tells the truth about what the Kooks headers do or don't do and why. That's what I for one want to know (LT2/Z51) Stingray C8. AF

[@BlinkyBill_]

Emm Hartford going to be pissed

[@andrewstout777]

It sounds the same because you didnt put the Kooks high flow cats on it, 6 inches of extra primary isnt going to net much sound difference without changing the rest of the exhaust, as for the pipe diameter thats a crock of shit, it should be a full 3" which could attest to the power loss, thats just my take on it.

[@robertjohnson4784]

So you spend $1,000 or more on Kooks Headers to lose horsepower 😂 what the HELL. So it's time FOR CSP to develop a header for the C8. Also I'm glad that no cats were killed during the filming of this video.

[@mbsnyderc]

The factory header looks hard to improve on if you have restriction it's more likely cat back.

[@GoGoggansGo]

Most of the gains will come from deleting the cats or using a good high flow cat. It’s very difficult to make a better short tube header than what GM has already done. You would need to actually make real real tubes which isn’t possible on the C8

[@lsdemon7773]

Your the second person with kooks headers for the c8 that lost power. Hmmmm.

[@kumaquattro]

It can't be inexpensive changing those headers, and to lose HP after all that, now that's sad .

[@BansheeZR1]

The restriction, extra sound and power gain are all in the cats. The stock headers are very well designed.

[@ro63rto]

Just as well Emelia opted for their green cats then

[@user-tw9su8rb9j]

Looks like Emelia Hartford will lose to DDE after all after that smack talk 😂😂

[@mooojojojo4937]

Well hers included the cats, so she likely has different results

[@TxHammer757]

Maybe you should have put on the green cats from Kooks....then you would need to tune it

[@bluebomber697]

Wow... That is pretty shitty results. Thanks for the unbiased review of these. Super weird that they would release it with a smaller collector than stock. What a waste of money those would be.

[@cjennings4936]

So what your saying is leave the bolts on’s alone and Twin turbo it 😁

[@leebooker4216]

Richard holdener did testing on the new LT engine family and found that they didn't gain any performance from headers. Anyone looking to do performance mods should save their money and put towards something else. Actually saved a friend of mine from buying them and his tuner confirmed when he double checked

[@superchief15]

The heat shielding stopped part of the noise in the cabin! I’m listening to the dyno run on the Bluetooth hearing aids I wear due to my misspent hot rodding youth. The after production stuff can’t compete with factory headers the real engineers developed when the LT2 engine was riding around in the Holden Mule!

[@gustavo-gs6jy]

Kooks typically make good products, but there’s no denying the engineers at GM did a great job making them. Those are serious for OEM manifolds lol

[@kennethimpelmance9107]

I love a nice set of headers but honestly the factory set looked better than the cooks also.

[@2camsam]

Stock stuff is excellent

[@SuperSilvi1990]

I think it's more for looks than anything. They look way better in that engine bay. What I want to see made are some equal length headers for the C8 just to really confuse people when you drive by.

[@zioo3117]

Kooks made no bones about it. 20 Horsepower with the header as they constructed it. How on earth could a company like Kooks put a restriction onto their headers, putting a fastener that is the opposite, for example, of what porting and port matching does for any car? You used the words, "Bull Shit." I hope you send those headers back along with a scathing letter. Having just put my credit card order in, I'm not paying for, nor getting the headers. Now I know why they didn't answer my e-mail to them. This reminds me of the kind of BS that Hennesy pulled according to some former employees that appeared on a utube vlog. This also smacks of bait and switch. The appearance of the headers; the much longer unbent lengths; the smoother mandrel bends all appear to scream horse power. But a loss during the entire Rev range? Total BS. These people did not pay attention to one of the basics of automotive exhaust work. AF

[@ssoffshore5111]

I'd be pissed if I spent that kind of money and lost power and all that important heat shielding!

[@ssoffshore5111]

Oh, and the beefier OEM headers will likely outlast those Crooks headers!

[@thereissomecoolstuff]

You are the second or third to do headers. The biggest gain was 7 hp, 2 hp and then yours. I think chevy nailed the design and Max engineered the manifold. Just think you would have been perfectly happy if you gained 20 hp. for $1200 plus installation. Kooks couldn't do it. I'm not doing anything but porting the exhaust manifold. If I do anything to it. It's pretty badass for massed produced.

[@cudavrage]

Corvette Direct only saw a 5hp increase with the green cats and headers from kooks... 🤔🤐💣

[@travish9334]

Maybe the cats are worth +10 HP, and the headers are worth -5HP, giving a net gain of +5.

[@Properwraps]

Have you tested the American Racing Headers?

[@completestreetperformance]

I would be happy to do so. But check out the more recent Kooks video, they now have a two inch version that picked up great

[@dannyh5700]

I wonder if American Racing has a better product coming.

[@hogrod]

Those stock headers appear to be a tri-y design not 4 into 1 like the kooks. Tri-y will always outflow due to exhaust scavenging working better when the pipes match the engine timing.

[@markjmaxwell9819]

No suprise the headers lost power... Cats and an exhaust seem to be the way to go...

[@Motleymick]

Since your stock headers are off the car I would try to bore the insides out as much as possible. (Maybe do a ceramic coating too, to keep the heat down.) And then get a high flow cat axel back exhaust set up.

[@jaxjax5322]

Thank you for your info real good and lets wait for american raging headers always prefer them over kooks

[@erichaley6776]

Wow. They look really nice in there too

[@Reffuhnayr]

This isn't a relevant test until the A/F is corrected for the changes made.

[@kc2giw]

Kooks won’t like that

[@kheaslett]

That's Bad news for KooKs .... try using the sport cats that chevy dude used in his c8,,, i think it gave him more power...change the cats and you will have more power & more better sound

[@keemerbecks3941]

If not BROKE, don't MESS with IT.

[@thegonz7833]

I bet Andrew would have love to have been at Kooks when they dyno tested to get the results they claim.

[@CamaroThings]

14:23 ... RONA!!!!

[@JBWHITEGT]

What was Kooks thinking?

[@PNW_Car_Mods]

Sales

[@mikeylikethailand]

To Parrot what has been already said ... Disappointing ... just because it is louder does not mean more HP ...

[@ijmodified]

You should check and see if the factory headers are equal length

[@chadworth66]

Aren't people buying headers just for the sound upgrade at this point lol. I'd sacrifice some hp to make this car sound like it should.

[@Rhett.Castillo]

Reminds me of a typical shorty header that is emissions compliant.

[@rodneybetz3886]

What about fire risk with the lack of heat shielding?

[@rodneybetz3886]

Hopefully they fix their product.

[@Cubanb407]

Awesome video keep it up

[@ronb3410]

Can you do the same thing with a set of ARH’s?

[@completestreetperformance]

If arh would like to send me a set I'll be happy to test. At this point though I've already spent thousands to do this test so I'm not interested in spending more lol

[@UltimateXreviewr]

Thanks for the heads up man I am wounder the numbers from the titanium new exhaust from armatronix will be ?

[@illnatured2192]

Well well well kooks is here

[@therealfearsome]

what about torque?

[@joel9873]

With the C8 being such a new car, give these manufacturers some time developing these parts. Also without a tune doesn't the computer need some time to adjust to these new performance parts?

[@sepg5084]

most (if not all) cars gain HP when they receive better exhaust even if no additional ecu tuning is done, and they gain even more with a tune. you can also do ecu tuning on stock headers so that they produce more power since factory tuning is geared towards meeting regulations. don't need aftermarket headers for that gain in HP. i don't think this is a tuning issue. 3 inch vs. 2.5 inch collector is kind of a dead giveaway.

[@markpointer4747]

Good that you are putting the Kooks Headers to the test. I've heard they say you'll gain up to 27HP. I would think they should make them to remount the heat shields. Thanks for putting them to the test. The Dyno speaks or it self. I believe high flow cats and a aftermarket lighter exhaust could make a gain in HP. Thanks for sàviñg everyone money!¡

[@bobmrkus3185]

Will you be able to wrap the headers to prevent heat from melting the carbon fiber stuff and other stuff in the engine bay?

[@raythemanroe]

Only mod it needs is better cats

[@dawnvasquez1139]

You cats got anything around back for sale?....rolling chassis...project etc???ty.

[@richarddjohanson]

Are those steel toe shoes you got on.

[@BenHayat]

How is the turbo project coming?

[@MarkJCarruthers]

Factory headers +1.

[@davidconley3610]

Evidently Kooks didn’t dyno this product!

[@arcticvette6573]

Lmao

[@ibidu1]

So with a C8 all you need is rear muffler and cat deletes, to have a good flowing exahsut

[@cindysue5474]

No cats that's a CEL and fix it ticket for sure.

[@ibidu1]

@@cindysue5474 They make o2 sensor foulers for such

[@cindysue5474]

@@ibidu1 Its just best to run hi flow ones 300 cell count.

[@Shiftnlift]

@@ibidu1 yup ive used the method.. tune also will turn it off

[@ntwtransam]

How can a company release something like that? Seems like they would of tested it beforehand. But I’m not sure how much gain there is to be had over that factory manifold.

[@billthibault107]

LMAO 😅 that's too funny

[@302vettelife2]

It appears to be a waste of $1500

[@redzedracer]

You should have known those headers would do nothing as GM Corvette engineers said their exhaust manifolds were practically headers and you could not improve upon the current exhaust system. And by koox coming out with a two and a half inch collector give me a break I'd sue the bastards in mean at least obviously ship them back and get your money back you're not going to get any power on the exhaust side. And no one's going to be able to crack the computer for years it will be into the z06 by then. Jeezz.

[@dirtysouthtv2209]

It’ll be cracked this year.

[@davedavis775]

That's wild. You lost power. It happens though. Did the torque change any? My 91 ZR1 makes 448 H.P. @ a little over 7000 rpm to the tires or 528 crank with stock cubes.

[@completestreetperformance]

Yes, torque dropped too

[@300zxdriver]

I’ve seen three different people on KZbin get disappointing results with kooks headers. Which makes me wonder how did Kooks get their results? Not impressed.

[@skip741x3]

Thats a shame bro...when I saw the diameter difference between the kooks collector and also the port opening on the kooks vs stock, I Knew that was a recipe for Less not more...How stuff like that gets into production is beyond me, who the heck OK'd the dimensions on the kooks b4 mass production? alot of othet youtubers went with kooks as well with similiar results... Are there no other companies making decent headers for c8?

[@RobertKohut]

Nice!!

[@PhillyDee215]

Nice🔥🔥🔥

[@Weyco23]

Well since no one has cracked the computer, and it will not be done anytime soon this is no shock. If you can’t tune the car for aftermarket parts your wasting your money.

[@Bigface281able]

You said 7 hp loss , from what I saw in the dyno graph the blue line was rock stedy and didn't have that little burp at the end , was that the 7 hp diffrence . How did the car feel driving with headers?

[@completestreetperformance]

The burp was mid-range and didn't change the peak horsepower. Thinking it was something with the trans possibly still breaking in. Car felt normal with the headers. No issues with drivability. Sounds wise they are a little tinny sounding compared to the factory with the shielding, also 4 cylinder mode was louder and more obvious (which is expected).

[@montefiveforty1]

So lets say there was no burp on factory headers,then it would have made equal power wich still proves the kooks headers are inferior.

[@completestreetperformance]

The burp didn't add to the peak power of the stock run. Did you guys even look at the graph? Haha

[@superchief15]

Hope those headers don’t make it catch fire like a Ferrari!

[@cindysue5474]

Yeah I would get them jet hot coated inside and out.

[@sepg5084]

the corvette does not have enough carbon fiber on its engine bay to get a fire from a header swap

[@superchief15]

Sep G Good to Know! There is no weight savings for carbon fiber in the engine bay it is just looks!

[@55Mrcry]

So as with any of these reviews there are always two sides of the fence...in another review it states: The headers also returned dyno-proven increases of 20 horsepower (bringing the car well into the 500s!) and 26 lb-ft of torque at the tires without any additional tuning. The cherry on top? The install didn’t throw a single check engine light.

[@completestreetperformance]

That's with the cats

[@sepg5084]

@@completestreetperformance true. it's the aftermarket cats that made the power gain, not the aftermarket headers. people can save money by just buying the aftermarket cats, or just by deleting the cats.

[@rynev3392]

Just put a Camshaft in it

[@aaronh6791]

Cuz you can’t toon bro

[@redstang70]

why are you even bothering with cat's, most guys run decatted anyway

[@bumtracksNew]

Your cats have carboned up and loss that power since your first time on the dyno when they were nicely newer. Dyno it with the performance cats on the Kooks.

[@danielibarra1618]

Corvette direct dyno his with the headers and cats and only had a 5hp gain 😐

[@MALR7]

And that car is still brand new unmodified , there’s no way the cats have degraded

[@jeffcooper8614]

So, where did the rear wing come from?

[@completestreetperformance]

I ordered the car with the rear wing

[@jeffcooper8614]

@@completestreetperformance I have a deposit down for a 21 C8 convertible. In the configuration setup on Chevy's site, I didn't see that wing as an option. Did I miss it somewhere?

[@MrCHAMMOND]

@@jeffcooper8614 You need the z51 package. The option may not be available for a convertible. Either way you should really be doing your own research or asking the dealer since it will be your car.

[@jeffcooper8614]

@@MrCHAMMOND I did....it was discontinued. z51 package only has the small spoiler available. That's why I was confused. The big one is no longer an option apparently.

[@MrCHAMMOND]

@@jeffcooper8614 Wow that's a bummer.

[@nickmoore4212]

The factory is a pretty good free flowing exhaust manifold the kooks header has a few really tight bends that's probably the problem that's causing the restriction in the air flow along with the bs collector flange

[@esaumoreno7405]

No cats plz

[@RobertKohut]

Longer collector, better scavenging....:-)

[@jaxjax5322]

Never buy kooks better american racing or awe

[@DukeSky]

Shit Kooks are not cheap this is a big disappointment...

[@frozenstang3868]

Thats pretty gay, no heatsheild and no ceramic coating.

[@sepg5084]

gay people don't have ceramic coatings

[@zachburke1]

#ameliahartford

[@AlpineWhitedub]

Emilia Hartford but yeah.. It's sucks for her.

[@cindysue5474]

All she likes to do is doughnuts and she is full of herself nothing but a brat.

[@gabrielgarcia5251]

emelia hartford installed the same headers kzbin.info/www/bejne/kIealoZqj8t1gZY

[@maxfly7079]

And got a terriffic sound out of them...why didn't he change the cats too?

[@ces69]

Max Fly He clearly said at the beginning he was going to upgrade in stages and measure the gains at each stage! It’s the only way to assess how much gain is being provided by each part!

[@maxfly7079]

@@ces69 Kooks gave him A SYSTEM!!!!!! not Just A Part!!!!...wtf...and nobody should work or film a vehicle in flipflops!!!!

[@chalachin4452]

i laugh when these aftermarket guys think they can improve against GM's army of engineers

[@Donnieburger80]

Kooks are garbage. Pacesetters are a lot cheaper and bettet

[@AC-kp8sp]

c8's are boring. They look kinda cool but meh. Until there's tuning and double the horsepower poss wide body more aggressive aero I'm out. I like the ls stuff but honestly the coyotes are running the streets seems like

[@dickmick5517]

Aftermarket has been doing this for years. They call it marketing! I would have liked to see the old and the new side by side. If it's there in the video I missed it.

[@jamesaustin4044]

C8's already have headers.

[@josephdixon507]

So instead of the KOOKS Headers being a ‘power adder’, they’re actually a power subtracter. I’ll wait for ARH but ideally I’d like to just swap cats and find a way to do new tips. BTW what is the size of the OE headers in comparison to KOOKS 17/8

[@jimd2895]

ARH is wrapping up their product now, be out soon !!