So just had hooker blackheart 1 7/8” longtube headers installed on my 2016 C7 Z51 as well as E85 flex conversion plus tune for pump and E85. Gained 40 hp from E85 alone, BUT I have open headers not connected to the “catback” (not like old school cars of course on these). The tuner had to fight with it for two days like a stage III cam install tune apparently, and he said I must put on an x pipe to regain the torque/hp I’m losing with no back pressure or scavenging. I wanted to put on longer pipes (distance the 02’s) with downturns, or leave it be, I like the sound very much, although I do cringe at cold start up. How much power am I losing with just open headers? And will installing an x pipe with downturns significantly alter my loud asf sound? Im weighing the potential power gains of the x pipe vs the loss of the raw exhaust sound I want. If the power gain is not significant I’ll leave it open and loud.

 

Personally, I would install an X pipe and either hook it up to the cat back or run straight pipes out the rear. In my opinion, having the exhaust coming out below the car isn't a safe thing to do in general due to carbon monoxide gas getting inside the car and doing it with a car that has a plastic floor is more than likely worse since plastic won't hold up to the increased heat as well as steel does.

Bill

 

Open headers is not good for low end torque. You're tuner is right. Very minimal power loss up top, if any, by adding the rest of the exhaust....including stock catback. I won't judge you for the foolishness of open headers in a street car even though I find it absurd.

 

Lmao

 

As suggested, it needs to have the exhaust run out the rear, one way or another... that is, unless you wanna fab lake-pipes.

 

It does give me a headache and ringing in the ears when driven for hours, but that’s due to the very loud racket it makes, I don’t believe the carbon monoxide is an issue, I’ve been in it off and on (mostly on) for 7-8 hours once a week for months with no adverse effects. I take the top off and that helps greatly with the ear ringing as well as the fumes that may penetrate the cabin
But it’s the Loudest car I’ve ever heard tbh, makes the mustangs and dodges cringe in fear. I have a ‘96 WS6 with LT4 hotcam kit, hooker longtubes, 3.73 gears, 3400 vig, cutouts (always open) and it actually beats that out, that car was voted loudest in the south Florida f-body club 😂 this was the plan: be the loudest most obnoxious car while being the prettiest red corvette at the same time.
Unless it’s burning **** I don’t see the issue with open headers, I guarantee you it does not lose any meaningful hp without scavenging or back pressure, if it was a blower car yeah I’d definitely want the back pressure. But like this old man I gave a ride to told me the other day it’s running like a raped ape actually 😭
I do appreciate the comments and concerns tho, all very valid no doubt. It’s just that I’m the 1 in 1000 guy who wants the obnoxiously loud car, kinda my thing. I’ll probably try the open x pipe eventually and see how it sounds/look at the hp difference. It’ll probably still sound pretty rowdy and maybe add some of that low end power back.
I’m putting headers on my ‘11 RS camaro llt 3.6 next week (never knew that was a thing, not sure why not?) as well as E85 plus tune next month. Surprise some 5.0s and 5.7s running close maybe? The catback busted both welds on the RS, so it’s been wide open after the exhaust manifold/cat pipes, VERY loud, nobody believes it’s a v6. So maybe the C7 x pipe soon after. I’ll post results so maybe people won’t ask so many x pipe questions, not that anyone is mental like me with open headers 😂 but seriously it was a happy accident on the RS, kept running over a high curb at the Taco Bell eventually busting the cat back loose on both sides. Couldnt’ve happened to a happier customer, weird how that worked out.
going with the new era cam package with 3400 stall in January, gotta sell the WS6 for funds first…..

 

I can't tell if you're trolling us or maybe just thinking with your mullet. Have you proven this theory of yours on the dyno?