Did you tune your car after installing headers and x-pipe?
12-02-2018, 10:28 AM
#3
Le Mans Master
I can't imagine why, honestly. Is there belief that the amount of change in fuel trims at WOT due to a simple exhaust change will really be outside the capacity of the block learn tables?
12-02-2018, 01:58 PM
#5
Pro
You dont have to but you will get a cel because you change the o2 sensors further back and if you eliminate the secondary cats that will also cause a cell. You will not get all the performance the headers can get you without tuning. I installed mine and ran the car without tuning for like 10 month untill i supercharged it
12-05-2018, 07:41 PM
#6
I installed the Kooks LTs + Kooks green catted x-pipe and no tune and no CEL. The green cats are designed to prevent CEL and it has worked for me, but I'm also running stock cold air intake. A couple others have installed the same exhaust as me but with CAI and got a CEL. I'm sure that I would gain a few more HP if I tuned it, but I was more concerned about exhaust sound improvement rather than squeezing extra HP out of it. Will likely tune it once out of warranty.
12-05-2018, 08:23 PM
#7
Le Mans Master
Dave
12-05-2018, 08:25 PM
#8
Former Vendor
There is power and throttle response in tuning with headers as well as other benefits. But we do have customers having us install headers without tuning. There is decent power gains on the dyno still on stock tune as well as the headers sound great. The downside is the check engine light staring at you while driving without tuning.
12-05-2018, 08:32 PM
#9
Le Mans Master
So the question is why would you install headers and not do a tune as that would be like taking a shower with your shoes on ..
Sure you can do things that will not light the CEL but the CEL you get is for CAT efficiency as the CEL is the rear O2 sensors which monitor for this and not anything else
So to spend that much money and not tune it for 25 HP and to think that the dealership or GM is just going to ignore headers if you have a warranty claim ....and to take a chance that you are lean at WOT .....lol
Worried about a tune voiding your warranty , then use a Diablo and get a custom header tune from Diablo Lew ...Will you leave a few HP on the table , maybe but it's way better than running lean on the top end ...... you can return it back to the stock tune and never leave a trace .....( I have a friend who .......)
Dave
Sure you can do things that will not light the CEL but the CEL you get is for CAT efficiency as the CEL is the rear O2 sensors which monitor for this and not anything else
So to spend that much money and not tune it for 25 HP and to think that the dealership or GM is just going to ignore headers if you have a warranty claim ....and to take a chance that you are lean at WOT .....lol
Worried about a tune voiding your warranty , then use a Diablo and get a custom header tune from Diablo Lew ...Will you leave a few HP on the table , maybe but it's way better than running lean on the top end ...... you can return it back to the stock tune and never leave a trace .....( I have a friend who .......)
Dave
Last edited by Dcasole; 12-05-2018 at 08:34 PM.
12-07-2018, 09:14 PM
#12
Le Mans Master
12-07-2018, 09:24 PM
#13
I spent a ton of money on what I feel is the perfect exhaust note. Folks are spending twice the amount I have in my headers for Akrapovic cat back system with minimal potential for HP gain. My car is plenty fast for me and gaining 20 to 30 more HP isn't really needed. The sound gain was worth every penny spent. I did the install myself so I saved a few bucks there.
Last edited by lakemg; 12-07-2018 at 11:24 PM.
12-13-2018, 04:04 PM
#15
Pro
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You don't "have" to tune the car. However, it would be naive not to. Buying and installing headers simply for sound is kind of ridiculous IMHO considering you can just swap out the axle-back if you don't have NPP.... or install cutouts (no, you don't have to buy a $5,000 Akrapovic system to get a good exhaust tone). If you go catless, you will throw a CEL and fuel trims will be impacted both catted and catless due to the increased airflow of the headers compared to stock. Sure the computer can correct for some of it, but not for 100% of it, especially at WOT. Can you drive it like this? Sure. Are you leaving horsepower on the table? Definitely. Can it hurt the car driving it like this without a tune? Over time... Probably, especially with aggressive driving. Can you live with the CEL on, especially with every single passenger asking you why your check engine light is on every time they get in the car? I know I can't.
It's your own money though. Do with it as you please on whatever makes you happy.
It's your own money though. Do with it as you please on whatever makes you happy.
Last edited by DomLS3; 12-13-2018 at 05:58 PM.
12-13-2018, 05:11 PM
#17
Le Mans Master
Also at WIDE OPEN THROTTLE , the ECM is in open loop so there is never a chance for even a little bit of correction with the ST and LT fuel trims ....
Dave
12-13-2018, 05:32 PM
#18
Pro
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Just some clarification around your statements ....You will throw a CEL even if you have CATS with long tubes because its the rear O2 sensors which measures Cat efficiency that cause the CEL , no cats , its a no brainer , because there are no rear O2 sensors but with cats and Long Tubes the cats are located to far downstream in the exhaust system which causes the rear O2 sensors trip the CEL
12-13-2018, 05:40 PM
#19
Team Owner
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C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Required, no, advisable, yes.
If youre only going for sound, and don't care about the engine light, by all means. If you want the most power possible, then yes. Its all about what you want and what you'll live with.
If youre only going for sound, and don't care about the engine light, by all means. If you want the most power possible, then yes. Its all about what you want and what you'll live with.
12-13-2018, 06:14 PM
#20
Le Mans Master
the only way to avoid a CEL with Long Tubes with cats is to use simulators that take the O2 sensor out of the stream
https://www.corvetteforum.com/forums...rs-no-cel.html
Long tubes with cats and no simulator not getting a CEL are few and far between ....
Dave