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Discussion Starter #1
I know there is a lot of guys that say don't do this without a tune but then there's guys that have went without a tune.

If you have done headers and went a while without a tune please let me know if you have had any side affects and how long you have drove like this.

I also have a cortex would it be better to return it to stock if I do headers or just keep it how it is?
 

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I installed my Kooks 1 7/8 LT headers, removed the cats, stock mid pipe, Solo axle backs and ran it for probly 4 or 5 months with the Cortex 91 octane tune with Vararam update. Shift points raised 200 rpm, Superchips shift firmness & speed limiter raised. I just went and got my dyno tune and they first did a pull with the Cortex tune and it was only a little lean off idle beyond that even with the tune set as I described it ran "fat" as the tuner said thru the whole rpm band. Car ran fine never had a single issue out of her plugs all looked good when I swapped them out before I went for my tune (they had 62,009 miles on them)

Now I will also add that I used sparkplug anti-fowlers on the down steam O2 sensors so it wouldn't throw a cat code and once I went in for the tune they turned off the downstream O2's and I removed the anti-fowlers because they're just plain old steel and would eventually rust out and cause problems.

My base line pull was 337 rwhp with the above mentioned mods and after the tuning I was able to pick up 20 rwhp for a net of 357 rwhp with the dyno tune.

Anything else? :D
 

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Discussion Starter #3
Did you baby it untuned?

Other than that that answered everything lol
 

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Did you baby it untuned?

Other than that that answered everything lol
Did I baby it? LMAO! I took it to back roads and empty highways and did data logging run after run after run to see what my improvements were as I tried different things with the Cortex. I mean sure I drove it normally too but I never drove it like my 73 year old mother was with me 24/7. I never babied it ever! From what I had done to it and what RPM (the tuner) told me that Cortex tuner won't hurt anything running it with LT headers.*

*LEGAL DISCLAIMER; Every car is different unless you mod yours 100% the same as mine then I can not tell you 100% that NO damage may happen to your car. As with any mods you assume all liability once you install them. All I can do is tell as to my experiences please do not take them for more then they are meant.*
 

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The Roaming G8
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Spark Plug anti fowlers? What are those and their purpose? 4-5 months? That's pretty good. AND in Maryland??? You're good.
 

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The anti foulers worked for me when I had just solo hfc but when I went headers and hfc the anti foulers no longer did the trick because I got a code about 3 days later after the header install.

With no tune or the cortex tune I don't think you will hurt anything but it won't be dialed in at its absolute greatest potential.
 

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Spark Plug anti fowlers? What are those and their purpose? 4-5 months? That's pretty good. AND in Maryland??? You're good.
They are originally designed for cars that burn oil, you remove the spark plug and thread the anti-fowler into the hole where the spark plug goes then the spark plug is installed and threaded into the anti-fowler. What it does is gets the spark plug out of the combustion chamber so it does not get fowled with oil. What it does in the exhaust is gets the O2 sensor out of the exhaust stream and only allows a small amount of exhaust gas to get to the sensor there-by greatly decreasing the amount of exhaust the sensor sees and reports to the computer. I stuffed steel wool into the anti-fowler to even further restrict the amount of exhaust gas getting to the sensor, the steel wool MAY have been what had kept it from ever throwing a code even with LT headers and no cats at all.

The link that Gulfcoast included in his post works well too. But I used what I had in my garage rather then go buy more stuff. Both work well but I try not to spend money if I don't have to.
 

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I used the fuel filters like posted above and still got a cel to come on. But I would still use them at least until you get tuned
 

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These types of threads are frustrating to read through. For me personally I would NEVER cut corners when modding my car just to save a few bucks. Do it right the first time and get a local dyno tune at a reputable speed shop or purchase a mail order version from Livernois or VMS. Sell your Cortex tuner to offset your costs. My $.02
 

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These types of threads are frustrating to read through. For me personally I would NEVER cut corners when modding my car just to save a few bucks. Do it right the first time and get a local dyno tune at a reputable speed shop or purchase a mail order version from Livernois or VMS. Sell your Cortex tuner to offset your costs. My $.02
If I had local and reputable at the same time near me I would.

Sent from AutoGuide.com Free App
 

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You could always drive a few miles (lightly)? How far away are you from Baton Rouge LA?
About 130 miles give or take.
 

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Agose25,
Thanks! I honestly do not like halfassing things and i would feel much better about getting it done right. I did all of my stuff with my old foxbody in NC/VA. So I am still new down here and got of of the modding scene for a while. I appreciate the assistance!
 

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Good luck! Wish you were closer, I know of quite a few here fairly local. I know that's a stretch for you but I do agree with Agose, a road trip might be worth it to get it done right... just my .02 and again, good luck!
 

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These types of threads are frustrating to read through. For me personally I would NEVER cut corners when modding my car just to save a few bucks. Do it right the first time and get a local dyno tune at a reputable speed shop or purchase a mail order version from Livernois or VMS. Sell your Cortex tuner to offset your costs. My $.02
RPM, a very reputably tuner here, are the ones that told me the Cortex tune did NOT run lean anywhere except just off idle and even then just by "a little" according to them. The only thing using an anti-fowler does is keep you from getting a CEL by running LT headers and no cats a veeery old trick. The "right way" that everyone here raves about and says "must be done" only gained me 20 rwhp. So $300 netted me 20 rwhp not exactly Earth shattering gains over the Cortex tuner. Oh and along with that 20 rwhp I got the top speed limiter and down stream O2's turned off.

I'm just curious as to why a "real tune" MUST be done when the Cortex is safe to run? Turned off top speed limiter and 20 rwhp just don't seem to be worth the cost IMHO. I'm not hating nor trying to cause trouble I'm honestly trying to find out what the big deal is and why a "real tune" is so needed. Is RPM wrong and the Cortex tuner a problem that will damage an engine or are people just so scared to try anything else that they'll condemn anything beyond what they know? Or have Cortex tuners gotten better over the years and people just don't know it?
 

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Its Good To Be Tha King
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I'm just curious as to why a "real tune" MUST be done when the Cortex is safe to run? Turned off top speed limiter and 20 rwhp just don't seem to be worth the cost IMHO. I'm not hating nor trying to cause trouble I'm honestly trying to find out what the big deal is and why a "real tune" is so needed. Is RPM wrong and the Cortex tuner a problem that will damage an engine or are people just so scared to try anything else that they'll condemn anything beyond what they know? Or have Cortex tuners gotten better over the years and people just don't know it?
To add, you can disable the speed limiter with the Cortex....top speed is well over 200mph+, something we'll never see.

And I have also data logged with the Cortex tune, and my long term fuel trims show safe on my car (+3.7), with the 91 Rotofab tune, LT's with no cats.

...and clearing the cel takes less than a min.
 

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Here is my take on your comment Jack. At the end of the day its your car, do what you please. I'm not a tuning expert, nor do I claim to be. What I am is a no non-sense kind of person, and for me using a product (hand held tuner) that has only been endorsed by its creator for CAI and Catback bolt-ons is not a risk I want to take. I spent $35K on my G8 back in 2009, it's my daily driver, and I plan on owning this car for many years to come. So for me I follow the direction of tried and proven modifications. I'm not scared of anything and I'm not condemning your decision. Maybe the few who have started doing this over the last few months are on to something? Maybe there aren't any long term side effects? Maybe? Superchips ended updates and forum activity years ago. What are they going to say when someone calls in for customer support and tells them they are using the tuner for what it was not intended for?

If you guys are monitoring your fuel trims and keeping an eye on things, then have at it, and enjoy the economic value of not having to upgrade. Why don't you start an official thread with a disclaimer stating your results and experiences? I think there needs to be more documented data before this is discussed as "No Big Deal". I guess this is where my frustration lies that I mentioned above. When I was a noob to the forum and G8s I appreciated the sound advice I found on this site. I wish the same for others and am just providing my subjective opinion.
 

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Without "doing your homework" by datalogging fuel trims and wideband AFR (not possible with cortex) you really don't know "for sure". Cortex will not honor their own "two year powertrain" warrantee if you have headers or HFC's, so any "expectations" of such would be maligned. That should tell you something right there.

When I tested way back when (and was critiqued from Drcustomparts, oh yea) I found that HFC's leaned out the mixture on my car specifically, and moreover, I datalogged to prove my findings. When I sold my superchips and went with livernois, the fuel trims were back in check.

There are variations between model years, dates when cars were built, and even engine wear characteristics that makes the assumer who says "well it worked for these 2 guys, it's probably fine" that will learn quickly that if his experiences differ by using a canned tune optimized for cold air intakes ... when he is also using headers or hfc's or something else altogether, that stuff can happen in a bad way.

The danger is without an AFR gauge, you can't really tell IF your running lean or rich out the tailpipe... and if you go part throttle, the MAF and narrowband O2s provide input to conditions to try to burn at stoich, however, when you go WOT, it applies a pre-programmed (and in the case of the cortex, a "cold air intake only modification tune") formula to the existing fuel trims. This is where the problems can happen. Is it a guarentee that it will damage your engine if you tune with the cortex with headers? Probably not. Is it a safety umbrella that it is always 100% safe to run? Probably not. Have people said "yes, my real AFR is such-and-such from my dedicated sensor which emperically proves that my air fuel ratio is SAFE at WOT". I HAVEN'T SEEN ANY. These people are only relying on a single piece of the puzzle, the fuel trims as reported by the cortex, and their "tuning guy". For what it's worth.

Someone with HPTuners experience and an AFR gauge needs to datalog and prove this once and for all.

Everyone individually knows their own "tolerance to risk".

My tolerance was lower (as it pertains to the Cortex) than others.
 
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