RevUP with JBA Headers

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WestMIPath
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RevUP with JBA Headers

Postby WestMIPath » Tue Oct 13, 2020 6:52 pm

Hey all, I've been reading quite a bit of chatter about reprogramming the computer after installing the JBA long tube headers. I have never tuned a vehicle before (or had one tuned for that matter) and am feeling a lot over my head at this point. Currently, my Pathy is sitting a little depressed in my garage, awaiting a third set of manifolds... They are under warranty, and I'd just swap them out for a new set (again), but they are currently out of stock and the crack is not a crack anymore but a full separation of the cat from the manifold at the rearmost cylinder. So now I'm contemplating doing the header swap instead, which is what I should have done in the first place. So, my question(s) is this, how much is it to get the computer re-tuned and where does one go for this (I'm in west Michigan)? I have a super tech savy 16yo who's gaining interest in cars that may be able to help me out too.

I've called a couple tuning/custom shops around here, but most say that they either don't do that kind of modification, or that it's not needed as the truck will re-learn and reset itself (which makes me not trust them after reading the threads on here).

I'm hesitant to drop a bunch of money on this rig, as it has seemingly survived SMOD coming back from a 3000 mile trip hauling a camper a couple years ago. But I feel that the trans would probably drop as soon as I put some money into it...

Other than SMOD and the repetitive manifold replacement, this has been a fantastic rig and has done me very well.

Manifold Separation Anxiety: https://photos.google.com/share/AF1QipN ... c5ems4OGRR


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blink32
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Re: RevUP with JBA Headers

Postby blink32 » Wed Oct 14, 2020 2:16 am

I don't know if I'd personally bother with a custom tune if all I did were long tube headers. The ecu probably would relearn and get it close enough. But now if you had other mods then might as well. If you've been calling shops that have an in-house Dyno and they are saying they don't do that work or that you don't need a custom tune then they probably just don't want your work. You'll just have to keep calling around. I'd say you'd be in it for at-least $1000, call it $600 for an UpRev piggy-back ecu with licenses and such + $400 for some dyno time somewhere. Figure $100/hr for dyno time or for X number of pulls depending on the shop with a wideband O2 sensor and print out. Just my worthless cents.

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smj999smj
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Re: RevUP with JBA Headers

Postby smj999smj » Wed Oct 14, 2020 2:47 am

If you are going to install long tube headers, you'll be deleting the upstream catalytic converters in the process. Besides triggering the P0420/P0430 catalyst efficiency codes, it also causes these engines (both the V6 and V8) to run lean, which is why you need to get the ECM re-tuned. You can do this yourself or go to an UpRev tuner, which you can find by going to their dealer locator at their website:

https://www.uprev.com/

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WestMIPath
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Re: RevUP with JBA Headers

Postby WestMIPath » Wed Oct 14, 2020 6:04 pm

I have an email into revup, and I think I may have a local tuner willing to take a look.

Not to show all my ignorance, but what are the long term affects of running lean?

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blink32
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Re: RevUP with JBA Headers

Postby blink32 » Thu Oct 15, 2020 2:26 am

You could burn a hole through your pistons among other things. Run fat and you could foul plugs and maybe cats. Running lean is when the really bad stuff happens.

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smj999smj
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Re: RevUP with JBA Headers

Postby smj999smj » Sat Oct 17, 2020 4:16 am

Lean mixture leads to pre-ignition detonation. As mentioned already, it'll damage the pistons and can potentially melt the ends of the spark plugs.

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WestMIPath
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Re: RevUP with JBA Headers

Postby WestMIPath » Mon Oct 19, 2020 7:13 pm

Hopefully the plugs will melt before the pistons do... jk, I'm not going to run this without re-tuning.

I've been talking to a few well-intentioned friends who suggested wiring in a resistor with the proper ohm reading to replace the post-cat O2 sensor. While excited about this prospect, my initial thought is that it would only be the proper reading when at operating temp and not when cold. I'm assuming the computer is looking for a range based on the engine temp. Thoughts on this? Is it a viable option to spending $500+ on re-tuning?

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smj999smj
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Re: RevUP with JBA Headers

Postby smj999smj » Wed Oct 21, 2020 11:19 pm

When you start your engine cold, the ECM is in open loop. It will not enter closed loop until the coolant temperature reaches the proper temperature. Also, at this time, heaters in the oxygen sensors are used to help warm up the sensors quicker. Once the vehicle enters closed loop, the ECM will use the data it receives from various engine sensors to adjust the air/fuel mixture. Intake air temperature, fuel temperature, mass air flow sensor reading, throttle/pedal position and upstream air/fuel ratio sensor info, among other info, is used by the ECM for engine management.
As far as spending $500+ on engine tuning, I wouldn't call it an option, rather a necessity, if deleting the upstream converters on these engines. Does it make sense to go through the work and expense of installing long tube headers on the engine and NOT re-tune it so that the engine can properly and safely run the engine and not have it damage one or more pistons? If you are going with UpRev, you don't need to do any modification to the rear oxygen sensors, as far as I know. The new ECM program will keep the catalyst efficiency codes from triggering due to the removal of the upstream converters.


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