Mishimoto R&D: JL Wrangler 2.0T Performance Intake

[AnnDee4444]

That's true, but the ECU will be in both open and closed loop throughout a given drive cycle, so it must not reference the MAP at all in closed loop. Otherwise the piggyback would need to switch off depending on which strategy the ECU is in.

I'm honestly surprised piggyback systems work at all on these ECUs/engines, given how complex the programming is and how sensitive everything is to modification.

Thanks for working through that logic with me @AnnDee4444. I'm sure a Google search would have solved it, but where's the fun in that?

Thanks,
-Steve

No worries Steve, I'm working through it too.

I envision the piggyback working by reducing the peak voltage of the MAP sensor so that it never actually reads peak boost (at least until the piggyback wants to limit it). This way the engine would be in a portion of the VE table would still be somewhat close, and the tune would allow the fuel/timing needed for more power. Example: if peak manifold pressure allowed is 25 psi, the piggyback would not allow a signal greater than 24 psi. Everything below 24 psi would be unchanged ant the motor would operate as normal. The piggyback could also make 26 PSI output the value for 25 psi, so that the boost doesn't get too uncontrolled. Fueling is probably off, but the ECU won't care due to this condition only existing in open loop (where the O2 sensor not read).

Again this is just my current theory, feel free to make suggestions or correct something.

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[AnnDee4444]

Hmm. Maybe it tries to command an injector pulse width at X MAP pressure but the pcm essentially sees its already there in the fueling tables because it’s essentially lied to? Or something like that.

I would expect the ECU to limit torque with both fuel & timing. I don't think just adding fuel at specific MAP values would give much power (if any). For this to work the factory tune would have to be pretty lean at peak torque.

 

[DadJokes]

I would expect the ECU to limit torque with both fuel & timing. I don't think just adding fuel at specific MAP values would give much power (if any). For this to work the factory tune would have to be pretty lean at peak torque.

I was just giving one example. If they are manipulating/intercepting factory signals, why do you believe it would be lean anywhere and more specifically peak torque? And how lean are you guessing it would be?

 

[AnnDee4444]

I was just giving one example. If they are manipulating/intercepting factory signals, why do you believe it would be lean anywhere and more specifically peak torque? And how lean are you guessing it would be?

Stock, I don't think it is lean. I think a piggyback that just manipulates the MAP would basically be operating in the top part of the VE table, making it act like it is "expanded". Operating like this, the VE table is probably not correct but "close enough" to make more power. If anything, I would expect it to be lean from the additional airflow (although it could be rich from piping restrictions/turbulence/etc.). The only way to know for sure is to measure the AFR with an O2 sensor, and I doubt the factory O2 is a wide-band.

I suspect that the way the factory ECU "limits" torque is actually part of the tune. I think that at a peak MAP, the ECU's fuel & ignition are reduced so that additional torque is not made. If the ECU only reduced fuel but left ignition alone, the motor would run lean at peak MAP. I'm fairly certain that they wouldn't allow this high MAP lean condition, which is why I believe ignition timing is actually what is limiting the torque, and the AFR is adjusted to match.

A piggyback that increases just the pulse width of the fuel injectors could only make additional power if the motor was running lean (which it's not... I think). To make more power the piggyback would also need to adjust timing, and thats assuming that the ECU would disregard the increased MAP.

 

[DadJokes]

Stock, I don't think it is lean. I think a piggyback that just manipulates the MAP would basically be operating in the top part of the VE table, making it act like it is "expanded". Operating like this, the VE table is probably not correct but "close enough" to make more power. If anything, I would expect it to be lean from the additional airflow (although it could be rich from piping restrictions/turbulence/etc.). The only way to know for sure is to measure the AFR with an O2 sensor, and I doubt the factory O2 is a wide-band.

I suspect that the way the factory ECU "limits" torque is actually part of the tune. I think that at a peak MAP, the ECU's fuel & ignition are reduced so that additional torque is not made. If the ECU only reduced fuel but left ignition alone, the motor would run lean at peak MAP. I'm fairly certain that they wouldn't allow this high MAP lean condition, which is why I believe ignition timing is actually what is limiting the torque, and the AFR is adjusted to match.

A piggyback that increases just the pulse width of the fuel injectors could only make additional power if the motor was running lean (which it's not... I think). To make more power the piggyback would also need to adjust timing, and thats assuming that the ECU would disregard the increased MAP.

I’ve only tuned JTEC up until 10 years ago with MAP. There were no VE tables in the SCT software so I’m just visualizing as best as I can. Maybe they effectively, by workaround, rescale the table/s.

 

[AnnDee4444]

I’ve only tuned JTEC up until 10 years ago with MAP. There were no VE tables in the SCT software so I’m just visualizing as best as I can. Maybe they effectively, by workaround, rescale the table/s.

My experience is pretty limited too (only Hondata's FlashPro), but it was with VE tables & DBW throttle (and VTEC yo). From how I understand, the VE table literally defines the pumping losses with pressure vs RPM. This is then used to estimate the amount of air entering the motor, which dictates the fueling (along with the adjustments for IAT/Load/etc.)

 

[Mishimoto]

Appreciate the discussion everybody! Our tuning specialist is out at SEMA for the week, but when he gets back I'll pick his brain a bit on the piggyback tuners.

I should also have an update on the intake for you soon!

Thanks,
-Steve

 

[DadJokes]

My experience is pretty limited too (only Hondata's FlashPro), but it was with VE tables & DBW throttle (and VTEC yo). From how I understand, the VE table literally defines the pumping losses with pressure vs RPM. This is then used to estimate the amount of air entering the motor, which dictates the fueling (along with the adjustments for IAT/Load/etc.)

VE is the ability to fill a cylinder before IVC and doesn’t reflect negative work, pumping losses.

 

[AnnDee4444]

VE is the ability to fill a cylinder before IVC and doesn’t reflect negative work, pumping losses.

I chose my words poorly. Pumping losses have nothing to do with VE.

 

[Jnrscaping]

Unfortunately, tuning isn't really in our wheelhouse, but I'm sure we're not too far out from having ECU tuning for the JL. I haven't ever used a piggyback tuner like the Racechips system, but I've heard of others having good results on BMWs and VWs.

Thanks!
-Steve

There’s somebody from Haiti think they build is called cme build Haiti @Cme

Yeah, without a tune, you might see a 5-7 HP gain on a cool day. We saw an average max gain of 4.5 HP with the intake alone, which we don't even consider a gain as it's low enough that a hot day would negate it. Like @Crusifix said, the main factor in performance is going to be the computer's torque target. We have seen positive results in repeated testing of our intercooler pipe, however, so the ICP may be limiting flow enough to put output below the PCM's allowable torque limit.

You can't really open up the exhaust too much on modern turbocharged engines, especially on a high-reving 2.0L. The biggest issues with a big exhaust is getting an oxygen sensor in the middle of the exhaust flow and scavenging. But, you can always put the 02 directly after the turbo and once you're into that big of an exhaust you're likely looking at monitoring individual cylinders and are well beyond the scope of bolt-on mods. I would bet a high-flow cat with a 3-inch exhaust would be enough for upwards of 400 HP—there are plenty of Subaru 2.0/2.5Ls and VW 2.0L's pushing into the 500 HP range with 3 inch catted exhausts.

Thanks everybody!
-Steve

There’s someone from Haiti who cracked the tune. Think the thread was called C-M-E rubicon something like that just not sure I trust it too much. But he’s claiming to have good results. Problem is they say you have to send your ecu to them.

 

[Jnrscaping]

There’s somebody from Haiti think they build is called cme build Haiti @Cme


There’s someone from Haiti who cracked the tune. Think the thread was called C-M-E rubicon something like that just not sure I trust it too much. But he’s claiming to have good results. Problem is they say you have to send your ecu to them.

@JL-Rubicon-Haiti

 

[oceanblue2019]

There’s somebody from Haiti think they build is called cme build Haiti @Cme


There’s someone from Haiti who cracked the tune. Think the thread was called C-M-E rubicon something like that just not sure I trust it too much. But he’s claiming to have good results. Problem is they say you have to send your ecu to them.

I asked them over dyno results and none in Haiti. I would be very concerned with a tune from someone who has zero access to a dyno.

 

[JL-Rubicon-Haiti]

I asked them over dyno results and none in Haiti. I would be very concerned with a tune from someone who has zero access to a dyno.

The tune was not developed by us, it was developed for us to the exact modifications we installed in the CME-Rubicon build.....In Haiti we do NOT need a dyno as the HP does NOT matter to us, it is just the fact that the vehicle runs great with the setup we have in the streets of Haiti where it is mostly about bottom end power and torque right off the back.....And the results are amazing even with 37" tires.... Email me at: [email protected] for more info.

 

[oceanblue2019]

The tune was not developed by us, it was developed for us to the exact modifications we installed in the CME-Rubicon build.....In Haiti we do NOT need a dyno as the HP does NOT matter to us, it is just the fact that the vehicle runs great with the setup we have in the streets of Haiti where it is mostly about bottom end power and torque right off the back.....And the results are amazing even with 37" tires.... Email me at: [email protected] for more info.

Without a dyno and/or extensive test drives with a wideband o2 sensor and ECU data logging any tuning is just a shot in the dark. You could be far from the ideal tune and would never know it as the butt dyno is not a precise instrument; even in Haiti.

 

[JL-Rubicon-Haiti]

Without a dyno and/or extensive test drives with a wideband o2 sensor and ECU data logging any tuning is just a shot in the dark. You could be far from the ideal tune and would never know it as the butt dyno is not a precise instrument; even in Haiti.

No need to argue...... We each have our objectives, our objective was exceeded with this tune, we are MORE than satisfied with the results as it is not a performance tune for HP gain purposes...It just removes all restrictions the factory had put in place with the catalytic converter which we eliminated with our custom 3" down-pipe from MagnaFlow and our performance air-intake from A.F.E. Power.... We are EXTREMELY satisfied with the tune.......

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