Mishimoto R&D: JL Wrangler 2.0T Performance Intake

[AnnDee4444]

Some vehicles also measure the acceleration of the crank based on the cam/crank sensors, but piggy-backs don't tend to work on those systems.

Interesting... I wouldn't think that would work correctly with the varying weight between vehicles & loads.

Sponsored

 

[Mishimoto]

Interesting... I wouldn't think that would work correctly with the varying weight between vehicles & loads.

Yeah I'm not 100% sure on how it works to measure torque output, but I do know crank acceleration is also part of how some systems detect misfires. That many variables is beyond my brain power without beer

Thanks!
-Steve

 

[Engmoreau]

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

Si are you guys planning a plug in runner project after this? Or do you recommend anyone out there like racechips

 

[Mishimoto]

Si are you guys planning a plug in runner project after this? Or do you recommend anyone out there like racechips

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

 

[Minty JL]

Steve - its been 62 days now with your Beta version!

Not a single CEL since I left the shop. I will pull some scans for validation, but I think yall are good to go now!

 

[Mishimoto]

Steve - its been 62 days now with your Beta version!

Not a single CEL since I left the shop. I will pull some scans for validation, but I think yall are good to go now!

That's awesome to hear! We also have another intake up in Colorado with @mrjking2000 to make sure there aren't any issues with altitude like what we had with the catch can as well.

I should have another update for you in a couple weeks!

Thanks again,
-Steve

 

[DadJokes]

Well if Jeep knows their Volumetric efficiency at a given rpm, they’ll know how much fuel is commanded for an Air/Fuel target and from there they should know the cylinder pressure/torque produced at that rpm point. That’s why a piggy back should work. The pcm thinks the commanded torque is the same. If I understand correctly...

 

[AnnDee4444]

Well if Jeep knows their Volumetric efficiency at a given rpm, they’ll know how much fuel is commanded for an Air/Fuel target and from there they should know the cylinder pressure/torque produced at that rpm point.

Hmm... so it's literally built into the tune. It's not measuring the torque and clipping when it reaches 295 lb-ft, instead the tune doesn't allow any more fuel/ignition at specific RPM/MAP values. Almost like a soft rev limiter.

This is the best explanation I have seen so far.

 

[Crusifix]

Hmm... so it's literally built into the tune. It's not measuring the torque and clipping when it reaches 295 lb-ft, instead the tune doesn't allow any more fuel/ignition at specific RPM/MAP values. Almost like a soft rev limiter.

This is the best explanation I have seen so far.

That is a big part of what the ECM is looking at.

 

[oceanblue2019]

Hmm... so it's literally built into the tune. It's not measuring the torque and clipping when it reaches 295 lb-ft, instead the tune doesn't allow any more fuel/ignition at specific RPM/MAP values. Almost like a soft rev limiter.

This is the best explanation I have seen so far.

Yes, and this has become more advanced over the years to get better economy and less pollution.

More sensors, faster ECU's to run closed loop, and more up-front characterization/calibration all help get more out of an engine with less pollution; but also make it tougher to modify until you can get access to the ECU to re-calibrate.

 

[PaleoDan]

Sorry, I just found this thread, is there an anticipated release date?

 

[Mishimoto]

Well if Jeep knows their Volumetric efficiency at a given rpm, they’ll know how much fuel is commanded for an Air/Fuel target and from there they should know the cylinder pressure/torque produced at that rpm point. That’s why a piggy back should work. The pcm thinks the commanded torque is the same. If I understand correctly...

Yup, pretty much. Most of the piggybacks intercept the MAP sensor, so the ECU thinks it's making less boost and therefor lower VE, it then adjusts the wastegate duty cycle to match the commanded VE. What always trips me up about the piggyback sensors is that they don't adjust the O2 sensor reading, so the ECU should read a lean condition, unless part of the fueling table says, "If wastegate duty cycle decreases by X, increase injector duty cycle by X" or it just trusts the MAP reading and increases fuel to correct the lean condition. I would assume it's most likely the latter.

Thanks!
-Steve

 

[AnnDee4444]

What always trips me up about the piggyback sensors is that they don't adjust the O2 sensor reading, so the ECU should read a lean condition

Wouldn't this condition only exist when in open loop? If it's like other ECUs, it wouldn't care what the O2 reads while in open loop.

 

[DadJokes]

Yup, pretty much. Most of the piggybacks intercept the MAP sensor, so the ECU thinks it's making less boost and therefor lower VE, it then adjusts the wastegate duty cycle to match the commanded VE. What always trips me up about the piggyback sensors is that they don't adjust the O2 sensor reading, so the ECU should read a lean condition, unless part of the fueling table says, "If wastegate duty cycle decreases by X, increase injector duty cycle by X" or it just trusts the MAP reading and increases fuel to correct the lean condition. I would assume it's most likely the latter.

Thanks!
-Steve

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.

 

[Mishimoto]

Wouldn't this condition only exist when in open loop? If it's like other ECUs, it wouldn't care what the O2 reads while in open loop.

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

Sponsored