Does a cold air intake add power on a 4.0?

[SSTJ]

Not at all, we tend to see the programming adapt to the power adder and eventually return it back to the stock power level. I'd like to see if you found a way to circumvent that.

I am also curious why Blaine has seen the results of those mods get tuned out by the PCM over time, so that’s interesting for sure too.

Reviving an old thread. I'm wondering if there was ever any further testing on this topic above, whether tested by @Jezza or by others. Has anyone run a simple mod like this long enough, without a tune to go with it, to find out whether the PCM will simply adjust to changes in air intake (e.g. removing stock box, true CAI, etc.) and return the engine to stock performance?

 

[Tray Burge]

Reviving an old thread. I'm wondering if there was ever any further testing on this topic above, whether tested by @Jezza or by others. Has anyone run a simple mod like this long enough, without a tune to go with it, to find out whether the PCM will simply adjust to changes in air intake (e.g. removing stock box, true CAI, etc.) and return the engine to stock performance?

Not really by itself, but combined with headers, free flow exhaust, cat delete and any other changes, ie cam swap, gearing, etc. along with a custom written tune and a pcm reflash to tie everything together can drastically make a difference according to guys doing it on my Ram forum. It's more of just a piece of the puzzle from everything I've read and researched from guys actually doing it. I've also read the pcm will just return back without a reflash for a custom tune and the mods to support it.

 

[Tray Burge]

My set-up right now and about to add this once it's finished, but it's just another piece of the puzzle at this point.

View: %5BURL%5Dhttps://imgur.com/a/Hm1pIYi[/URL]

 

[Tray Burge]

 

[GoldenGorilla]

Reviving an old thread. I'm wondering if there was ever any further testing on this topic above, whether tested by @Jezza or by others. Has anyone run a simple mod like this long enough, without a tune to go with it, to find out whether the PCM will simply adjust to changes in air intake (e.g. removing stock box, true CAI, etc.) and return the engine to stock performance?

The 97-04 JTEC/JTEC+ PCMs are very different from the 05-06 NGC3. The earlier ones run on MAP and RPM tables.

With the JTEC PCMs, if the filter and intake plumbing reduce restriction, they WILL increase the MAP value at WOT at peak RPM and that improvement will not be adjusted/learned out over time. They may also slightly improve the air/fuel mixture. If you are not at WOT, then the vehicle is in closed loop, constantly mapping for 14.7:1 combustion and learning trim adjustments. At partial throttle you could say it "learns" it out and has "no effect".

When I got my wideband O2 sensor installed I was seeing it run too rich on the stock open loop fuel map plus power enrichment. However, stock on my 04 didn't kick over from closed loop to power enrichment for about 12 seconds. But then at peak power, it runs way too rich at 10.8:1 to make power efficiently at my elevation.

I've edited my setting so that it kicks into open loop after .5 seconds and power enrichment doesn't go past 12.8:1 at any rpm. It doesn't unlearn this, even after disconnecting the battery.

But this is the thing with the CAI and windstar cowl intakes. They only start making any difference at 3000rpm WOT and don't peak until 4500 where the stock cam rolls over.

 

[SkylinesSuck]

Reviving an old thread. I'm wondering if there was ever any further testing on this topic above, whether tested by @Jezza or by others. Has anyone run a simple mod like this long enough, without a tune to go with it, to find out whether the PCM will simply adjust to changes in air intake (e.g. removing stock box, true CAI, etc.) and return the engine to stock performance?

He sold the dyno so I'm guessing no. But also no, the PCM will not adjust to return the engine to stock performance. This is an old wive's tale started by people who didn't understand how things work and didn't bother to learn. There is no mechanism to facilitate it in a JTEC PCM. Ask anybody who claims it for proof and they will point you at some other forum where somebody else said so.

 

[SkylinesSuck]

Not really by itself, but combined with headers, free flow exhaust, cat delete and any other changes, ie cam swap, gearing, etc. along with a custom written tune and a pcm reflash to tie everything together can drastically make a difference according to guys doing it on my Ram forum. It's more of just a piece of the puzzle from everything I've read and researched from guys actually doing it. I've also read the pcm will just return back without a reflash for a custom tune and the mods to support it.

No and no. Jezza saw measurable gains from the intake alone. And like I said above, complete hogwash. Please quit repeating it.

 

[macleanflood]

I was looking at tuning... specifically Flyin Ryan...after stroking my 4.0...and it's in the neighborhood of $1200 and that doesn't include the $400 for an HP tuners box.

Then I'm tuning a PCM that effectively has 18 PIDs. It's primitive and while results can be had...they seem to be hard won.

Really leaning towards a Haltech. I can practically buy it for the cost of one tuning session.

And I've got my old engine on a stand. So I can build a harness and play with proof of concept.

-Mac

 

[SkylinesSuck]

If Haltech can be made to be semi-plug-and-play and drive my factory gauges, I'm in. SO much more capability.

 

[macleanflood]

If Haltech can be made to be semi-plug-and-play and drive my factory gauges, I'm in. SO much more capability.

I'd replace the factory gauges with one of their LED screens and a 3d printed mount.

You could replicate the factory gauges with the screen...and then swipe or mash a button and have more data like actual oil pressure and temp, fuel pressure and temp.

Plus the Haltech can integrate in the can bus for my iBooster.

And run my lockers and accessories...lights.

-Mac

 

[ColoJeep]

I'd replace the factory gauges with one of their LED screens and a 3d printed mount.

You could replicate the factory gauges with the screen...and then swipe or mash a button and have more data like actual oil pressure and temp, fuel pressure and temp.

Plus the Haltech can integrate in the can bus for my iBooster.

And run my lockers and accessories...lights.

-Mac

Be glad you don't have emission testing forced upon you .

 

[SSTJ]

With the JTEC PCMs, if the filter and intake plumbing reduce restriction, they WILL increase the MAP value at WOT at peak RPM and that improvement will not be adjusted/learned out over time. They may also slightly improve the air/fuel mixture. If you are not at WOT, then the vehicle is in closed loop, constantly mapping for 14.7:1 combustion and learning trim adjustments. At partial throttle you could say it "learns" it out and has "no effect".

Very helpful, thank you.

But also no, the PCM will not adjust to return the engine to stock performance. This is an old wive's tale started by people who didn't understand how things work and didn't bother to learn. There is no mechanism to facilitate it in a JTEC PCM.

Thanks. And although I realize it's not quite the same thing, do you agree with the distinction that GoldenGorilla makes above? I could see how the closed-loop behavior that he describes might be described by some as "PCM adjusts to return the engine to stock performance".

Not at all, we tend to see the programming adapt to the power adder and eventually return it back to the stock power level. I'd like to see if you found a way to circumvent that.

I have a 99. For a couple of years, we went to Big Bear every weekend that was not winter and a few in the winter. Same trip along the toll road. Last toll booth is at the top of a long hill. With the cruise control set at 65 it would invariably downshift to second right even with a particular sign without fail.

I added several things one at a time. All the typical stuff, CAI, High flow filter, high flow exhaust. But only one thing at a time.

Each item would work very well the first trip over the hill and delay the downshift by a noticeable margin sometimes even pulling the hill to the top in drive. The next trip it would be right back to downshifting into second at the exact same spot.

Thanks for this. Do you agree that this behavior would fall under the category of closed-loop behavior, at partial throttle, as GoldenGorilla described above? If so, then maybe the answer to your original question, about running the mod for a month and then re-testing, is that it would still show the same improvement, since the improvement was in open loop mode at WOT and above 3k RPMs?

 

[Tray Burge]

No and no. Jezza saw measurable gains from the intake alone. And like I said above, complete hogwash. Please quit repeating it.

Sure thing Mr. Suck.
PCM's are adaptable and do learn your driving habits. But, I believe we're just splitting hairs here on the entire topic?
I do agree some CAI's do add a noticible difference, but very little by themselves. The Vararam is the only CAI on the market with Dyno proven gains, but then, that also depends on the experience of the Dyno technician too.
Bottom line, CAI alone doesn't do too much, I agree some do a little, but to see true gains you have to complete the whole puzzle.

 

[GoldenGorilla]

Thanks. And although I realize it's not quite the same thing, do you agree with the distinction that GoldenGorilla makes above? I could see how the closed-loop behavior that he describes might be described by some as "PCM adjusts to return the engine to stock performance".

I know it sounds like what I'm saying, but it isn't precisely.

All PCMs have long term and short term fuel trim tables which it adjusts over time while you're driving. If you disconnect the battery or otherwise force the PCM into relearning, you might notice that it runs a bit different for a while as it rebuilds those tables. It's constantly reading the narrowband O2 sensor voltage in closed loop and adjusting the fuel to run at stoichimetric which is 14.7:1 for pump gas. It uses those tables to predict what is needed. Changing the restriction in the system might mean for 20 minutes of driving the PCM is "learning" a change. But when we go into wide open throttle, it kicks out of closed loop (after some time) and moves to the open loop tables and those are static MAP and RPM driven.

A CAI really doesn't seem to have any performance effect at all in lower rpms in WOT and I would assume zero effect in part throttle into even higher rpms. No change in MAP, no change in rpm = no change in the PCM commands to the spark or fuel. So there is really nothing to learn or unlearn. Maybe up in the 4000rpm range you start to see some part throttle situations where the CAI is flowing better than stock and you see less pressure dip in the intake. Maybe it's a bit more efficient in certain situations.

It's kinda like the placebo effect of a 62mm throttle body. The stock motor can't pull more air into the cyclinder than the stock throttle body supplies, so it's not a restriction. But the larger bore of a 62mm throttle body means that the throttle cracks open more with less push of the pedal, making you "think" the throttle is sharper or more responsive. On the dyno they're ineffective on a stock 4.0L at wide open throttle.

 

[Tray Burge]

I know it sounds like what I'm saying, but it isn't precisely.

All PCMs have long term and short term fuel trim tables which it adjusts over time while you're driving. If you disconnect the battery or otherwise force the PCM into relearning, you might notice that it runs a bit different for a while as it rebuilds those tables. It's constantly reading the narrowband O2 sensor voltage in closed loop and adjusting the fuel to run at stoichimetric which is 14.7:1 for pump gas. It uses those tables to predict what is needed. Changing the restriction in the system might mean for 20 minutes of driving the PCM is "learning" a change. But when we go into wide open throttle, it kicks out of closed loop (after some time) and moves to the open loop tables and those are static MAP and RPM driven.

A CAI really doesn't seem to have any performance effect at all in lower rpms in WOT and I would assume zero effect in part throttle into even higher rpms. No change in MAP, no change in rpm = no change in the PCM commands to the spark or fuel. So there is really nothing to learn or unlearn. Maybe up in the 4000rpm range you start to see some part throttle situations where the CAI is flowing better than stock and you see less pressure dip in the intake. Maybe it's a bit more efficient in certain situations.

It's kinda like the placebo effect of a 62mm throttle body. The stock motor can't pull more air into the cyclinder than the stock throttle body supplies, so it's not a restriction. But the larger bore of a 62mm throttle body means that the throttle cracks open more with less push of the pedal, making you "think" the throttle is sharper or more responsive. On the dyno they're ineffective on a stock 4.0L at wide open throttle.

This guy obviously know's his shit.

 

[GoldenGorilla]

PCM's are adaptable and do learn your driving habits.

The 97-04 PCMs have very little to learn and I can assure you they aren't "smart" enough to learn anything about your habits. The only impact throttle position has on them it to kick them into WOT condition at 100%. There are some spots in the tables for tuning part throttle fuel enrichment, but I've honestly NEVER seen evidence of it using that in logs (ie high load at low rpm part throttle) and I've tried to create such conditions with very long log files.

The 05-06 NGC3 PCMs have a little more sophistication but I haven't spent enough time with the one I have access to, to know for sure if can actually "learn" anything.

 

[ColoJeep]

But the larger bore of a 62mm throttle body means that the throttle cracks open more with less push of the pedal, making you "think" the throttle is sharper or more responsive. On the dyno they're ineffective on a stock 4.0L at wide open throttle.

This is true , and reminds me of trucks we had at the county I worked for. The 08 Ram 2500 with the 5.7 Hemi had a real aggressive " tip-in " built into the electronic throttle. You felt like it had a lot of power , ( rated @ 345 h.p. ) . The 01 HD2500 Chevy , ( rated @ 310 h.p. ) had cable TB and felt very linear . However the 6.0 would run away from the Ram every time , and pulled our Kubota M-4900 on a 2 axle trailer much better. Much of vehicle performance is based on impressions rather than statistics .

 

[SkylinesSuck]

I know it sounds like what I'm saying, but it isn't precisely.

All PCMs have long term and short term fuel trim tables which it adjusts over time while you're driving. If you disconnect the battery or otherwise force the PCM into relearning, you might notice that it runs a bit different for a while as it rebuilds those tables. It's constantly reading the narrowband O2 sensor voltage in closed loop and adjusting the fuel to run at stoichimetric which is 14.7:1 for pump gas. It uses those tables to predict what is needed. Changing the restriction in the system might mean for 20 minutes of driving the PCM is "learning" a change. But when we go into wide open throttle, it kicks out of closed loop (after some time) and moves to the open loop tables and those are static MAP and RPM driven.

A CAI really doesn't seem to have any performance effect at all in lower rpms in WOT and I would assume zero effect in part throttle into even higher rpms. No change in MAP, no change in rpm = no change in the PCM commands to the spark or fuel. So there is really nothing to learn or unlearn. Maybe up in the 4000rpm range you start to see some part throttle situations where the CAI is flowing better than stock and you see less pressure dip in the intake. Maybe it's a bit more efficient in certain situations.

It's kinda like the placebo effect of a 62mm throttle body. The stock motor can't pull more air into the cyclinder than the stock throttle body supplies, so it's not a restriction. But the larger bore of a 62mm throttle body means that the throttle cracks open more with less push of the pedal, making you "think" the throttle is sharper or more responsive. On the dyno they're ineffective on a stock 4.0L at wide open throttle.

This x100. I've typed that out (or something similar) so many times. I don't bother anymore, but thank you GG for fighting the his fight!

And also yes, I agree a high flow and/or cold air intake is not going to make a significant difference for most people driving their TJ's in a sane way.

 

[SSTJ]

I know it sounds like what I'm saying, but it isn't precisely.

All PCMs have long term and short term fuel trim tables which it adjusts over time while you're driving. If you disconnect the battery or otherwise force the PCM into relearning, you might notice that it runs a bit different for a while as it rebuilds those tables. It's constantly reading the narrowband O2 sensor voltage in closed loop and adjusting the fuel to run at stoichimetric which is 14.7:1 for pump gas. It uses those tables to predict what is needed. Changing the restriction in the system might mean for 20 minutes of driving the PCM is "learning" a change. But when we go into wide open throttle, it kicks out of closed loop (after some time) and moves to the open loop tables and those are static MAP and RPM driven.

A CAI really doesn't seem to have any performance effect at all in lower rpms in WOT and I would assume zero effect in part throttle into even higher rpms. No change in MAP, no change in rpm = no change in the PCM commands to the spark or fuel. So there is really nothing to learn or unlearn. Maybe up in the 4000rpm range you start to see some part throttle situations where the CAI is flowing better than stock and you see less pressure dip in the intake. Maybe it's a bit more efficient in certain situations.

It's kinda like the placebo effect of a 62mm throttle body. The stock motor can't pull more air into the cyclinder than the stock throttle body supplies, so it's not a restriction. But the larger bore of a 62mm throttle body means that the throttle cracks open more with less push of the pedal, making you "think" the throttle is sharper or more responsive. On the dyno they're ineffective on a stock 4.0L at wide open throttle.

Thanks again. So, to be sure I follow this: would you agree that the PCM's long- and short-term fuel trim tables, being constantly adjusted over time to achieve 14.7:1, would explain why Blaine's hill experiment seemed to show no gains despite the hardware changes? That is, assuming that he was driving below WOT, and likely in closed-loop mode? But since Jezza was at WOT, he did see gains above 3k RPMs in open-loop mode?

If I'm still wrong, please feel no need to give another lengthy reply. I have a lot to learn.

 

[GoldenGorilla]

Thanks again. So, to be sure I follow this: would you agree that the PCM's long- and short-term fuel trim tables, being constantly adjusted over time to achieve 14.7:1, would explain why Blaine's hill experiment seemed to show no gains despite the hardware changes? That is, assuming that he was driving below WOT, and likely in closed-loop mode? But since Jezza was at WOT, he did see gains above 3k RPMs in open-loop mode?

Yes.