Does a cold air intake add power on a 4.0?

mrblaine said:
I'll repeat this again for more redundancy. 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.

32RH, geared to 4:10's on 33's.

Not an exact science by any means but clear enough to me that nothing I did was going to have an effect long term without programming changes.

We have the benefit nowadays of that being available, it was not back then in 99.
Click to expand...

That is quite interesting. In terms of science, there seems to be negative feedback of sorts implemented in the programming that cancels out what is seen as anomalous to what the ECU had already learned and stabilized at. It would be really fun to understand how that is implemented.

@Wranglerfix is this something that is very obvious to you given what you know about the TJ ECU?
 
  • Like
Reactions: ColoJeep
mrblaine said:
This is why I tend to avoid these discussions. You know I am not the least bit unintelligent. You know I don't embellish or exaggerate and yet that's your response?

Same hill, same sign, same long pull every weekend for a couple of years and it would downshift at exactly the same spot every time. How much more fucking exact do you want that to be?
Click to expand...
I don't doubt your intelligence in the least, and I value your experience, input, and talent. That's why I'm not attacking you or trying to be a dick. It's not worth it to me if I'd lose your valuable input on the future.

I did say I wasn't arguing your data and it seems like you are stuck on that point. I don't think it's at all conclusive proof but I'm not talking about that at the moment. What I am asking is, if you did these mods and they helped initially, but then stopped helping because the PCM learned around them, wouldn't that prove the mods work fine? Shouldn't we instead be saying performance mods on TJs aren't effective unless you can figure out a way to handle the PCM?
 
psrivats said:
That is quite interesting. In terms of science, there seems to be negative feedback of sorts implemented in the programming that cancels out what is seen as anomalous to what the ECU had already learned and stabilized at. It would be really fun to understand how that is implemented.

@Wranglerfix is this something that is very obvious to you given what you know about the TJ ECU?
Click to expand...
There is an interesting 120'ish page book on how JTEC PCMs work. It goes over what inputs affect timing, long and short term fueling, limp home mode, etc. I'll see if I can dig it up. It's worth the read if you are really interested in how it works.
 
@mrblaine I'll also admit I might be conflating your argument with Jerry's a bit. He is staunchly of the opinion that the factory intake on a 4.0 is perfect and there is zero power to be had by replacing it. Maybe you aren't arguing exactly the same thing and I'm reading that wrong. Apologies if so.
 
Yet there are a few here who will jump on anyone who says such mods don't help performance. Because if they had done them, as I have with a CAI that came on my present TJ, plus a K&N with a "Rock-It" air tube plus a throttle body spacer I installed on my previous TJ in 1998, they'd actually learn from first-hand experience they don't really help. I installed what's at https://www.quadratec.com/products/17010_007.htm on my previous TJ in 1998 and everything they claimed was bullshit. It didn't take me long to learn it was all bullshit despite their lying ads I believed at first. I was naïve then and believed it all... but no longer, it didn't take long to figure out it was all lies. In other words, I'm not making this shit up and I didn't just dream up my 'no' performance gains opinion.

And then there's those few who tack on their favorite face palm avatars pointed at those who say they won't help because they believe they must help because the ads and their cousin Billybob say they work. Once those naysayers get some actual first-hand experience with all that bullshit then they'll finally understand what most of us have been saying for many years.
 
  • Like
Reactions: Zorba
SkylinesSuck said:
There is an interesting 120'ish page book on how JTEC PCMs work. It goes over what inputs affect timing, long and short term fueling, limp home mode, etc. I'll see if I can dig it up. It's worth the read if you are really interested in how it works.
Click to expand...

I would like that very much. Really enjoy reading that kind of stuff. Please do share.
 
  • Like
Reactions: Zorba and SkylinesSuck
Jerry Bransford said:
Yet there are a few here who will jump on anyone who says such mods don't help performance. Because if they had done them, as I have with a CAI that came on my present TJ, plus a K&N with a "Rock-It" air tube plus a throttle body spacer I installed on my previous TJ, they'd actually learn from first-hand experience they don't help. I installed what's at https://www.quadratec.com/products/17010_007.htm on my previous TJ in 1998 and everything they claimed was bullshit, and it didn't take long to learn it was all bullshit... despite their lying ads.

And then they'll tack on their favorite face palm avatars pointed at those who say they won't help even though they believe they must help because the ads and their cousin Billybob say they work. Once those naysayers get some actual first-hand experience with all that bullshit then they'll see what most of us are saying.
Click to expand...
I am again confused. You are deriding heresy from cousin Billybob but when presented with actual dyno results you say "trust my butt dyno and this guy I talked to one time." I will repeat that a "cold air intake" isn't going to do what most people want it to do on a stock 4.0. It isn't going to help push your TJ up a hill in 5th at 2500rpm and it isn't going to turn your TJ in to a race car. 10hp is barely noticable in a 4k lb vehicle. There is also filtration to consider. All that being said, look again at the first post in this thread and see what I have said over and over. Those are hard numbers, not butt dyno tinglings or this guy I talked to on the phone one time's musings.

I don't even disagree with you about recommending an intake for 99% of TJ applications (but consider what the OP is doing in his application and why it's on a dyno). I do get riled up at group think and getting offended by people daring to question the "well established facts." Let's discuss from data and facts not who has the biggest internet street cred. Reference facepalms, those that live in glass houses....

Screenshot_20220326-203618.png
 
  • Like
  • Face Palm
Reactions: srimes, reddvltj, Jamison C and 4 others
SkylinesSuck said:
I am again confused. You are deriding heresy from cousin Billybob but when presented with actual dyno results you say "trust my butt dyno and this guy I talked to one time." I will repeat that a "cold air intake" isn't going to do what most people want it to do on a stock 4.0. It isn't going to help push your TJ up a hill in 5th at 2500rpm and it isn't going to turn your TJ in to a race car. 10hp is barely noticable in a 4k lb vehicle. There is also filtration to consider. All that being said, look again at the first post in this thread and see what I have said over and over. Those are hard numbers, not butt dyno tinglings or this guy I talked to on the phone one time's musings.

I don't even disagree with you about recommending an intake for 99% of TJ applications (but consider what the OP is doing in his application and why it's on a dyno). I do get riled up at group think and getting offended by people daring to question the "well established facts." Let's discuss from data and facts not who has the biggest internet street cred. Reference facepalms, those that live in glass houses....

View attachment 318583
Click to expand...
I actually don't give a fuck what you think. And having a little more experience with seeing dynos in operation than many do, they are NOT the precise machine many believe they are. Their numbers and pointers on their gauges twitch and jump continuously and, yes, they can be manipulated to show anything that is wanted.

That a dyno can show a consistent, like a 5 hp gain for example, on every test after a modification is bullshit, the next run it might show a 5 hp LOSS. Pick the best run for your goals and go for it, that's how their results are used. Dynos are not precision devices and they do NOT give consistent results. For those who think they do give precise and totally repeatable results as you apparently believe, they're living in a dream world.
 
  • Like
Reactions: Wranglerfix
I have been on a dyno a time or 3, including probably 4 or 5 different sessions with my TJ. An expert that does not make me. OP posted multiple back to back runs for consistency. Are you questioning his numbers because you think he was intentionally manipulating them to achieve a desired result or just chalking it all up to statistical variation?

*All of these numbers in comparison to your butt dyno of course.
 
SkylinesSuck said:
I have been on a dyno a time or 3, including probably 4 or 5 different sessions with my TJ. An expert that does not make me. OP posted multiple back to back runs for consistency. Are you questioning his numbers because you think he was intentionally manipulating them to achieve a desired result or just chalking it all up to statistical variation?

*All of these numbers in comparison to your butt dyno of course.
Click to expand...
I question YOUR statements. I know enough to know that dynos are NOT consistent despite your claims. That you claim they're consistent is laughable.
 
  • Like
Reactions: Lorenzo Altarocca
FWIW I don't have a dog in the fight here. I don't sell these things and I didn't buy this one. It was a used unit that came on my '02 and was removed when I went turbo. The only real reason I did this is the Jeep was already on the dyno getting baseline numbers for the upcoming turbo install. I actually anticipated only a 3-5HP gain which would have been within what I would have considered margin of error. The fact is it did twice that amount and did it consistently. The results were not "manipulated" in fact I took reasonable effort to make the inputs as consistent as possible. I have all the runs numbered with the corresponding data, and did not "pick the highest ones". Some dynos are more touchy than others, this one will repeat within a few HP if all the conditions are equal.
 
  • Like
Reactions: Jamison C, SPECWAR, freedom_in_4low and 1 other person
Also if anyone wants I can post or link the raw data from the runs which includes all the timestamps, conditions etc..
 
  • Like
Reactions: SkylinesSuck
Jezza said:
FWIW I don't have a dog in the fight here. I don't sell these things and I didn't buy this one. It was a used unit that came on my '02 and was removed when I went turbo. The only real reason I did this is the Jeep was already on the dyno getting baseline numbers for the upcoming turbo install. I actually anticipated only a 3-5HP gain which would have been within what I would have considered margin of error. The fact is it did twice that amount and did it consistently. The results were not "manipulated" in fact I took reasonable effort to make the inputs as consistent as possible. I have all the runs numbered with the corresponding data, and did not "pick the highest ones". Some dynos are more touchy than others, this one will repeat within a few HP if all the conditions are equal.
Click to expand...
Jezza , for what it's worth I appreciate you posting the dyno results. Again I see your not trying to promote an agenda, your just trying
to establish a solid quantifiable baseline for future mods. My first post poked fun at the " Groupthink " phenomenon, apparently
I severely underestimated the ability of some not to just see your post for what they are, non biased observations.
Don't let the doubters get you down ! I look forward to the new TURBO ! build.
Stay the course my brother !
 
  • Like
Reactions: D's Jeep Wrld, inkedrose, reddvltj and 5 others
Top Bottom
Back