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I asked this on another thread, but got no response from the experts. I believe exhaust mods, bigger throttle bodies, headers, CAI and other bolt on mods will NOT increase performance unless a tune is part of the upgrade. I believe this because the fuel input is controlled by a computer. Unless the computer is "told" that mods have been incorporated, it will believe that it should schedule fuel flow/ratio for a "Non Modded Car."

Others disagree. Some have stated that the computer will adjust for increased airflow accordingly. What say you (Modermuscle/Arrington/Stevewhite/Duablosport/ etc.) ?
 

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Discussion Starter #2 (Edited)
I wonder if the vendors will NOT answer this because....

...it could cut into PROFITs? Perhaps they fear they may NOT sell components UNLESS they sell tuners? Perhaps Diablo Sport WILL answer because my logic favors sales for them?
 

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Discussion Starter #3 (Edited)
The Sunday afternoon silence is deafening...

....I suppose confirmation has been received.... by LACK of vendor/SME response:

1. They won't answer because they could get in trouble (company bottom line trumps everything....I get it)?

2. MOD's DO NEED TUNE's, as the modder, who bolts on performance components without a tune, just blew hard earned $$$ on a CAI, Intake or exhaust, etc, that will yield ZERO gains. These MOD's may decrease performance?

Now I open this thread to non-vendors, who have knowledge/experience...who may "enlighten" us.
 

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I agree with you. You'll get most out of your mods with a tune. Even the simple cai and exhaust bolt on will benefit from a tune. We live in a different world now when it comes to cars. I've spoken to many old timers (mechanics) that have no clue about the new stuff.
The reason you're not getting a response from vendors is because they don't wanna admit it on public forum and will hurt their bottom line.
There's a lot of misinformation out there. So I say do your homework before you do the mod. You'll be surprised what you'll learn.


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Whatever upgrade in power you will get from a cai or exhaust will be negated by pcm's adaptives and torque management. The tune removes almost all of the torque management so the car can realize the gains from the tune
 

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Most ECM's have some "give" to them to allow for some added O2 to come into the system and they will add fuel accordingly. This is how many people can add 100hp shots of NO2 to a stock setup and be OK. The system really uses the O2 sensors and the MAF sensor to determine what O2 is coming in and out of the system to adapt fuel trims.

Once the injectors hit (I seem to recall) 90%+ duty cycle, you have pretty much run out the amount of fuel that can be added by the current setup and tuning/bigger injectors are required.

SO, in many cases till you start to hit the limits of the system, tuning probably buy you very little. Remember, the factory tune has to take into account many thing BESIDES performance, there are LAWS manufacturers have to take into account as well as possible warantee issues. I would say, for most normal driving, all this stuff is generally just a way to lighten your wallet.
 

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Wait wait...because your question here was not answered within 5 1/2 hours ON A SUNDAY...you are claiming you've won some argument in another thread?

OooooKayyyyy...
 

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I remember when I was watching a youtube video posted by dodge, the guy was putting in a mopar CAI and he said that you wont notice a difference at first, but after 50-60 miles, the computer will reset and it will accomodate it.
 

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Sublime is correct, your wrong :bigthumb:. Cause no company would EVER make claims that was not true. I mean I learned from him that I can get 16hp from just a cat-back exhaust!!:notallthere: Order has been placed! I mean because they make a video and claim 16hp then it is true, I mean surely they could have atleast had a 3rd party do the testing for them. But why do that when it will show that you don't gain crap from a cat-back.

Either way its always best to tune for mods, just slapping everything on without tuning you will see a small gain. But tuning it after is where you will see the most gains and better performance out of your mods. Except for cat-backs, as most everyone (hint everyone) knows cat-backs are more for the sound than power, you may get lucky and gain 1-2hp out of it.
 

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I asked this on another thread, but got no response from the experts. I believe exhaust mods, bigger throttle bodies, headers, CAI and other bolt on mods will NOT increase performance unless a tune is part of the upgrade. I believe this because the fuel input is controlled by a computer. Unless the computer is "told" that mods have been incorporated, it will believe that it should schedule fuel flow/ratio for a "Non Modded Car."

Others disagree. Some have stated that the computer will adjust for increased airflow accordingly. What say you (Modermuscle/Arrington/Stevewhite/Duablosport/ etc.) ?
Follow up with Luke at Steve White. I've spoken to him in person and you can get HP gains without a tune. For example, my conversation was in reference to an R/T and the addition of shorty headers which typically yield 15-20 HP without a tune. You have an SRT with great factory manifolds so you would need long tube headers to see any benefit. I would reach out to Luke though.
 

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without a tune most common bolt on mods will be limited in their benefit.
a tune is needed for any significant/measurable gains.
the two most common bolt on mods I see people doing (intake and exhaust) are 99% of the time for looks and sound.

now whether there is an organized attempt by vendors to keep down the knowledge of bolt on's being limited without a tune I'll leave to the conspiracy therorists to discuss at length
 

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....I suppose confirmation has been received.... by LACK of vendor/SME response:

1. They won't answer because they could get in trouble (company bottom line trumps everything....I get it)?

2. MOD's DO NEED TUNE's, as the modder, who bolts on performance components without a tune, just blew hard earned $$$ on a CAI, Intake or exhaust, etc, that will yield ZERO gains. These MOD's may decrease performance?

Now I open this thread to non-vendors, who have knowledge/experience...who may "enlighten" us.
If my memory is correct I believe were about the same age. (48). Remember the old days? When you replaced your stock intake, carb, and exhaust manifolds with a Holley, headers and aluminum intake in most cases the car would perform better. Now if you took the time to truly tune the car ( rejet the carb, recurve the distributor etc) the car would perform much better. Back then we used a CO meter, engine analyzer etc to get the best possible tune. I was lucky to learn at a very young age that tuning a car correctly (even stock) would always equal a better performing car.

Today, I believe the same concept still applies with the difference being today the tuning is performed on the computer.
Data logging and a good computer tune will make a stock car perform better (canned tune) and a car with mods properly tuned (data logging with a custom tune or dyno tune) perform even better. Just like the old days but using today's technology.
 

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Discussion Starter #16 (Edited)
No.

Wait wait...because your question here was not answered within 5 1/2 hours ON A SUNDAY...you are claiming you've won some argument in another thread?

OooooKayyyyy...
"Some gains?" What does that mean? 3 HP? I asked the question on another thead...It was ignored. It's now Monday, 5:42 PM EST. Want to make a bet that they respond with REAL Data.
 

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What data are you looking for? be more specific , problem is most of the time when a customer has their car on a dyno it is for a dyno tune.

It is not the independent shops responsibility to test every manufactures product to see what gains can be had with no tune. We can only go by what the manufacture tells us what the gains are. However when it comes to minor bolt on's IE: Cold air intakes, Ported TBs, most of the gains are had without the tune. When you start looking at High flow cats and Long tube you need a tune period for the car to perform and not throw a code but I do not consider headers a mild bolt on.
 

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Most ECM's have some "give" to them to allow for some added O2 to come into the system and they will add fuel accordingly. This is how many people can add 100hp shots of NO2 to a stock setup and be OK. The system really uses the O2 sensors and the MAF sensor to determine what O2 is coming in and out of the system to adapt fuel trims.

Once the injectors hit (I seem to recall) 90%+ duty cycle, you have pretty much run out the amount of fuel that can be added by the current setup and tuning/bigger injectors are required.

SO, in many cases till you start to hit the limits of the system, tuning probably buy you very little. Remember, the factory tune has to take into account many thing BESIDES performance, there are LAWS manufacturers have to take into account as well as possible warantee issues. I would say, for most normal driving, all this stuff is generally just a way to lighten your wallet.
You are right on the money.
 

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Discussion Starter #19 (Edited)
I'm looking for info on the actual effect of boltons without tunes:

What data are you looking for? be more specific , problem is most of the time when a customer has their car on a dyno it is for a dyno tune.

It is not the independent shops responsibility to test every manufactures product to see what gains can be had with no tune. We can only go by what the manufacture tells us what the gains are. However when it comes to minor bolt on's IE: Cold air intakes, Ported TBs, most of the gains are had without the tune. When you start looking at High flow cats and Long tube you need a tune period for the car to perform and not throw a code but I do not consider headers a mild bolt on.
Examples of the following: I know you guys have the data. (All of You have done enough to have the data).

1. Longtube Headers with, and without tune. (no other mods)
2. Shorty Headers with, and without tune. (no other mods)
3. Supercharger (without tune...is it possible?)
4. CAI with, and without tune. (no other mods)
5. Bigger throttle body with, and without tune. (no other mods)

I'm not interested in combined effects of multiple mods as there are too many variables. By isolating a single mod (you pick the brand), we can see the effects of the mod with and without tune. Just interested in the relationship of computer control over single mods. I'm interested in this, Example: Brand X Long Tubes without tune yield 5 HP. With Tune 15 HP. Tune only yields 7 HP.

Or: Brand Y 87 mm throttlebody yields 0 HP without tune. But yields 11 with tune. I don't care if you use the term "Brand X or Y," as I'm not interested in brands specifically. Just want to understand real effects.
 

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Most ECM's have some "give" to them to allow for some added O2 to come into the system and they will add fuel accordingly. ...
SO, in many cases till you start to hit the limits of the system, tuning probably buy you very little.
This is my take on the situation.

Up to a point, the stock ECM will accommodate some changes, and will adjust the system accordingly. That ECM operates within a given set of parameters, however. Parameters that might be expected to occur with a stock, or mostly stock system. (thinking CAI, and maybe some low restriction mufflers, or a resonator delete. Stuff considered "bolt-on".)

When you start adding long tube headers. cams, big throttle bodies, etc, you will eventually run the parameters of the stock tune "up against a wall". Optimal performance will then require a tune.

Regarding canned tunes on mostly stock systems... Manufacturers design the stock tune for the "best all around" performance, taking a lot of factors into consideration. The main factors they are worried about are reliability, emissions and fuel economy. It's all a compromise.

As enthusiasts, our priorities are probably a bit different. I would guess that, by and large, we give little thought to emissions. As long as we can squeak by the test, we don't care. (If there is even a test in our neck of the woods.)
Maybe just a little more thought is given to fuel economy, but we still don't have to meet CAFE requirements, like a manufacturer does. We'll frequently settle for "good enough".
Reliability? Well... most of us say we want it, but that doesn't always stop us from adding another degree of ignition advance or another pound of boost, if it will gain us another tenth at the strip. If something breaks, well, awshit...
A canned tune stacks the "compromise" more towards performance, without changing anything enough to a point that something is going to break. The tune will likely still have to pass emissions (even if "just barely") and will have to not break stuff.

Kind of a long winded answer, but that has been my observation, over the years, and with different manufacturers.
 
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