[SS_Don]

Do re-tunes work?

I can understand re-tuning when you add a CAI as you are changing the dynamics of the engine by allowing more air into the intake. Same goes for changing the exhaust, adding a super charger or turbocharger, or anything else that changes the operating characteristics of the engine. But when you don't make any changes can a re-tune do anything?

If you search the internet you find a number of companies that claim to be able to boost your HP and improve MPG simply by re-tuning your ECM. There are 3 ways I have found that the ECMs can be re-flashed. You either need to take it to their shop, plug a module into your OBD-II connector and leave it plugged in, or connect your laptop into the OBD-II connector to perform the re-tune yourself.

So my questions are:

1. Do these re-tunes actually work or are they just blowing smoke up your ass?
2. If they do work why don't the car manufacturers tune the ECM at the factory to achieve these HP increases and MPG savings? Seems like it would be a good selling point if a car got more HP and better MPG, especially a sports car.

I hope this leads to a spirted but respectful discussion. It would be interesting to hear from some people who have performed one of these upgrades without changing anything else and have measured before and after to see what the improvements were. Looking forward to the responses.

[m6-lt1]

My understanding on this regarding our cars is this. Chevy already did a really good job with the tune. If you were to get a bone stock car tuned it would gain a little bit of power but not much. Probably won’t really notice it in the seat of your pants.

The reason it’s not tuned like that already is because Chevy will not tune the car on the edge of being lean (which I believe is what these tunes do) because they have to warranty your engine whereas these tuning companies do not. Again Chevy already did a great job with the tune so you’re not going to gain more than single digit hp.

[MatthewAMEL]

Because GM builds tens of thousands of LT1/LT4's. They put the performance right in the mean of power vs reliability.


You can buy crate versions of the LT1 and LT4 with FAR more horsepower, but they don't come with a 5 year warranty.


https://www.chevrolet.com/performanc.../crate-engines



If you make changes to the engine, you need to tell the computer about them. Else, the ECU reads it as a problem/failure and very bad things can happen.


The 'cheapest' power adder for the LT1 is adding E85/FlexFuel.

[Joshinator99]

Good points by the others.

I had a very well respected tuner give me a tune for my bone stock 2017 SS back when it was new. The car was .2 slower and lost 2 MPH in the quarter, on a colder day with identical 60’ times no less. So if you’re staying stock, save your money.

But if you want to make more power than stock, then you will need to tune for the mods you added. The sky is the limit but obviously the warranty goes bye bye. I kissed my warranty goodbye with a whopping 501 miles on my car.

[MightyBobo]

If you have no mods, typically very small gains, if not losses as mentioned above.

If you have some minor mods, typically some mostly small gains typically. The biggest gains are found when you do major mods like a cam swap, or forced induction...

In essence, for a mostly stock car? Save your money, usually.

[SS_Don]

It’s as I thought, blowing smoke.

The only mod I plan right now, once I get the car, is to add the GM CAI.


Sent from my iPhone using Tapatalk

[MightyBobo]

Originally Posted by SS_Don

It’s as I thought, blowing smoke.

The only mod I plan right now, once I get the car, is to add the GM CAI.


Sent from my iPhone using Tapatalk

It was more impactful years ago, on the LS1's and whatnot in older Camaros.

Nowadays, they are tuned pretty damn well.

[Number 3]

It takes a couple of years with a new engine to develop the calibration. An engine comes off the Dino at 50%. First prototypes you see on the road are at 65% cal. It takes a ton of work to get to a launch calibration.

Two weeks after launch “tuners” will come out with what they claim is more HP, better fuel economy and even more wildly, better durability.

OEMs have to balance emissions/fuel economy, performance AND durability in their calibration. “Tuners” do not.

[arpad_m]

Originally Posted by Number 3

It takes a couple of years with a new engine to develop the calibration. An engine comes off the Dino at 50%. First prototypes you see on the road are at 65% cal. It takes a ton of work to get to a launch calibration.

Two weeks after launch “tuners” will come out with what they claim is more HP, better fuel economy and even more wildly, better durability.

OEMs have to balance emissions/fuel economy, performance AND durability in their calibration. “Tuners” do not.

There is certainly some truth to that, and of course not all tuners are equal, but there is no need to dismiss them en masse and put the term in those derisive quotes.

The main inherent advantage OEMs have over them is access to source code and design data, while a tuner has to reverse engineer everything.