Tuning on Boosted Engine vs a N/A Engine

[HydroTurboss]

Hey fellas!!

My name is Blair and im new to the tuning world. I have been combing this forum for a while now and have learned quite a bit from everyones knowledge. Recently I have been reading the opinion that "Tuning" really only benefits boosted( Turbo/ Supercharged) engines and that Naturally Aspirated Engine don't yield that much of a gain.

Now......This is not my opinion, it is something that I have been hearing about for a bit now from different people on other forums. Being the forum junky that I am I FULLY understand that on forums there are different opinions and everyone has one. I also understand that if you want a Valid answer then you have to talk to the "WALKERS" not the "TALKERS".

So here I am......im asking you. The HP Tuners Experts. What is your take on this claim??

Im curious to know the different changes (remember im new) that can be made on a "boosted" engine vs a "N/A engine". I can only think of changing the Boost pressure on the turbocharger for the advantage of being boosted( changing the air pressure) since this is not possible on an N/A engine( save for adding a bigger intake, Porting and polishing, anything that reduced air restriction)

please be very specific with your responses using the correct "tech Talk". As ive mentioned before, im new to the tuning world and VERY eager to LEARN so I want to learn the "correct theory" of tuning, "different Terms" and "parameters" that a tuner can change on different engines.

Im especially eager to hear from the LS guys. ya know, the LSA/LS9 vs the LS7/LS3 Tunes.

Thanks everyone, im very eagar to hear the answer to this question so I have a CLEAR understand!!

[HydroTurboss]

im not feeling much love for this thread lol

[Pekka_Perkeles]

I guess it depends in which side of the world you happen to reside.

In some countries turbocharged engines - albeit small compared to LS engines - are quite common and by "chip tuning" there can be some notable level of performance gained. Not so typically with normally aspirated engines.

In other words, there's no magical key to unlock some kind of previously unknown, hidden potential of stock LS engines. There may be some exceptions with those engines having adjustable cam (L99 I guess) as well as LS9/LSA that are originally designed (and manufactured) with boost in mind, but I think that's about it.

[DSteck]

I don't really understand what you're asking. Are you asking how to modify a car?

[Pekka_Perkeles]

I don't really understand what you're asking. Are you asking how to modify a car?

I originally had to re-read it, but I think this was the question:

"Recently I have been reading the opinion that "Tuning" really only benefits boosted( Turbo/ Supercharged) engines and that Naturally Aspirated Engine don't yield that much of a gain."

[HydroTurboss]

Ya I apologize for the confusion I was trying my best to get my point acrossed but ^^this guy above my post hit the nail on the head.

I've been told by people that tuning an N/A car isn't wOrth it. Which I don't totally agree is true. They said that tuning a boosted car really on makes tuning worth while

[oakley6575]

Who is "They"?

[Chris@HPTuners]

short answer is "it depends". For example, here in Australia the early LS1's in '99 were detuned by about 50hp. Was a very easy gain.

Most boosted cars are tuned well below the limits for service life requirements. In general it is easier to make power with boosted engines but it is also easier to break things!

I guess when it comes to OEM NA engines many modern small ones (like V6 and below) are tuned very close their mechanical/airflow limits. They require hardware changes to the engine to make bigger top end power gains. However, many can still see good low and midrange power increases.

OEM boosted engines generally make excellent midrange increases and smaller top end, although it depends on the exhaust, intake and OEM turbo/supercharger sizes and if a reasonable intercooler is fitted (in some cases there isn't one).

There are definiately gains in tuning NA engines, but you might need to make some hardware changes to improve airflow, on the flipside most OEM boosted engines are capable of increasing airflow (increasing boost), but might need to make some hardware changes to make them more reliable.

There are many NA LS1 engines out there making incredible power, and then there are many boosted LS1 engines out there making ridiculous power too I've owned both and while i loved the instant tire frying capabilities of my blown LS1, the loping idle and high RPM sound of a tough NA LS1 is hard to beat.

Chris...

[HydroTurboss]

They = other members on various other car forums

[HydroTurboss]

Thanks for the answer dude! On a boosted engine what "variables" can you change?
Besides jacking up the boost what else can be change during tuning?

Knock retard, ignition timing, fuel trims, air/fuel. What are other things that can be changed ? Thanks remember I'm new

[Chris@HPTuners]

Thanks for the answer dude! On a boosted engine what "variables" can you change?
Besides jacking up the boost what else can be change during tuning?

Knock retard, ignition timing, fuel trims, air/fuel. What are other things that can be changed ? Thanks remember I'm new

again, the answer is "it depends" - you'll notice this is a common theme. There is always a compromise.

It's mostly about finding the right balance of boost (airflow and hence fuel) and ignition timing, the balance that makes the most power at each RPM (within the limits of the engine hardware). This balance mostly depends on the effciency of the compressor you are using and also the intercooler setup being used. Higher boost means higher temperatures, higher air temps is the main cause of detonation (for a given compression ratio, fuel etc.). A bigger or better positioned intercooler helps cool the higher temperatures. You also have to be careful of retarding the timing too much because that raises exhaust temps which may exceed the thermal limit of your engine hardware (or dramatically shorten their life). You also have to consider the airflow capabilities of your engine, if the exhaust is restrictive, the camshaft, the supercharger or turbocharger is smallish, etc. Think bicycle pump with your finger blocking the end and how you can burn your finger for no good reason!

Higher boost doesn't always mean more air is entering the engine, and more air entering the engine at higher temperature and less ignition timing, may not make as much power as less air at lower temperature and more ignition timing, especially on a restrictive engine. Often, less boost, lower temps and more timing makes more power and certainly more reliable.

So you can see that i almost talked around a complete circle there, and this is what engine tuners do, continually chase their tail to find the best compromise. Typically the limiting factor is temperature and how long you want things to live. If you are an OEM calibrator, you want that to be the life of the vehicle or at least the length of the warranty. If you're an all out drag race tuner, maybe 1320ft and 9 seconds is all you care for.