what exactly 'tuning' means?
Thread Starter
Team Owner
Joined: Nov 2004
Posts: 20,715
Likes: 25
From: Sorrento Italy
what exactly 'tuning' means?
hi all...i have a '77 C3 with a carbed 575hp stroker and a tvr griffith 5 ltr, for what my cars is concerned tuning means nothing to me for the first car and just a change or re-chip the ecu for the second, but in modern car/new C6 corvettes? i guess is fix a computer to the ecu box and then find the best complement between the many variables of the engine? what program do you use? i'm planning the purchase of a C6Z here in europe and of course i'll mod it the very same day of delivery but i dont kow if any local (spain) tuner will have the proper tools to do the right job, or the programs used in usa are of common use everywhere? is there a masterpiece program which all tuners refer to? thanks for your cooperation
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
LS2edit or HPtuners is the software. It tunes the existing computer.
In the old days a/f was done by turning a screw on the carb, delaying secondaries, changing jets....on the C6 you cant even change the idle for a different cam without reprogramming. Idle isnt just the rpm level...its timing at idle, an Idle air motor allows more or less air in while not under load and there is rate of rpm decrease after you rev.
Timing....you used to turn a distributor for the entire timing range to advance or retard but you could also change counter weights and their springs to change the rate of advance.
Now you map the entire RPM band by load and add where you want and retard where you want.
A/F is measured by O2 sensors in closed loop operation to maintain stoic and when it is lean the car increases the injector fuel delivery and if you are rich, the opposite. At wide open throttle it takes measurements from your previous driving to make the car run 13:1 and the O2's are out of the loop.
When you make changes to the car those changes throw off the car's preset tables that it iuses to estimate proper fueling and timing and then runs wrong and gives you check engine lights since sensors like the manifold absolute pressure doesnt agree with predicted airflow from the other sensor's readings.
Changing exhaust backpressure for instance clears out the cylinders more efficiently causing less remaining hot spent gasses and allows cooler air and fuel to take its place faster...this would cause a lean condition since the air going in is more dense.....lean long term fuel trends = richer WOT operation. Same thing with a more efficient intake manifold...more air gets in than predicted and the car cant compensate unless you tune it to your specific mods.
In the old days a/f was done by turning a screw on the carb, delaying secondaries, changing jets....on the C6 you cant even change the idle for a different cam without reprogramming. Idle isnt just the rpm level...its timing at idle, an Idle air motor allows more or less air in while not under load and there is rate of rpm decrease after you rev.
Timing....you used to turn a distributor for the entire timing range to advance or retard but you could also change counter weights and their springs to change the rate of advance.
Now you map the entire RPM band by load and add where you want and retard where you want.
A/F is measured by O2 sensors in closed loop operation to maintain stoic and when it is lean the car increases the injector fuel delivery and if you are rich, the opposite. At wide open throttle it takes measurements from your previous driving to make the car run 13:1 and the O2's are out of the loop.
When you make changes to the car those changes throw off the car's preset tables that it iuses to estimate proper fueling and timing and then runs wrong and gives you check engine lights since sensors like the manifold absolute pressure doesnt agree with predicted airflow from the other sensor's readings.
Changing exhaust backpressure for instance clears out the cylinders more efficiently causing less remaining hot spent gasses and allows cooler air and fuel to take its place faster...this would cause a lean condition since the air going in is more dense.....lean long term fuel trends = richer WOT operation. Same thing with a more efficient intake manifold...more air gets in than predicted and the car cant compensate unless you tune it to your specific mods.
Last edited by SpinMonster; Dec 9, 2005 at 05:29 PM.
Thread Starter
Team Owner
Joined: Nov 2004
Posts: 20,715
Likes: 25
From: Sorrento Italy
hi and thanks for the explanations...i was going to sell my C3 bad a...to be able to buy a C6 but you made me nearly change my mind, all this electronic iussues smell burnt 
to me, or am i a dinasour 
???
to me, or am i a dinasour ???
Advanced
Joined: Sep 2005
Posts: 77
Likes: 0
Well if you're really interested, the man to talk to is Kikis at EuroAmerican car services but he's located in London UK. Quite a drive up for you. I imported mine with him to the UK and have it as a visitor in Cyprus for 6 months to avoid the heavy duties here... will be selling it in 6 months
Kikis has all sorts of american cars in his garage and modifies anything u can imagine, he had a twin turbo srt10 dodge ram, a supercharged new mustang, couple of oldies, a C4 2 C5s and my C6 around a month ago in his garage... ull find anything from ferraris to trucks there... search him out on the net.
His garage is in north london and his number is +44 207 281 8018, ask 4 Kikis. He is a Cypriot too that has been in London for the past 30 years or something
Kikis has all sorts of american cars in his garage and modifies anything u can imagine, he had a twin turbo srt10 dodge ram, a supercharged new mustang, couple of oldies, a C4 2 C5s and my C6 around a month ago in his garage... ull find anything from ferraris to trucks there... search him out on the net.
His garage is in north london and his number is +44 207 281 8018, ask 4 Kikis. He is a Cypriot too that has been in London for the past 30 years or something
Burning Brakes
Joined: Nov 2005
Posts: 1,037
Likes: 126
St. Jude Donor '07
Originally Posted by SpinMonster
LS2edit or HPtuners is the software. It tunes the existing computer.
In the old days a/f was done by turning a screw on the carb, delaying secondaries, changing jets....on the C6 you cant even change the idle for a different cam without reprogramming. Idle isnt just the rpm level...its timing at idle, an Idle air motor allows more or less air in while not under load and there is rate of rpm decrease after you rev.
Timing....you used to turn a distributor for the entire timing range to advance or retard but you could also change counter weights and their springs to change the rate of advance.
Now you map the entire RPM band by load and add where you want and retard where you want.
I have no access to tuners. If I just go with a cat back (Corsa Sports) and CAI will the car need to be tuned? Thanks.
A/F is measured by O2 sensors in closed loop operation to maintain stoic and when it is lean the car increases the injector fuel delivery and if you are rich, the opposite. At wide open throttle it takes measurements from your previous driving to make the car run 13:1 and the O2's are out of the loop.
When you make changes to the car those changes throw off the car's preset tables that it iuses to estimate proper fueling and timing and then runs wrong and gives you check engine lights since sensors like the manifold absolute pressure doesnt agree with predicted airflow from the other sensor's readings.
Changing exhaust backpressure for instance clears out the cylinders more efficiently causing less remaining hot spent gasses and allows cooler air and fuel to take its place faster...this would cause a lean condition since the air going in is more dense.....lean long term fuel trends = richer WOT operation. Same thing with a more efficient intake manifold...more air gets in than predicted and the car cant compensate unless you tune it to your specific mods.
In the old days a/f was done by turning a screw on the carb, delaying secondaries, changing jets....on the C6 you cant even change the idle for a different cam without reprogramming. Idle isnt just the rpm level...its timing at idle, an Idle air motor allows more or less air in while not under load and there is rate of rpm decrease after you rev.
Timing....you used to turn a distributor for the entire timing range to advance or retard but you could also change counter weights and their springs to change the rate of advance.
Now you map the entire RPM band by load and add where you want and retard where you want.
I have no access to tuners. If I just go with a cat back (Corsa Sports) and CAI will the car need to be tuned? Thanks.
A/F is measured by O2 sensors in closed loop operation to maintain stoic and when it is lean the car increases the injector fuel delivery and if you are rich, the opposite. At wide open throttle it takes measurements from your previous driving to make the car run 13:1 and the O2's are out of the loop.
When you make changes to the car those changes throw off the car's preset tables that it iuses to estimate proper fueling and timing and then runs wrong and gives you check engine lights since sensors like the manifold absolute pressure doesnt agree with predicted airflow from the other sensor's readings.
Changing exhaust backpressure for instance clears out the cylinders more efficiently causing less remaining hot spent gasses and allows cooler air and fuel to take its place faster...this would cause a lean condition since the air going in is more dense.....lean long term fuel trends = richer WOT operation. Same thing with a more efficient intake manifold...more air gets in than predicted and the car cant compensate unless you tune it to your specific mods.
Thanks.
Burning Brakes
Joined: Jun 2004
Posts: 1,200
Likes: 14
From: Playa Vista CA
Originally Posted by Driver_WT
I have no access to tuners (small town in Canada). If I am having cat back (Corsa Sports) and CAI installed will I need to have the car tuned?
Thanks.
Thanks.
Joe
Race Director
Joined: Oct 2004
Posts: 10,089
Likes: 14
Originally Posted by panic
hi and thanks for the explanations...i was going to sell my C3 bad a...to be able to buy a C6 but you made me nearly change my mind, all this electronic iussues smell burnt to me, or am i a dinasour ???
to me, or am i a dinasour ???
The computerized systems give you much more control than you had in the old days. You just have to learn how to use different tools. Instead of turning a screwdriver, changing jets, adjusting a choke, recurving a distributor, etc, you simply need to learn how to enter numbers into a laptop. Much easier, much quicker, much less trial and error.
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