Interesting article on tuning....
Interesting article on tuning....
I came across this article while investigating water injection. The ideas in the article are not new and are fairly well known but they are fundamental and I found it helpful to see it all broken down, soups to nuts.
http://www.aquamist.co.uk/info/docum...aper/title.htm
One interesting highlight is the list of the three fundamentals of tuning methodology: boost profile, fuel profile & timing profile. I've seen Al employ all of these, as I'm sure any tuner worth their salt does. However, the first fundamental, building the desired boost profile is often overlooked or assumed to be correct when the car rolls in the door. I don't think many tuners spend alot of time looking at the boost profile as a first step and assume it to be correct and skip to tuning fuel and timing. Only when crap isn't working as expected is the system examined for boost problems. I can speak from personal experience that boost problems have generally caused me more issues with performance and driveability than the state of my fuel tuning or ignition tuning. Frankly, finding boost leaks can be a pain in the *** unless you've got the right tools. If you're going to spend the time and money to purchase a performance tune for your forced induction vehicle, make sure your boost system with all of it's associated plumbing and it's control systems are in good working order. Failure to make sure your system is leak free and has effective boost control systems in place will only lead to dissapointment with your tune.
The article concludes that the obvious key to unlocking the maximum potential of your motor is through leaner running conditions. The closer you can get to AFRs of around 12.5:1 the more power you are likely to make. The only way to acheive these AFRs without grenading your motor is by lowering charge air temperature and reducing in cylinder temperatures to keep knock under control. Bear in mind that the factory ECU keeps knock under control by dumping fuel and pulling timing. It even does this preemptively, before it even hears knock! Fuel consumption goes up and power and torque go down. As an alternative to dumping fuel, water injection is an extremely effective means to combat knock. When a water injection system is properly designed with effective safeguards in place, it is safe as well as effective.
I'll put the soapbox away now. Happy motoring...
http://www.aquamist.co.uk/info/docum...aper/title.htm
One interesting highlight is the list of the three fundamentals of tuning methodology: boost profile, fuel profile & timing profile. I've seen Al employ all of these, as I'm sure any tuner worth their salt does. However, the first fundamental, building the desired boost profile is often overlooked or assumed to be correct when the car rolls in the door. I don't think many tuners spend alot of time looking at the boost profile as a first step and assume it to be correct and skip to tuning fuel and timing. Only when crap isn't working as expected is the system examined for boost problems. I can speak from personal experience that boost problems have generally caused me more issues with performance and driveability than the state of my fuel tuning or ignition tuning. Frankly, finding boost leaks can be a pain in the *** unless you've got the right tools. If you're going to spend the time and money to purchase a performance tune for your forced induction vehicle, make sure your boost system with all of it's associated plumbing and it's control systems are in good working order. Failure to make sure your system is leak free and has effective boost control systems in place will only lead to dissapointment with your tune.
The article concludes that the obvious key to unlocking the maximum potential of your motor is through leaner running conditions. The closer you can get to AFRs of around 12.5:1 the more power you are likely to make. The only way to acheive these AFRs without grenading your motor is by lowering charge air temperature and reducing in cylinder temperatures to keep knock under control. Bear in mind that the factory ECU keeps knock under control by dumping fuel and pulling timing. It even does this preemptively, before it even hears knock! Fuel consumption goes up and power and torque go down. As an alternative to dumping fuel, water injection is an extremely effective means to combat knock. When a water injection system is properly designed with effective safeguards in place, it is safe as well as effective.
I'll put the soapbox away now. Happy motoring...
Last edited by propellerhead; Oct 31, 2004 at 09:00 AM.
Good article
On Evos - the boost level and boost leaks - (if any) become critical becuase on the Evo - unlike many other cars - the small stock turbo comes stock being worked fairly hard. By the time you are adding a few modifications and doing tuning you are starting to reach the maximum power delivery levels of the stock turbo very quickly. Taking that turbo out of its efficiency range has very poor consequences on the power efficency.
Especially when it comes to tuning the car on a dyno - which in many cases loads the car entirely differently than the street, learning how to set the boost on the dyno in order to closely replicate the real world relationship between turbo loading and power level is critical.
Of course - street tuning is much easier as you simply are adjusting your boost control method to obtain the desired boost level which in most cases we have already figured out through lots of practical experience with Evos.
As far as the boost profile - I can not over stress the importance of having a proper boost control device.
MANY of the electric boost control devices out there now will never produce excelent reults on an evo as they have been deisgned for totally different kind of vehicles. Through a lot of trail and error we have found that the Hallman Pro is the ideal partner to the stock turbo and will produce a near ideal boost profile.
Many of the other boost controllers we have seen either spool too slowly - - have too much boost tapering - - OR have oscilating and wavy boost curves.
On Evos - the boost level and boost leaks - (if any) become critical becuase on the Evo - unlike many other cars - the small stock turbo comes stock being worked fairly hard. By the time you are adding a few modifications and doing tuning you are starting to reach the maximum power delivery levels of the stock turbo very quickly. Taking that turbo out of its efficiency range has very poor consequences on the power efficency.
Especially when it comes to tuning the car on a dyno - which in many cases loads the car entirely differently than the street, learning how to set the boost on the dyno in order to closely replicate the real world relationship between turbo loading and power level is critical.
Of course - street tuning is much easier as you simply are adjusting your boost control method to obtain the desired boost level which in most cases we have already figured out through lots of practical experience with Evos.
As far as the boost profile - I can not over stress the importance of having a proper boost control device.
MANY of the electric boost control devices out there now will never produce excelent reults on an evo as they have been deisgned for totally different kind of vehicles. Through a lot of trail and error we have found that the Hallman Pro is the ideal partner to the stock turbo and will produce a near ideal boost profile.
Many of the other boost controllers we have seen either spool too slowly - - have too much boost tapering - - OR have oscilating and wavy boost curves.
Last edited by DynoFlash; Oct 31, 2004 at 09:04 AM.
Water/Alcohol injection is the way to go especially with our terrible 91 octane here in California. I had good success with my Aquamist System on my Talon Tsi AWD with a small 16G turbo. I've pulled that system from my Talon and will be installing it on my EVO one of these days.
Al, would there be any advantages of getting a tune after installing a WI kit? (about to) I just figured I would start out by trying to crank up the boost, but I'm sure fueling and timing could be adjusted too ey?