Hey, when you guys talk about dyno time, what exactly are you tuning? air-fuel ratio? cam timings? just wondering why you need that. thx~

 

you can tune anything you want that would require using a dyno....it's your call 'cause you pay for the time.

 

from what i know, fuel, air, timing, and that should be it. but for vtec, you have high cam and low cam, and then you have to street tune because the car is on the dyno which has no load on the motor. so if you tune on the street also, you get to tune with the motor under load.

 

Some dyno's are just a measure of whp and wtq. Others have a wideband O2 that measures your fuel ratio based on the RPM range. This measure of fuel allows you to make various adjustments to fuel pressure and timing that can improve your power output. The best way to make these adjustments is with a tunable EMS like Hondata, Uberdata, Neptune, Chrome, etc.

 

Thanks for the insight. And when people go for FI, what else do they tune? What are those blue boxes? VAFC or something...

 

The Greddy blue box is an untunable controller that acts as a 'piggy-back' to your ECU. The VAFC/SAFC are also piggy-backs. These allow you to make minor adjustments to fuel trim and timing (I think). They are not as detailed or tunable as a full EMS.

You can use these tuning units with NA or FI. You are more likely to need them for FI because the OEM computer was not made to account for boost and run correctly with that upgrade.

 

excellent knowledge, thanks~ and if you happen to re-read this thread, finally... what controls the amount of boost?

 

if using a dynapack, it allows you to place a load on the engine, so you can do 'street' tuning while on the dyno.

as far as i know the afc's dont have any ignition timing control

 

a boost controller

 

Well.... secondly, the bc controls boost, but first and foremost the wastegate is your boost controller. The wastegate is what essentially controls boost by the tension of the spring inside of it (external WG). If you don't have a boost controller at all then the boost is totally controlled by the WG. This works by the amount of pressure that builds up from the exhaust ports on your head into the turbo. Once the pressure reaches a certain PSI (or BAR), the WG spring can no longer keep the WG closed so it opens, allowing the extra pressure to bleed off either to a section of exhaust piping after the turbo or to open atmosphere.

When using a manual or electronic boost controller, you can boost up to approximately four times the installed WG spring PSI rating - I was able to hit 16 psi on my 4 psi spring and upgraded to a 10 psi spring. These extra boost controllers work off of vacuum/boost pressure and hold the wastegate closed so that more pressure is able to build, thus creating more boost pressure.

It's a lot to digest, but I hope I've enlightened you a bit.