PFC 4 boost settings & duty cycles?

GoRacer · 04-26-07, 11:55 AM

I know 2 of the 4 are for the twins (secondary settings) but when converted to single, which of the two primary does it use? I don't know of any way to switch from one to the other unless you just leave it highlighted when you exit that screen.

I know the duty cycle affects boost but how do I calculate why duty cycle I should be at for my boost level. I don't remember the settings Steve Kan had. With my last tune Neptunespeed changed the duty cycle to 40%, did a tune to 13psi and changed the boost afterwards to 15psi. ...yes I know, won't go back there ever.

rynberg · 04-26-07, 12:44 PM

The only way to switch is to leave it highlighted if you are using the Commander. There is no formula for adjusting the duty cycle, just start experimenting (this is why a separate EBC is better IMO).

dradon03 · 04-26-07, 12:48 PM

I remember reading in the manual that if you switch from twins to single you have to have prim=sec on your setting. It is in the boost section of the Apexi power FC manual.

GoRacer · 04-26-07, 01:59 PM

I'm not sure what "prim=sec" means? I know there are seperate two settings 1 & 2. Within those two, it's split again for primary and secondary (for the twins). For a single turbo, only the secondary setting is used. (at least that's what I remember and how I interprited it).

So the questions are:
* Do you loose boost setting #2 (or #1) when going single?
...or is it still possible to just highlight and exit (will have to find open road to try).
* How do I determine the correct duty cycle for my boost level?
...if someone is runnign a GT35R @ 15lbs could you tell me what your duty cycle is at?

dradon03 · 04-26-07, 02:09 PM

Your correct duty cycle I don't get it.

I meant Primary Boost = Secondary Boost. The two settings are two setting which you choose to use and the one you leave highlighted is used.

You determine your correct duty cycle because looking at your wideband during pulls you see if you are running too lean or too rich and adjust your injection accordingly and you follow your duty cycle % from there. Most places I have seen don't recommend over 85% duty cycle for fear of injectors sticking but then again I have run 91% without problems and I know people who have run 96% without problems.

GoRacer · 04-26-07, 03:00 PM

I thought the duty cycle was refering to the solenoids? If it is refering to fuel, then 40% is insane low!

Primary = secondary? don't understand that either. Do you mean it only uses setting #2?

I know only the seondary on both is used if both setting #1 & #2 can be used seperately.

rynberg · 04-26-07, 03:01 PM

Quote:

Originally Posted by GoRacer

So the questions are:
* Do you loose boost setting #2 (or #1) when going single?
...or is it still possible to just highlight and exit (will have to find open road to try).
* How do I determine the correct duty cycle for my boost level?
...if someone is runnign a GT35R @ 15lbs could you tell me what your duty cycle is at?

1. No. Dradon was stating that you would set the primary and secondary values to the same number. You have to highlight and exit, as I said above.

2. As I said above, there is NO formula for entering duty cycle, you have to experiment.

Quote:

Originally Posted by dradon03

You determine your correct duty cycle because looking at your wideband during pulls you see if you are running too lean or too rich and adjust your injection accordingly and you follow your duty cycle % from there.

We're talking about the wastegate solenoid duty cycle adjustment, not fuel injector duty cycles.

GoRacer · 04-26-07, 03:08 PM

oh ok, I had just set the primary as low as possible since I thought it didn't matter or wasn't looked at. I will make both primary and secondary the same values.

ok, good to know I still have dual boost settings. Allthough it's not as quick as pushing a single button on a Blitz or Greddy.

GoRacer · 04-26-07, 06:59 PM

Here is a pic of the settings from NeedFd's thread. I tried playing with the duty cycle. The higher I change it to the more overboost but less fuel duty. I need to stay under 40 to prevent boost spikes. If you look at the pic below, his primary and secondary are not the same and the duty is way high on both setting #1 and #2.