why different boost settings for pri and sec?

skotx · 02-18-02, 01:56 PM

This may have been discussed, but I don't think it has come up recently. Why does the stock PFC come set for 0.80 primary and 0.70 secondary boost levels (setting #1)? It would seem to me that the stock computer isn't set up that way since you are supposed to see an X-Y-X boost pattern. So I wonder why Apexi chose to do this?

If I choose to set both pri and sec at 0.80, would I use the same % base duty for both? Now that I think about it and look at the stock PFC settings I see that in both #1 and #2 the sec % is higher. Is this because the wastegate needs to be open more often to accomodate boost from both turbos?

Please provide some insight for me if you can. I'm going to the dyno saturday and am eager to see how tweaking boost affects my results.

-Scott

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7 eleven · 02-18-02, 06:24 PM

Two reasons first at the lower rpm your injectors can handle the extra flow needed for higher boost Second if you see a dyno run the curve stays constant with th staggered boost due to the increase in VE when the second turbo comes on. other wise there is a large step.

The duty cycle is the oppsite way you have it in your post. The higher number allows the waste to stay shut longer. The number is the percent of the time the solenoid is open to vent pressure away from the waste gate acc folling it to think that there is less boost and keeping the waste gate shut.
Keep a eye on your inj duty cycle Mine set on the first stock bst setting of .80 and .70 will hit 93% right now.

Hey what's up with your site?

skotx · 02-18-02, 07:14 PM

I just checked the site and it's up. Are you going to this address: http://www.exorzero.com/skotx/powerfc/? The site has always been a bit flaky because my buddy hosts it off his cable modem. It may have been dead for a couple days this weekend because of the whole @Home bankruptcy. Our provider just did the switchover on Friday.

Thanks for the info about the boost settings. I still need to digest and think about it before I come up with questions. Right now I need to digest some dinner.