dr_jones

iTrader: (1)

Can anyone clarify what exactly is meant by:

Enrichment Value = (Previous Accel. Enrichment Value - Decay Time Value)

as regards the Apexi PFC:

My thoughts are:

EG: Assuming (2000 rpm) Enrich Val (4.0ms) Decay Val (1.0ms)

SO:

At 2K throttle opened suddenly and 4 ms is added to the injector opening time.
Next injector opening + 3ms added
Next injector opening + 2 ms added
Next injector opening + 1ms added
Finally back to normal

And further to that being 4 stroke the injector fires at a rate of a quarter of the rpm ie once every 4 rpm...

Right??

brunny42

speak to andy forrest he will know the answers

silent running

Did you get anywhere with your enquiry about acceleration enrichment? I've just had my Power FC mapped and it seems very jerky on sharp throttle, whereas gentler acceleration feels normal. If I put my foot down suddenly it takes a fraction of a second for the engine to 'catch up' (with quite a shunt through the transmission!) even though the boost is there immediately. Does this sound like the sort of thing that enrichment fixes?

Scott.T

iTrader: (2)

AFAIK it's pretty much as you state.
Decay time is subtracted from the enrichment value each cylinder stroke.

I think the preferred method is big enrich value and small decay. I have heard of people doubling the default enrich value.

see my question here http://bbs.22b.com/cgi-bin/ultimateb...c;f=7;t=000956

Andy.F

Sure does What values do you have in there just now ? in the 1000, 2000 and 3000 rows.

Andy

silent running

Well I've been out and tried fiddling around with the settings yesterday (my esteemed mapper didn't think it would be this, but thought i might as well give it a try) and after some fairly thorough tests, it doesn't seem like the hesitation / jerkiness on sudden throttle opening is caused by the acceleration enrichment. I tried adding 50% to the values, then 100%, reducing decay, targetting only one specific rpm point for changes to see if throttle response at that point showed up different etc, but I could not iron out the throttle lag, and now I'm thinking that it was maybe there all along but it's just that getting a remap focussed me on it or something... accel. enrichment seemed a possible cause, but now I think I can eliminate it for definite - as my mapper said in the first place!

BUT on the bright side, I have now trawled around and think I've found exactly the phenomenon. It's in the drivetrain forum, and I've posted on the thread from 2003. So if anyone can pop over there to have a look that will be helpful. In the thread there's a lot of people claiming it's turbo lag, but it definitely does not feel anything like that. Alternative would be a slightly slipping clutch, but again, it just does not feel like that. My clutch holds on tight at 21psi, so I think it can handle a slight prod of the throttle at 3000 revs!