> -----Original Message-----
> From: owner-dakota-truck@bent.twistedbits.net
> [mailto:owner-dakota-truck@bent.twistedbits.net]On Behalf Of Tim Berry
> Sent: Wednesday, April 02, 2003 10:01 PM
> To: dakota-truck@dakota-truck.net
> Subject: Re: DML: #24 FMS Injectors
>
>
>
> The SAFC I have has a high and low throttle setting, and you
> set the curves
> per throttle percentage, say, your low is set at 0 and high
> is at 60% and
> your curve is -10% at 3000RPMs, low throttle, and +30% at
> high throttle.
> You happen to be at 30% throttle, its correction factor will
> be +10%, it is
> not a set % per RPM or throttle, it will caculate the %
> needed as per your
> tuning curves... not a sudden change...
> http://members.cox.net/coolva1/safc.mpg
>
> I have it on the neon to just play around w/ it while the
> truck is gettin
> worked on.... the video is shakey, but if you look at the
> bottom reading,
> that is the correction %...
>
> I understand what you are saying, but I think w/ the SAFC
> you'll get it
> pretty darn close... 8 points of adjustment, from 1000PMS+
> (under 1000 will
> give you correction for what the 1000 is set at)
>
> I mainly got it for using bigger injectors and a big cam....
> (I'm sure you
> know the darn MAP sensors suck when its time for a cam and idleing)
> Tim Berry - Chesapeake, VA
> 97 Dakota CC 360 Auto 4300lbs
> best ET to date: 13.03@103.76
> 355.8RWHP 395.2RWTQ
> 99 Neon R/T Daily Driver
Tim, here's an attempt to better explain the problem:
2500 2700 2900
S1 S2 S3
| | |
| | |
V V V
^ ^
| |
| |
M1 M2
2600 3000
Let's hope this carries through the email formatting. This is to show the
granularity problem of the stock map versus the mod points of your SAFC.
Let's say that your stock map value at S1 is 3% off the mark in trying to
achieve proper A/F on your brand new 408. Let's also assume that at point S2
you are 8% off on the rich side, then 12% off at the point S3. The top most
and bottom most are the rpm point at which values change on the stock
mapping(top) and bottom correction by the SAFC(bottom)
S1 = stock fuel setting at 2500 rpm, 3% lean
S2 = stock fuel setting at 2700 rpm, 8% rich
S3 = stock fuel setting at 2900 rpm, 12% rich
M1 = fuel trim in % modified at 2600 rpm by Apexi
M2 = fuel trim in % modified at 3000 rpm by Apexi
Now if Bernd wants to step in here and stick to the topic at hand rather
than deflecting the criticism of the box by talking about mysterious 11 sec
trucks and 10 sec Vipers, then maybe we can all actually learn something.
He appears to be the resident expert on this Apexi box, so please provide
the M1 and M2 values, as percentages since that is the way this box seems to
work, that will bring the values S1 thru S3 all down to zero. Keep in mind
that a 3% miss from your target can result in A/F readings that are .5 off
the mark. Dunno what you consider acceptable or "tuned", but that would be
less than desirable in my book.
This is a hypthetical scenario, but nonetheless a scenario that very
accurately illustrates the problem of mismatch between the Apexi box and the
stock maps. If anything the hypothetical values I've given(and the resulting
difficulty of the tuning problem) may be on the CONSERVATIVE side for anyone
attempting to tune for a 408, as you soon will be Tim.
And just to clear the record, Bernd you're about 10 months behind on current
events if you think I'm using a tuning box of any type and a few behind if
you're vaguely referring to Scott using a S/S box on his 11 sec truck.
Bob
This archive was generated by hypermail 2b29 : Fri Feb 06 2004 - 11:46:09 EST