Synch vs Asynch fueling

[1project2many]

Well, that's a little different. I'll have to investigate a couple of different cals and the recorded data to see what's causing that.

[EagleMark]

Did a lot of reading today and going through hacks and bins... I just don't understand why any cal would be Async always from factory? It's not just V6 $42 either, there are some 7.4l and even $0D, $0E, $E6...

Some of the old DIY-EFI posts quote Async as firing every 12.5 Msec and has nothing to do with DRP, this would explain the accumulater/timer and saving some then dumping what's left if not used. Just sounds like a bad way to do things...

I'm now wondering if a couple rigs I tuned awhile back was a poor choice of starter bin/cal and not noticing this? Never had an issue with 5.7L stuff as I alwas start with ASDU, since then I have used it for everything. One's I had issues with were 7.4L and 4.3L, went back and looked and sure enough they were Async!!! I hate Async!!!

Because of all the research today $42 ended up with a few more paremeters, most importantly 2 BPW times, with these you can now spot an Async always bin... also filled in at least 100 descriptions in paremeters. All my notes from papers written, posts found and all my personal finds, it's like an EFI tuning dictionary now!

[JeepsAndGuns]

How can you tell a async only bin from a regular bin?

[EagleMark]

Until I do some testing on these $42 bins the only way be sure is data log.

But if you look at this picture and compare you will see the differences, bin is Async, compare bin is Sync.

Sync is so easy to tune and idles so much better...

[EagleMark]

Looking through $42 hack it's easy to see how Async could be used to calm down injector pulse at idle or add fuel at WOT. At 2400 RPM it is 1.0 so even, under that it is taking away and over that it is adding.

Also makes it impossible to watch Injector Duty cycle?

 ;----------------------------------------------

; ASYNC MULT vs RPM TABLE

;

;

; THIS MULT IS USED TO CONVERT SMALL PW

; (PW/CYL)TO ASYNC (PW/12.5 Msec) INJ.

; FOR ASYNC INJECTIONS

;

;

; ASYNC IS BOTH INJECTORS, SYMO

; SYNC IS ATRNATING INJECTIONS

;

; FACTOR = (NUM CYLS/2) * (RPM/60) * (0.0125/2)

; .0125 = PULSE PERIOD, (80 Hz)

;

;

; TBL = MULT * 64

;----------------------------------------------

LD46B: FCB 8 ; 9 LINE TABLE

;

; MULT RPM

;----------------------------------

LD46C FCB 0 ; 0.000 0

LD46D FCB 21 ; 0.328 800

LD46E FCB 43 ; 0.672 1600

LD46F FCB 64 ; 1.000 2400

LD470 FCB 85 ; 1.328 3200

LD471 FCB 107 ; 1.672 4000

LD472 FCB 128 ; 2.000 4800

LD473 FCB 149 ; 2.328 5600

LD474 FCB 171 ; 2.672 6400

[RobertISaar]

Also makes it impossible to watch Injector Duty cycle?

depends. if it's done entirely on the 80Hz loop, you know that 80 times per second, the BPW displayed is being injected.

if it can flip between 80Hz async and sync, then you'll have a really tough time dealing with it.

[EagleMark]

OK, but what about the mulitlier? it starts at .328 to 2.672 depending on RPM... I don't even want to think how to make a Injector Duty Cycle % gauge for that!

This whole Sync - Async thing started awhile back for me until I noticed it in Data, then realized Sync was so much easier and smoother. Then this summer I tuned a Jeep engine conversion and noticed the Async always? Swaped bins and viola! POOF! Good runner and easy tune. Since then he told another Jeep buddy with a TBI conversion and sure enough another Async system, started with new bin and POOF! Good runner and easy tune. I thought it may be a GM V6 engine needing this and issue to the long intake runners of a Jeep engine? Still have not had my hands on a GM V6... but I have screwed up a perfectly good tune in my V8 Suburban trying to get an Async tune to run. No way to get it even close to running as well as Sync?

So I'm back to my origanal question, why Async?