rusefi.com

Re: Fast start features

2020-04-05T01:40:43

Perhaps I will enhance the starting ability by adding supercapacitor.

Or a proper battery

Seriously, its easy to get caught up in trying to make something perfect and end up with something unusable or fragile instead.....I've fallen for that many times over the year

Statistics: Posted by mk e — Sun Apr 05, 2020 1:40 am

Re: Fast start features

2020-04-01T21:00:43

I agree with your thought for a race engine, and specifically one with a dry sump.
But for my very standard engine with a bike battery, I would like to have some margin not to stay caught in a desert place. Perhaps I will enhance the starting ability by adding supercapacitor.

Statistics: Posted by JPh — Wed Apr 01, 2020 9:00 pm

Re: Fast start features

2020-03-31T14:48:18

I have always felt that fast start is best left to OEMs trying to satisfy irrational customer perceptions and racers want start DELAY so there is time to get oil, often thicker and much slower moving than the 0W20 many OEMS now use , flowing BEFORE the engine comes to life. Years ago before EFI I hooked ignition to the oil pressure safety switch on a setup....much like Honda lawnmower engines connect it to the oil low switch today. That was a drysump much like my current setup and cold it was at least 1-2 revolutions before there was oil flowing everywhere but with carb and distributor it could start ...probably 1/2 a rev which was bad.

When my engine finally goes back together I will be adding an oil pressure transducer to feed pressure info to the ECU and will use that to enable fuel during cranking and probably to force a limp condition at below normal oil pressure and shutdown at some low oil pressure value. Still just a plan at the moment but as I continue to repair damage from low running with low oil pressure because I didn't believe the gauge it a pretty firm plan along with a more full appreciation of the standard approach of redundant sensors on critical items.

just a though

Statistics: Posted by mk e — Tue Mar 31, 2020 2:48 pm

Re: Fast start features

2020-03-31T12:52:54

Just something to note here, I have found the lower my battery charge the longer the engine takes to fire, with a charged battery I can get OEM quality starting.

I am investigating this a little as I am wondering if this is an effect of not having a voltage correction for dwell and a large voltage drop during cranking.

Whats your cranking settings now?

I am thinking of enrichments etc you had best luck with.

Statistics: Posted by 960 — Tue Mar 31, 2020 12:52 pm

Re: Fast start features

2020-03-31T09:15:56

Just something to note here, I have found the lower my battery charge the longer the engine takes to fire, with a charged battery I can get OEM quality starting.

I am investigating this a little as I am wondering if this is an effect of not having a voltage correction for dwell and a large voltage drop during cranking.

Statistics: Posted by Simon@FutureProof — Tue Mar 31, 2020 9:15 am

Re: Fast start features

2020-03-22T06:54:19

If I see well the sync tooth is just before the sensor granting an immediate sync.
As stated above its the main condition of fast start.

Statistics: Posted by JPh — Sun Mar 22, 2020 6:54 am

Re: Fast start features

2020-03-22T06:49:17

Thanks Abricos for the video.
I will be happy with such a starting.

Statistics: Posted by JPh — Sun Mar 22, 2020 6:49 am

Re: Fast start features

2020-03-21T22:24:15

But we have to wait for cam sync to begin fuel and spark or does it switch to crank sync?
In fast spin-up mode, we wait for crank sync. Ignition/injection will start right after the first sync point of the primary trigger.
Please be aware that this mode works only for certain trigger types (e.g. 60-2).

I think it works on most trigger types with enough teeth - I know it works on my 24 tooth LS trigger pattern.

Statistics: Posted by mck1117 — Sat Mar 21, 2020 10:24 pm

Re: Fast start features

2020-03-21T20:09:25

iframe

Statistics: Posted by Abricos — Sat Mar 21, 2020 8:09 pm

Re: Fast start features

2020-03-21T17:38:33

But we have to wait for cam sync to begin fuel and spark or does it switch to crank sync?

In fast spin-up mode, we wait for crank sync. Ignition/injection will start right after the first sync point of the primary trigger.
Please be aware that this mode works only for certain trigger types (e.g. 60-2).

Statistics: Posted by andreika — Sat Mar 21, 2020 5:38 pm

Re: Fast start features

2020-03-21T12:09:50

I believe it has something to do with trigger-wheel tooth patterns and synching methods.
With old-style distributor-based ignition you get the right spark immediately after you start cranking, while here we wait for the missed tooth + then another entire crank rotation (at least this was true some time ago).

Statistics: Posted by puff — Sat Mar 21, 2020 12:09 pm

Re: Fast start features

2020-03-20T20:12:28

Thanks for that exemple.
On every rusefi start I have seen on videos, it seems allways to be some sort of a delay before something happens.
I hope I will soon have my engine starting to make measurements to compare between oem and rusefi.

Statistics: Posted by JPh — Fri Mar 20, 2020 8:12 pm

Re: Fast start features

2020-03-20T19:48:01

By the way - batch fuel is pretty good by itself. It's actually pretty hard to detect a difference between batch and sequential without an accurate dyno, fuel flow meter, and exhaust gas analyzer.

Here's what a startup sounds like on my car (5.3L v8, no cam sensor connected, batch fuel, wasted spark):

iframe

(don't mind the tach reading zero )

The startup fueling isn't ideal, so it could probably start a bit faster with some tweaking. I know @OrchardPerformance has been doing some work to make his car start up really nice, so he might be able to share his progress here.

Statistics: Posted by mck1117 — Fri Mar 20, 2020 7:48 pm

Re: Fast start features

2020-03-20T13:06:37

Thanks for the tip.
But we have to wait for cam sync to begin fuel and spark or does it switch to crank sync?

Statistics: Posted by JPh — Fri Mar 20, 2020 1:06 pm

Re: Fast start features

2020-03-20T10:27:00

I have read some lines about rusefi having fast start features
Can we switch to wasted spark and batch fuel during cranking?

Yes, that's true. If you enable this option, it will use batch fuel/wasted spark right after the first sync (until fully synced):

faster_engine_spin-up.JPG

Statistics: Posted by andreika — Fri Mar 20, 2020 10:27 am