DIY Fuel injection thread.

[yoeddynz]

16 minutes ago, kpr said:

If its  map based tune,  run vac to reg.    if running itb's and tps tune (alpha n)  that doesn't reference map,   I would run a flat fuel pressure. 

Map based tune so fpr it is. Worked fine on the V6

[kpr]

20 minutes ago, Roman said:

I'd have thought that whatever the load source, you'd just have slightly different VE numbers at low throttle with it disconnected?
 

 

Yeah, doesn't matter that much in most cases.   some things and ecu's,  the fuel equation is expecting a 1:1

[ajg193]

Deadtime is supposedly affected by fuel pressure so in theory you might start to have a little difficulty in getting consistent results at low loads but in practice it is probably minimal?

[yoeddynz]

Why is it that oem injector wiring features a smaller (20~22 awg) wire for the return to earth via the ECU compared to the larger 'feed' wire from the ignition supply. 

I'd always the amperage rating would need to be the same on both sides of a powered device? 

I've been searching Google for an answer to this question but no luck so far. 

 

[ajg193]

One feed to multiple injectors, one ground per injector?

 

[yoeddynz]

They all have the sane feed wire size that can either branch off from one or be in series.  But whether branched off or in serious the feed is alot shorter then the earth returns which have to make their way back to the ecu. 

I'm wondering if it's something to do with the injectors needing to open quick (big low resistance feed to the injector coil) and shut quick (smaller earth returns can disipate the risidual energy quicker/hold less of it) 

#imnotanelectroniczspecialist

[vk327]

7 hours ago, yoeddynz said:

Why is it that oem injector wiring features a smaller (20~22 awg) wire for the return to earth via the ECU compared to the larger 'feed' wire from the ignition supply. 

I'd always the amperage rating would need to be the same on both sides of a powered device? 

I've been searching Google for an answer to this question but no luck so far. 

 

cable feed is sized to suit the fuse feeding it(fuse is there to protect wiring not the injector/end device), the injector limits how much current can flow and the ecu trigger side only has to  carry the current of a single injector. in reality  20 awg/0.5mm  is fine for injectors, I normally  splice all injectors to a common feed of 14awg or similar  

[RXFORD]

Currently involved in a Stockcar re-build and need some wisdom in regards to the importance of a cam angle sensor...

The engine is a 6cyl Falcon AU3 VCT but its had the VCT parts removed and a blanking cover fitted as per class rules. 

We are mocking up a new loom for the current setup which runs a Link G4 Storm ecu, which has 8 injector and 8 coil drives available. It has 6x individual Ls1 style coils setup. We have an aftermarket crank trigger wheel which does all the firing/juicing but are wondering that if we don't run a cam angle sensor, will we only be capable of batch fire injection or semi-sequential instead of full sequential?

Is this true or does it depend on the trigger wheel and ecu map? As far as we know, none of the other efi engines in this class run a cam angle sensor.

We have converted to e85, and think the current fuel tank volume may be on the limit for the added fuel usage so any fuel wastage may be an issue, albiet we don't know how much wastage there might be between the 2 so may be overthinking it.

Efi has only been allowed for 1 season so alot of the speedway engine builders are still pretty secretive about how they set things up. Our sparky is going to power up the ecu which was supplied by an engine builder who said he has put a startup map on it, so we will see if that gives away any secrets on how the injection is setup, but I figured I may as well ask here too. 

 

Cheers

[vk327]

6 hours ago, RXFORD said:

Currently involved in a Stockcar re-build and need some wisdom in regards to the importance of a cam angle sensor...

The engine is a 6cyl Falcon AU3 VCT but its had the VCT parts removed and a blanking cover fitted as per class rules. 

We are mocking up a new loom for the current setup which runs a Link G4 Storm ecu, which has 8 injector and 8 coil drives available. It has 6x individual Ls1 style coils setup. We have an aftermarket crank trigger wheel which does all the firing/juicing but are wondering that if we don't run a cam angle sensor, will we only be capable of batch fire injection or semi-sequential instead of full sequential?

Is this true or does it depend on the trigger wheel and ecu map? As far as we know, none of the other efi engines in this class run a cam angle sensor.

We have converted to e85, and think the current fuel tank volume may be on the limit for the added fuel usage so any fuel wastage may be an issue, albiet we don't know how much wastage there might be between the 2 so may be overthinking it.

Efi has only been allowed for 1 season so alot of the speedway engine builders are still pretty secretive about how they set things up. Our sparky is going to power up the ecu which was supplied by an engine builder who said he has put a startup map on it, so we will see if that gives away any secrets on how the injection is setup, but I figured I may as well ask here too. 

 

Cheers

will need cam trigger, normally something like a 36-1 (i think those falcon engines are 60-2 on factory  trigger) wheel on the crank and a 1 tooth cam sync signal to allow sequential injection/ignition, without the cam sync will only be batch fire and wasted spark as it has no reference to  sync no1 cylinder, probablly wont see a huge benefit from e85 unless it has massive compression and timing is knock limited. on an NA engine maybe 20-30% more over pump gas, would be worth running a flexfuel sensor so can tune to run either or a mix of e85 and pump gas. the link storm is fully configurable as to injection/ignition mode so just a setting change to go from batch/wasted spark to full sequential(with appropriate sensors wired)  side note with reluctor 2 wire trigger sensors you need to make sure polarity is correct or will  get timing drift (see  the link help file for info)

[RXFORD]

Bugger, Ok thanks, owner should have done more research before buying the more expensive parts aimed at sequential inj/ig. Will do some investigation into cam trigger without the vct unit attached and see what we can come up with.

A few of us did try talk him out of e85 because of the added problems surrounding it and that fact hes limited to max 10:1 compression but he rekons most of the competitive cars are running it so wants to be a sheep. Will try push for dynoing both e85 ad pump 98 to see what difference there is.

Yes we will be fitting a ethanol content sensor inline and have pushed for him to run a wideband o2 fulltime for safety which he wasnt planning to do as not many other cars do apparantly. 

Thanks for heads up about the polarity.  

 

[RXFORD]

If the injectors are cc'd to e85, do you think there will be an issue running 98 through them, in terms of getting too much fuel?

[vk327]

2 hours ago, RXFORD said:

If the injectors are cc'd to e85, do you think there will be an issue running 98 through them, in terms of getting too much fuel?

e85 injectors will be specced larger flow than pump gas for the same engine capacity, injectors are easily scaled in the ecu the whole point of a flex sensor is to tell the ecu ethanol content and it can change fuel pulse width (and timing) to  suit, doesn't need to  be a straight e85 or 98 deal either, it will interpolate between the 2 based on % ethanol  content, a bit more involved at tuning as will need to tune both pump gas and e85. would recommend running a wide band o2 so can use close loop fuel  trims as well

[gibbon]

does speeduino require an RPM or cam/crank position input in order to schedule fuel flow? or will it happily do it based on airflow and temperature inputs alone?

[Roman]

Will require some sort of positioning signal, as otherwise it doenst know the frequency of firing injectors.
However are you wanting to use one for something else? 

You could probably put it into a test mode or generate a fake signal easy enough.

[gibbon]

I was hoping there was a flow per second option rather than being RPM reliant. easy enough to take a signal from the coil I suppose

[yoeddynz]

Yeah a coil signal is enough for a rudimentary setup that will still be better than any carb system. 

[bigfoot]

I have a few questions, might belong here or in the tech thread.

I am currently assembling a new,  (slightly better) engine for my lancer(4g63) The engine came with arp rod bolts and kelford 272 cams

1) Can I use the rod bolts without getting things resized? I am using different rods/pistons to what came with the engine

2)Will I need to get better valve springs for the big cams?

3)Where is a good place to get bigger injectors with deadtime data etc that aren't  massively oversized for my engine. Current injectors are around 240cc and hitting 85% duty cycle

[vk327]

On 03/10/2024 at 17:28, bigfoot said:

I have a few questions, might belong here or in the tech thread.

I am currently assembling a new,  (slightly better) engine for my lancer(4g63) The engine came with arp rod bolts and kelford 272 cams

1) Can I use the rod bolts without getting things resized? I am using different rods/pistons to what came with the engine

2)Will I need to get better valve springs for the big cams?

3)Where is a good place to get bigger injectors with deadtime data etc that aren't  massively oversized for my engine. Current injectors are around 240cc and hitting 85% duty cycle

1. Yes would normally resize rods with the arp bolts at least measure very carefully journal to crank and bearing clearance

2. depends on cam check with kelford

3. Depending on what power your aiming for a set of 731cc injectors from MSEL would give you plenty of head room at 3 bar base or 860 something at 4 bar  pressure going boosted? , if NA the 371cc @3 bar  ls3 injector would prob be adequate, MSEL have plenty of options 

[HumberSS]

So school me on this shit. On the 4V in the Dyna I'm weighing up the idea of a speeduino efi conversion. Maybe a future project once running, or maybe before.. my reasons are that I need a set of plug leads, which will set me back a few hundy, and the carb needs a rekit. After which it will still be a leaky carb.. ive previously discovered 2zz toyota coils fit perfectly (conveniently also dirt cheap and common), and was thinking I'd drill/weld bosses to factory manifold for the injectors. Might do this anyway to give the future option if i dont commit immediately. I'd have to run wasted spark, and apparently I wouldn't need cam phasing due to it being a wasted spark v8. So crank trigger and throw the dizzy away? And how many teeth? Curious as to best injectors (300hp would be ambitious for this donk). I like the idea of being able to tune for economy rather than outright power, no shitty fuel seeping carb and associated smells, and all-weather consistent running. I don't like the scope creep, but am entertaining nonetheless. Hardware wise it appears simple, of course the devil will be in the detail. Fuel pump and delivery setup recommendations also welcome. Speeduino recommendations? TPS? MAP? Throttle body or just gut the carb and use?? Apologies for naivety.

[yoeddynz]

Definitely go for a 36-1 trigger wheel. Run wasted spark and batch injection and even the basic Speeduino will still give you the ability to tune the lot to run way better than any carb will.

Its all basic stuff and once you get stuck in its super fun to learn and quite addictive to keep striving for an even better tune.

Have a chat with @kws about Speeduino. He's been down that road already.

I still think there's better support for megasquirt and more information on a wide variety of setups. Both platforms utilise the same tuning software.  So keep a look out for megasquirt deals.