Additional Injector R4 Calculator

[Lex]

I have put up on our site a calculator to be used with the R4 additional injector controller. This should make life easier when setting up 5th and 6th port kits.

Stratified R4 Fuel Calculator

It doesn't have complete instructions yet but will soon. I am putting this out there for you guys to try out and give some feedback on:

Quick setup tips:

1. Copy your current MAF table (before scaling) into the MAF table in the calculator at the MAF voltage you want to start injecting:

2. Set the parameters:

Percentage of fueling by aux injectors(%): - the amount of fueling you want the aux injectors to cover as a percentage of total fueling. Then scale your MAF down by 100% - this value. Default is 30%. Scale your MAF at the starting voltage by 70% (0.7) if you are using 30%

Target WOT AFR (Air to fuel Ratio): Desired AFR. This should match the AP desired AFR.

Total fueling from all aux injectors(cc/min) @ 43.5psi: Total rated fuel supplied by all the aux injectors. Default is for 2 1000cc injectors (2000cc)

Fuel Pressure(psi): Actual fuel pressure. This is usually in the 50-60psi range but depends on in tank pump and demand

Number of times injectors fired during cycle: Set the R4 controller in 2 cylinder mode, 2 stroke to fire for each ignition event. This means it will fire at every ignition event

Injector Opening Time(ms): Most PI injectors have an opening time of 1ms

Fuel Trim(%): Due to how the fuel is delivered - most often pre throttle body - and fuel pressure that is unknown you might want to trim the value based on the AFRs you are measuring under WOT compared to target. This gives you a quick way to trim the R4 tables. 90% trims them down 10%, 110% adds 10%.

3. After doing the calculation simply copy and paste the tables into the R4 controller maps starting at the voltages that update at the top of the tables once you hit the calculate button.

Give this a try and feedback is welcome!

Stratified R4 Fuel Calculator

[Lex]

So who's been using the calculator?

[BuddySpeed3]

Originally Posted by Lex So who's been using the calculator?

I recently purchased the Guardian Angel, and plan on using it with the AEM AFR fail safe once I get a 6th port kit, but I just have a few questions

When using 2 injectors, does the Split Second controller fire both injectors simultaneously but at a lower IPW than only 1 injector, or do they alternate?
Edit* Just found out that they fire simultaneously.

Once values are calculated, do we just copy and paste them into the R4 fuel map, load it to the SS controller, and that's it?

I noticed the Calculator starts at a Maf voltage no lower than 3.5 volts, is there a reason for that? (I doubt aux fuel would be needed at anything lower than that).

If the AFR is slightly off from target, is tweaking the R4 fuel map recommended over tweaking the maf curve?

I also read that some people had issues with injectors not firing when selecting 1 millisecond for injector opening time, and that a minimum of 5 milliseconds was needed. I can't remember where I read this though.

Thanks @Lex;

[Fstrnyou]

If your MAFCAL is good to start with, I would adjust the R4 fuel map and leave the AP maf curve alone.

[BuddySpeed3]

Originally Posted by Fstrnyou If your MAFCAL is good to start with, I would adjust the R4 fuel map and leave the AP maf curve alone.

Yeah that's what I was thinking also. Ideally, with OL fuel trims disabled I'd like to get the maf curve dialed in almost perfectly with IDC's just touching 100% and then interpolate the maf curve up to 5 volts.

From there, using the R4 calculator I'll ADD 5% fuel and see if the AFR enriches evenly across the rev range. If there are uneven variances I'll tweak that region in the fuel map in order to hit AFR targets and then try another pull. Once AFR is enriched evenly I'll PULL 5% of the maf curve and check again.

I'll do the same for 10%, 20%, etc. Small changes over several fuel map / maf curve revisions.

I'd rather slowly collaborate the aux fuel into the stock fueling curve instead of going straight to adding 30% aux fuel, and pulling 30% of the maf curve.

This way I can ensure that 1) The aux injector(s) are working, and 2) There won't be any significant risks from running excessively lean.

For every percentage increase in aux fueling, and percentage decrease in the maf curve, IDC's will decrease.

So I'll be able to increase boost slightly for every revision. The boost pressure I settle at will depend on how drastic the low side fuel pressure drops from the added fuel demand, and injector manifold delta. I'm hoping to monitor fuel pressure with a gauge.

Once I start to see any sign of fuel pressure drop, I'll decrease boost by 1-2 psi, and settle at that boost pressure.

Then while still monitoring fuel pressure, I'll continue to slowly increase the percentage of aux fuel while pulling the same percentage from the maf curve until my IDC's are around 75-80%. I wanna have IDC's at a safe number to maintain good in cylinder atomization.

Once everything is finalized, I'll re-enable OL fuel trims to account for small variances in AFR.
Hopefully my plan works out

Does anyone want to share some of their experiences tuning 5th/6th port injection?

[Fstrnyou]

You don't really interpolate up to 5volts. Once your MAF curve is pretty close, you plot the known range in excel and generate a best fit curve. That curve will have a formula. For MAFvolts above your used range, plug the Volt cell value in the formula at it will spit out a g/s value.

[BuddySpeed3]

Originally Posted by Fstrnyou You don't really interpolate up to 5volts. Once your MAF curve is pretty close, you plot the known range in excel and generate a best fit curve. That curve will have a formula. For MAFvolts above your used range, plug the Volt cell value in the formula at it will spit out a g/s value.

Thanks I read a thread by @rfinkle2; which went into more detail about that here:
Using Excel to dial in your maf curve (meth users, perfectionists, etc.)

I quickly read through it a while back but didn't fully understand it, so I'll definitely read it again

Are you using or planning to use aux fuel?

[Fstrnyou]

Not currently, but I have plans on going 4-port with the Damond FoST kit.