Injector Dynamics Dead Times and Calibration

[candal82]

Hi everyone,

Hoping to get some help on this subject. My car is a 2006 S2000 and I'm running Flashpro Manager 1.5.1.0.

I installed a brand new set of ID725's a few weeks back, and used the dead time settings from the Injector Dynamics website at http://www.injectordynamics.com/ID725.html. Please note that I previously had OEM injectors, and running a custom map which had part throttle fuel pretty near-perfect.

ID725 data from Injector Dynamics


My injector settings from flashpro.


After uploading the new calibration, the idle was running poorly and the s.trims were off the chart. The ECU was dumping in an extra ~30% fuel at idle. When performing part throttle fuel tuning, some parts of the map required as much as an additional 30-35% fuel. Fearing that maybe one of the injectors was dead, I sent them to a local shop for testing. They all checked out ok, so I know now its not the injectors.

Also, I spoke with Tony over at Injector Dynamics to discuss this issue. He recommended using 60 psi for the "current injector test pressure" (since it is closest to the stock/actual fuel pressure), and using the corresponding flow @ 60 psi which is 850cc according to ID. Furthermore, he said because the 06+ S2000 uses a returnless fuel line, that I should compensate for ~10psi vacuum at idle by using the dead time settings listed for the 70psi test pressure.

So, his suggested starting settings would like like this:



Before testing these settings out, I poked around the base calibrations supplied in FP Manager, and found an "ID1000" calibration. I decided to open it up, and have a look to see how the injector data compared to whats listed on the ID website for their 1000cc injectors.

ID1000 Flow and Dead Time Data:


Hondata ID1000 starting calibration:


When comparing the data, I cannot see any correlation between the Hondata basemap and the supplied specs from ID. This has gotten me even more confused than ever. I have since switched back to my OEM injectors until I can get some more info.

So I guess the main question is, what settings should I use for ID725's to get them working correctly?

Cheers,
Alan

[Hondata]

Our settings for the ID1000 was set on a stock S2000. We have found that generally the dead times need to be higher than what ID quotes. However, you injector size is low - it should be closer to 900cc than 715cc.

In brief:
1. Tune the car with stock injectors until the fuel trims are low.
2. Put in the ID750s, set the injector size, reset the dead time to the ID specs.
3. Check the fuel trims at moderate load (50-70kPa, 3000-4000 rpm). They should still be low, otherwise either the initial tuning was out or the injector size is not correct.
4. Tune the dead times at very light throttle (overrun). If it goes very rich just before the injectors cut off, reduce the dead times.
5. Increase electrical load to drop the battery voltage and set the 12.5V dead times.

[candal82]

Thank you very much for the reply.

I will try these injectors again using your suggestions.

Just to clarify, when you say the injectors should be closer to 900cc than 715cc, do you mean at 60psi they should be closer to 900cc (i.e. 850 as quoted by ID's spec chart).

[Hondata]

If the S2000 fuel pressure is 60 psi then your injector size should be about 850cc. There is a bit of variation since at idle the pressure will be closer to 70 psi due to manifold vacuum.

[candal82]

Thank you.

So at 850cc, do i set the test pressure to 60 psi per ID data, or set it to 70? I currently set the dead times to the 70psi values and injector size to 850cc at 60psi, as suggested by Tony.

However, i still had make considerable fuel changes to the map. For columns 9 and 10, around 5% increase across the range to get afr to 12.8-13. The rest of the map required 5 - 10% extra, more at light throttle and idle. Is that considered normal? Or should I instead be tweaking the injector settings until it suits my map? Is there any downside doing it the way ive described?



Thanks

[Hondata]

Injector size from the actual fuel pressure, so 60 psi. Dead times I always tweak based on the injector cutoff.

[candal82]

Great, that's exactly what I set it to.

I got the fuel maps pretty close to where I think they need to be, so I started to look for the AFR going rich after injector cut off to tweak dead times. Here's what I found...







In the above images, very light throttle, then off throttle. AFR went from ~14.8 down to 13.8, 12.7, 13.4. So from your previous suggestion, is this considered "very rich" thus requiring dead times to be reduced? Or is this an acceptable amount?

Thank you again for all the help, and my apologies if any of my questions are repetitive.

[Hondata]

Reduce the injector dead times until the AF is flat until cut off.

[angelf1974]

And, what is the overrun fuel cut delay exactly?

[Spunkster]

This is what people feel as rev-hang. Lowering the numbers will reduce the rev-hang.

[angelf1974]

This is what people feel as rev-hang. Lowering the numbers will reduce the rev-hang.

Thank you

[jun1or]

I sincerely apologize for bringing this thread back from the dead, but we're in the same boat, and I'm dying to know a few things.

1.) Does changing current injector test pressure adjust an "overall fuel trim" in the background?
2.) What does "current fuel pressure" field changes do, and should it be adjusted?

I'm 2006 s2000, but return-style fuel system converted. Tonight I increased base fuel pressure from 43.5 to 60psi, and wow trims were way off. I had to increase injector size from 1000cc (ID1000's) to 1400cc just to get somewhere near the ballbark on my previous good tune. Should it be that high (1400?).

Sorry again, to threadjack, but what is the proper way to increase base fuel pressure and retain a ballpark tune.

Assumptions are: this is the proper order, but it didn't go so hot:

• 1.) Increase physical fuel pressure with adjustable FPR vacuum hose off. From 43.5psi to 60psi in my case.
  2.) Increase calibration "Current Injector size" to approx 1180cc per http://injectordynamics.com/injectors/id1000/
  3.) Increase calibration "Current Injector test pressure" to 60.
  4.) Leave "Current fuel pressure" value alone!?!?
  5.) Trims should be low! FAIL. -20 to -30 STFT (pig rich)

Thanks in advance,

Mike

[pyro6314]

Sorry to bump this up from the dead.. Hondata posted about tuning the latency by the over run cutoff and I was hoping someone could explain the reasoning behind it?

Our settings for the ID1000 was set on a stock S2000. We have found that generally the dead times need to be higher than what ID quotes. However, you injector size is low - it should be closer to 900cc than 715cc.

In brief:
1. Tune the car with stock injectors until the fuel trims are low.
2. Put in the ID750s, set the injector size, reset the dead time to the ID specs.
3. Check the fuel trims at moderate load (50-70kPa, 3000-4000 rpm). They should still be low, otherwise either the initial tuning was out or the injector size is not correct.
4. Tune the dead times at very light throttle (overrun). If it goes very rich just before the injectors cut off, reduce the dead times.
5. Increase electrical load to drop the battery voltage and set the 12.5V dead times.

[jun1or]

I'm not sure of the dynamics behind why fuel overrun is best for tuning dead times, but it works. It helped me.

Are you using this method or looking for another or just trying to deep dive into dynamics of injector opening?

Mike

[pyro6314]

I'm well educated on injector dynamics, new to tuning them.
I am having issues with idle, consistent fueling, and primarily cold start. My over run hangs lean and doesn't have a clean cutoff. My cold start seems to be very lean. This is with stock fuel injectors, stock injector calibrations, stock fuel pressure and no other known issues. All this points to a latency issue, caused by a poor wiring job, and more pronounced on cranking.

Look here for some data log graphs -> http://www.romraider.com/forum/viewtopi ... 15&t=12318

Thanks for your input jun1or.