I am one of those that's running 1600cc injectors in primary and secondary positions with E85. I ran into an interesting (somewhat expected) issue while tuning idle. I'm injecting sequentially so I can get away with the large primaries but there still seems to be an injector opening time minimum limit I have found. Including injector dead time I have not been able to go lower than approximately 1.5 ms of opening. Lower than that I find that my idle gets lopy, afr gets inconsistent and my egt's front to rear rotor stray apart. I believe one of my primaries is handling the low opening times better than the other. I was wondering what opening times others have found to be the minimum with these larger injectors? I have yet to play with the idle rpm (currently 850 rpm) or fuel pressure to raise the opening times in order to lean my idle out.


I also found an interesting article that talks about the minimum opening times of saturated/peak and hold and disc verses pintel.

http://suprasonic.org/public_html/so...rs/RCtech.html

 

1.3ms, tec3, 1680cc primaries...

 

1.3ms does that include the dead time?

I am at ~1.75ms with no dead time comp (right now) on e85 with a base pressure of 45psi.

 

1.05 to 1.15 ms microtech 1600 primaries

 

Are these with or without dead/lag times?

 

Just because the injector(s) is opening does not mean that it is accurate within the (usually unreliable) extremes of it's specs. For that matter, it's performance may be chaotic and inconsistent but still flow some indeterminate amount .

That said, I've learned most of what I know about injector dynamics from Paul @ YawPower. He is definintely an expert on the subject. For starter, you may want to read the article on his website (http://www.yawpower.com/injectordeadtimesarticle.html and if you still have questions, give him a call at the shop.

In full disclose, he is working with me on my Motec install. You can also check the EFI101 Forum for further credentials.

 

I understand we are at the extremes of the range and dead or lag time would make a great impact. I also have read the Yaw article. Which is why I don't believe they are actually metering at 1.3 ms maybe with out lag times added. On the 1600's they have extremely large lag times (.6- .8 ms @14 volts) anyway and that 1.3 would probably be in the 2.0 ms range anyway. I just was looking for what others have been able to go down to as I'm having issues below 1.5 ms with lag times. I have noticed the inconsistancy based on my egt changes for each rotor at 1.5 ms. I have heard from others that they have been able to use them down to this range and wanted to confirm or deny decent control at these extremes. I am going to have my 1600's dynamically tested to determine if they can be controlled accurately at these openings. On the car will surely be different than a bench setup but should be a good start for determining an appropriate minimum.

 

I sent my Bosch 160 lb "blues" 0280150842 to Injector Rehab. Everything flowed well and were fairly consistant across the board. I ask them to check out whether these injectors would operate in the 1.5 ms range. They did some dynamic tests on one of the injectors and found it would not operate at below 2.0 ms of opening. Hmm, explains some of the problems I was having in the 1.7 ms opening range at idle. Again all these numbers do not include lag times which are around 0.7-1.0 ms. I guess RC was correct in that these injectors really should be kept to a minimum of 2.0 ms of opening with lag times. Injector Rehab said they would try and get a video of the injector having issues below 2.0 ms of opening, when they do I will update this thread with the video.

 

I will try to find an example chart of what these injectors look like dynamically, very non-linear down low...

 

I had the 1680 blue tops down to 1.1MS with a steady idle. I did find that fuel pressure had a huge effect with these and got the best results with a base pressure of 40 psi. I of course have no way of knowing what the actual effective open time was, but it was consistent enough to keep the car idling around 900 rpm.

 

Slo, do you know what your lag settings are for those injectors?

 

Using an E8, is there a lag setting other than the battery correction map/injector dead time map?

injector dead time map: 0 at 14 volts linearized to .05 at 13 but it was close to 14 volts at idle, as I have a strong alternator.

 

the dead time map is the lag setting, same thing.. Your dead times are way off, and am really surprised it would idle at all with almost no lag at 1.1ms...

 

Go here to update your lag/dead times you should be around .7-1.0 for the 1600's and 13-14 volts.

http://injector-rehab.com/kbse/lag.htm

 

I hadn't really messed with the dead time map, the project car gets worked on very sporadically. Correct me if I'm wrong, but the dead time map just adds that amount on top of the calculated injection time, is that correct?

 

I pulled the 160 lb "blues" and switched to a 120 lb lucas injectors on the primaries. The EGT's came back inline when I changed them out. It also drove up my opening times which makes me feel better even though I will be limited in overall horsepower now. The 120 lb injectors do idle nicely though, but I have yet to get lag times on them. The 160 lb "blues" must have had sporatic flows/spray pattern in the low opening times and caused my idle problems even after cleaning them.

Slo, I believe the Haltech's do just add the dead time to the injection time from the fuel map.

 

If you're having problems idling with E85 using 1600cc injectors running a Haltech E8/11 then something is deffinately up. On E85 I have rotaries idling at 13.0-13.5 and piston motors idling at 14.5-16.1 afr's.
The key to a smooth idle and part throttle cruise with huge injectors is to have the injector dead time/battery compensation map and the end of injection map correct. With the haltech having the right current setup on the injector drivers also helps. You can also change the fueling scale factor to gain more resolution.

 

I have played with all of those settings. I believe that some of the these 160 lb injectors are different than others and maybe the low opening times may be the problem. I was using approximately 1.4-5 ms of opening and after the dynamic test was told that the one injector they dynamically tested did not inject accurately under 2ms. Its not that the car would not idle it would, but was rather loppy and the individual rotor egts were not in sync with each other. When I switched to the Lucas injectors and the larger opening times the egts are back together again. I may have just had a problem with the one injector though.

 

A lot the 160's on the market presently are just rebuilt injectors being advertised as new when they are not. Most if not all are rebuilt out of the country by just cleaning and changing the filter and adding a fresh paint job to make them look new!
The important part of the injector in stiil old, used and abused.
As of late most are failing and producing very inconsistent results. You got to be carefull where you purchase them from. I only use the ones that have been match flowed. Offcourse you're going to pay more for that but in the long run it pays off when you got a lot invested.
There are applications that run as much as 5-7 X 1600cc injectors per rotor. Imagine any of those injectors being inconsistent at that level.

 

fritts, where did you buy yours?

I got my 160lb blue tops from http://www.yourperformancesource.com

Mine "looked" brand new. They weren't painted, all plastic.

 

I believe I bought them through Spray it Racing. They did have the case of the injector painted black is that what your talking about viking. I still think they we are asking quite a bit from these injectors at these low openings.

 

I think my cases are plastic, not metal and they didn't look painted at all.

 

Kitty approved?

 

And they are painted!

Most of the inconsistent ones that fail were 'white tops'.

 

Oops thats the same ones i got.