Can we talk Injectors?

I picked up a set of Injector Dynamics ID1000's. However, i'm now having 2nd thoughts especially regarding idle quality. My car has always been a "street" car first so having idle that is NOT better than stock (stock isn't anything to write home about) would be a bummer and not acceptable.

There are so many ID1000 fan boys online that rave about how good idle quality is but often times these guys are pushing high HP or otherwise running above 1000rpm idle rpm.

I'm thinking maybe I should have gone with the ID725.

Anyone have experience with the idle quality on ID725 vs. ID1000?

Mine are 1300 cc not Injector dynamics but same family . No problem . Even 2000cc EV14 is good with HKS ecu . There is also "new" EV14 1540 cc made for ethanol . But dead time ( latency)
must be correct ! 1000usec/ 13,5 volt is common value .

I went with 725cc ID's and regretting it, wish i went bigger.

Next year i'll be going bigger.

jaffaz32 said:

I went with 725cc ID's and regretting it, wish i went bigger.

Next year i'll be going bigger.

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Iirc you're pushing some serious HP? +500 club?

im hoping to stick to below 400. 350 is probably my sweet spot

Idle quality is not dependent on the cc, but on the tuner. I've seen 1600cc IDs run on a stock 4 cylinder with unnoticeable idle. 725cc injectors will just be cheaper on your wallet. ID Injectors are not magical injectors like the internet says. I've run big RC injectors, FIC Injectors, 440cc Injectors, and now DonkeyPower Injectors. It is 95% in the tuner Ryu. ID has the largest marketing campaign, but in real world testing they were not better than some name brands.

I am running IDs 725 with a low boost Comptech Supercharger hitting at 340 HP. Appears to be a good mix without any issues.

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jones83 said:

Idle quality is not dependent on the cc, but on the tuner. I've seen 1600cc IDs run on a stock 4 cylinder with unnoticeable idle. 725cc injectors will just be cheaper on your wallet. ID Injectors are not magical injectors like the internet says. I've run big RC injectors, FIC Injectors, 440cc Injectors, and now DonkeyPower Injectors. It is 95% in the tuner Ryu. ID has the largest marketing campaign, but in real world testing they were not better than some name brands.

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I agree with jones83 that in the end the performance of your injectors/engine will be the tune. I have had my NSX tuned twice. The first tune worked but was not great. I had it tuned a second time with a tech that knows the NSX and owns one. He did a fantastic job.

Larger injectors can create an idle problem if the required fuel at idle results in an injector pulse width that is in the injectors non linear area of operation.

At low commanded pulse widths, such as would occur at idle, all injectors start to enter an area of operation where the fuel flow ceases to follow a linear relationship with the commanded pulse width ( a 1000 cc /min injector ceases to be a 1000 cc injector). Typically, this area of non linear operation starts somewhere around pulse widths of 1 - 2 msec. A larger fuel injector requires a shorter pulse width to deliver the same amount of fuel as a smaller injector. If (as a hypothetical example) you had 500 cc injectors and your engine was idling with a pulse width of 2.5 msec and you replace the injectors with 1000 cc injectors and reprogram the ECU with the new base flow rate, the ECU is going to command a 1.25 msec pulse width. If the 1.25 msec pulse width is in the injectors non linear zone of operation you are likely going to get erratic operation.

Some of the later OEM ECUs have the ability to model a two piece linear flow curve which allows them to operate safely in the top portions of the non linear section of the injector flow curve. They do this primarily for enhanced emissions compliance. I am not aware that this is a feature available on aftermarket ECUs where emissions compliance is a non issue and idle is less of a concern.

If you are operating in the non linear area of the injectors flow curve at idle, you may be able to tune around it by repositioning some of the RPM axis cells on the fuel map and putting more around the idle point so you can deal with the injector curves non linearity (really only works if your ECU supports very high resolution fuel maps). Otherwise you may just have to suck it up.

It is fairly easy to determine if you have entered this no go zone. Connect your laptop (or whatever) to your ECU and find out what your fuel pulse width is at idle. Once you have your idle pulse width, go to the ID website and get a copy of the injector characteristics for their 1000 cc injectors (this stuff used to be on their website). Find out the pulse width where the non linear operation of the injectors start (or just ask them what their recommendations are for the minimum pulse width at which the flow rate on their injectors remains linear). If your idle pulse width is longer than that minimum pulse width you should be safe and there is likely a problem with your tune. If your idle pulse width is really close to or less than that minimum pulse width you are probably going to have to live with a poor quality idle.

I was reading thru this manufactured published blog http://injectordynamics.com/articles/low-pulse-tech/
[MENTION=26435]Old Guy[/MENTION] i'll take a look at my ECU parameters. thanks for the insight!

Based upon that curve, if your idle pulse widths are 1.4 - 1.5 msec or larger then it looks like you should be safely in the area of linear operation for the ID 1000 injector. From the curve it looks like the ID1000 offset is about 1.1 (and a bit) msec (holding a ruler up to the screen and eyeballing isn't too precise).

Injector Dynamics used to have the raw flow rate data on their website from which you could plot the data to get a better handle on the actual offset. I fuzzily recall that ID used to publish this data for different fuel pressures since the offset can be changed by the operating pressure of the injector. The raw data was interesting because it seemed to show that the injectors did not comply perfectly with the theoretical calculation for change in flow versus fuel pressure (Q1 = Q2x(P2/P1)**0.5). It was very close; but, not perfect so it might have just been measurement error. Incorrect offsets entered into the ECU will mess up fuel delivery over the complete range of operation; but, have the greatest impact at idle and the least effect at wide open throttle (which is where most tuners seem to concentrate their attention).

In my previous post I was probably loose in the terminology I used in describing injector pulse widths. However, since I don't think there is an ANSI standard for this stuff I get to claim innocence. Its more a case of 'common understanding for the terms' which is not always so commonly understood. The ECU calculates a required amount of fuel (ml) for each combustion event at different engine operating points. The calculated PW to deliver that fuel is then PW = (req fuel(ml))/(injector flow rate (ml/sec)). The actual pulse width applied to the injector is different. The actual pulse width is the calculated pulse width plus the injector offset time (some people refer to it as injector opening time which is not completely correct). This is a super simplified description of the calculation - don't take it as literal.

I think most ECUs that you can interface with report actual injector pulse widths. However, once again there is no standard so you need to confirm what your ECU is doing. If your ECU reports the actual pulse width applied to the injector and if your tuner has entered a correct value for the injector offset then it looks like an 'actual injector pulse width' of 1.4 - 1.5 msec should be into the ID1000 range of linear operation. 1000 cc injectors on FI cars are a little out of my head space so I have no intuitive feel for what the PWs should look like at idle and whether this would be marginal operation.

When you check your idle pulse widths, do it with the engine up to full operating temperature. During warm up, the ECU (depending on what your tuner has done) adds additional fuel to facilitate smooth operation. This increases the actual pulse width applied to the injector. You could have a condition where the injectors are in there linear region of operation during warm up and then drop a bit into the area of flakey operation once the engine is hot.

[MENTION=26435]Old Guy[/MENTION] - you're bringing back some memories now of when we initially setup the HKS F-con Vpro for my NSX. We used the RDX 410cc (I forget exactly the size) injectors and had to mess around with the injector offset value a few times because I could not find the exact injector flow rates online at the time (well, the information was contradictory).

Good info here. You bring up a few aspects I had taken for granted that my tuner setup for me. I've been busy fine tuning the timing, throttle, and fuel maps, I had forgotten about the work needed during setup.

Great information from Old one.

Here is a video from Tony Palo using ID2000's at 1.0ms idleing on a stock 1.8: https://www.youtube.com/watch?v=RX1xIvOWcNk

If you watch the video Tony does identify that 1.0ms is really too low but it does idle fairly well considering. It sits at 8xxrpm albeit on the rich side. Consider those were 2000s and the NSX has a larger displacement per cylinder which only helps.

To add a more NSX specific reference. My car idles at 9xx rpm range at 1.63 - 1.67ms on ID1000s maintaining steady 14.6 afr. I'm sure I could put some time in and get it to idle a little lower but at 9xxrpm I haven't had a desire to improve it. It idles smooth, relatively quiet and at the target afr. You will find many setups that idle in or around 900-1100rpm. This is in part due to the size, but also due to other tuning mechanics that are affected by where the idle is at. These may include decel from high rpm right to idle, or accel at idle. The lower the idle the more time consuming tuning the other areas can become. With that said, yes the 750's can likely idle better at a lower rpm, but I haven't met anyone that has been dissatisfied with ID1000s as it pertains to idle and well....any other facet of the injector.

E-Nough Logic said:

Great information from Old one.

Here is a video from Tony Palo using ID2000's at 1.0ms idleing on a stock 1.8: https://www.youtube.com/watch?v=RX1xIvOWcNk

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Now you piqued my curiosity and as a result I had to go back and look at the ID website data.

The ID 2000 lists a 12v / 43.5 psi offset of 0.68 or 0.972 msec. The ID 1000 lists a 12v / 43.5 psi offset of 1.24 or 1.379 msec. The lower offset value is taken from the basic specifications on their web page. The second higher value is taken from the application specific data for Fords. I didn't spend enough time to figure out why there is this apparent discrepancy for the same operating point; but, it would be worth pursuing the correct number if you are trying for a smoother idle. For this discussion I am going to stick with the smaller offset value.

The ID 2000 Ford data lists a minimum pulse width of .284 msec (this has to be what I called the calculated fuel pulse width because you cannot have an actual pulse width shorter than the injector offset). Using the ID 2000 lower offset value of .68 msec and ID's recommended minimum pulse width of 0.272 msec gives you an 'actual' minimum pulse width of 0.68 + 0.284 msec = 0.964 msec, so that idle pulse width of 1 msec E-Nough Logic mentioned would appear to be within ID's recommended range of operation; but, right at the lower end of that range.

The ID 1000 Ford data lists a minimum pulse width of 0.272 msec which would suggest that the minimum actual pulse width for the ID 1000 would be 1.24 + 0.272 msec = 1.512 msec.

The ID 2000 data would suggest that it works better than the ID 1000 at short pulse widths, which is sort of true. However, remember that under idle conditions (on the same engine as an ID 1000) it has to be able to operate at shorter pulse widths because it is pouring approximately twice as much fuel into the engine with each pulse. According to the flow curves, the ID 2000 at a 1 msec pulse width is delivering 0.010 ml of fuel per pulse and is right on the very edge of acceptable operation. To deliver 0.010 ml of fuel the ID 1000 needs about a 1.6 msec pulse which gives you slightly more margin relative to ID's recommendations on minimum pulse width. If the NSX is idling with a pulse width of 1.63-1.67 msec it seems like it should be in the ID 1000 injectors range of linear operation and should be a reasonable fit, although again it is operating close to the edge of ID's recommended range of operation.

The offsets I listed above are for an operating voltage of 12 v. The ID injector offsets display more sensitivity to operating voltage than what I am used to. The potential upside to this is that if your car runs around 14 volts at idle the offset on the ID 1000 is about .25 msec shorter which would park you nicely in the injectors linear operating range if the idle pulse widths are around 1.63 - 1.67 msec.

One other factor to consider in up-sizing an injector is the pulse width resolution of the ECU. Lets say that the ECU can command a pulse width to a resolution of 0.01 msec. With an ID 1000 a .01 msec change in pulse width changes fuel delivery by about 0.17 ul per pulse. For the ID 2000, you get about a 0.46 ul change. So, if your ECU is trying to respond to small changes in RPM and MAP, the ID 1000 will you give you a much finer scale control on fuel delivery and probably a smoother idle (and an ID 725 would be better than an ID 1000). Of course, this would all come at the expense of less fuel delivery capability under max load conditions, which may or may not be an issue.

I don't know what RYU's peak horsepower objectives are. If they are in the 600 - 650 hp range I would think that the ID 750 would be a good fit. In addition to giving finer scale control at low fuel deliveries it also offers the advantage of a smaller offset than the ID 1000 which makes sure that it is operating in its lnear range. Based upon the data, the ID 1000 can probably be made to idle OK with the appropriate tuning (if RYU's idle PWs are the same as E-Nough Logic's). However, it would probably be easier to do with the ID 750 (providing that they meet the peak fuel delivery requirements).

I'm guessing [MENTION=20915]RYU[/MENTION] wants to use E85, hence the interest in higher-flow injectors compared to his current (RDX?) injectors.

jwmelvin said:

I'm guessing @RYU wants to use E85, hence the interest in higher-flow injectors compared to his current (RDX?) injectors.

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If that is the case then the much lower stoichiometric value for E85 (compared to 100% gasoline) means that the injector pulse widths at idle will need to be much higher than they are with 100% gasoline. If an NSX with ID 1000s is running idle pulse widths of 1.63 - 1.67 msec then on E 85 the injector would likely be well into its linear range of operation and any idle issues (if hey still existed) could not be attributed to operating in the injectors non linear flow region.

Good point [MENTION=26435]Old Guy[/MENTION].

jwmelvin said:

I'm guessing @RYU wants to use E85, hence the interest in higher-flow injectors compared to his current (RDX?) injectors.

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With the way I like to drive, i'm actually considering a 87 oct tune instead of going the other direction. The RDX injectors have been great but i'm concerned about long term reliability as I have the duty cycle on the RDX injectors pretty much maxed out. I'd like a little more headroom in case my fuel pump starts to go weak or other issues in the fuel system. I have a little bit of Auto-Tune programmed in to compensate for up to 15% of variance to my base tune. 15% might even be too high...

In retrospect the ID725 would have been enough but there was a small devil on my shoulder telling me if I ever decided to go for more power i'd have the headroom - this is never go to happen in the near future but if the idle performance was the same between 725 vs 1000 then why not I thought.

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[MENTION=26435]Old Guy[/MENTION] - much thanks to you sir! I still have to reread your post several times as this has been quite the education for me. Thank you again.

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@E-Nough Logic thanks for the input as well! I'm hoping to tune for a CA Smog/Emissions friendly condition so an idle at 14.6 might be too rich. I'll likely need slightly less fuel at around 15.0 - 15.5 I reckon. I need time on a dyno with emissions testing equipment. Sigh....

RYU said:

With the way I like to drive, i'm actually considering a 87 oct tune instead of going the other direction. The RDX injectors have been great but i'm concerned about long term reliability as I have the duty cycle on the RDX injectors pretty much maxed out. I'd like a little more headroom in case my fuel pump starts to go weak or other issues in the fuel system. I have a little bit of Auto-Tune programmed in to compensate for up to 15% of variance to my base tune. 15% might even be too high...

In retrospect the ID725 would have been enough but there was a small devil on my shoulder telling me if I ever decided to go for more power i'd have the headroom - this is never go to happen in the near future but if the idle performance was the same between 725 vs 1000 then why not I thought.

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@Old Guy - much thanks to you sir! I still have to reread your post several times as this has been quite the education for me. Thank you again.

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@E-Nough Logic thanks for the input as well! I'm hoping to tune for a CA Smog/Emissions friendly condition so an idle at 14.6 might be too rich. I'll likely need slightly less fuel at around 15.0 - 15.5 I reckon. I need time on a dyno with emissions testing equipment. Sigh....

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I think the info supplied (so far) suggests that you should be able to get a reasonable idle with the ID 1000 injectors (I am assuming that you have an OEM flywheel and camshafts - changes to those items can compromise idle performance). I would concentrate on nailing down the appropriate offset for use with the injector and make sure that the offset voltage sensitivity is correctly programmed into the ECU.

I am curious about why the ID 1000 basic specifications web page lists a 12 v offset of 1.24 msec while the Ford specific application data for the ID 1000 lists a 12 v offset of 1.379 msec. That is a significant difference and having the wrong value will certainly mess up idle tuning. The 12 v latency for the Subaru application matches the listed 1.24 msec so perhaps the Ford systems operate with a much higher fuel pressure which increases the injector offset? Anyway, it might be worth asking to ID to confirm what the appropriate offset value would be for your ECU and fuel pressure.

I hope your tuning efforts work out for you.

Hey Regan, I'll pipe in a little. I am running the ID1000 as I had planned on tuning for E85. I don't have an issue at all with my idle at 850-900 and it holds steady. No issues whatsoever. I'm running AEM Series 2 and the tune is great. It makes all the difference. But with E85, a completely new tune will need to be applied. So out comes all of your precious gasoline, in goes 100% E85 and a new tune is laid on top. The controller measuring the amount of E85 in the fuel supply will then regulate the ECU to move parameters to timing and fuel flow to keep the engine safe and working at maximum output. I too wanted the headroom for more power and feel safe and secure with the ID 1000's.

Valhalla said:

Hey Regan, I'll pipe in a little. I am running the ID1000 as I had planned on tuning for E85. I don't have an issue at all with my idle at 850-900 and it holds steady. No issues whatsoever. I'm running AEM Series 2 and the tune is great. It makes all the difference. But with E85, a completely new tune will need to be applied. So out comes all of your precious gasoline, in goes 100% E85 and a new tune is laid on top. The controller measuring the amount of E85 in the fuel supply will then regulate the ECU to move parameters to timing and fuel flow to keep the engine safe and working at maximum output. I too wanted the headroom for more power and feel safe and secure with the ID 1000's.

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That's huge! Thanks JC. More importantly i'm glad you're happy with it. I know we can get pretty picky. Hope all goes well with the new place my friend.

I second ID1000's being perfectly fine. I run a Haltech Elite and the car idles better than stock with the ID1000's.

My only feedback is that ID injectors fit like shit in the NSX fuel rails and intake manifold. When we installed ours we called ID and they basically told us to just jam them into the intake manifold OEM seats as they don't provide a proper rubber seat, and same for the top's (the jamming part, they provide o-rings). The tops also need to be pushed into the rail to the point where the aluminum on the injector may hit the aluminum on the fuel rail (some hit on mine, others didn't). We tested and didn't have any leaks, and ever since I've been driving 3-4 times a week without any issue. Once you accept the fitment isn't perfect, they are amazing injectors.

foundry3 said:

I second ID1000's being perfectly fine. I run a Haltech Elite and the car idles better than stock with the ID1000's.

My only feedback is that ID injectors fit like shit in the NSX fuel rails and intake manifold. When we installed ours we called ID and they basically told us to just jam them into the intake manifold OEM seats as they don't provide a proper rubber seat, and same for the top's (the jamming part, they provide o-rings). The tops also need to be pushed into the rail to the point where the aluminum on the injector may hit the aluminum on the fuel rail (some hit on mine, others didn't). We tested and didn't have any leaks, and ever since I've been driving 3-4 times a week without any issue. Once you accept the fitment isn't perfect, they are amazing injectors.

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really appreciate that feedback! I just assumed a decent company like ID would have proper fitting injectors. That's good info. Thanks for sharing!

foundry3 said:

I second ID1000's being perfectly fine. I run a Haltech Elite and the car idles better than stock with the ID1000's.

My only feedback is that ID injectors fit like shit in the NSX fuel rails and intake manifold. When we installed ours we called ID and they basically told us to just jam them into the intake manifold OEM seats as they don't provide a proper rubber seat, and same for the top's (the jamming part, they provide o-rings). The tops also need to be pushed into the rail to the point where the aluminum on the injector may hit the aluminum on the fuel rail (some hit on mine, others didn't). We tested and didn't have any leaks, and ever since I've been driving 3-4 times a week without any issue. Once you accept the fitment isn't perfect, they are amazing injectors.

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Have they fixed this issue?

These fits like a clove

http://as-motorsport.com/site/en/ca...8/fuel-injectors-blueprinted-700-1300cc-p-503

Operator said:

These fits like a clove

http://as-motorsport.com/site/en/ca...8/fuel-injectors-blueprinted-700-1300cc-p-503

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3 or 4 leaf?:biggrin:

Hanska by finnish !