Injector upgrade for stage 2 - needed, or not?

[JKWMD]

OK, I think it's time we all try to put something to rest - does the RS3 need modified injectors for stage 2, or not. Uni requires it; APR says they've maxed out the OEM injectors, so upgrades aren't needed. I'm APR 1+ currently, and am considering going to stage 2 APR, but I'd like to use the upgraded injectors Uni specifies; I'm not sure this is currently possible though, because I'm guessing APR would have to change their code for the new injectors. Arin, (APR rep), told me recently APR would be looking into the upgraded injectors with some dyno numbers, to see if the new injectors are a worthy addition to their stage 2 tune; I'm suspecting this won't happen any time soon, though.
Has anyone logged the APR stage 2 tune to see what kind of duty cycle the OEM injectors are running, because if they're really "maxed", I'd be concerned about longevity.

I'm aware I could just go Unitronic, but for the sake of argument, let's assume I'll be sticking with APR for now.

Any thoughts?

[P5stunna]

If you're sticking with APR why not heed their advice? You're going to get a lot of conjecture here asking the public.

[JKWMD]

I'm OK with a little conjecture; just seeing if anyone might have some actual data on the injectors that Uni is requiring, and what the OEM injectors are doing on the APR stage 2 tune.
I'm not against going Uni, I just want to pick the set-up that gives me the most power, safely, and with longevity in mind.

[Ross_T_Boss]

Figures speak for themselves, APR Stage2 is "only" (!) making 574hp, which is within the capabilities of stock injectors even on E85.

Other tuners Stage 2 maps run similar times/power, unless they move to injectors, which allows the turbo to be maximised and gives another 40-50hp.

So I think you can conclude that APR stage2 is not maxed on the injectors but not really worth bothering with over their 1+ tune. Your switch to another tune shouldn't be due concern over running the injector duty too high, it should only be because you wan more power on E85.

[JKWMD]

Figures speak for themselves, APR Stage2 is "only" (!) making 574hp, which is within the capabilities of stock injectors even on E85.

Other tuners Stage 2 maps run similar times/power, unless they move to injectors, which allows the turbo to be maximised and gives another 40-50hp.

So I think you can conclude that APR stage2 is not maxed on the injectors but not really worth bothering with over their 1+ tune. Your switch to another tune shouldn't be due concern over running the injector duty too high, it should only be because you wan more power on E85.

I was kind of thinking the same thing, but this begs the question why APR sticks with the OEM injectors, when they could more closely match Unitronic's numbers with upgraded injectors on their stage 2 tune. The main reason I started looking at Uni when I began considering stage 2 was the lack of much gain going to stage 2 with APR.

[jl87]

I'm not tuned, so no skin in the game- but I do notice 2 out of 3 of the popular tuners "require" them for stage 2 E85. I think OP is right in stating we need to see logs of duty cycle to understand it, but personally I would want as much safeguard as possible.

[r26372]

If staying Apr I wouldn't even bother with stage 2 of you're running e85. Also, uni requires injectors I believe on stage 2 only if using e85 file. If you'll run 93 then no injectors with either stage 2 I believe


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[JKWMD]

If staying Apr I wouldn't even bother with stage 2 of you're running e85. Also, uni requires injectors I believe on stage 2 only if using e85 file. If you'll run 93 then no injectors with either stage 2 I believe


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I'm planning on running E85. I put a question out to APR about running their stage 2 tune with the upgraded injectors, but I'm pretty sure what answer I'm going to get back. It just seems odd to me they don't offer a tune with the upgraded injectors if it's safe, and good for another 40+ hp; if they ever do offer it, it'll probably be called stage 2+.

[Brian@Unitronic]

We logged and tested on multiple cars for almost a year before launching this software. Based on our findings we chose to require injectors. My personal car maxed out the stock injectors on stage 2 e70 power levels and I have a "healthy" lpfp.

By adding the port injectors the stock fueling is safe on e85 for quite a bit more power than the stock turbo can achieve. To me the safety of running lower injector duty cycle and making maximum "safe" power is worth it and that's why we chose to go this direction.

Brian

[JKWMD]

Thanks Brian.

I believe the Unitronic website states specific ECU files are required to run the new injectors.
What would happen if you run the new injectors without special coding?, does the ECU treat them as if they were OEM?; might there be problems?

Just wondering.

[Evilevo]

Thanks Brian.

I believe the Unitronic website states specific ECU files are required to run the new injectors.
What would happen if you run the new injectors without special coding?, does the ECU treat them as if they were OEM?; might there be problems?

Just wondering.

The car won't start. Too much fuel at idle will keep it from running. You need specific calibrations for specific injectors. If you want to run larger injectors, I suggest switching to Unitronic from APR.

[JKWMD]

The car won't start. Too much fuel at idle will keep it from running. You need specific calibrations for specific injectors. If you want to run larger injectors, I suggest switching to Unitronic from APR.

Thanks, that’s what I thought.



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[SlowSedans]

We logged and tested on multiple cars for almost a year before launching this software. Based on our findings we chose to require injectors. My personal car maxed out the stock injectors on stage 2 e70 power levels and I have a "healthy" lpfp.

By adding the port injectors the stock fueling is safe on e85 for quite a bit more power than the stock turbo can achieve. To me the safety of running lower injector duty cycle and making maximum "safe" power is worth it and that's why we chose to go this direction.

Brian

this was essentially my exact same experience and path.

[Evilevo]

this was essentially my exact same experience and path.

But APR has "magic" software that fixes hardware limitations, so they're good.

[paulmc]

2018 RS3 already has 10 injectors (port injectors) Max power about 650bhp on stock injectors

[whitewaterguy87]

If someone was already APR stage 2 how would they go about testing/ logging the duty cycle? What would or should someone with a stage 2 car have to log and test there car for best safety practice?

[OE2]

Upgrade your primary injectors. Only after confirming that your tune can support it. Bosch 850cc are the standard upgrade for the port injectors.

[Eat.Sleep.Race]

I'd got with Untronic Stage 2 w/injectors. Much safer and not maxing out the stockers.. Just my 2 cents.

[allmotor_2000]

The car won't start. Too much fuel at idle will keep it from running. You need specific calibrations for specific injectors. If you want to run larger injectors, I suggest switching to Unitronic from APR.

Why is that? Port injectors don’t do anything until under boost.

[John@Unitronic]

When upgrading to our MPI Injector Upgrade, you must flash to the corresponding ECU file, for use with the Port Injector Upgrade. If you don't switch files after installing the injectors, the engine will not start/idle. We have Stage 2 ECU calibrations for 91oct, 93oct, 104oct, and E85 (E60-E85) using our MPI Injector Upgrade. We also have Stage 2 91oct and 93oct calibrations for use with the stock port injectors, if users won't/don't foresee using 104oct or E85.

[whitewaterguy87]

When upgrading to our MPI Injector Upgrade, you must flash to the corresponding ECU file, for use with the Port Injector Upgrade. If you don't switch files after installing the injectors, the engine will not start/idle. We have Stage 2 ECU calibrations for 91oct, 93oct, 104oct, and E85 (E60-E85) using our MPI Injector Upgrade. We also have Stage 2 91oct and 93oct calibrations for use with the stock port injectors, if users won't/don't foresee using 104oct or E85.

Hey John, If someone was already APR stage 2 how would they go about testing/ logging the duty cycle? What would or should someone with a stage 2 car have to log and test there car for best safety practice?

[John@Unitronic]

Hey John, If someone was already APR stage 2 how would they go about testing/ logging the duty cycle? What would or should someone with a stage 2 car have to log and test there car for best safety practice?

Please send me an email to js[at]getunitronic.com.

[r26372]

Hey John, If someone was already APR stage 2 how would they go about testing/ logging the duty cycle? What would or should someone with a stage 2 car have to log and test there car for best safety practice?

Why are you asking a Uni guy about an APR tune? Just get the APR mobile dongle as it logs. Work with that tuner as they can send you out log files that you can run.

[Evilevo]

Why are you asking a Uni guy about an APR tune? Just get the APR mobile dongle as it logs. Work with that tuner as they can send you out log files that you can run.

Maybe he wants some good customer service?

[VargasTurboTech]

Why is that? Port injectors don’t do anything until under boost.

I can say at least on 2019 the car will start, and run fine on a Stage 1+ Uni tune intended for stock injectors on the upgraded injectors. My tech installed all the Stage 2 parts on Thursday, but could not find the flashing cable. I was away on a fishing trip, and he needed to move the car inside. My experience with MPI Aux fueling is it doesn't add any fuel until it's needed so when he called and said he couldn't flash, I told not to worry about it, and pull the car into the shop on the Stage 1+ stock injector file. It fired up and ran as normal to just move it. With that said. You should NEVER install something fuel related, not flash the corresponding map, then try to drive the car hard. The results could be anything from poor running to a blown motor...

[0000 RS5]

I assume there is no need for injectors on Stage 1+ on E85.

[John@Unitronic]

I assume there is no need for injectors on Stage 1+ on E85.

Correct.

[S3DUDE]

Just FYI, APR just did this test specifically to clarify the Stage 2 injector question:

https://www.audizine.com/forum/showt...-(Stock-Turbo)

[Arin@APR]

Just FYI, APR just did this test specifically to clarify the Stage 2 injector question:

https://www.audizine.com/forum/showt...-(Stock-Turbo)

Correct, not needed. There is a little more to be had, but the gains are pretty small, especially peak to peak.

I’d love to offer a 2+ tune and hardware, but I don’t think we will based on these results. The gains just were not there.

[Evilevo]

Correct, not needed. There is a little more to be had, but the gains are pretty small, especially peak to peak.

I’d love to offer a 2+ tune and hardware, but I don’t think we will based on these results. The gains just were not there.

All your posts make me think that you just threw larger injectors in and didn't tune for them.

[Arin@APR]

All your posts make me think that you just threw larger injectors in and didn't tune for them.

FWIW, that’s not quite possible. These injectors are dramatically larger than stock. Tuning is required.

[JKWMD]

FWIW, that’s not quite possible. These injectors are dramatically larger than stock. Tuning is required.

Thanks for testing the injectors, Arin.


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[Evilevo]

FWIW, that’s not quite possible. These injectors are dramatically larger than stock. Tuning is required.

But you said that more tuning could clean up the losses down low that you saw from too much fuel. Obviously you guys didn't try too hard.

[a4000]

Apparently apr's numbers are down. Getting out gunned by the other guys. Pretty pathetic they need to resort to these tactics. Some amazing trolling going on.

[Ross_T_Boss]

Apparently apr's numbers are down. Getting out gunned by the other guys. Pretty pathetic they need to resort to these tactics. Some amazing trolling going on.

The APR numbers I have from 'street' pulls are accurate to the power claims and very consistent. I have no beef with them, but lost some respect with the attitude. I accept their conclusion that they found no need to upgrade injectors - but at the same claimed power levels, neither do the competition. It would be interesting to see logs as the figures don't stack up for me that they have the turbo pegged, and suggest they are also making their increased claimed power (that APR dispute).

Example - I'm seeing 5.4s best and 5.5-5.6s typical 100-200km/h, TTRS full-weight on the road running blended E65. The APR cars are running 6s dead consistently. So regardless of what APR state the figures really don't lie. Not just my car other, logs for MPI-equipped show other tuners hitting the same times.

Pays your money, Takes your choice...

(Edit to add - 93 times much closer, still a bit quicker but only by .1-.2s. Times across all the tuners I've seen are within the same range, 6.5-6.7s 100-200km/h)

[a4000]

The APR numbers I have from 'street' pulls are accurate to the power claims and very consistent. I have no beef with them, but lost some respect with the attitude. I accept their conclusion that they found no need to upgrade injectors - but at the same claimed power levels, neither do the competition. It would be interesting to see logs as the figures don't stack up for me that they have the turbo pegged, and suggest they are also making their increased claimed power (that APR dispute).

Example - I'm seeing 5.4s best and 5.5-5.6s typical 100-200km/h, TTRS full-weight on the road running blended E65. The APR cars are running 6s dead consistently. So regardless of what APR state the figures really don't lie. Not just my car other, logs for MPI-equipped show other tuners hitting the same times.

Pays your money, Takes your choice...

(Edit to add - 93 times much closer, still a bit quicker but only by .1-.2s. Times across all the tuners I've seen are within the same range, 6.5-6.7s 100-200km/h)

Numbers as in sales numbers.

[Evilevo]

Numbers as in sales numbers.

HP numbers

[a4000]

HP numbers

No, that's what I meant ffs.

[chris164935]

If someone was already APR stage 2 how would they go about testing/ logging the duty cycle? What would or should someone with a stage 2 car have to log and test there car for best safety practice?

Depending on the logging software, the injector duty cycle might be calculated for you and you can reference that. Otherwise, you'll have to calculate it yourself by logging the injector pulse width (how long the injector is energised to be open). Then you would divide that number by the time it takes the motor to do 2 revolutions at the specific RPM you are looking at.
More info here: https://www.stealth316.com/2-calc-idc.htm