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Author Topic: MAF and Injector Scaling  (Read 53561 times)
elRey
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« Reply #30 on: April 23, 2010, 02:13:18 PM »

This is what I found:

minimales TE bei VA (TEMINVA)
minimales TE (TEMIN)


I believe VA refers to Overrun, but I'm not sure.
« Last Edit: April 23, 2010, 02:16:43 PM by elRey » Logged
99pwr
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« Reply #31 on: April 24, 2010, 06:29:05 AM »

Thanks,
You know which is correct MIN. TE value for 630 cm3 injectors?
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paracaidista2.7T
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« Reply #32 on: April 26, 2010, 01:11:20 PM »

That depends on fuel pressure. You should not have to change it from the stock value. It is sufficiently low.
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Tony@NefMoto
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« Reply #33 on: April 30, 2010, 03:02:20 PM »

Thanks,
You know which is correct MIN. TE value for 630 cm3 injectors?

The easiest way to do it, that most people use, is to scale the constant by the difference in injector flow rate.

new min injection time = original min injection time * (flow rate original / flow rate new)

That way if you put in larger injectors that flow more, you end up needing a smaller min injection time.
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« Reply #34 on: June 14, 2010, 07:41:09 AM »

KRKTE always must be calculated when larger injectors are fit!

We do not set KRKTE randomly but there is a formula from Bosch that calculate it! You analyze it before but you have to watch that this formula
do not use the injectors gasolines flow rate at cc/min but uses the gasolines n-heptan flow rate with units g/min!

So watch out!

I usually tune larger injectors only with KRKTE without having problems, injectors till 600cc! Over 600cc you have to adjust injectors lag time and some more that you have found and you explain before!

Well done for your well job on that topic!

Regards
Fotis
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groovetek
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« Reply #35 on: June 19, 2010, 02:15:57 PM »

Great forum Tony.

Sorry if I've missed it, but is there a constant for the fuel consumption display?  Or will this affect the tune as well.

I have 3 cars running the same program at the moment and tweaked via unisettings; with minor differences between fuelling and MAF setups.  All are running perfectly now, but the fuel consumption reading is way off (~40% lower than in reality).
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hammersword
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« Reply #36 on: June 19, 2010, 04:59:57 PM »

Great forum Tony.

Sorry if I've missed it, but is there a constant for the fuel consumption display?  Or will this affect the tune as well.

I have 3 cars running the same program at the moment and tweaked via unisettings; with minor differences between fuelling and MAF setups.  All are running perfectly now, but the fuel consumption reading is way off (~40% lower than in reality).

yes,

go and set KVB properly

Wink
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Tony@NefMoto
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« Reply #37 on: June 22, 2010, 02:08:54 PM »

Great forum Tony.

Sorry if I've missed it, but is there a constant for the fuel consumption display?  Or will this affect the tune as well.

I have 3 cars running the same program at the moment and tweaked via unisettings; with minor differences between fuelling and MAF setups.  All are running perfectly now, but the fuel consumption reading is way off (~40% lower than in reality).

Yes, there is a separate constant for fuel consumption. It has no effect on fuel injection, just consumption calculations.
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« Reply #38 on: June 23, 2010, 06:24:36 AM »

that constant is KVB that I say before
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kelesha
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« Reply #39 on: September 04, 2010, 11:48:54 AM »

And what about Hysteresis for lambda control?
Yes thats another important part to get good idle with big injectors.
Sometimes i have bouncing idle issues with injectors 630cc or higher, even when in same time lambda correction is +/-3%, on VCDS i see that injectors pulse is changed in example from 1.36ms to 1.70ms and idle speed is changes in such time(bounce), so i think if the correction is not 0.34ms but 0.15ms in example than bounce issue will be eliminated or lower.........unfortunately i still cant find the values in ME7 software what are referred to lambda hysteresis on idle.......
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lave3k
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« Reply #40 on: September 10, 2010, 11:20:15 PM »

One more thing to look into is the warm-up fuel maps.  In my 1.8t these are:
(KFFWL_0_A)   12X12
(KFFWL_1_A)   12X12

My car ran very rich on cold starts prior to playing with these.
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Jason
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« Reply #41 on: November 22, 2010, 09:45:13 AM »

I'm kind of cross-posting this as I think this may be a more appropriate place to discuss:

http://www.nefariousmotorsports.com/forum/index.php?topic=170.0title=

(cliffs notes for the above link:)

I took Tony's 85mm + 60lb/hr with idle tuning file, and it ran terrible on my car, idle hunting and small throttle angles would really upset it.

Ignoring the additional load requested at idle, I looked at TVUB, and what Tony did with the latencies made sound logic and sense - the siemens injectors are faster than the stock injectors and the changes Tony made are congruent with the latency difference.

For some reason, my car prefers much higher values in this table than Tony's, but lower than the stock M box values... It also does not exhibit any idle misfires.

My question is, does the ME7 use a dynamic flow model outside of the injector constant KRKTE?  Obviously these injectors open faster - but they also close faster - and outside of these two differences, I'm sure the slope of the fuel delivery is considerably different (at least from what my brain thinks).

Obviously these differences have little to no effect at WOT, but at idle, I think the injector close time is going to play a big role in idle fueling, because if the injector closes faster and the ECU is not aware of this, the pulse-width calculated is going to be too short and the result will be underfueling at idle - something that no amount of latency tweaking is going to solve.

Thoughts?
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Tony@NefMoto
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« Reply #42 on: November 23, 2010, 05:53:41 PM »

I started with theoretically correct values, and then slowly changed the injector scale and constant based on my long term fuel trims at partial load and idle.

If the fuel trims are happy, then I am sure everything balances out.
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Tony@NefMoto
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« Reply #43 on: November 24, 2010, 05:38:02 PM »

Here is a good reference for fuel injector latencies: http://injector-rehab.com/shop/lag.html
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Jason
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« Reply #44 on: November 25, 2010, 11:07:05 AM »

That is exactly the site I used to reference the latencies...  I'm really curious to know what could be different between our cars.

Do you know what the voltage values are for the TVUB axis?
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