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Author Topic: LPG tuning  (Read 43182 times)
prj
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« Reply #30 on: April 12, 2013, 09:52:29 AM »

I've seen no disadvantage of disabling KFMRES torque, to be honest there's no difference in engine idle at all. Besides from running at normal 10-20deg ignition advance instead of ridiculous 0 degs and so. 

Yeah, try turning your power steering or turning your aircon on.
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lezsi
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« Reply #31 on: April 12, 2013, 10:18:45 AM »

Yeah, try turning your power steering or turning your aircon on.

Tried both, plus switching lights and rear defog.  Tried to switch more of them at the same time. 
Don't see much difference to original.  Cheesy
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prj
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« Reply #32 on: April 12, 2013, 10:30:12 AM »

Let me put it this way. If what you say was true, and there was "no difference" then no OEM would run torque reserve on idle, as idle is a significant contributor to the EPA fuel mileage estimation cycle.

You tune your car like you want, but calling OEM's stupid is not very intelligent.

If you had any experience with idle tuning, then you would know that by removing torque reserve you kill fast path idle intervention.
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papasound
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« Reply #33 on: April 13, 2013, 03:20:43 AM »

Nice try lezsi, when there's so little info on a topic it's really helpful to have working examples such as latter. 
I will try to incorporate this incrementally on tt225 lpg and lets see what logs are saying.
« Last Edit: April 13, 2013, 02:43:04 PM by papasound » Logged

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Acki
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« Reply #34 on: April 13, 2013, 09:12:05 AM »

I'm not sure but a friend told me that his engine sometimes runs backwards because of complete wrong ignition.
I'm not sure in which direction he failed the ignition...
How ever - when it runs stable at stock ignition - fine. Smiley
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papasound
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« Reply #35 on: April 13, 2013, 02:34:00 PM »

*
« Last Edit: April 14, 2013, 04:03:17 AM by papasound » Logged

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Acki
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« Reply #36 on: April 13, 2013, 11:54:18 PM »

Well. There are a lot of timing settings which run in the first moment without issues but during daily driving you could get a problem.
At the idle some tuning of the ignition is not needed because fuel economy or power is no aim.
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lezsi
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« Reply #37 on: April 15, 2013, 05:16:48 AM »

Let me put it this way. If what you say was true, and there was "no difference" then no OEM would run torque reserve on idle, as idle is a significant contributor to the EPA fuel mileage estimation cycle.

You tune your car like you want, but calling OEM's stupid is not very intelligent.

If you had any experience with idle tuning, then you would know that by removing torque reserve you kill fast path idle intervention.

I respect OEM's efforts and results, that's why I kept ME7 instead of installing a stand-alone (sitting on my shelf a long time).

OEMs have their priorities and constraints.  I don't have the same fortunately. 
I don't need to pass such strict emissions standard, don't have to calculate for worn engines with clogged injectors and weak spark, etc.

The interesting part is that it seems even with KFMRES zeroed out, ME7 still have the ability to advance idle to catch-up when necessary.

I have some difficulties with ME7logger to make a high sample-rate demonstration, but I'll make a video shot or something if you're interested.
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ABCD
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« Reply #38 on: August 05, 2013, 10:23:50 PM »

I'm going for LPG to, does the LPG injection follow the ME7.5 strategy? Or it uses one one external ECU that overrides the OEM ECU??

generally peak & hold injector are used for LPG.
hence, the other external unit is used to provide peak current
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ABCD
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« Reply #39 on: August 05, 2013, 10:27:19 PM »

Hi,

thanks for the info. Have you got a source for the thesis, that EGT goes upon LPG, when lambda goes lower than 0.9?

This would be very interesting to me. I have also seen some LPG-damaged engines, but on all of them reason for the failure was a bad LPG-conversion. The AFR-mixture went very lean on high rpms in high gears and caused the engines to melt.

So any source of information about LPG-EGT-temperatures is interesting to me.

Latent heat of vaporisation !

Yogi
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ABCD
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« Reply #40 on: August 05, 2013, 10:31:16 PM »

Why would you go lambda 1.09? This hurts fuel economy, as it's too lean. 1.05 is enough.
Not to mention, I am curious how you achieved it? Hacking the O2 sensor voltage? ME7 won't request leaner than 1.0 without ASM hacks.This is a bad idea, as won't make any difference for fuel economy, and will hurt drivability.

Hi prj:
bit off topic, but
i am curious to know that how can you you use your narrowbands for lambda>1. Any hints!
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rogerius
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« Reply #41 on: October 11, 2013, 06:54:40 AM »

Hi!
I am new here, I have installed LPG on a 1.8T 300ps minimum (off the WG), I do have switching maps installed and 2 softwarez.
I will ask a tuner to tune for LPG as soon as I figure out what are the best parameters for burning the LPG fuel.
I have liquid injected LPG that follows the PW of the petrol injectors and has the advantage of cooling the charge when changing phase.
I would like to learn what would be the most suitable target AFR and Ignition Timing curve if turbo spools till 3500rpm and has 1.1bar constant till redline.
Any hints, what should I read first?
TIA!
Alex
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marian_gbg
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« Reply #42 on: January 22, 2017, 07:24:39 AM »

This is my tuned KFZW (KFZW2) map for working on LPG fuel (ignition angle difference). What do you think?
Prj your opinion Please ?

PS. For 018A box
« Last Edit: January 22, 2017, 07:26:45 AM by marian_gbg » Logged
prj
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« Reply #43 on: January 25, 2017, 04:15:43 PM »

My opinion is that you should drive the car.

Low down is OK, top end is NOT ok. Why would you retard the ignition? At top end you can probably run close to KFZWOP because LPG has very high octane.
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marian_gbg
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« Reply #44 on: January 27, 2017, 12:45:58 PM »


Low down is OK, top end is NOT ok. Why would you retard the ignition? At top end you can probably run close to KFZWOP because LPG has very high octane.

Thanks Prj!
I retard the ignition at low rpm because LPG burn slowly. What do you suggest to do in top end of this map(s) ?
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