Alfa 156 JTD 8V 115HP

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Alfa 156 JTD 8V 115HP

Postby sike_145 » Mon Nov 03, 2014 8:38 pm

This is my "who knows which number" tune...not jet tried in car, but difference between previous version which is currently in my car and this version is only in slightly more advanced SOI around 2000 RPMs.
With previous map (where SOI is also advanced, but little less than this), car goes very well, occasionally cluch slips in 4th or 5th gear (even in 3rd if driving uphill)...but I think that is because car has 130k km on road with previous owner, and 50k km in my driving style. It is not problem for me...I will drive it as long as clutch no slips in everyday driving conditions.

Reason for posting this is to somebody looks in this remap and tell me if SOI values are in safe values; as I understand, in stock maps SOI is retarded for purpose of ecology and NOx emissions but fuel economy than suffers. I am trying to achieve better fuel economy, and my driving conditions is road with lot of uphills and downhills...there is almost no any flat road near me. Because of that I have to achieve most power from engine at lowest gas pedal position and IQ. SOI should be one thing to do and I think that increasing boost will be other. Am I wrong?

Please review this tune...should this be safe to drive for long period?
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Re: Alfa 156 JTD 8V 115HP

Postby mladenke » Fri Nov 07, 2014 4:09 pm

What are you do with duration? How did you come to this values for biger IQ?

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Re: Alfa 156 JTD 8V 115HP

Postby sike_145 » Fri Nov 07, 2014 9:00 pm

I "stole" them from some other remap. Actually, don't know how to precise calculate duration for IQ; I cannot figure out stock calculations of duration for desired IQ and railP. They are weird.

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Re: Alfa 156 JTD 8V 115HP

Postby mladenke » Fri Nov 07, 2014 9:59 pm

Yeah, i think that you do that.
duration is in us. soi is in degrees. you must transform duration us to degrees, than soi-duration=eoi.

if you have 850rpm, and soi 1 degrees BTDC, duration time 800us...

60/850rpm=0.070 second. that is 70000 microseconds.
70000 microsecond/ duration 800us=87.5

than. 360 angle/87.5=4.11 degrees. Now you now duration in degrees.

so.. if inj timing start at 1 degrees BTDC (before TDC), than EOI will be (SOI =1) - (Duration = 4.11)= -3.11 degrees ATDC (after TDC)

Factor for soi is 0.023437. put that in you soi map and you will have inj start. dont need factor for duration becose duration is in microseconds in that ecu.
Look what rail pressure you have for some XXX rpm, and than look in your duration map, for duration time for that rail pressure.

soi-duration=EOI

use linear interpolation for now IQ in your duration. this duration is not good for your new IQ.

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Re: Alfa 156 JTD 8V 115HP

Postby sike_145 » Sat Nov 08, 2014 5:42 pm

Yes, I know how to calculate EOI. I put some calculator that I think is OK here:
tuning-calculator-for-edc15c7-t7157

But I think that EOI has nothing to do with duration of injection and IQ quantity. You are right, look to RPC map, for some RPMs and desired IQ there is CR pressure. And for that CR pressure and desired IQ in duration map there is injection energizing time. So for really good calculations, there should be some more parameters known; delay of opening injector, flow charactesristics of injector, delay of closing injector, difference between cylinder and CR pressure.

As I said, stock duration map is very strange, and had nothing to do with linear interpolation or common sense. Here is example:

For 2000 RPMs and IQ > 50mm^3 there is desired CR pressure of 1000 bar. Now look at duration map for this CR pressure and IQ of 50 mm^3. There is duration of 814 us. For IQ = 60mm^3, duration is 910. That is a difference of 96 us for 10mm^3 difference. And for IQ= 65mm^3, there is value of 1025 us. That is 115 us difference of duration for 5 mm^3 increase (from 60 to 65) what is bigger than 10mm^3 increase (from 50 to 60mm^3), And now, for 70mm^3 there is value of 1127 us. That is difference of 102us for 5mm^3 increase (from 65 to 70). So, why is difference between 50 and 60mm^3 lower than 5mm^3 increase between 60 to 65 and 65 to 70?
Does not make sence....we are talking about same CR pressure so IQ flow through injector should be more likely linear with increasing duration. But in stock map...it is far from that.

Maybe I'm not considering some other things...so if someone can actually explain this to me...please do.

What are correct values for duration in your opinion?

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Re: Alfa 156 JTD 8V 115HP

Postby mladenke » Sat Nov 08, 2014 6:19 pm

If you now how to calculate EOI, why don't you adjust SOI for best EOI for jtd 8v?

you have diferent railP for 50,60,65.. IQ, diferent rpm and so... I dont think that for 70mm3 you will have 1000 railP, it will be like 1250 to 1350. Some value from railP map and other map, ecu never use but it still there in map.
Best to do is, do log with inj time and duration and railP and you will see what rail pressure you have for certain IQ.

And if you open railP limit by IQ map you will see what railP are there for 50,60, 70.. IQ

For really good calculation of EOI you must calculate it on dyno, with EGT, cyl. pressure, and so many other factor. And that you can't do it on paper. ;)

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Re: Alfa 156 JTD 8V 115HP

Postby sike_145 » Sat Nov 08, 2014 7:00 pm

Because I don't know what is best EOI for jtd 8V :) Like you said, it should be done on dyno. However, with half to one degree advanced at IQ up to 30mm^3 and around 2000RPM I have at least 0,5 liter lower consumption. Not jet measured, because I'm testing it with refueling tank to full when reserve lamp lights up. And now I have still more than half tank of fuel, and more than 500km trip.

With next tank of fuel, I will test one to two degree advance...

Well...maybe I'm looking at wrong x axe data for railP map so because of that I see same values for railP for IQ > 50mm^3.
Can you tell me what are right address for x axe for railP?

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Re: Alfa 156 JTD 8V 115HP

Postby mladenke » Sat Nov 08, 2014 7:46 pm

if you have egr off, 2 degrees <30mm3 will be ok, if you looking for economy. But you must try it.

I dont now exactly mapp addres for you soft. ecu, but you must have iq dependant by rail and rpm, railp dependant by iq and rpm, and 2 or 3 more. I dont have time now, but i will do it tonight maybe.

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Re: Alfa 156 JTD 8V 115HP

Postby mladenke » Sat Nov 08, 2014 9:48 pm

7a46c 16x16

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Re: Alfa 156 JTD 8V 115HP

Postby sike_145 » Sat Nov 08, 2014 10:16 pm

Yes, I know that map, but x and y axes are not near so I'm not sure what are addresses of x and y axe data.

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