kaross
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« on: May 10, 2013, 12:47:24 AM »
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Hi! Haven't found topics with my answers, so I am making new one. I am interested how variable valve timing works on 2.7T. As I understand on 1.8T there are only 2 positions. 0degrees - no advance and 22 degrees advance for better spool up and performance. Found also map on 1.8T, but can't find it in 2.7 file. in damos: NWWUE From this graph I understand that there is more than 2 positions.  Anybody can explain how it works on 2.7T |
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« Last Edit: May 10, 2013, 12:55:20 AM by kaross »
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catbed
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« Reply #1 on: May 10, 2013, 12:51:19 AM »
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Same as 1.8t. There are only 2 positions, advanced and not-advanced. VVT has little effect on k03, but does have more effect on k04 and up. RS4 is different from S4 as it has bank independent control.
How do you see more than 2 positions from that graph?
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kaross
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« Reply #2 on: May 10, 2013, 12:59:14 AM »
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what do you mean by bank independent control?
I don't understand this graph. I thouhgt that grey area is advance degrees. And it is changing depending on RPM. How do you understand this graph?
For example If I install better intake camshaft and want to tune this timing, what I need to search for?
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catbed
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« Reply #3 on: May 10, 2013, 01:43:25 AM »
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what do you mean by bank independent control?
I don't understand this graph. I thouhgt that grey area is advance degrees. And it is changing depending on RPM. How do you understand this graph?
For example If I install better intake camshaft and want to tune this timing, what I need to search for?
Meaning, on the S4 the solenoids are controlled in unison with a shared pin on the ECU. In RS4, each bank has its own ECU pin, thus independent. The domain axis of the graph is RPM and the range says load, but I suspect it is requested torque, so the VVT is only active at high load from 1k-4k RPM. The map you need to look for to tune this is KFNWSE, although there are a multitude of NWS maps. Hope this helps.  |
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kaross
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« Reply #4 on: May 10, 2013, 02:31:55 AM »
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great! That is what I wanted to know! Thanks.
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vagenwerk
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« Reply #5 on: May 10, 2013, 02:56:11 AM »
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VVT has little effect on k03, but does have more effect on k04 and up.
From my experience (little) on k03 vvt is useless and decrease performance and boost.... |
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phila_dot
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« Reply #6 on: May 10, 2013, 05:17:40 AM »
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Meaning, on the S4 the solenoids are controlled in unison with a shared pin on the ECU. In RS4, each bank has its own ECU pin, thus independent. The domain axis of the graph is RPM and the range says load, but I suspect it is requested torque, so the VVT is only active at high load from 1k-4k RPM. The map you need to look for to tune this is KFNWSE, although there are a multitude of NWS maps. Hope this helps. It is load. Also, KFNWSE doesn't exist in ME7.1. You want to look at the Alpha FR for this. |
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catbed
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« Reply #7 on: May 10, 2013, 10:01:16 AM »
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It is load.
Also, KFNWSE doesn't exist in ME7.1.
You want to look at the Alpha FR for this.
Right, so it's just KFNW for 2.7 then? |
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nyet
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« Reply #8 on: May 10, 2013, 10:15:07 AM »
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Right, so it's just KFNW for 2.7 then?
Yes. As far as I can tell. Also KFNWWL (for warmup) |
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ME7.1 tuning guideECUx PlotME7Sum checksumTrim heatmap toolPlease do not ask me for tunes. I'm here to help people make their own. Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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Snow Trooper
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« Reply #9 on: May 10, 2013, 11:02:33 AM »
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Its pretty straight forward, you want to advance the cam as you start to spool and keep it advanced until just after peak tq and the load settles, keep it in for a few hundred rpm and then let it shut back down towards redline. On the ko3 (stock) setup it shuts off so soon because as the rpm climbs the turbines become very restrictive and that overlap isnt beneficial.
On a big turbo with a low turbine inlet pressure (tip) you can run it out much further. Personally on my big single I come on with it around a measured load of 80 at like 3200 rpm and it stays on to about 5800 rpms, being fully switched off by 6100-6200
Something I never see mentioned is the time in which the solenoid needs to transition, it isnt instantaneous. You will need to play around with this to get it right.
The way i tune VVT is to turn it off completely at all points, go and do a few pulls in various gears. Then i turn it on completely (I wont run it over 7000 just for safety sake) and do the same pulls over again. Then I over lay the maps to see whats is what. The non advanced pulls will be laggier with a softer tq peak but stay level on power up top. The fully advanced pulls will spool faster but lose some power up top. This paints the clear picture of where its beneficial to be on vs off and you can set your maps accordingly.
I have tuned a few cars where I ended up having it come on, then off, then back on and back off for a short period up high in the rpms. Every setup will be different in what is going to maximize power. Port sizes, turbo sizes, manifold types and even wastegate type can all influence a given system and how it behaves with the VVT.
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« Last Edit: May 17, 2013, 05:52:58 PM by Snow Trooper »
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cartoons?
6A 61 72 65 64 40 76 6C 6D 73 70 65 63
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jibberjive
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« Reply #10 on: May 11, 2013, 03:49:00 PM »
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Its pretty straight forward, you want to advance the cam as you start to spool and keep it advanced until just after peak tq and the load settles, keep it in for a few hundred rpm and then let it shut back down towards redline. On the ko3 (stock) setup it shuts off so soon because as the rpm climps the turbines become very restrictive and that overlap isnt beneficial.
On a big turbo with a low turbine inlet pressure (tip) you can run it out much further. Personally on my big single I come on with it around a measured load of 80 at like 3200 rpm and it stays on to about 5800 rpms, being fully switched off by 6100-6200
Something I never see mentioned is the time in which the solenoid needs to transition, it isnt instantaneous. You will need to play around with this to get it right.
The way i tune VVT is to turn it off completely at all points, go and do a few pulls in various gears. Then i turn it on completely (I wont run it over 7000 just for safety sake) and do the same pulls over again. Then I over lay the maps to see whats is what. The non advanced pulls will be laggier with a softer tq peak but stay level on power up top. The fully advanced pulls will spool faster but lose some power up top. This paints the clear picture of where its beneficial to be on vs off and you can set your maps accordingly.
I have tuned a few cars where I ended up having it come on, then off, then back on and back off for a short period up high in the rpms. Every setup will be different in what is going to maximize power. Port sizes, turbo sizes, manifold types and even wastegate type can all influence a given system and how it behaves with the VVT.
Interesting, thanks for sharing your experiences. I'm looking forward to playing with this once I have all the other areas of my tune ironed out. |
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3iverson
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« Reply #11 on: May 11, 2013, 05:16:06 PM »
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very intesting info , thanks to all for share it , i was finding info about of vvt for 1.8t Me 7.5 , this help me so much
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julex
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« Reply #12 on: May 16, 2013, 07:40:38 AM »
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Very informative. I am leery about having the intake advanced though up to 7k on test runs... are these WOT? I assume they are...
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elRey
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« Reply #13 on: May 16, 2013, 08:58:24 AM »
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Trooper, how do you fine tune timing for each VVT state with tuning method above?
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Snow Trooper
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« Reply #14 on: May 17, 2013, 05:52:27 PM »
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Very informative. I am leery about having the intake advanced though up to 7k on test runs... are these WOT? I assume they are...
yes, this is all for WOT and i agree, its sketches me out having it on over 7k. none of us really have any business running it over 6500 |
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cartoons?
6A 61 72 65 64 40 76 6C 6D 73 70 65 63
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