Cam switchover @ 3K

[PLF8593]

So as I understand it, @ 3K rpm there is a “can switchover” (which I admittedly don’t understand quite what that means in detail, but understand that the engine goes into making power/advancing timing mode).

It’s weird though, my car feels like it’s pulling timing at this exact spot everytime. It makes a weird sound, almost like the DV dumping boost, and hesitates. But then it advances through the rest of the band and doesn’t pull anymore timing, which seems weird to me running Shell 93 on the Uni Stage 1 (91 octane/low torque) file. I feel like it should just go and go and go, no hesitation.

So basically I’m asking people who are tuned and have logged their car, is this hesitation normal, and simply indicative of the cam switchover, or am I pulling timing? I went down to 91 from the 1+ 93 map bc timing pull was annoying and I don’t have an intercooler or access to E85.

I do have NGK RS7s and RS3 coilpacks itching to be installed. Current plugs have 23k on them, coils are factory


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[swcrow]

Interesting. I'm Uni stage 1+....I'll have to test this out over lunch.

 

[flipflp]

So as I understand it, @ 3K rpm there is a “can switchover” (which I admittedly don’t understand quite what that means in detail, but understand that the engine goes into making power/advancing timing mode).

It’s weird though, my car feels like it’s pulling timing at this exact spot everytime. It makes a weird sound, almost like the DV dumping boost, and hesitates. But then it advances through the rest of the band and doesn’t pull anymore timing, which seems weird to me running Shell 93 on the Uni Stage 1 (91 octane/low torque) file. I feel like it should just go and go and go, no hesitation.

So basically I’m asking people who are tuned and have logged their car, is this hesitation normal, and simply indicative of the cam switchover, or am I pulling timing? I went down to 91 from the 1+ 93 map bc timing pull was annoying and I don’t have an intercooler or access to E85.

I do have NGK RS7s and RS3 coilpacks itching to be installed. Current plugs have 23k on them, coils are factory


Sent from my iPhone using Tapatalk

Same tech as Audi's Valve Lift:

Small cam lobe helps to spool the turbo with less overlap, big cam lobe aids in power by increasing flow in higher RPMS.

I've never heard of timing issues, that might be a question for your tuner to see if they have concerns about your logs. That change over might cause that, or there could be a hiccup in the tune or something else causing it.

 

[Hoon]

It could be a boost dip, not a timing pull. Without the ability to log, you'll never know for sure.

Without getting very technical, the ECU has two different airflow tables for the different cam positions. When the cam changes over, the table the ECU is referencing also changes.

There can be some smoothing required in this area to maintain a perfect boost curve, depending on the approach the particular tuner takes.

 

[Twist1]

My old car was very jumpy when switching over the profiles at 3100.

My mk7.5 is smooth as silk.

 

[nate704]

VTECH Yo!

 

[Benihana]

So as I understand it, @ 3K rpm there is a “can switchover” (which I admittedly don’t understand quite what that means in detail, but understand that the engine goes into making power/advancing timing mode).

It’s weird though, my car feels like it’s pulling timing at this exact spot everytime. It makes a weird sound, almost like the DV dumping boost, and hesitates. But then it advances through the rest of the band and doesn’t pull anymore timing, which seems weird to me running Shell 93 on the Uni Stage 1 (91 octane/low torque) file. I feel like it should just go and go and go, no hesitation.

So basically I’m asking people who are tuned and have logged their car, is this hesitation normal, and simply indicative of the cam switchover, or am I pulling timing? I went down to 91 from the 1+ 93 map bc timing pull was annoying and I don’t have an intercooler or access to E85.

I do have NGK RS7s and RS3 coilpacks itching to be installed. Current plugs have 23k on them, coils are factory


Sent from my iPhone using Tapatalk

I have the same issue with my MAP stage 2 tune, it almost seems like a dead spot. I always thought it was normal, but since I'm getting protuned in a couple of weeks I'll know if it's tune related or not.

 

[Diggs24]

Tuning around 3k is difficult. Depending on turbo pressure/airflow, octane, IAT, cam changeover, etc... you have to make a lot of tweaks to make it feel smooth. The ECU looks at air mass (among other items) to determine timing and since this can be quite variable depending on a ton of factors it's the hardest part to "get right" and when you have to get it right for everyone (canned tune) it won't be perfect for everyone. Smoothing it out takes work and even then you change 1 variable and it can mess it up. I'm still smoothing mine out so it isn't making massive corrections all the time.

 

[swcrow]

Just tested mine during lunch in manual and 1-4 gear from 2800-3500 I can't say I noticed anything "off"

 

[littco]

Depending on the engine there is vvl variable valve lift and vvt variable value timing.

The valve lift gives an extra 1mm lift and the valve timing can swing the cams from -30° to 30° and is totally variable.

There are maps for both these and associated timing maps so depending on how its maps will dictate how or what happens at the switch over. It's not uncommon to see timing differences due to a gap in valves from 1 map to the next .

Big gains can be had from utilising these maps

 

[wordsthatiwrote]

I have the same issue with my MAP stage 2 tune, it almost seems like a dead spot. I always thought it was normal, but since I'm getting protuned in a couple of weeks I'll know if it's tune related or not.

Check with MAP.
They have released updates for many if not all of their tunes.

 

[Benihana]

Check with MAP.
They have released updates for many if not all of their tunes.

I'm throwing on the EQT turbo on Saturday and then protuning with EQT so I won't be running the MAP tune anymore.

 

[MadMen]

Depending on the engine there is vvl variable valve lift and vvt variable value timing.

The valve lift gives an extra 1mm lift and the valve timing can swing the cams from -30° to 30° and is totally variable.

There are maps for both these and associated timing maps so depending on how its maps will dictate how or what happens at the switch over. It's not uncommon to see timing differences due to a gap in valves from 1 map to the next .

Big gains can be had from utilising these maps

Dan - assuming you mean the difference between a 1.8 and 2.0, as opposed to different variations in the same 2.0 engine for instance?

 

[shortyb]

So as I understand it, @ 3K rpm there is a “can switchover” (which I admittedly don’t understand quite what that means in detail, but understand that the engine goes into making power/advancing timing mode).

It’s weird though, my car feels like it’s pulling timing at this exact spot everytime. It makes a weird sound, almost like the DV dumping boost, and hesitates. But then it advances through the rest of the band and doesn’t pull anymore timing, which seems weird to me running Shell 93 on the Uni Stage 1 (91 octane/low torque) file. I feel like it should just go and go and go, no hesitation.

So basically I’m asking people who are tuned and have logged their car, is this hesitation normal, and simply indicative of the cam switchover, or am I pulling timing? I went down to 91 from the 1+ 93 map bc timing pull was annoying and I don’t have an intercooler or access to E85.

I do have NGK RS7s and RS3 coilpacks itching to be installed. Current plugs have 23k on them, coils are factory


Sent from my iPhone using Tapatalk

Any changes to the induction system?