gear shifting and lag?

ramzy_86 · Jan 14, 2009

Hi
I have a ibiza mk 4 100pd and has been remapped. Prior to remap and even now when giving it heavy right foot and shifting as fast as possible the revs seems to take longer than usual to normalize?even though the car has no esp/tcs,it feels as if it has and when shifting from say 2nd to 3rd it really has a lag from the time i shift to the time 3rd gears power is actually working. The car has done 3.5k.I was putting this down to either because the car is new or just because that just how this diesel works.In gear performance is excellent and cannot flaw it,there is no boost spike etc.If anyone has an idea to why this happens or how to reduce the lag between shifting and power actually working in next gear,please share.
This is my first diesel as i had a lc before so maybe thats why im not used to it,unless its not meant to happen.It is really annoying esp as when I have a good take off and power is good then as soon as I shift the lag (or what feels like esp kicking in,even though no esp present) til the next gear seems longer than usual,in comparison to my lc.:confused
Thanks

Muttley · Jan 14, 2009

What point in the rev band are you shifting at?

ramzy_86 · Jan 14, 2009

Muttley said:
What point in the rev band are you shifting at?

4k, or just over,which is peak bhp and the next gear falls at round 2.5 to 3k, past the lag which is below 2k
I have been told that some cars have a safety mechanism to avoid clutch failure,so its enabled,therefore slowing the actual change
and also been told to ,when shifting, to not let go of accel,therefore wastegate does not open.
Any ideas?

muddyboots · Jan 14, 2009

This might sound daft, but are you taking your foot right off the clutch after changing gear ?
If you dip the clutch pedal ever so slightly, which can happen if you rest your foot on it, that will cut engine power.

ramzy_86 · Jan 15, 2009

muddyboots said:
This might sound daft, but are you taking your foot right off the clutch after changing gear ?
If you dip the clutch pedal ever so slightly, which can happen if you rest your foot on it, that will cut engine power.

No not daft,
Im sure im doing it right as i used the same techqniue in my lc and never had this prob.I assume its a diesel thing or because the car has done 3.5k miles

Muttley · Jan 15, 2009

Well, I'm pretty sure that keeping your foot hard on the throttle pedal while changing gear isn't doing your clutch any good at all, and maybe you're getting clutch slip.

Whoever gave you that advice perhaps has shares in a clutch business? You are changing at the right point, so you should have masses of power.

All the VAG diesels after the TDI90 have VNT turbos, which don't have a wastegate. Even if they did, the wastegate only opens when there is too much gas flow, to stop the turbo overspeeding i.e. at high revs. You are more likely to open a wastegate by keeping your foot on the throttle while upchanging, quite apart from the enormous amounts of damage you will do to the clutch. Seriously, this is barbaric.

In any case, there are switches on the clutch and brake pedals that tell the ECU when the pedals are pressed. The ECU cuts power when either pedal is pressed.

Your PD100 Ibiza isn't going to perform anything like as impressively as your LC. Even so, it takes serious abuse to knacker the clutch in 3500 miles. Sadly, from your description, that is what you've been giving it.

ramzy_86 · Jan 15, 2009

Muttley said:
Well, I'm pretty sure that keeping your foot hard on the throttle pedal while changing gear isn't doing your clutch any good at all, and maybe you're getting clutch slip.

Whoever gave you that advice perhaps has shares in a clutch business? You are changing at the right point, so you should have masses of power.

All the VAG diesels after the TDI90 have VNT turbos, which don't have a wastegate. Even if they did, the wastegate only opens when there is too much gas flow, to stop the turbo overspeeding i.e. at high revs. You are more likely to open a wastegate by keeping your foot on the throttle while upchanging, quite apart from the enormous amounts of damage you will do to the clutch. Seriously, this is barbaric.

In any case, there are switches on the clutch and brake pedals that tell the ECU when the pedals are pressed. The ECU cuts power when either pedal is pressed.

Your PD100 Ibiza isn't going to perform anything like as impressively as your LC. Even so, it takes serious abuse to knacker the clutch in 3500 miles. Sadly, from your description, that is what you've been giving it.

Thanks for the input
Yeah,i understand what you are saying about pressing acc when changining,not that I do anyway,and no I havnt been torturing the car from day 1,mqajority of time I take it really easy to maximise mpg but now and then use it to its max.
I prob just book it in for a checkup soon.although It would be odd for someting to be wrong.
thanks again

muddyboots · Jan 15, 2009

ramzy_86 said:
and also been told to ,when shifting, to not let go of accel,therefore wastegate does not open.

I missed that bit....

Really bad idea.... no need on a TDI. TDIs don't have throttles, therefore no pressure buildup when you lift off to stall your turbo. And they're VNTs which don't have a wastegate anyway.
You'll end up knacering your clutch in no time, as instead of letting engine speed drop during changes to match flywheel & gearbox speeds, you're doing the opposite, giving the clutch a really hard time, not to mention the violent forces you'll be transmitting to your engine mounts etc.

jabbasport · Jan 15, 2009

Maybe because you've had a remap and it's building to a higher boost level it feels like it's taking longer to make power whereas actually, it takes the same time to make the boost/power that it would have done pre remap, you're just adding a bit more time to that for the extra boost required by the remap?

ramzy_86 · Jan 15, 2009

muddyboots said:
This might sound daft, but are you taking your foot right off the clutch after changing gear ?
If you dip the clutch pedal ever so slightly, which can happen if you rest your foot on it, that will cut engine power.

Thanks,i dont do that !someone had told me.But yeah im new to diesels so im still learning

.
Last night,tried actually to shift as fast as I could and it made a big diff as the lag in the shift wasnt so noticeable.Im guessing from previosuly driving the lc,I had been used to shifting in a sort of way and maybe the lc(remapped)just could shift better so could rely on the car and less on me actually making an effort,if that makes sense.
thanks again!

Ibiza Dan · Jan 15, 2009

Mine starts to pull very hard from about 1.6k revs, full boost at about 2.1k revs.
Just guessing as im not sat in my car

Also mine has a slightly bigger turbo aswell so may be more laggy than standard ?
Oh and take your foot off the throttle before you change gear

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gear shifting and lag?

ramzy_86

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Muttley

Catch that diesel!

ramzy_86

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muddyboots

Still hanging around

ramzy_86

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Muttley

Catch that diesel!

ramzy_86

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muddyboots

Still hanging around

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ramzy_86

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Ibiza Dan

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