[notsa101]

Hi all,

I'm looking for some advice on a strange occurrence I have noticed recently whilst driving in sport plus mode. I keep having strange moment where the car feels like it lags then lurches. Its a very strange feeling and I'd love to find out if it is something I am doing or if it is a problem with the car.

This issue seems to happen just shy of 2000 revs. When I am on around 1700-1800 and I put my foot down the car starts to pull, lags a little then lurches forward accelerating again. I have notice a very weird rev blip on the counter a few times it has done this. The revs will briefly jump to about 2200 then dip back down to about 1900 and the car will pull forward. I don't think this has anything to do with auto rev matching since it doesn't always coincide with gear changes. This also doesn't happen if accelerating from below about 1400rpm, as expected with the bi-turbo that is just nice and smooth all the way through.

I am wondering if this has anything to do with the bi-turbo system. I don't know where about in the rev range the larger turbo starts to take over, if its at around 2000 could this just be some lag at a very specific point in the revs?

The thing I don't understand is this is a manual gearbox. How can the revs jump up by 400 then back down with the clutch pedal fully disengaged and with no change in acceleration?

Grateful of any help and suggestions on this,
Thanks

[lacrimarum]

20d engine on f3x generation is not a biturbo one, "twin power turbo" means single, but twinscroll turbocharger in this case.

It's better to run some diagnostics to read the errors and rule out that this behavior is caused by any engine problems, but, according to your description, it seems the most likely to me that this is a slipping clutch. If it has high mileage or was overheated on a few occasions, it could be quite worn and can start to slip when engine produces enough torque. Maximal torque is reached approximately from 1800 rpm with those engines. If you accelerate steadily from lower rpm, torque also rises in a steady way, so clutch still can handle it or slips in a less noticeable way.

[notsa101]

Originally Posted by lacrimarum

20d engine on f3x generation is not a biturbo one, "twin power turbo" means single, but twinscroll turbocharger in this case.

It's better to run some diagnostics to read the errors and rule out that this behavior is caused by any engine problems, but, according to your description, it seems the most likely to me that this is a slipping clutch. If it has high mileage or was overheated on a few occasions, it could be quite worn and can start to slip when engine produces enough torque. Maximal torque is reached approximately from 1800 rpm with those engines. If you accelerate steadily from lower rpm, torque also rises in a steady way, so clutch still can handle it or slips in a less noticeable way.

Sorry it took me a while to reply back. It clicked with me as soon as I saw the reply. You were bang on, clutch. I kept it going for another 1500 miles and changed it myself yesterday. wasn't the pig of a job I had expected it'd be. Not exactly nice in the cold and wet but doable on fairly high ramps. Good as new now. 95k miles and feels like it just rolled out the factory!!

Thanks very much for your advice mate

[lacrimarum]

That's great, I'm glad I was able to provide a little of help
I hope you'll have many more thousands of trouble-free miles on your car. F30 appears to be a great and efficient daily driver, I plan to keep it at least until 200k km.