RC F rear axle/diff noise

[Smithers]

Hi all, newbie here so be kind!
 

Had my 2018 RC F delivered this week and I have to say after initial indifference, I have grown to like it…..in fact I really like it!
 

Drove it on a 400 mile trip in mixed conditions and it was surprisingly economical, reasonably comfortable and went well when needed. I found the steering a little light, but have got used to it don’t really notice it now. Subsequently drove it on lots of local runs as well.

 

However, I noticed that when pulling off - especially when the car is turning - there is an initial feeling of drag and slight noise up to about 20mph. Doesn’t matter what driving mode it is in but does seem to be less noticeable if you are rolling…for instance at a roundabout. The best way I can describe it is similar to when you have brand new tyres on they give that hard slip/grip feel for the first few miles. Driven lots of rear wheel drive cars and never experienced this…just stepped out of  BMW 640D M Sport with 20s on.

Is this a characteristic of the car, or a diff setting etc? The car has 18k FLSH and was serviced less than 1500 miles ago.

[Jgtcracer]

8 hours ago, Smithers said:

Hi all, newbie here so be kind!
 

Had my 2018 RC F delivered this week and I have to say after initial indifference, I have grown to like it…..in fact I really like it!
 

Drove it on a 400 mile trip in mixed conditions and it was surprisingly economical, reasonably comfortable and went well when needed. I found the steering a little light, but have got used to it don’t really notice it now. Subsequently drove it on lots of local runs as well.

 

However, I noticed that when pulling off - especially when the car is turning - there is an initial feeling of drag and slight noise up to about 20mph. Doesn’t matter what driving mode it is in but does seem to be less noticeable if you are rolling…for instance at a roundabout. The best way I can describe it is similar to when you have brand new tyres on they give that hard slip/grip feel for the first few miles. Driven lots of rear wheel drive cars and never experienced this…just stepped out of  BMW 640D M Sport with 20s on.

Is this a characteristic of the car, or a diff setting etc? The car has 18k FLSH and was serviced less than 1500 miles ago.

Welcome! 
 

Does the car have a TVD or Standard LSD?  A lot of cars with LSDs will scrub tyres on full lock, and I notice it in my RCF when turning on the gravel car park at work.  This can make noise but it’s the gravel rather than the diff making the it.  Don’t notice it at all on paved roads.

Id be amazed if something is broken, I believe both diff types are robust.

[Smithers]

Thanks for coming back, I believe it has the LSD but what would be the best way to check?

[Jgtcracer]

9 minutes ago, Smithers said:

Thanks for coming back, I believe it has the LSD but what would be the best way to check?

If you have TVD you would probably know.  There is a TVD button in the centre console next to snow I think and you will have a diff setting graphic on the dash next to drive mode. 

[Smithers]

Yep, definitely the standard LSD.

[Jgtcracer]

19 minutes ago, Smithers said:

Yep, definitely the standard LSD.

Good, glad could help.  If you are getting funny noises from the diff, particularly when driving straight it may be worth getting it looked at.  At  slow speeds I think 1st gear is a bit rubbish, car is definitely more comfortable on the move.  Don’t suppose you have tried it in manual rather than with box in auto?

[Smithers]

Ok…tried it in manual and it doesn’t seem to do it. 

[Jgtcracer]

36 minutes ago, Smithers said:

Ok…tried it in manual and it doesn’t seem to do it. 

Is it a knocking or something?  Sound like something mechanical?

I think 1st is just a bit rubbish, almost like throttle map has been dulled down to resist jerky driving.  
 

1st gear is a manoeuvring gear really, not much use for anything else.

[L55 RCF]

Mine is on standard diff and does it too. Nothing to worry about. 
It’s the nature of the beast with a Torsen diff. 

[Smithers]

Cheers both, much appreciated.

[Smithers]

Oh while I have you, what tyres are you running and do you have any advice. Looking at mine, although legal, are the originals judging by the DOT code and I’m going to swap all 4. Has the Mich 4S on at the moment.

[Jgtcracer]

7 hours ago, Smithers said:

Oh while I have you, what tyres are you running and do you have any advice. Looking at mine, although legal, are the originals judging by the DOT code and I’m going to swap all 4. Has the Mich 4S on at the moment.

I’ve still got Supersports on mine at the moment but will probably be fitting something else when it needs them. MPS4S are undeniably good though I feel wear is quite quick, had good experiences with the Goodyear Eagle F1 assy 5. 
 

it’s quite a personal choice to be honest.

[L55 RCF]

As jgtcracer said above, it’s personal choice. I’m on brand new Michelin PS5’s and they feel really good. 
But I’m a Michelin fan. The Goodyears are really good too though. As above. 
I’m not a fan of Pirelli’s or Bridgestone but that’s just personal choice. 

[hockeyedwards]

10 hours ago, Smithers said:

Oh while I have you, what tyres are you running and do you have any advice. Looking at mine, although legal, are the originals judging by the DOT code and I’m going to swap all 4. Has the Mich 4S on at the moment.

Having gone through a few different options myself, I'll give you my 2 cent. Btw I like Michelin! 😆

The PSS are 'designed' for the car, but I found them to have essentially no rear end grip in anything but dry conditions. Drove B-roads on the daily route to work and it got silly that I couldn't have any 'fun' without lighting up the dash. These were low when I acquired the car, so possible factor as to their performance.

PS4 - superb tyre, couldn't fault them other than I felt they wore out pretty quick.. (could be my driving style), handled amazing in wet conditions, even one day where I got snowed in at work, it managed to get me home. They are more of a road biased tyre say in comparison to PS4S (see below), so if you fancied a few tracks days in the car, I wouldn't consider them.

PS4S - the only reason I put these on instead of another PS4 set was a discount code giving them to me for the same price. They are night and day the best tyre I've had and other than maybe seeing what the PS5 are all about, I'd stick with these. They are brilliant in all conditions and are designed to give you the option for a few laps on track as well.

[Smithers]

Cheers all, really useful.

[Rob RCF]

On 7/3/2022 at 8:36 PM, Jgtcracer said:

I think 1st is just a bit rubbish, almost like throttle map has been dulled down to resist jerky driving.  
 

1st gear is a manoeuvring gear really, not much use for anything else.

I beg to differ. I sometimes drop into 1st at around 20-30mph when coming off say a slow roundabout. Gives insane acceleration vs just staying in 2nd.

Maybe the "dull" feeling is the torque converter? 1st gear is the only one where the torque converter doesn't lock.

[Jgtcracer]

12 minutes ago, Rob RCF said:

I beg to differ. I sometimes drop into 1st at around 20-30mph when coming off say a slow roundabout. Gives insane acceleration vs just staying in 2nd.

Maybe the "dull" feeling is the torque converter? 1st gear is the only one where the torque converter doesn't lock.

That’s interesting, funny how people use the same car in different ways.  Unless I want to go sideways out of a junction, will never drop down into 1st manually.  
 

Marcus

[Rob RCF]

I'm not trying to go sideways either. But flooring it from the bottom of second gear can be a bit underwhelming as it's such a long gear.