MK7 GTi weird chassis shudder on the limit
Discussion
Hey guys,
Something I've been noticing odd recently while driving my 2014 GTi performance pack on track days, and it's confusing me as to whether it's something which can be solved.
When coming into corners in the car, late on the brakes and turning in to get the back end moving, just as the rear end begins to let go there is this rumble/shudder which comes through the entire chassis from the back of the car. It almost feels as if the rear tyres are gripping and slipping but at very high frequency. Sometimes it even rattles the door cards and bits of interior trim.
I have hacked the systems so that the stability control is completely off, so it isn't that intervening. The car is quite stock, but has a Clubsport S rear sway bar and is running on 19' Santiago wheels with Michelin 4 S Tyres. Standard suspension and bushing setup, and I have recently tried using a rear chassis brace across the boot but that didn't seem to help either.
Is this just flex from all the suspension bushings in the rear suspension? Would Poly bushes solve this?
Thanks,
Chris
Something I've been noticing odd recently while driving my 2014 GTi performance pack on track days, and it's confusing me as to whether it's something which can be solved.
When coming into corners in the car, late on the brakes and turning in to get the back end moving, just as the rear end begins to let go there is this rumble/shudder which comes through the entire chassis from the back of the car. It almost feels as if the rear tyres are gripping and slipping but at very high frequency. Sometimes it even rattles the door cards and bits of interior trim.
I have hacked the systems so that the stability control is completely off, so it isn't that intervening. The car is quite stock, but has a Clubsport S rear sway bar and is running on 19' Santiago wheels with Michelin 4 S Tyres. Standard suspension and bushing setup, and I have recently tried using a rear chassis brace across the boot but that didn't seem to help either.
Is this just flex from all the suspension bushings in the rear suspension? Would Poly bushes solve this?
Thanks,
Chris
https://youtu.be/_kBxBbL88hc
Please have a look at this link and let me know what you all think! Cheers, Chris
Please have a look at this link and let me know what you all think! Cheers, Chris
SAS Tom said:
Seems like ESP to me too. My Fabia did the same thing.
With the ESP, what I’ve done so far is use Carista to turn it to completely off, as far as I know. The car will happily spin up the front wheels without any intervention, and when it’s sliding i don’t feel it braking any wheels to bring the thing back in line, feels like I have to catch it myself. I don’t get any dashboard lights flashing either. It feels like I could happily lose control of the car if I wanted to, which I wouldn’t think ESP would allow me to do if it was on.
https://www.youtube.com/watch?v=fStHaQLsLxI
In this video, an instructor is demonstrating the function of ESC. At roughly 2 minutes, he does a demonstration WITHOUT ESC and the car spins, and as its sideways it makes the exact same juddering noise as my car. With ESC he of course doesn't spin at all.
Edited by chrissyh_1988 on Friday 8th November 08:40
I'm on my 3rd VW group car with ESP
You don't get any lights when the ESP is doing its thing. You only get a light when the traction control part (ASR) is intervening to stop the front wheels spinning.
I haven't looked into this in depth but I did see a guide to disabling ESP with vcds and in that example the ESP disable did look succesfull however it came back on after the car was switched off and back on again. The change wasnt permanent.
Maybe try putting the ESP back on to compare ?
You don't get any lights when the ESP is doing its thing. You only get a light when the traction control part (ASR) is intervening to stop the front wheels spinning.
I haven't looked into this in depth but I did see a guide to disabling ESP with vcds and in that example the ESP disable did look succesfull however it came back on after the car was switched off and back on again. The change wasnt permanent.
Maybe try putting the ESP back on to compare ?
Drive Blind said:
I'm on my 3rd VW group car with ESP
You don't get any lights when the ESP is doing its thing. You only get a light when the traction control part (ASR) is intervening to stop the front wheels spinning.
I haven't looked into this in depth but I did see a guide to disabling ESP with vcds and in that example the ESP disable did look succesfull however it came back on after the car was switched off and back on again. The change wasnt permanent.
Maybe try putting the ESP back on to compare ?
Thanks for the input... Good idea, next track day I go on I will do the traction control on and off, and compare the noises and feel. You don't get any lights when the ESP is doing its thing. You only get a light when the traction control part (ASR) is intervening to stop the front wheels spinning.
I haven't looked into this in depth but I did see a guide to disabling ESP with vcds and in that example the ESP disable did look succesfull however it came back on after the car was switched off and back on again. The change wasnt permanent.
Maybe try putting the ESP back on to compare ?
Disappointing as I was pretty confident that I had managed to get the ESP fully disabled due to the amount of movement I can now get in the car. Very irritating if it can't be fully disabled by any means. Don't suppose there's a hack, like taking the fuse out or disconnecting the ABS sensors?
Has anybody managed to watch the second YouTube clip of the car spinning around? That's the same noise.
SAS Tom said:
One of the above posts reminded me that I’ve seen how to disable esp as well but it goes back to normal once switched off. I don’t believe there is a permanent way to turn it off.
Every time I get into the car to go on track I hold the ESC button down for 3-5 seconds and then it says 'ESC deactivated'. This is a hack, from stock it only allows 'ESC sport'. Is 'ESC deactivated' not fully off then? I don't feel it braking the outside wheels like I do when it's in ESC sport.
What else could it be other than the ESC? Would soft/loose/worn suspension bushes not allow a bit of movement which might create this noise?
Novexx said:
Thanks novexx, I've already done this though. Not with VCDS, but with Carista... it has made exactly that change. So ESC is fully off.Novexx said:
I take it that the car doesn't have DCC?
Nope, standard fixed springs and dampers.I think we’ve covered the ESC angle enough, let’s assume it’s not that. The car goes sideways...
Can anybody watch the second YouTube video I linked at 2 mins when he spins the van? It’s the same noise. And that video is a demonstration of what happens WITHOUT ESC. That’s what I’m trying to locate...
chrissyh_1988 said:
Can anybody watch the second YouTube video I linked at 2 mins when he spins the van? It’s the same noise. And that video is a demonstration of what happens WITHOUT ESC. That’s what I’m trying to locate...
Could be wrong, but the noise at 2:00 / 2:01 sounds like tyre scrub, probably exaggerated by the fact that it's a van with big, resonating panels. The external video shows the rear axle travelling at 90° to the direction of travel immediately before the stop - the same place as the noise appears in the in-cabin section.The sidewall is being loaded, deforming & recovering at a rapid rate, generating the vibration / noise. The rear axles & bushes are likley to be going through a similar process- well something like that?
Edited by Novexx on Saturday 9th November 22:16
Novexx said:
Could be wrong, but the noise at 2:00 / 2:01 sounds like tyre scrub.
The sidewall is being loaded, deforming & recovering at a rapid rate, generating the vibration / noise. The rear axles & bushes are likley to be going through a similar process- well something like that?
That feels like what I have going on with my car. The question is, can it be solved? Can stiffer bushes and tyre sidewalls possibly eliminate this? The sidewall is being loaded, deforming & recovering at a rapid rate, generating the vibration / noise. The rear axles & bushes are likley to be going through a similar process- well something like that?
Edited by Novexx on Saturday 9th November 22:16
Anybody who has tracked their street cars on standard suspension had similar issues? If it’s tyre and bushing flex you imagine it would happen to all sorts of different cars and be quite a well understood issue.
My cars done almost 60k miles so it could be possible a few of the bushings are more worn than they should be.
chrissyh_1988 said:
That feels like what I have going on with my car. The question is, can it be solved? Can stiffer bushes and tyre sidewalls possibly eliminate this?
It no doubt can be solved, but it might be expensive & time consuming to just start replacing stuff without having a good idea of what the issue is (alignment, tyres, shock's, bump stops, bushes & more bushes.....). I think I would be tempted to get it on a ramp & have it looked over thoroughly by someone that knows their stuff. Maybe get it properly aligned at the same time - won't do any harm & can rule out some issues.chrissyh_1988 said:
Anybody who has tracked their street cars on standard suspension had similar issues?
Never tracked, but have done & still do plenty "drive it like you stole it" miles in Mk7 GTI's & have never encountered an issue quite like this. My previous GTI suffered a rear axle vibration problem once on a long, flat gentle sweeper at about 80'ish, it started when the N/S/R loaded up & remained after coming out of the corner & straightening up, then disappeared. It was pretty prominent, but not detrimental to handling. Had the car checked out after this, no concerns found & it didn't do it again, so a bit of a mystery - very much got the impression that it was a shock or DCC issue.
Thanks for the info and opinion novexx! Sounds like you’re experienced with these... My Car was recently set up and aligned as I’ve just installed front camber plates (034 fixed ones) and a rear anti roll bar from the clubsport S.
With the new setup the car is significantly more keen to oversteer into a corner than it was before, and it feels like it’s really leaning a lot harder on that rear outside tyre... you barely have to twitch the steering at all to get it rotating now. Slight oversteer feels the quickest way to get the car around a lap, but I can’t help feeling that when the car was designed and the bushes and suspension arms were specced, they weren’t expecting it to be driven this way. That said there are plenty who do use GTi’s on track so I was hoping for someone to pop up and say ‘oh yeah, that’s X component, it’s too soft’ or whatever. It did do it also before I made the recent setup changes, but it was less obvious as to get it over steering I really had to throw it around.
Your vibration story does sound similar, on track there are plenty of corners at around that speed, and leaning on the car for a lot longer than you would be on a road too.
With the new setup the car is significantly more keen to oversteer into a corner than it was before, and it feels like it’s really leaning a lot harder on that rear outside tyre... you barely have to twitch the steering at all to get it rotating now. Slight oversteer feels the quickest way to get the car around a lap, but I can’t help feeling that when the car was designed and the bushes and suspension arms were specced, they weren’t expecting it to be driven this way. That said there are plenty who do use GTi’s on track so I was hoping for someone to pop up and say ‘oh yeah, that’s X component, it’s too soft’ or whatever. It did do it also before I made the recent setup changes, but it was less obvious as to get it over steering I really had to throw it around.
Your vibration story does sound similar, on track there are plenty of corners at around that speed, and leaning on the car for a lot longer than you would be on a road too.
There is a known issue with rear suspension on Mk7's which originates from the OE shock's & causes knocking, noise & vibration, although generally it seems to be a lower speed / normal driving thing. Although it's obviously not the same issue as yours, it may be connected. Might be worth a look if you have OE fitted & Bilstein seem to be the favoured replacement.
Google "golf mk7 rear suspension noise" & you will get plenty of hits / vids.
Good luck.
Google "golf mk7 rear suspension noise" & you will get plenty of hits / vids.
Good luck.
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