Vibration in 5th and 6th after remap

[Chris haworth]

Hey guys , had my 40tdi rolling road mapped about 2 months ago , everything has been perfect but noticed a big vibration when the car is under load , only seems to be in 5th and 6th , I’ve read it could be dmf, has anybody had any experience of this , don’t really want to loose the power and was thinking if it is is there a performance option cheers Chris 

[Steve Q]

What miles has the car done? 

How much bhp and torque has the car now got. I ask as the MSP might be putting too much power through it. 

[Chris haworth]

It’s only done 32k it went from 200 to 240bhp was 400nm to 520nm

[Steve Q]

Yea do the dmf shouldn't be failing. 

The only thing I wondering if there's too much torque ect for the current dmf and clutch. 

What was the max the current one can take, from the research you've done? 

[Chris haworth]

Unsure at the min , wasn’t even sure if mine had a dmf in it, gonna have to keep digging , I’m sure the napping company would of known that before hand as they are a massive company , not sure how I would find that out really 

[Steve Q]

Think all aidis have dmf now. Even my old a6 does. 

Here's someone with a similar issue but there's is an auto. There problems also started after a remap. I notice their torque is less than yours but that'll partly be due to there's being an auto. 

https://www.google.com/amp/s/www.audi-sport.net/xf/threads/audi-a6-40-tdi-c8-gearbox-vibration.431231/%3famp=1

I'd definitely recommend speaking to the tuning company. 

If it is the dmf you might need to upgrade it with an aftermarket one that's stronger, do a solid single flywheel conversion and uprated clutch. Here's an upgraded one for an example, but notice when the upgraded one can't handle over 475nm of torque whereas you're running over 500nm on the stick set up. 

https://clutchstop.co.uk/products/luk-dual-mass-flywheel-sachs-performance-clutch-kit-for-volkswagen-audi-seat-skoda-02q-6-speed-gearbox.html 

I've heard people talk about this company for upgraded clutches etc. But I don't see the A6 c8, but might be worth emailing them: 

https://clutch-specialists.co.uk/

[K200CWC]

Is the reason it only shows up in 5th & 6th because these are the only gears you can use the full 520nm? 

[Chris haworth]

That’s for your help guys , mine is a auto and if the uprated one will only hold that then it must be to much , I’ll get them to turn it down if possible 

[Steve Q]

9 hours ago, Chris haworth said:

That’s for your help guys , mine is a auto and if the uprated one will only hold that then it must be to much , I’ll get them to turn it down if possible 

No probs, sorry I can't give you more positive news. 

[Chris haworth]

No problem Steve thanks again 

[Steve Q]

Please keep us posted on how you get on. It'll be interesting to see what the remapper says. 

[Chris haworth]

Will do mate , my thinking at the minute is take it back to stock for now , and get in touch with dark side developments ( diesel tuners ) see if they know of upgrades I can get )

[Optimus]

would remapping the gearbox help? Or could it be clutch slip as a result of excessive wear and tear.

Much to some people’s surprise, 5th, 6th and 7th are overdrive gears. Meaning they are simply designed for final gearing for speed vs engine loading providing better mpg. 

bhp and torque peaks in 4th gear meaning if it was relating to the mapping it would be happening under load here.

If the car is FWD it could be differential, you’re experiencing hopping at speed and under load. Then again this would be present in 4th.

I recall a friend of Mine had his golf r remapped and then had problems with power band and sloppy gear changes with all sorts of vibration due to clutch slip then had his gearbox remapped and it fixed this issue.

[Chris haworth]

Yes mate I had a gearbox map done whilst it was there , unsure really, been on all the other mapping companies and they seem to go no higher than 480nm most around the 450 mark , havnt seen any running 520 ish , but again , it’s not a small company so you would think they would know what the car can handle 

[Optimus]

It may be possible that this map if out the box and not a custom map which is entirely different is meant for the Quattro model.

If it was a torque related issue this would be present from 3rd gear (top end).

I'm not an expert, but I have worked in customer facing automotive fault finding with engineers previously for a couple of car manufacturers whom make performance/limited built road going production cars which had a reputation for such niggles. At high speed 1/3 of the front mass weight is distributed onto the rear axle promoting tyre hop or axel bumping on front wheel drive cars. Which higher torque you’re experiencing the tyres spinning with barely any weight to keep them stuck to the ground on uneven bumpy roads. The car will limit this by retarding the fuel and air to manage slip as the differential does not have torque vectoring. The car may not display the symbol for traction control as there is always a little give in rotational slip before it kicks in. You could try and turn off traction control and see if it makes a difference.

So the issue may be feedback from the ground to tyre to track rod ends to differential. I don’t know much about the differentials in this model but I know they are basic (standard) for the 7-speed gearbox. Whereas the 8 speed auto boxes come with a trix’d out ‘real Quattro’ system with bias to rear axle. 
 

The other likely issue/ cause is fuelling issue, indicating the pump or injectors are maxed out and that vibration you are getting is a fuel starvation problem.

Fuelling problems tend to be more prevalent at higher speeds or top end rpm because the air/fuel ratio tend to lean out, more so on diesel engines to promote good mpg figures. 
 

Only way to find out is to simply drive it absent remap and see if the problem persists. If it does this should indicate a purely mechanical problem (likely).

If it doesn’t indicating the remap was faulty (most likely).

[Steve Q]

13 hours ago, Chris haworth said:

Will do mate , my thinking at the minute is take it back to stock for now , and get in touch with dark side developments ( diesel tuners ) see if they know of upgrades I can get )

Darkside are well known and very experienced 

[Chris haworth]

Quick update , contacted pendle performance, apparently the vibration is due to wrong fueling and values of the map so easy fix hopefully , booked in next Wednesday , keep ya posted 🙂👍

[Steve Q]

10 hours ago, Chris haworth said:

Quick update , contacted pendle performance, apparently the vibration is due to wrong fueling and values of the map so easy fix hopefully , booked in next Wednesday , keep ya posted 🙂👍

Fingers crossed 🤞 keep us posted on how you get on. Hopefully no other damage caused to the car from their mistake 

[Chris haworth]

Quick update , finally got to the bottom of it I think , contacted dark side , they said the vibration is caused by to much torque and is probably flywheel judder ,I asked if there would be any damage caused , they said probably not as I’d only felt it about 5 times before I took it back to stock  they recommend full custom dyno with more progressive torque delivery and to get the most out of the map they recommended a gearbox map with increased torque limiter and other settings like 1st and 2nd delay fix , quick shifting , quicker launch from stand still and other things , they recommended stage 3 gearbox map with custom tune as they have the capability to match the torque to the flywheel , very clued up on what they was talking about , they said they have never done this exact model , and said they wanted it for 2 days so they can really get into it with road tests , I’m definitely impressed with the gearbox side of things , they even come out with you in it for the test , it’s booked in on the 11th October , so hopefully this is it , sounds like they know there stuff , hopefully this will help others on here with similar problems 🙂

[Optimus]

13 minutes ago, Chris haworth said:

Quick update , finally got to the bottom of it I think , contacted dark side , they said the vibration is caused by to much torque and is probably flywheel judder ,I asked if there would be any damage caused , they said probably not as I’d only felt it about 5 times before I took it back to stock  they recommend full custom dyno with more progressive torque delivery and to get the most out of the map they recommended a gearbox map with increased torque limiter and other settings like 1st and 2nd delay fix , quick shifting , quicker launch from stand still and other things , they recommended stage 3 gearbox map with custom tune as they have the capability to match the torque to the flywheel , very clued up on what they was talking about , they said they have never done this exact model , and said they wanted it for 2 days so they can really get into it with road tests , I’m definitely impressed with the gearbox side of things , they even come out with you in it for the test , it’s booked in on the 11th October , so hopefully this is it , sounds like they know there stuff , hopefully this will help others on here with similar problems 🙂

Look forward to hearing the outcome.

i must admit when I spoke with them there was back and forth with emails and they wanted the car for at least a day to tweak it. 
 

Please be weary to misleading information. My gut feeling is it wasn’t the torque that was the problem but mapping/fuel starvation. Regardless of their opinion/experience. The symptoms speak for themselves.

shuddering vibration occurs when there the rotational velocity of the flywheel against the clutch friction plate starts to slip (clutch slip). this normally occurs at the highest or peak torque which is achieved at lower gearing not higher gearing.

Now yes, most cars have torque limiting to prevent wheel slip during acceleration. But this is normally reduced up to 50% for 1st gear 30% for 2nd gear and 20% for 3rd gear. when the gear ratio becomes 1:1, typically at 4th or 5th gear, there is no electronically restriction, this is normally your rolling road testing area to determine true values for peak horse power and realistic peak torque figures. Between 3rd and 4th gear is the infamous clutch slip telling you your clutch or flywheel need rethinking. 

Everything they’re after is purely fuel starvation related that causes engines to shudder from a mapping point of view. 

if it goes pop and bang with no drive, you’ve cooked it from a over confident map chasing numbers.

 

[Chris haworth]

You sound more clued up than me mate , everything you said sounds right , just hope they know what they are doing as I don’t want to here it go bang that’s for sure 🤦‍♂️

[Optimus]

48 minutes ago, Chris haworth said:

You sound more clued up than me mate , everything you said sounds right , just hope they know what they are doing as I don’t want to here it go bang that’s for sure 🤦‍♂️

When I spoke with them, they seem to know their stuff and were reluctant to suggest or imply it was a case of slap on a map and go. They wanted to run tests and look at the numbers have the car for at least a day. 

I just think they dropped the ball or tried something that didn’t work out. In order for it to go bang is the temperature range and boost. The higher the boost the higher the temperatures. There are some well known tuners out there which chased numbers and did not make reasonable endeavours to ensure various acceptable levels of reliability were factored in. It pays to do your research and ask lots of questions. I’ve remapped plenty of cars in the past and I always worked on the highest number I could make in power and torque and then drew that back by at least 30% before up rating parts, then repeat the process. This is the ideal area for performance vs reliability for road going cars. Tuning for racing is an entirely different process as your tuning to and inch of failure to maximise the power to each and every given race/circuit where you will be dismantling the engine and gearbox and rebuilding it between every race. 

The fuel pumps on the C8’s are not particularly great, which given your experience is likely an early indication of a limiting factor when remapping. I’ve been looking into whether it’s possible to swap the 40TDi pump out for the Q5/S6, I believe the 73 litre tank is the same.

[Chris haworth]

So you have had a bad experience with them mate ? What exactly happened ? From the you tube vids they seem to monitor temps and things , I’m a bit nervous now and I’ve paid the deposit 

[Chris haworth]

Obviously I don’t want it pushed to an inch of its life , and if that’s what they are going to do that would be a expensive mistake in having it done , do they have a warranty ?

[Optimus]

No bad experience, I’ve never used them, based on google reviews for diesel tuning they seem to be top of their game. 
 

The masses of people that go to tuners want numbers and they will chase numbers and get you to accept terms of conditions that in the event of you accept responsibility of the car breaking. 
 

I’ve always made sure asking the tuning garage the numbers they got is that the most they can do, was it the most they could get and what should I consider with reliability concerns.