I should be able to collect data for you in the next few days.

Tell me what you need for comparison 2007 3.6 TDV8

That would be really helpful and appreciated Cheezels.

Really the only discrepancy found so far was the difference in MAF accross banks and the specialists test showing the n/s bank read high.

If you could look at MAF whilst at idle and then whilst driving around and let me know if yours correlate quite closely or if there is a noticeable difference between banks that will at least help me rule the MAFs out fully.

Cheezels has very kindly sent me some data recorded from his own car (thanks again!) and from this I can see that his MAF sensors
never differ more than 10 kg/hr between banks whereas my RR has a difference of up to 30 -40 kg/hr between the banks.

The specialists test stated the n/s MAF was reading high. Any suggestions as to what would cause a MAF to over read / see more airflow?

Have you swapped the MAF sensors round to see if the sensors is faulty, or if it is a correct reading? 09 RR Westminster 3.6TDV8 - Stornoway Grey / Black interior - now gone (sad face)
Nissan X Trail 1.6TDCi Tekna
Fiat 500 1.2

Faulty Maf or poor remap. Swsp them over and do another data run and see if the issue moves to the other bank. If not it has to be the re-map. 2007 Vogue TDV8 in Zermatt Silver with Charcoal

Ive already tried swapping the MAF sensors over and the same bank still over reads. I have also tried substituting in a new MAF sensor but no difference.

I can understand why all fingers would be pointed at the remap at this point but logically I cannot understand why it would suddenly become faulty at coincidentally the same time as the hose splitting.

The remap (quantum Blue) had been on the car a month and half at that point and the RR was driving brilliantly.

I agree but what else is left.
Very strange 2007 Vogue TDV8 in Zermatt Silver with Charcoal

Is this the same MAF as the split hose and new turbo? 2007 3.6 TDV8

Forgive me if you mentioned this in the previous pages but have you tried having the map returned to 'standard' by quantum? My local Quantum agent keeps the original map backed up. As its fitted by via obd port ( so handy enough to do )perhaps they would replace the old map so you can rule out the remap as a possible cause. 2015 4.4 AB
GSXR 1000 K5
R1 1998

Same MAF as the split hose but not the new turbo that was the other bank (o/s) replaced by misdiagnosis. (Argh!)

I can get the maf put back to standard but it'll be another £250 and the EML will come on due to the blanked EGRs.

Ive already spent circa £2000 chasing this issue so very reluctant to spend more on a guess.

I don't see how the fixed remap data could have changed and again it would have to be a pretty big coincidence it happened at the same time as the hose split

I didn't realise they would charge to refit the old map. I would agree with it being a big coincidence but you seem to have covered most bases. Have you tried a different fault reader ? Again , feel free to ignore my post if these questions have been previously asked. 2015 4.4 AB
GSXR 1000 K5
R1 1998

The really curious thing is how and why did removing and replaciing the offending top hose provide a temporary cure. Its just baffling. Is this a red herring?
But at the same time the MAF sensor reading is high on that side too. No physical blockages can be found. So it boils down to data the ecu is getting. You also said it was worse high up in the hills where the air is thinner. Again points to a MAF sensor. These have been ruled out so it can only be how the data is being processed. As suggested different diagnostics could pick up something.
I wouĺd get in touch with Quantum head office and explain your plight. They take pity.
Or bite the bullet and book it in with BAS for a custom tune.
The only other possible cause is the engine loom has a break but then the live data reading would erratic.
Actually it would be worth your time calling BAS and talking to them. They know RR engines inside out.
Keep us posted and good luck 2007 Vogue TDV8 in Zermatt Silver with Charcoal

That I cannot answer Grofus.

The car has been scanned by 3 versions of SDD, Icarsoft, Autel and snap on. No codes that give any direction on this issue.

Ive already spoken to Quantum head office who were extremely helpful but very skeptical that the remap would be causing the issue. The chap felt that if I was going to have issues I would have experienced them very quicky after having the map done.

I agree regards the engine loom.

I will give BAS a call when I get a spare minute.

I have just noticed something else on my way to a customer which I wondered if you guys could check on your cars?

When I accelerate briskly to between 2-2.5k rpm there is a rushing air sound behind the dash on the n/s.

If I then let off the throttle after accelerating into this rpm range I hear a 'shhh' noise again behind the dash n/s.

Sounds a bit like a dump valve / blow off valve.

I will do check for that but can fairly confidently say I get nothing like that.
Were you able to check all the hoses that connect to the N/s turbo. 2007 Vogue TDV8 in Zermatt Silver with Charcoal

Never got anything like that on my 3.6  2015 4.4 AB
GSXR 1000 K5
R1 1998