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Anyone using Shell V power on a tuned petrol engine?

6312 Views 49 Replies 10 Participants Last post by  Dave Kwatro
You may want to grab a brew or beer, then read this. :)

Shell, last month (April) 2021) revised it's blend of V power with Dynaflex giving more cleaning abilities and 4% more power.

Great, that sounds good! Right? Erm, maybe, I don't have any proof yet, but bare with me.

I have a tuned S5 3.0 V6 Supercharged. It was remapped 2 years ago on Shell V power. Tuners recommend using Tesco Momentum 99 when remapping as it gives the best results on reducing timing pulls due to it being souped up with Ethanol whereas VPower was other additives to increase the octane.

I believe VPower to be slightly superior over Momentum mainly due to its cleaning etc, where as Momentum is said to get you those extra few bhps on the dyno!?

Anyway, I'm not getting into 'that' debate shell Vs Tesco. This is different, I think.

I've been filling with Vpower for the past month or so, sometimes with the odd fill of Tesco. I didn't really see a difference in performance, maybe Tesco had a 'sharper' edge to it than Vpower. I also found mpg seemed slightly lower on Tesco.


Since last month, I have found my S5 to running sweet and seemed like it was pulling harder. Now I work from home, real everyday driving isn't comparable as driving the same route to and from work, so it may be placebo as I'm not driving as much, so just enjoying driving. But like I say it seemed to be driving very well like someone had tinkered with my ECU map.

I was having a blast when all of a sudden, the power went like it does when traction control kicks in, but I now always turn my traction control to sport (Half off) since the S5's power will spin all 4 wheels. So now when driving spiritedly, I do a quick cockpit check/change to exhaust flaps fully open, Traction to Sport, Auto start stop off, and Gearbox in sport manual. :)

Going back to the power loss. It started on the gear change into 3rd with WOT. Pressed the throttle a few times, nothing, then the power came back to normal. It did it once more on the drive and this was after driving for around an hour. No CEL lights or anything. Checking with VCDS gave P0089 Valve for fuel metering - implausible signal, P2279 Leak in air intake system - intermittent, P310B Fuel pressure outside Specification on low pressure side! Bowlocks!? I've read from the guys in the US that this is common on stage 2 and it's the tank fuel pump not keeping up with demand. Also going back to stock tune, the fuel pressure wasn't an issue as the demand is lower. But the Low pressure fuel pump should regulate at 5 bar, mine went to 7.3 bar!? so I would have thought a high pressure would be ok as it would still be supplying fuel? Anyway, according to the guys who have had this, the fuel pressure drops, then over pumps giving the 7.3 bar. The solution was to replace the tank fuel pump, but I'm not sure. My fuel system appears to be running fine and the fact the pump can do 7.3bar leads me to think it can supply enough fuel?

Still with me? In the US E85 (85% Ethanol) fuel can be used and it's equivalent octane rating is the same as race fuel, up at 105 (not sure if this is US rating). Also when running on with Ethanol the mpg goes down and a higher volume of fuel is used so the fuel pumps are working harder, hence the high pressure fuel pump upgrades like Autotech's HPFP piston upgrade.

Back to me. I went out again in the car and it pulled power again under WOT in 2nd gear. The fuel was V power and low level in the tank. It doesn't cut power every time. And no fault logs in VCDS since the first time it did this power cut.

I've been researching and pricing up the tank fuel pump as last resort to cure this problem. But last week, I refilled with Tesco and not filled with Tesco for the past 2 maybe 3 fills. Been on a decent drive, no power cuts, no fuel pressure codes in VCDS, but the power doesn't feel as sharp as the shell stuff now!?

Only time will tell and if I refill again with shell to see if the performance improves and if I get power cuts again!? I will obviously update.

But it's only with the guys in the US talking about needing to upgrade the fuel pump to flow more fuel which is what high ethanol fuels need, I looked at Shell's website and they revised their V power blend in April which is when I got this fault. The car has been as I said at stage 2 for 2 years with no problems!

Also September this year the UK government has announced ALL unleaded fuels are to contain 10% ethanol in the fuels (E10). It is E5 (5%0 at the moment. So will this aafect us with Ethanol demanding more volume? If this is true why doesn't the Tesco 99 give me fuel cuts it it's octane is upped by use of ethanol.

This is my car saga at the moment and not conclusive if it is the fuel blend or an actual issue with my car. But I do want to try Shell again as the 4% extra power, I think was there on my car!

I'm going for a little rolling road run to check my car's performance/health in a week or 2, so don't want another issue as before I had a charge cooler issue when mapping my car.

Fingers crossed it was a glitch. I'll continue with my 'testing' of Tesco Momentum and Shell.

If any of you can add to my findings or suspicions, please do let me know! :)
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Great post Dave. I only use Vpower or Momentum, with 90% of the time being Vpower.

MRC stage 2 and I have had a loss of power when WOT a couple of times in the last year since the remap.

I can't recall the error codes now, but they indicated coil packs. I've not changed them, but will check the errors next time this happens.

Like you I don't drive it often enough to recognise the difference between the two fuels.
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Traction control off (long hold on the button). First time was on the way home from Doug, and was on the M25, traction off, in sport and floored it at about 70mph...

The second time was from rolling from about 20mph, full WOT and then huge power loss. Had to stop to switch off and on to reset.

Both times there were error codes, and when I looked at them the indication was coil pack cylinder 3.

I've not mentioned it to Doug since as I've not had the issue again, but I have changed my driving style to be slightly less full on/off so not had it since. Next time I'll change the coils as this was what Doug said on the day I should do if it goes into limp mode
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Well that's interesting. Was out yesterday going somewhere and pulled out onto the A1. Traction off and in sport mode, floored it through the gears on auto and I think 2nd to 3rd at the DSG farts it went into limp mode with a error light on the dash (can't recall which one). I had a miss fire afterwards too, sounded like at least one piston was not firing.

Stopped at the next traffic lights and turned off and back on and all back ok.

I've not read the codes yet, but will check later on. I suspect one of the coil packs needs replacing.

Only thing different is that the Mrs filled up recently with some unknown super brand (she doesn't know what apart that it wasn't Momentum or Vpower).
So pulled the error codes tonight, and it's the same as last time:

15074 - Cylinder Disabling
          P130A 00 [096] - -
          Intermittent - Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 57111 km
                    Date: 2021.07.18
                    Time: 11:06:20

                    Engine RPM: 6902.50 /min
                    Normed load value: 100.0 %
                    Vehicle speed: XX km/h
                    Coolant temperature: 89 °C
                    Intake air temperature: 32 °C
                    Ambient air pressure: 1010 mbar
                    Voltage terminal 30: 13.789 V
                    Unlearning counter according OBD: 40
                    Misfires per 1000 revolutions of cyl. 1 intake manif. injection: 0
                    Misfires per 1000 revolutions of cyl. 4 intake manif. injection: 0
                    Misfires per 1000 revolutions of cyl. 3 intake manif. injection: 500
                    Misfires per 1000 revolutions of cyl. 6 intake manif. injection: 0
                    Misfires per 1000 revolutions of cyl. 2 intake manif. injection: 0
                    Misfires per 1000 revolutions of cyl. 5 intake manif. injection: 0
                    Engine torque: 456.31250 Nm
Interesting to note the RPM, 6902, which is quite high.

So it's cylinder 3 and I recon the coil pack will be my first port of call. I'll swap cylinder 3 with another as a test in the first place and see if the error moves.
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