Chip, Tune, Map or Do Nothing

[Nermaloids]

Hello,

 

Model: Superb MK3

Variant: Manual 1.6 TDI, 120 PS

Other: 14 months of warranty left

 

I've had my Superb for a little over a year now and I'm really feeling it is hamstrung by a torque curve that eludes my efforts to keep it in the zone when pulling away. I drove my wife's 1.2 TSI Rapid today and couldn't believe how much low down torque it had compared to my Superb.

 

What options do I have to improve performance? I'm lost between remapping, chipping and/or tuning? I'm not necessarily after maxing out, just an improvement to stop me hankering after another car. If possible, I'd like to not invalidate what's left of the warranty!

 

Thank you.

 

[MartiniB]

just change TDI to TSI

[Rainmaker]

The 1.6 TDI Superb has 250Nm of torque between 1,600rpm and 3,250rpm and maximum power of 120ps between 3,600rpm and 4,000rpm. A power band stretching between 1,600rpm and 4,000rpm isn't half bad for a diesel, even if it won't sound very good achieving it. That's not intended as a dig, rather most diesel drivers (myself included when I'm at the wheel of one) will naturally change up early because the engine sounds so loud and asthmatic above about 2,500-3,000rpm. The engine itself will however keep pushing maximum power for at least another 1,000rpm, which is a lot of missed opportunity if you're changing up early!

 

Even the most powerful 1.2 TSI Rapid only has 175Nm of torque in comparison. The extra weight of the Superb won't help of course, but it shouldn't be that bad... My Mk2 Superb had the 1.9 PD with only 103ps and that was adequate. Your engine has almost 20% more power and the mk3 weighs less, so you shouldn't be finding it terrible. The main difference you're feeling between the two cars is likely a combination of a lighter car with a lighter engine over the nose, as well as reduced NVH control (i.e. the Rapid has less soundproofing etc) allowing you to feel the acceleration more.

 

Also, don't mistake torque for power. Despite the common turn of phrase, you can't feel torque. Torque (times revs) is just how power is made, it's not the actual power delivery. What you're describing as low down torque is just an engine making more power lower down. A nit-picking technical difference, perhaps, but it's important to understand when you're figuring out how best to drive a car. Both your petrol Rapid and diesel Superb are forced induction - turbocharged in this case - and thus put out peak torque (and thus more power) lower in the rev range, so they shouldn't feel massively different low down really. The bonus of the petrol comes with its flexibility to keep on revving where the diesel needs an extra gear change or two.

 

At what revs are you changing gear? I'm assuming it's a manual gearbox here of course. Maybe you're changing up too early (e.g. 2,000rpm) and thus ending up well and truly off the boil in the next gear up. Regardless of the engine type, ideally you need to keep the revs in the power band the whole time, so changing up towards the end of peak power and having the next gear up land nicely in the realms of maximum torque ready to continue the process. If you're changing up early then you're literally just staring to tickle peak torque, changing gear and starting from zero again. Rinse and repeat. What you really want to be doing is stretching the revs a bit so that you're well into peak power (not just peak torque) and then the next gear will land squarely in peak torque to allow you to continue accelerating strongly - or at least as strongly as the engine output will allow.

 

Perhaps try changing up at 3,000 or even 4,000rpm and don't move out of first too early. Many drivers will literally change from 1st to 2nd the moment the car is rolling, despite 1st being the best gear for starting brisk acceleration. It's a bit easier on juice but it's awful for acceleration, especially with a combination of heavy car / lower powered engine. Although petrols are different I revved out my manual 1.2 TSI Rapid courtesy car and 1.2 TSI Fabia courtesy cars to around 3,000rpm in 1st and anything up to 4,500rpm or so in the following gears. It didn't hang around and I returned 53mpg zipping about the city that day (from a petrol!)...

Give it a go, you might surprise yourself. Just don't rev the nuts off it when it's cold, no matter what fuel it takes.

Edited 2 June, 2017 by Rainmaker

[Nermaloids]

Thanks @Rainmaker for the torque / power definition and recommendation to push the revs. I have been changing, particularly in 1st and 2nd too early. On the way home last night I changed much later than previously to stay in the power zone, the car felt much more lively!

[drewellis]

I used to own a Renault Megane 1.6dci (130bhp)

 

I had similar issues, so bought a Blufin device and applied the "plug and play" remap. The difference was insane, it made me laugh how fast it was....the estimate gain was around 50bhp and a tonne more torque. Interestingly the turbolag became even more apparent - floor it in 3rd gear at around 30mph and there would be <nothing....nothing....nothing....BOOM...head smashes against headrest> ..........it was fun