I would like to get a bit more power out of my old polo and was thinking of replacing its ECU with a speeduino ECU. Is it possible to do so? Would I get any more power this way?

I think you'd need to do intake, exhaust and even engine modifications to make noticeable changes that would give more than the stock ECU could handle.

 

You might be able to change the feel of the engine in lower rev range with just Arduino ECU programming with a custom map

(and still pass emissions tests).

 

But at higher revs the engine pump rate of air is limited by the inlet and exhaust and valve diameters and opening durations, no matter how much more fuel you squirt in.

 

If it was a 1.4 16v engine you could get a remap file for the stock Marelli ECU €50

https://oldskulltuning.com/vag-ecu-tuning-marelli-4lv-with-tunerpro/

but no explainer of how to download it, or undo if not better.

 

The 16v breathes better (thin valve stems, more valve area) so has more headroom to pump air faster.

 

I can see remap companies claim 10% gain from 60hp to 66/67 for 1.4 8v but I can't see a price or independent review for any of these, sorry.

Thank you for helpful information! Will do some engine mods before i get to ECU tuning then.

Glad to help. I had a fantastic time in Croatia last summer.

Gregor 6Ninski agrees.