Difference between 90TSI and 103TSI engines?

Hi, I’m a new Golf owner, having just picked up my 90TSI Comfortline on Saturday. So far I am enjoying driving the car, I do however have a question about the engine. Is there any mechanical difference between the 1.4 litre engine in the 90TSI and 103TSI?

Looking at the brochure, it seems that the mechanical specifications between the two are exactly the same, i.e. 74.5mm bore, 80.0mm stroke, 1,395cc capacity, and 10.0:1 compression ratio.

The only differences seem to be in max power, and torque, with the 103TSI having 13kW more power, and 50Nm of torque. I don’t know much about cars, but this is leading me to suspect that the only difference between the engines in the two models must be the ECU. Or is that the two engines have different size turbos?

If it is just the ECU, is it theoretically possible to flash the ECU, or replace the ECU in the 90TSI so it gives the same output at the 103TSI?

If it is, would the cost of doing so be worthwhile? Would I notice a 13kW increase in power? And a 50Nm increase in torque?

Also, in case anyone is curious I chose the 90TSI over the 103TSI because I like driving a manual transmission, and because there is a $AU7000 price difference between the 90TSI and 103TSI.

G'day from Melbourne!

I bought a base 90tsi almost a year ago! Such a great car! I was wondering the exact same thing as you. All the specs seemed to be the same, and I wanted to see if I could flash it to 103tsi spec for the bigger kick. However unfortunately, it seems like the turbo's are actually different!!

That's what I've heard. But this makes sense because if you look around, the tunes for the 90tsi and 103tsi are actually different tunes and can't be interchanged. I think the 90tsi can hit 118kw from memory.

there will be mechanical changes, I know that the 140 & 150PS 1.4TSI have vari cams on inlet & outlet, 122PS only has one vari cam (can't remember if inlet or outlet.)