1.2 VW polo 55 and 65 BHP

[Jamiyjames]

I have a VW polo 1.2 55 BHP and i was looking at the difference between the 65 and 55 BHP engine. In my search all i could find is that the 55 BHP is a 3 cylinder 6v engine and that the 65 BHP is a 3 cylinder 12v engine, now firstly is that the only difference between the two? And secondly I've seen reconditioned cylinder head units for £200 on eBay for the 3 cylinder 12v, now if i bought this and fitted it to my engine would I need to do anything else to the system to get full use of the power?


I only ask because I was considering getting a cylinder head change, then a new mushroom air K&N air filter and maybe a remap to try and get about 90 BHP or so out of the car to give it a little more ooompphh

Thanks for any help :-D

[E-bmw]

Firstly, I stress that I am not intimately acquainted with the 55bhp polo, so these are generic statements based on some experience modifying cars before.

An increase to 90bhp is around a 40% power hike, which is VERY unlikely (assuming you were to start at 65) on a normally aspirated petrol engine.

Such conversions rarely involve just a head swap, a new chain/tensioner/crank pulley/ECU/manifold other parts may well be required.

Even if you don't you will be spending the £200 on the head.

£60 for a head gasket kit.

Over £70 for a half decent induction kit (a mushroom filter is not the way forward, you just get more noise) complete with new air plumbing & cold air inlet.

And then £200 for a cheap remap without dyno runs.

You then have a car that is modified and therefore you NEED to tell your insurance company or you will be uninsured.

In total if you do the above, it has now cost you probably more like £1000 and you will likely have approaching 75bhp.

Sound like money/time/resources well spent?

The better bet would be to change the car.

[Super Slo Mo]

I was going to reply along the same lines. The engine would need a fairly aggressive set of cams to go along with the induction and exhaust mods that will be necessary. Finding someone who makes the necessary parts for a 1.2 Polo will be somewhat tricky if you ask me.

I think it'd be an interesting conversion, but probably a bit futile really.

It's probably better to find a 1.4 litre car instead, which will have 80-85 bhp to start with, and which drive quite nicely in my experience.

Alternatively, and I had one of these and rather liked it, the 1.9 tdi version (105 bhp) goes pretty well. I know, I know, "fuel of Satan" and all that blather, but it's a very muscular engine in such a small car.

[Mr2Mike]

6V head has a single camshaft with vertical valves with a flat combustion chamber shape, 12v has two camshafts with inclined valves and a pent roof style combustion chamber, so the pistons are very likely to be different. The cam drive system will obviously be different as well. Inlet and exhaust manifolds are different, and obviously the mapping will be different for the more powerful engine.

Bearing in mind just how far VW went to get another 10bhp from this engine, do you still think a K&N air filter and a remap is going to take it from 65bhp to 90bhp? Getting 90bhp in normally aspirated form from this engine would be a very expensive exercise.