Polo 9n 1.6 n/a project

**NachoBides** · 30-05-2018, 09:23 PM

ITBs are very good and quite popular with the 1.4/1.6 small block vw engines. Unfortunately, 9n platform is electronic throttle so it's really difficult to adapt them. Aftermarket ecu will be necessary and again it's very difficult. Either way, there are people who achieved good power 1.6s on single throttle body. Almost 200hp has been reached.

My ecu is a magneti marelli 4mv. It's quite restrictive and not very willing to deal with rpms higher than 7200. It's ok for my setup, but I'm looking into swapping a bosch me7.5 ecu, found in the late golf mk4 and bora 1.4. It's quite similar to the 1.8t one, which gives a lot of advantages. For example multimap switching (95ron, 100ron, 100ron+octane booster), launch control, epc as shiftlight, knock warning with check engine light etc. I need to unlock the immo and other than that it's working with the stock wiring loom.

**Sydneykid** · 31-05-2018, 02:46 PM

Originally Posted by NachoBides

ITBs are very good and quite popular with the 1.4/1.6 small block vw engines. Unfortunately, 9n platform is electronic throttle so it's really difficult to adapt them. Aftermarket ecu will be necessary and again it's very difficult. Either way, there are people who achieved good power 1.6s on single throttle body. Almost 200hp has been reached.

The advantage of the ITB's is not ultimate horsepower it's throttle response, with ITB's the ability to control the attitude of the car is much greater than with a single TB with a lot of air between it and the inlet valves that dulls the response. Plus of course you need a much bigger single throttle than with ITB's, so it is harder to control the exact amount of throttle required.

Converting from drive by wire throttle to throttle cable actuation is easy, we just leave the position sensor on the throttle pedal and adapt the OE throttle position sensor onto the ITBs. Then set the TPS table in the ECU to 1 to 1 always. It doesn't know that there is a throttle cable doing the work, all it knows is that the pedal moves and the throttle moves at the same time.

Cheers
Gary

**NachoBides** · 02-07-2018, 12:52 AM

Some updates

The head I will be using came out pretty clean from the AUB donor engine.

Took it to the machine shop and had it checked. Valve seats and valve guides are pretty good, no cracks/leaks etc. Had new valve stem seals installed and was skimmed 0.1mm.

Car had new exhaust fitted. 55mm ext, 52mm int pipe from the manifold till back box. Unfortunately I don't have any photos of that.
Right now I'm looking for a 1.6 engine block. I will be using a cast iron rather than an aluminium one, because they have cylinder sleeve problems resulting to piston slap issues. I also will be using stock aub cams until I find a good set of used dbilas. Surprisingly stock valvetrain and rotating assembly is ok for 8000rpm, which even though not needed gives a safety margin. Mine will be revving to 7200rpm with stock aub cams and later to 7500-7600 with the dbilas set.

My main concern right now is to find a good 1.6 block, which maybe will be honed along with new piston rings.

**NachoBides** · 26-08-2018, 01:53 AM

Some updates.

Engine has been fitted to the car. I used a 1.6 bcb cast iron engine block which has been honed and installed new piston rings. These blocks are much better than the 1.4 aluminium ones. Much stronger for turbo applications, closed deck, no bore wear issues leading to piston slap etc. The only problem they had is that if you used the longlife service schedule along with cheap oil, you could end up with stuck oil rings leading to oil consumption. But this affects car with 200k km mileage and more. Either way I didn't want to risk it so I put new rings.

To fit this block on the 9n platform you have to use the 1.4 oil pan, because the lower 2 bolts which bolt onto the gearbox are different. 1.6 is used with the old type 085 gearbox, while the polo 9n has the newer 02t gearbox. Also head gasket and bolts used are for the 1.6 bcb even though the head is a 1.4 aub. The 1.4 bolts are longer and head gasket has some different passages. Otherwise it's a straight forward swap.

All new gaskets and bolts. This is a photo after I received the parts from the machine shop.

Polo 9n 1.6 n/a project-img_20180725_155212-jpg

During installation

Polo 9n 1.6 n/a project-img_20180809_124035_1-jpg

Polo 9n 1.6 n/a project-img_20180809_123812-jpg

Engine on the car.

Polo 9n 1.6 n/a project-img_20180810_145210-jpg

Now. After running in the new rings, I pushed the car. Ecu file is still original 1.4 bby with 75hp, with very different characteristics than those that new engine has. Revlimit is at 5800rpm and is a soft cut, meaning that is starts to limit the power after 5500rpm. These cams wake up at about 4200 rpm and achieve the max power at 6000+ rpm. For these reasons I can't have a clear opinion on the car yet, even though it's much faster. What is really noticable is that it has more torque in low end due to 1.6 capacity and it is much more rev happy. A remap is much needed, so that the revlimit will be raised at 7200rpm and fuel - timing characteristics are better suited to the current setup.

Next thing on the list is to find a better intake filter setup. The filter I'm using is really cheap and the way it's installed doesn't help very much as well. I have 2 options. BMC CDA filter or Pug 206 (yes you read it right) simota intake. Many people who tried the 206 setup in Greece say that this is the best option. It fits on our cars with slight modifications and it costs about 60 euros.

In the next post I will reveal some of my future plans for the car.

**sambb** · 27-08-2018, 09:17 AM

Good progress mate. What do you reckon the car will weigh compared to say a 9N3 Gti? I really like the look of that Peugeot intake. That kind of thing would probably work well in the GTi too. They'd be hard to find cheap here in Australia though I think.

**rgvlee** · 27-08-2018, 12:35 PM

I reckon you'd struggle to get that intake on a gti, the intake mani would prevent it.
On this motor the exhaust is at the front giving a bit more real estate to work with.

**sambb** · 27-08-2018, 01:01 PM

shifted across to the passenger side a bit though maybe? it'd be a pricey gamble though.

**NachoBides** · 27-08-2018, 09:13 PM

It will be lighter compared to a 9n3 gti, I don't know how much though. The intake works really good on n/a engines, but I don't know about 20vt.

So, after some research it seems that dbilas 252/10 cams is the best option for an otherwise stock engine and ecu. It has been tested many times with good results. I'm looking for some used ones, because new they cost 700 euros. Using these cams along with an aftermarket intake manifold I should be able to reach close to 160hp. From there and on it gets more expensive, so that's my target for now.

**NachoBides** · 29-12-2018, 10:39 PM

Some updates on my build.

I bought a custom made intake manifold. It uses the stock afh runners and a custom plenum. Here are some photos.

The manifold has the throttle plate and map on the opposite side compared to the oem manifolds. That means that I have to extend the wiring for both throttle body and map sensor. One advantage is that on the passenger side there is more space for an intake setup. I think I'm going to use a bmc cda filter and guide the air directly from the front grill. EGR will be deleted as well.

I also bought a pair of Schrick 252/9 cams.

Both manifold and cams costed me 400 euros, so I'm quite happy. Next step now is finding a megane 2 throttle body and cleaning the aub injectors. Then the parts will be installed on the car, as much closer to the remapping date as possible. That will probably happen in the beginning of February.