What did you do to your Polo today?

[TDIfan]

Been doing a lot of reading on engine tuning lately and the deeper I go in the more I realise the tune on my car was so awfully done

So I've decided to make my own tune, it's a really huge subject so I'm taking my time

No progress yet only been reading and comparing maps from different engines

Only fiddled with the Launch Control with negative outcome on the drag strip so far
Well at least I get a baseline for this tune and any future tunes should give batter time than this

A lot more reading is required to make a good tune

Been doing lots of logging on the car lately, and changing the software bit by bit. The thing with self tuning is you have to learn everything from scratch and you don't become a pro in just a few months. So don't try to attempt this if you don't want to invest your time into it.

So far I've calibrated the software to run with the upgraded hardware. Changed the diagnostic limits so that I can see what the car is doing in the log. Went through most of the limiters making sure nothing in the software will limit what the hardware can do. Then I moved on to fuelling, the injectors would support more power than the turbo so I set it to where the turbo is at.
Everything was going alright up until when I moved on to boost, it was overboosting quite badly. The actual boost just spikes over requested at 2200rpm and staying over until 3200rpm, sometimes after the N75 corrected this spike there was no more actuator movement left to control boost so it would stay slightly over till redline. Every attempt to change in the software would not make much difference to that overboost, which makes me to think it's a hardware problem. I asked the vendor who sold me the turbo, and he said the actuator is set at a safe limit and will need to be fine tuned by a tuner. So after eliminating all other elements, it comes down to the actuator. I've extended it by 2 turns(VNT vanes open more in the whole range) to see if I was going in the right direction, and I see the N75 gets more actuator movement left to control boost after correcting the boost spike. Then I did 4 more turns and the result had something I've not expected. The turbo wouldn't spike as high as before and actual boost would stay closer to the requested after the spike. While the boost curve stayed more or less the same down low, I get a lot more torque there than before. It would start to pull as early as 1500rpm where as before all the torque comes in after 2200rpm. Amazingly how this is matching with the log data I got. Looks like as the VNT vanes staying more open the engine gets less backpressure and would produce more torque. That's how low end torque should feel like, and that means I've been driving the car under powered for a long long time.
Hum well that solved the mystery of 'why my TDI has no low end torque' which was bothering me ever since I did the hardware upgrade.

And this is where I'm up to now, the actuator might need a bit more adjustment. Then I'll move on to Start of Injection(SOI), which is equivalent to ignition timing in petrol engines. Which is a big job and that's why I leave it till last, hopefully I won't lift the head while fine tuning that.

[MattSA9N3]

Got myself these goodies from Germany. Eibach springs, Bilstein B8 shocks and an H&R F+R sway bar kit.



Fitted on car.

[sssstew]

looks good Matt

[MattSA9N3]

looks good Matt

Thanks, very happy with the ride quality. Can definitely feel the difference the sway bars make.

[simon k]

brought it home, started making a list of what needs fixing

[NGT18T]

Got a new battery and filter in

[sssstew]

brought it home, started making a list of what needs fixing

Lol! how long is the list?

[simon k]

Lol! how long is the list?

it's not terrible - it's been sitting since I brought it home and waiting for me to fix some damage to my Focus and put it up for sale, that's done so now I can work on it.


The car stunk of cigarette smoke so it's after I brought it home I emptied a box of Bi Carb Soda all over the seats, carpet, dash etc. and put an ice cream container of vinegar too. Internet says that works, at the moment it just smells of vinegar so can't tell if it's worked. If it hasn't killed the smell then there's a Meguires product that is apparently a good thing

I replaced the reversing light switch a couple of weeks ago, it was stuck on - switch was buggered

The left rear quarter has some damage (like it's scraped against a letterbox or something) and the PO did a horrid job of painting over it, so I've rubbed that back and will spray it at some point.

So with the Focus done, this afternoon I started on the timing belt (10,000km overdue), hopefully the Focus will sell soon so I can register it

[Stuwey]

If it hasn't killed the smell then there's a Meguires product that is apparently a good thing
it

Bowdens Own do a great one; Pong Go Pong-Go - Lovely smelling deoderiser for your car.

[simon k]

put it all back together, should be right for RWC & rego - and someone is interested in buying my Focus!