Author Topic: Project AAV turbo  (Read 19900 times)

Offline cheys03

  • Members
  • *****
  • Posts: 794
Project AAV turbo
« on: November 29, 2010, 12:00:18 am »
I’ve regretted not having a build thread so far…so here it is.  From the beginning….

We’ve a bit of a history of Polos in the family. My grandparents have had various models over the years, I think a Mk1 and a few Mk2s including a Formel E. My grandfather had a Mk4 which suffered an engine bay electrical fire. The remains were traded in for this example in 1996, an M-reg 1.3L Genesis in Alpine White. My grandmother drove the car for a number of years after my grandfather passed away. In March 2008 she wanted something a bit easier to drive, power steering etc. so it was offered to me. I’d literally 2 weeks earlier passed my test (at age 23!). It was great – a year’s MOT, 6 months tax, sporty-looking Hella grille and a mere 44,000 on the clocks.

The first drive was spent mostly stalling, I’d learnt in a diesel – that’s my excuse and I’m sticking to it! Dad gave me a hand servicing and cleaning the car, removing the moss and T-cutting the paint to within an inch of its life. Didn’t know about blackening the bumpers back then..!

Thanks to UncleTerry for these two pics

The car served me well for a year, it needed only new discs, pads and shoes. In March 2009 the headgasket went after a particularly spirited weekend’s driving. Coolant poured into cylinder 1 giving it a beautiful steam clean. The Scottish AA man’s towing advice was “Read the card, brake when I brake – but if you forgot don’t worry, it’s only a wee Polo. I’ll probably not notice”!

I put the headgasket failure (after ~52,000 miles) partly down to some sketchy servicing on my grandmother’s behalf by the chap who she paid to maintain the car. The brake fluid and coolant were definitely not changed in recent years and I’ve since found various ‘oddities’ about the car. He once even left the wheel bolts loose. Tool.
Anyway, the headgasket failure came at probably the best time. I’d recently picked up a GT injection setup to fit and was about the service the car – new filters, oil etc. so only the old oil and coolant were affected.
With help from the CP forum and following a guide Andy Strange had written 8 years prior the headgasket was changed and the GT injection fitted.

Out with the old

In with the new

 It felt great, definitely quicker. Initially I was concerned about a lean misfire @ 2,000rpm but I eventually just got used to it. At the rolling road day it made 82bhp.

In August 2009 I moved house and the 5 mile bicycle commute became a 37mile each way mix of motorways and A-roads, doubling annual mileage overnight. The car took it well and only once let me down when I put too much trust in the fuel gauge. Fortunately there was a gallon in the boot.
With the extended commute I found myself spending more time in the car and so could start to justify a bit more expenditure. After all, it had to get me to work and back reliably.

In March 2010 it was time to tackle the aging suspension – 3 original shocks and 1 original spring!
The two front springs were a little mismatched…!

 It was treated to a new set of Spax -40mm springs and shocks, G-Laderseite blocks, poly bushes, new lower arms, new steering arms, new wheel bearings, new top mounts and nearly every suspension nut/bolt renewed.

In September a GT rear beam was fitted with new VAG bushes and the (too harsh for me) Spax rear springs swapped for carefully chopped standard springs. Already fitted in 2009 were a ‘GED’ type  front brace bar and GT steering damper. PPP Stage 3 subframe in the pipeline.

Initially upgraded to new pattern part VWII callipers, Pagid plain discs and ATE pads with a 22mm master cylinder. More recently it’s had an Audi 256mm setup with Pagid discs/pads which are simply brilliant and is the first time I’ve actually been happy with the brakes. Rare. Expensive. But worth every penny IMHO.

Scirocco Avus ‘Scala, Snowflake’ wheels. Quick home refurb in gunmetal grey.

Took me a while to find a wheel and colour I liked. Maybe a bit plain for some but I love them. Tyres are Avon ZV-3 165-60/R14 and am very impressed with their grip, certainly much better than the random ditch-finders that were fitted to the steelies.

Decent alarm. Cheap Kenwood head unit, Maplin’s best £6 4” dash speakers and a 12” Fly active sub occupying a good portion of the boot.

Scirocco GT2 front seats mean my head isn’t constantly buffing the roof lining anymore.

GT/G40 arch+sill kit, Mk2 door handle inserts. Clear indicators and side repeaters. Door handle armoured plates. Hella lamp grille. Towbar.

AAV engine with GT management. Fahrvergnugen Tuning standard limit chip. SPI exhaust.

Inevitably I’m now looking for more power.
A few options occurred:
1.   1.6 ABU with GT management
2.   1.4/1.6 AFH with bike carbs
3.   1.4/1.6 AFH with standard management
4.   G40 conversion
5.   Turbo something-or-other

The ABU doesn’t really offer a huge power increase. AFH on bike carbs I’m too concerned about emissions with it being a post 1992 car. AFH on standard management was a very very attractive option. G40 would be too costly in charger rebuilds. Overall with the car doing ~20-25k/year the MPG still had to be decent. At the back of my mind I wanted to avoid upgrading for a smidge of extra power at a time – whatever I chose I wanted to be relatively easily tuneable in future years.

A turbo (K03) G40 seemed perfect – decent power achievable and it’s been well tried and tested. Crucially second hand K03 turbos usually cost ~£50 – much more pocket-friendly than charger rebuilds. After some research (thanks to the PoloG40 forum members) I decided to attempt to turbo the current AAV engine in the car, for a few reasons:
a)   I know the history of the engine well and know it has a good service history for the past 35k – a good strong engine.
b)   Using the AAV with CEG gearbox would save approx £500-£600 sourcing a PY engine and ATV gearbox.
c)   Stock compression ratio is 9.5:1 – within the realms of boost and not a million miles away from the compression with (admittedly far stronger, forged) Accralite 1341cc pistons used in overbore G40s.
d)   The higher compression should keep the off-boost driving pleasant

Clearly the disadvantages are that with the high compression ratio and boost is the risk of blown headgaskets or worse are greater. Also the lack of sodium-filled exhaust valves may be an issue, as may the late-spec 7mm valve stems. Ultimately it will be interesting finding out how the AAV takes it. Tommo had some very good results with his AAV carb’d turbo before going to ABD with turned-down pistons. He knew the science and engineering behind it all extremely well. I don’t so will be erring on the side of caution.

Engine spec will be:
1.3L AAV engine – 78k. Late spec with 7mm valve stems.
254/254 Piper cam (not ideal, but a good intermediary cam for this turbo I understand)
G40 ECU & management
250cc fuel injectors freshly serviced by PPP
#G40008 ECU chip from PPP
Adjustable full throttle boost switch to suit map
K03 turbo
K03 stainless manifold and 60mm downpipe from Phil J
Standard GT exhaust mid-box and G40 back-box
GT inlet manifold
Jabbasport G40 induction kit
Forge 007p recirc valve
FMIC - ebay specia. Had it modified to have the inlet and outlet to point backwards
13-row 235mm oil cooler with Mocal thermostatic sandwich plate
Wideband lambda – AEM UEGO
Oil pressure & temp gauges (TIM electric)
Boost gauge (Stack)
200mm LUK clutch
Catch tank

Boost will be low, perhaps 6-7psi on advice from the PoloG40 forum members. Am hoping for 120-130bh. Later there’s some chance the boost screw will be gradually turned up, haven’t made up my mind yet. Obviously the chance of something popping increases massively with higher boost :-\
Backup plan is a second AAV and set of G40 pistons…just in case..!

Offline cheys03

  • Members
  • *****
  • Posts: 794
Re: Project AAV turbo
« Reply #1 on: November 29, 2010, 12:03:35 am »
So, work begins!

Started to strip the GT injection

Old exhaust removed

Original mid box

Knackered flexi though!

Clocked the turbo – lots of Plus Gas, hacksaw, some blocks of wood and a breaker bar later…

More stuff stripped

Engine out

Empty bay

Engine on stand for new bits including VW belts and waterpump O-ring

Late spec AAV doesn’t have the knock sensor castings

Took the opportunity to paint the gearbox end plate

Throttle body modified to accept adjustable boost switch (copied from Doc J)

New sump with brazed oil return for the turbo, painted. Return is the same internal diameter as the port on the k03 and the original return on the Passat.

Oil pump gauze cleaned and chain tension checked

Oil filter hex head came off

Delicate use of a screwdriver resolved the issue

New engine mount rubbers and Lucas refurbished starter

Old starter bush removed with M12 bolt, swan-neck spanner and hammer

New clutch (LUK 200mm). Also in the pic is the oil return and sandwich plate. The hose was an extremely tight fit over the  metal pipe ends. Two hose clips on each end. Hope it doesn’t leak.

Alternative mounting for knock sensor – cleaned out the tap, skimmed the mating surface with several files and wet&dry. I hope the loom is long enough. Breather pod and separator tank were cleaned thoroughly. New water pipe with ISV bracket – on the GT injection it was just cable tied on.

Fan shroud ‘adjusted’. This was the first stage. It got a bit lighter still later on

FMIC with ports moved from the side to the back

The work was done as a quick job by a chap who makes the intercoolers for Noble cars

Positioning. Brackets were made and fitted after this pic

Engine back in and mostly re-assembled.

CV heat shield has to go. May wrap a little heat wrap around this section

Still lots to do. The cold isn’t helping

Offline Puncharado

  • Members
  • *****
  • Posts: 446
  • Back on the road in 2010! No, 2011! Maybe.
Re: Project AAV turbo
« Reply #2 on: November 29, 2010, 12:38:17 am »
Coming along nicely. Good work.

Offline PeteG40

  • Administrators
  • *****
  • Posts: 4011
  • Housewives heart throb
Re: Project AAV turbo
« Reply #3 on: November 29, 2010, 08:28:33 am »
nice one mate!

Offline Tommo

  • Members
  • *****
  • Posts: 292
Re: Project AAV turbo
« Reply #4 on: November 29, 2010, 08:52:41 am »
This looks great. Im sure it will happily make plenty of power on the stock C:R, and dont worry about the strength of the pistons, they are as strong as you will ever need. And if you ever want them skimming down a bit just give me a shout.

I ran a bar of boost on my AAV with no problems, although my turbo will have been delivering much cooler air than a K03 at that pressure.

Offline Andy

  • Traders
  • *****
  • Posts: 1496
Re: Project AAV turbo
« Reply #5 on: November 29, 2010, 11:13:25 am »
I reckon at 15psi you'd be fine, but probably best to work your way up there a step at a time whilst keeping an eye on temps. Even at 22psi my inlet temps are around 60degC in a 20degC ambient, so I don't think you've got that much to worry about.

With that CR, cam and the K03 you should find you get a good quick response from the turbo - am really interested to see how this turns out. Good work.

Offline JregGT

  • Members
  • *****
  • Posts: 134
Re: Project AAV turbo
« Reply #6 on: November 29, 2010, 04:30:16 pm »
Some real thought gone in to this, looks like it will be a top job, look forward to some more updates.


Offline cheys03

  • Members
  • *****
  • Posts: 794
Re: Project AAV turbo
« Reply #7 on: November 29, 2010, 11:31:42 pm »
Thanks for the comments and encouragement chaps, very much appreciated!
No further progress yet, had promised to take the lady to see Harry Potter tonight ::)
Great to hear there's the possibility of further step at a time though. I imagine 7psi will have me giggling like a schoolgirl, 15 and I'll probably crap my pants! :o

Offline MartinB

  • Members
  • *****
  • Posts: 286
Re: Project AAV turbo
« Reply #8 on: November 30, 2010, 04:08:46 pm »
Nice to see someone 'turboing an spi' properly, nice bit of research and development you've carried out there  :)

Offline cheys03

  • Members
  • *****
  • Posts: 794
Re: Project AAV turbo
« Reply #9 on: December 01, 2010, 08:51:14 am »
Thanks Martin :)

Fitted the new exhaust

The cat brace will go back after a little chop, for what it's worth

The tip doesn't quite exit the underside of the car despite making the joints as long as reasonably possible. The problem looks like the exit pipe from the back box it too short or the wrong shape. The back box itself is about as far back as it will go. Not my preferred look but it'll have to do. Or maybe some bending will sort it. The tip looked like the exhaust pipe was expanded into it so couldn't easily be removed.

Think tonight will be spent indoors with the wiring loom

Offline cheys03

  • Members
  • *****
  • Posts: 794
Re: Project AAV turbo
« Reply #10 on: December 09, 2010, 10:13:32 pm »
Been quite a productive week.

Had a good couple of hours with the loom testing, checking, soldering, adapting and wrapping in new tape.

Painted the intercooler black

And fitted the intercooler after assaulting the bumper bar with the angle grinder

Made brackets and bolted oil cooler on

Oil cooler hoses  (world’s most expert zip-tie usage)

Chopped and refitted the CAT brace

Then fitted the boost pipes, recirc valve, air filter, catch tank, oil gauge senders, spark plugs, dizzy and turbo oil feed

ECU & cambelt cover went on a little later.

Filled with oil & coolant. Took battery off charge and refitted. Went to start (without fuel and spark initially to circulate oil). Nothing. Just the starter solenoid clicked on and off. Heart sank. Began troubleshooting. Half an hour later after finding nothing wrong I could only figure that it was the starter itself. Quick whack with a length of wood and hammer and all was right! I guess it’d just been sat on a shelf for a while. Once a bit of oil was circulated I replaced the fuel fuse and hall sender cable and it started first time! Brilliant!

Let it warm up for a while, timed the ignition…then couldn’t resist a quick (very cautious) drive, keeping a close eye on the wideband and boost gauge. Didn’t want to rag it just yet, but still the car felt good. The recirc valve is actually quite audible which is a bit of a disappointment – must be the induction kit. Got 7psi of boost with the actuator vac hose unfettled with. It’ll stay at this level for a while at least.

Still to do (tomorrow):
Fit Piper cam &tappets (GT cam is a bit pointless! Runs out of boost too soon). Resurrected with fine wet&dry after getting scored on the bearings (duff oil, wrong torque or something). Still within tolerances.

-Sort turbo coolant pipes
-Calibrate 6psi boost switch
-Fit new windscreen washer pump and fill reservoir
-Find place for horn(s)
-Adjust headlights
-Repair stone chip and reinstall Hella grille (there’s enough space, made sure of that!)
-Cut fog light holes out of bumper and trim middle bit to better fit intercooler. Fit mesh to protect the coolers.

Then hopefully it’ll be time to have a more spirited drive ;D and no more time outside in the freezing temperatures! Already have a pretty ridiculous cold!

Offline Andy

  • Traders
  • *****
  • Posts: 1496
Re: Project AAV turbo
« Reply #11 on: December 10, 2010, 07:18:30 pm »
Good progress!

You might be able to find a place for the horn behind the plastic grille if there's space around the Hella lamps.

The new cam should change the driving characteristics for the better. I can still remember the first drive of my K03 conversion nearly 4 years ago now - I was using a GT cam and was bitterly disappointed with the response. After fitting a much dirtier cam it was like a different car.

You'll find the re-circ valve annoyingly noisy - the only way to sort it is to fit an airbox. I've got a different Bosch re-circ (stronger spring) and a stock G40 airbox to try on mine to sort this.

I think with 7-8psi you'll get around 130bhp or thereabouts. With the right cam it'll feel like a powerful Polo GT to drive.

Offline cheys03

  • Members
  • *****
  • Posts: 794
Re: Project AAV turbo
« Reply #12 on: December 11, 2010, 11:22:26 am »
Fitted the cam, adjusted the headlights, fixed the windscreen washer pump, sorted the turbo coolant pipes and calibrated the boost switch. My method for the boost switch will probably make a few people turn away in disgust though…

T-piece to the boost gauge, boost switch and dynamic pressure source (bike innertube). Multimeter reads the contacts.

Gauges - the oil gauges are holding the electical tape in place, not the other way around (honest)

Cheers Andy (and thanks for the help from Yoof and yourself via PM) – temporarily fitted the horn behind a  standard grille until the hella grille is repaired. The 254/254 cam is definitely a massive improvement! The boost is now available within a much more useful rev range. Much more fun. Aye, recirc is doing my head in somewhat. I’m already finding myself easing off the throttle a bit easier just to quieten the dump. Don’t know why I bothered with a recirc, should’ve just got a quiet dump! Ah well. See how it goes for a while.

The car’s a good laugh :) nice torque punch and not too laggy. The AFR is still quite rich on idle though (~11:1, warm or cold), perfect on closed loop and on boost it is always <11:1, normally the gauge reads a flat 10.0 indicating it’s 10.0:1 or below (outside its range)  :-[
I’ve tried to hook up a cheap VAGCOM but it doesn’t work (didn’t work with my GT ECU either, other people’s VAGCOMs work fine though) to see if there’s a duff sensor or something. I’m thinking either there’s a duff sensor or the map needs leaning out a bit maybe for this setup.

Boost will currently peak at about 7-8psi, but almost immediately after it will drop ~4psi. Is this normal, or should it sustain the 7-8psi?  If it’s normal, what causes the drop? Wastegate opening? If it’s not normal could it be a boost leak or the recirc valve opening etc.?

Driving 200miles to Manchester and back with it this weekend, with a boot full of tools and regular stops to look check under the bonnet for oil leaks etc. AA card as backup. Fingers crossed it doesn't come to using it though!
« Last Edit: December 11, 2010, 11:35:10 am by cheys03 »

Offline Andy

  • Traders
  • *****
  • Posts: 1496
Re: Project AAV turbo
« Reply #13 on: December 11, 2010, 05:08:57 pm »
Tighten up the actuator rod - the standard actuator spring is really soft, so they tend to spike a fair bit. Soft springs will always spike a lot with an internal wastegate - once your exhaust gasses have got a wiggle on they start pushing the wastegate open, so it's not just the air pressure on the compressor side of things fighting the actuator spring.

Tighten it 'til you hold 8psi, it'll spike a few psi above that. If you can't tighten it any more, knock up a DIY bleed valve. Find a tube that fits inside your actuator air line, and drill lots of tiny holes in the tube along its length. Cut your actuator line, and insert the tube. Completely cover the tube for base boost, and slowly expose more holes to raise the boost level. You might find that putting a boost gauge t-piece in there (leave one orifice open) achieves the desired effect too - pikey, but it works. As does adding an external supplementary spring to the actuator.

That chip is mapped for 15psi of boost, which means that at intermediate boost levels are fuelled so that on spool-up the engine is fuelled correctly - in your case these intermediate boost levels are steady-state rather than transient map points, so they probably do need a bit less fuel in. Your milder cam and slightly higher CR (than a 9:1 1341cc G40 with 'turbo' cam) will make the motor less fuel hungry too.

It's good that it's fuelling fine steady state, could do with leaning off a bit on full-throttle (see what it does once you've wound the boost up though!) and it sounds like idle needs a map tweak. Worth playing with the CO pot to see if you can lean the idle off a bit - and deffo worth checking that the idle/closed throttle switch is working.

Offline Andy

  • Traders
  • *****
  • Posts: 1496
Re: Project AAV turbo
« Reply #14 on: December 11, 2010, 05:13:45 pm »
And good luck on its maiden voyage!