Engine Efficiency

Three cheap/free things you should ALWAYS do to a G or a GT. If you haven't done these you are not looking for optimum performance from your engine!!!

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1.

Run a fresh earth cable, doesn't need to be super thick or anything, but thicker than std speaker cable, from the Lambda earthing point(on the inlet manifold) to the chassis. This can be behind the coil where it mounts to the chassis or even better straight from the battery! The engine is almost 15 years old, it might be earthed but isn't going to have a clean enough earth for sensory electronic equipment! No point messing about!

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2.

Get a new blue temp sender or check your current one. Even new ones can be dodgy so ideally this should be checked by an ohm meter or voltmeter to measure its resistance. Using a decent DIGITAL meter you should read:

5k to 6.5kohms at 0C

3.2k to 4.2k at 10C

2.1k to 2.9k at 20C

1k to 1.4k at 40C

520 to 670 ohms at 60C

280 to 370 ohms at 80C

you can use a voltmeter, but keep the sensor connected:

-1.80 to 2.25v at 0c

-0.95 to 1.25v at 20c

-0.50 to 0.85v at 40c

-0.20 to 0.40v at 80c

If you start the car without the sender connected it will start in diagnostics mode which will give you about 17mpg and will not run very well.

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3. (bit trickier)

Upgrade the pishy polo coil. The mk3 polo has an amp and coil built into one. Its crap, do not let anyone tell you different. Although its fine to run most polo's it couldn't run the T at all. So I did this mod and it makes the world of difference. Since then I have done it to my G40 and the GT and it helps greatly! SO...

Go find a late mk2 golf GTI or Passat of similar spec with DIGIFANT electronic fuel injection. The coil and amp are separate on these things so you need to unbolt the coil(should have a green sticker on it, and note which side is which in terms of positive and negative(red and black!!))keep the bracket and the bolts, and cut out the wiring loom between the coil and the amp. The amp looks like a little ECU(about the size of 2 matchboxes) that is bolted to the main ecu metal mounting plate(on the golfs anyway) using 2 self tapping screws. The Amp has a 6 way plug that goes to a loom that goes to the coil..... cut this out with as much cable as possible, you'll need it(only 4 pins of the 6 pin multiplug are used by the way!).

When the time comes to fit it to the polo, its pretty simple. The coil goes where the polo coil goes. easy, the amp I normally mount up in the bulkhead near the ECU and have the loom run down the side to the coil under the washer bottle.

The wires going to the coil in the polo now go to the amp with the exception of the black wire which goes to the negative side of the coil. The only mismatched colour as I remember is that the black and green from the polo goes to the solid green on the amp. the red from the amp goes to the coil as it did in the donor car. Solder them all up and away you go....

Polo MPGS: When running the digifant system in the turbo 20-25ish, got 17 once when running in diagnostic mode!!(blue temp sender disconnected).

In the G40 (chip, toothed belt pulleys and full blend) I do not get below 30, if I'm gentle 34, most I've ever had is 39.

GT: I get 37 all the time and I screw the nuts off it all the time! I can get above 40 if I actually try...

I've also heard of duff purge valves causing MPG problems too...

All this is assuming you have a decent Lambda sensor, which there are articles on testing on Club Polo If not get new ones from a bosch agent, half the price of VAG and are identical parts!

MORE ON COIL MOD…

As you can see, its a bit of as mess! If you have the amp and loom from the mk2 golf gti you will have 4 wires from the amp. on the pic this is coming from underneath the screen wash bottle as I have my coil up next to the ECU.

Amp wires go to:

Green - Black/green from engine wiring loom(hooked round my pinkie) previously on top of old coil pack

Red - Positive side of coil

Black - negative side of coil

Brown/white - goes to brown from engine loom (that goes to the multiplug next to the coil)

OK, so here’s where the wires from the top of the coil go just to be clear:

Black/green - goes to green on amp

Black - goes to Negative side on coil

Brown - to brown white on amp

clear as mud??

Here is the G, same thing different colour! The two red wires on the coil go to the same place so you only really need one.

Here is where the amp sits.... yet to be secured

Hope that helps.

I cannot stress how sensible this mod is!! It made the difference between the T making shed load of power and bogging down like a depressed lemming.

The amount of voltage required to make the spark jump varies on the conditions within the cylinder. It's all about working maximums. You don't need 200bhp to do 70mph. but a 200bhjp polo is going to do 70mph with far less effort (30% of maximum) as opposed to a 45bhp 1.0 litre that will work at 89% of maximum to do 70.

With a more powerful coil you are providing a stronger spark that is less likely to be hampered by changing conditions in the cylinder (ie sudden influx of a boost at a very rich mixture).

A system that is "adequate" will bog down, where a system that is far stronger that needed won’t even flinch..... It’s also to do with the current as well obviously. A mk3 system also delivers close to 50kv too but the amperes is lower hence... its crap... With a stronger ignition system you eliminate a potential performance hindrance. Anyway, even without the theory, every GT/G40 I know that done this has reaped benefits from the conversion. I highly recommend it, as everyone knows...

Mark Hunter

Originally posted on G40 Club

Edited 5 September, 200818 yr by carver

brilliant!

Fixed the images now

It wont help me,unless i go with a GT fuel system one day,but its my kinda thread - so a thumbs up for the effort and sharing nature all the same,Mark

i think i have seen this before somewhere is good post

It used to be on clubg40 before the site update, I'm going to do the gti coil on mine as i think the 1600 on a polo coil is stretched. Should help with bogging at low revs when hitting the loud pedal.

It's a bit specialised for the FAQ, but I've pinned this up as an interesting read.

Thanks Yeti

Can you at least put a comment on the end saying where you got that from since you basically just nicked it from an old version of the club g40 site?

It can be found in this thread on the club g40 site too:

http://www.polog40.co.uk/forum/index.php?topic=594

I didnt nick it, I'm not posting it claiming i wrote it! I posted it as someone asked earlier and i had it saved from a few years ago...

is it worth doing a simalar mod to a 1.6 6n ?

Any benefits to a Mk2 carb engine?

Mk2 has it anyway.

anychance of it working on a 1.3 CL? just wondering as i have all the parts so thought i might bung it in before doing a carb conversion.

Does anyone know if this will work with a mk1 golf coil and amp as I have one sat spare in my bedroom... Looking at the coil and amp, they look the same, but the colour of the wires are different...

Any ideas?

i wouldnt bother with the coil mod folks tryed and tested and iv lost 2bhp in the space of a week and the coil mod is the only thing that changed

i wish i had of stuck with the ecu controling the ignition as thats the only thing it was doing with having carbs

For those that have an ignition module or tci from a different car and not the 8v gti, the wire colours will be different so here it is using the pin numbers on the ignition module...

Pin 1 : Negative on coil : Terminal 1

Pin 2 : Brown from the polo coil loom

Pin 4 : Positive on the coil : Terminal 15

Pin 6 : Black and green wire from coil loom

For those that have an ignition module or tci from a different car and not the 8v gti, the wire colours will be different so here it is using the pin numbers on the ignition module...

Pin 1 : Negative on coil : Terminal 1

Pin 2 : Brown from the polo coil loom

Pin 4 : Positive on the coil : Terminal 15

Pin 6 : Black and green wire from coil loom

Just wanted to say thanks for the info here, very useful for those of us who have a different coloured loom Just used it myself so I can keep my original coil in my mk1 Golf. Worked a treat

I've just used this again on my mk3 Golf GTI believe it or not! New coilpack lasted less than 6 months so I wired up an old coil and amp using this guide and its back to life again!

Edited 28 May, 201313 yr by Phataz1

Is this still seen as a worthwile upgrade? I'm going through my gt's ignition set up at the moment as it has been misfiring from cold on the overun (neighbors love the bangs in the morning haha), the plugs are filthy and getting a weak spark on the cyclnder next to timing belt. I have the ignition loom and amp from my mk2 polo hz but no coil so considering a lucas sport coil?