Toyotec said: 28th July 2007 01:20
How to convert your Digi Golf 2 to MegaSquirt V3x. P3 28/11/11 The end of an era!
I have been going on for a while that I wanted to convert my 1990 8v GTi to Megasquirt.
So here is how it is done.
Digifant system is a very reliable system design for people who could not be bothered about pistons, camshafts and power but more about reliability and giving some “nippiness” to the shops or on the school run. But for petrol heads like me, who would not leave Briggs and Stratton 3.75bhp lawnmower at the stock governed speed of 3600rpm, this system is rubbish.
The car: 1990 8v GTi
with a 3A engine (called The 8V), which presently has a 3A head and 2E intake manifold.
The 2E/3A head parts have been made to work with a TPSless digifant 2 system.
After trying various methods such as, BMW E34 3.0 AFM, 57i K& N, dizzy tweaking and trying to find the ignition maps on the Motorola processor let alone writing to it, to get this motor to run as hard as my old K jet 8v car, I gave up… until now.
System used is a Megasquirt V3 extra for Hall trigger and TCH-I output..
To see and evaluate how this DIY system compares against a STD digifant EMS and a so called “chipped EMS.
To achieve a 0-60 time of 7.5secs and a 15.4@93mph quarter mile time.
To gain response at low and high revs.
To rectify pinging at low revs and high load and at 5000revs and high load.
To eliminate AFM.
To gain fuel economy and provide a smooth engine torque curve.
Well I have finally decided to get the tools out and start prepping the car for the process.
Yesterday I replaced the slipping clutch and changed oil etc.
The clutch suffered push rod bush failure
so I replaced this along with new seal and clutch and it
In preparation for the Aftermarket EMS that will be installed and in order to evaluate where the expected feel, I decided to test the car to find out how well it faired on the STD EMS. I was fortunate to have one of these 20 pound chipped control units that everybody goes on about as well. This was added to the test to compared against the STD VW digi 2.
After the car was optimised on the STD EMS, the AFRs were logged. Then straight line tests were conducted. The same was done for the EMS with the 20pound chip.
The results were very interesting.
Now the curves generated are the same you would get from a chassis dyno. The scaling (determined by the entered weight) is not important here as everything (driver, car. test surface, direction) is kept mostly constant best out of 4 runs. Black line = STD digi 2 and red line is the "chipped" ECU. AFR scaling on Y axis from 11 to 16AFRs. Top trace is the chipped, bottom std.
With a entered weight of 2450lbs the car made the most torque and power from the VW EMS. The so called “chipped one ran leaner and was flatter in feel.
I also observed that all control units lean the mixture out in the last 1000rpm with the bliz one running very lean. So lean that when I approached 5000 rpm you could feel the car hold back. This is why I have been experiencing pinging in the last few rpm. My conclusion is this 20pound chip is a waste of time and money. If you wanted a lean VE curve just tighten the AFM spring. Then you can lean out your engine for free!
Most likely the igniton data is not touched as the car pinked a bit worse on the leaner running chipped EMS.
Straight line tests were
0-60 8.8secs for chipped EMS and 8.1secs for STD unit.
1/4mile 16.7@83mph for chipped and 16.3@85mph for STD
Digi Torque = 89.1lbft@2942rpm
Chipped Torque = 84.8lbft@3954rpm
Digi actual road horsepower 78.5rhp@5186rpm
Chipped horsepower = 75.9@5100rpm
With ECU evaluation out of the way let the Megasquirt Werks begin.