How to convert your Digi Golf 2 to MegaSquirt V3x. P3 28/11/11 The end of an era!

Discussion in 'Throttle bodies & non-OEM ECUs' started by Toyotec, Jul 28, 2007.

  1. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    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
    [​IMG]
    with a 3A engine (called The 8V), which presently has a 3A head and 2E intake manifold.
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    The 2E/3A head parts have been made to work with a TPSless digifant 2 system.
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    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..


    Aims:
    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.

    26/07/07
    Well I have finally decided to get the tools out and start prepping the car for the process.
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    Yesterday I replaced the slipping clutch and changed oil etc.
    The clutch suffered push rod bush failure
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    so I replaced this along with new seal and clutch and it was fine.
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    27/07/07
    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.
    [​IMG]
    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.
    [​IMG]
    Watch this space.
     
    Last edited: Nov 28, 2011
  2. bens_cab Forum Junkie

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    top work there eddie this needs to be a sticky along with the 16v thread should open a few eyes as to how rubbish these 20 chips are
     
  3. Carl loader Forum Member

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    Excellent thread, have always wanted to have a go with megasquirt myself, keep the updates coming :clap:
     
  4. wcrado Forum Member

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    always been dubious of those chips..... i always considered the remapping of a car to be a custom process, set up for each individual car, not a 'one size fits all' sort of process.

    Would be interesting to see how this gets on, seeing as i've just installed the 2e block to my 8v digi. Mite be worth a shout if this gets good results.
     
  5. bens_cab Forum Junkie

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    Megasquirt is value for money when you look at the prices of other ems
     
  6. kingyvw New Member

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    another spot on topic eddie, so many people taking a big intrest into megasquirt!
     
  7. wcrado Forum Member

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    how much you talking roughly? to convert a digi to megasquirt
     
  8. bens_cab Forum Junkie

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    what do you how much ? just for the ecu or the whole conversion
     
  9. wcrado Forum Member

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    i understand the ignition curve is the rubbish part that lets down the 2litre conversion, so i guess the ecu would fix that, how much for an ecu then?
    do they supply an ecu which plugs in to the injection system, and then the ecu has to be mapped for the car?

    what does the whole conversion include, fuel rail, injectors and everything?
     
  10. bens_cab Forum Junkie

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    pm toyotec he builds the ecus
     
  11. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    Mk2 3A car is now powered by Megasquirt!!

    After the car prep and baseline evaluation last week I finally returned to this exercise today.
    The ECU was built and tested then I added blue clear LEDs for the indicators instead of the STD issue red, not that would not make the car faster but I just wanted to add some of these from RS.
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    With the ECU built I popped outside to start the wiring/interfacing of the loom.
    The AFM/Airbox and connector were removed and then slowly the digifant loom was removed from the dizzy, coolant temp, injector rail, terminal 15 and -ve on coil, WOT and idle swtich ISCV and grounds.
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    Pigtails were added to the existing sensors/actuators and a TPS and manifold inlet sensor were added.
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    These would be joined by the MS loom.

    When the digifant ecu and loom were removed care was taken to strip out wires needed to run the MS EMS.
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    This ECU was built to be triggered by the original hall sensor 4 window dizzy and output to the TCH-i unit and coil.
    All TCH-i wires remained intact on the 7 pin connector
    Wires present were as follows
    T7/1 Red/Black -ve coil
    T7/2 Brown/White ground/earth
    T7/4 Black +12v Terminal 15
    T7/6 Green ECU trigger output

    [​IMG]

    On the 5 pin connector
    T5/1 Red/White Heated Oxygen sensor + 12v supply ( not used in UK)
    T5/2 Red/Yellow Fuel Pump Relay signal to ECU
    T5/3 Red/Green Starter cranking signal ( this was removed for MS)
    T5/4 Black/Yellow +12v from digifant relay
    T5/5 Red/Black Fuel pump and Injector +12v supply.

    [​IMG]

    This is the RS MS diagram that we use with the loom to integrate to the vehicle.

    [​IMG]

    For CE1 and CE2 integration please use this link
    and ignore the information specific to ABF motors i.e T28a plug infomation and go to Vehicle pin info to RSA colour guide columns. G40 Dizzy config infomation can also be found in that post.
    This car being an H reg or 1990 MY uses a "Central Electric 2" fusebox.

    Now that we know how the ECU would be interfaced with the car the wire route was planned.

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    With this finished and all the grounds connected it was time to start the car.
    A 3A start up map was loaded to the ECU and the car started the first time after a few tweaks to the required fuel settings.
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    This engine has very strong vaccum at 28kpa resulting in a very smooth idle.

    Next. Harness sleeving, fine tuning, final mapping and comparison testing..
    Keep watching this space there is more to follow soon.
     
    Last edited: Apr 15, 2011
  12. TheSecondComing Forum Addict

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    Top class thread, ToyoT. :thumbup: :thumbup:
     
  13. bens_cab Forum Junkie

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    bump to the top for some good work
     
  14. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    Work done today 02/08/07

    Works continued today with mixed results.

    Airbox and intake hose modifications
    As the car would no longer use a AFM a solution had to be found to reinstall a suitable replacement. I have had good results from modified factory airboxes so I used a Golf Mk2 GTD airbox seen on the right.
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    Lots of the lower sections of the airbox are the same and as mine was gutted out this was retained
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    When it was mocked up in place the digihose could not reach.
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    To solve the problem I used a ABF intake hose the plastic bend section from a KR 16v inlet tube and some 70mm hose I had laying about to complete the intake ducting from air cleaner to throttle.
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    The STD airfliter was installed in the airbox.
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    The ISCV had no place to suck by pass air. The problem was encountered for the breather.
    I uses the ABF duct ISCV pick up area to push a hose for the breather into and on the duct near the throttle I did the same for the ISCV.
    [​IMG]


    Harness/loom

    Now that all components were in place the loom was insulated again and sleeving was wrapped and secured around it. A new TPS was purchased and a Inlet Temp sensor from a Volvo 850 was fitted to the rear of the airbox.
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    Engine was started to check for any problems and all was well.

    Tuning issues and Sods law.
    Later in the day I returned to the car and clamped on my WB sniffer and install all the gear I needed into the car for the final map and evaluation.
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    Before this was done the laptop was put into the engine bay and the timing was double checked to make sure what was on the display screen was what the engine would see.
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    This was confimed with an advance timing light.
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    Mapping the motor was going fine as I had almost completed mapping for the day. Unfortunately mapping ceased when the engine developed a bottom end rattle so this must now be inspected before the exercise can conclude with an evaluation..
    My work is cut out but I will not be beaten.
    Apart from this the day was very fruitful as we went from this
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    to this
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    in 2 days.

    Keep watching this space.
     
  15. Carl loader Forum Member

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    Superb, really good thread, should be an FAQ i think (unless its already been done)!
     
  16. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    Bottom end inspection

    Eager to continue the calibration process I got up earlish to find out my fate on what was causing the bottom to rumble. The sump was dropped and the oil pump removed. What I found was not good.
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    The big end on No 4 had beaten itself to death. Somehow the copper had spread and closed off the oil hole. As the bearing did not spin and the crankshaft was not scored I decided to put in some new bearings to eliminate the knocking and keep the car in its present state of tune so that the misses could carry on with activities.
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    When I replaced all the big end conrod bearing shells
    I added a VDO oil pressure gauge to keep an eye on the oil pressure. Thankfully I had 2 of these with matching 2 pin sender.
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    I used the sender on in place of the N/C 0.4bar switch then ran the gauge wire to the meter. I put the meter in the "blanks" area under the handbrake indicator The ground was taken from the demist switch and the power was taken from terminal 15 from fusebox.
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    With gauge in I let the car warm up. From cold and at idle the pressure was 5bar but as the oil temp went to 100 on my MFA the pressure dropped to 0.5bar. 2K revs only gives 1.8ish bar or just on the limit of the buzzer.
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    There is no rattling now but I fear the damage is more than just conrod bearings. Reminds me of the similar problems I had with the turbo and one piece mains.
    So it looks like the motor is going to have to come out . I have a spare Audi 80 3A which will have to get a freshen-up.
    Never thought the project would go in this direction but then that may be a good thing ;)
     
  17. altern8 Forum Junkie

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    gutting news bout the bottom end but great updates :)
     
  18. was8v Forum Member

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    Very interesting read. Has anyone written up a MS installation to a standard PB engine?

    Are you going to do your tests with the engine in this configuration before swapping the engine out to maintain consistency of variables?
     
  19. paul_c Forum Member

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    What was copper doing on the bearings?
     
  20. TheSecondComing Forum Addict

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    Being bearing material?
     

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