So how hard is it to tune Megasquirt?
  • Help
Results 1 to 20 of 20
  1. #1
    Member Boldy's Avatar
    Join Date
    Jul 2005
    Location
    Auckland
    Posts
    47

    Default So how hard is it to tune Megasquirt?

    I've been looking into replacing my 205's L-Jet brain with a megasquirt (fuel only). As the car is used as my daily driver I need to be able to revert back to my original state in a few minutes. This means using the original wiring harness, with an adapter cable to plug the MS in. I'm pretty sure I can do this with all the existing sensors as well as adding an oxygen sensor in the collector and replacing my throttle position switch with a sensor. I would leave the AFM plumbed in until such time I felt my fual maps were sorted.

    Advertisement


    I'm an electronics engineer by trade so assembley and splicing in of the MS doesn't faze me too much. I'm pretty much an EFI noob tho. My question is how hard is it too get my 8v up and running with MS? Nothing like getting your hands dirty in the learning process I know, but I still don't want to spend months of time on it if its not going to be worth my while.

  2. #2
    VIP Sponsor
    Join Date
    Aug 2000
    Posts
    9,467

    Default

    Quote Originally Posted by Boldy
    I've been looking into replacing my 205's L-Jet brain with a megasquirt (fuel only). As the car is used as my daily driver I need to be able to revert back to my original state in a few minutes. This means using the original wiring harness, with an adapter cable to plug the MS in. I'm pretty sure I can do this with all the existing sensors as well as adding an oxygen sensor in the collector and replacing my throttle position switch with a sensor. I would leave the AFM plumbed in until such time I felt my fual maps were sorted.

    I'm an electronics engineer by trade so assembley and splicing in of the MS doesn't faze me too much. I'm pretty much an EFI noob tho. My question is how hard is it too get my 8v up and running with MS? Nothing like getting your hands dirty in the learning process I know, but I still don't want to spend months of time on it if its not going to be worth my while.
    Very easy, just an hour or so on a dyno.
    Don't know about changing back though, a bit complex with all the wiring mods and why would you want to?
    Graham

  3. #3
    Member Boldy's Avatar
    Join Date
    Jul 2005
    Location
    Auckland
    Posts
    47

    Default

    oh I only mean I would want to change it back while I am tuning the megasquirt. So in the days/weeks that it would take me to sort it out properly I could revert back for a daily driver.

  4. #4
    VIP Sponsor
    Join Date
    Aug 2000
    Posts
    9,467

    Default

    Quote Originally Posted by Boldy
    oh I only mean I would want to change it back while I am tuning the megasquirt. So in the days/weeks that it would take me to sort it out properly I could revert back for a daily driver.
    It only took me a few hours to get the car driving better than with the L-Jetronic so not worth the effort to keep the old system.
    Graham

  5. #5
    Member Boldy's Avatar
    Join Date
    Jul 2005
    Location
    Auckland
    Posts
    47

    Default

    ok thanks Graham. What did you end up doing with your intake? Did you leave the standard air filter arrangement there? I was thinking it would be a good opportunity using a MAP to shorten up the intake with a cold air setup.

  6. #6
    VIP Sponsor
    Join Date
    Aug 2000
    Posts
    9,467

    Default

    Quote Originally Posted by Boldy
    ok thanks Graham. What did you end up doing with your intake? Did you leave the standard air filter arrangement there? I was thinking it would be a good opportunity using a MAP to shorten up the intake with a cold air setup.
    Just replaced the AFM with a piece of plastic pipe from the local hardware store.
    The 205 has a cold air intake as standard, just behind the grill, can't do better than that.
    Graham

  7. #7
    Member Boldy's Avatar
    Join Date
    Jul 2005
    Location
    Auckland
    Posts
    47

    Default

    ok thanks Graham. I take it you wired in a seperate air temp sensor. Where abouts did you locate this? Also I notice the megasquirt has a fuel pump pin to control the fuel pump relay. As far as I can tell the L-Jet system gounds the relay through the L-Jet ECU? Is this correct?

  8. #8
    VIP Sponsor
    Join Date
    Aug 2000
    Posts
    9,467

    Default

    Quote Originally Posted by Boldy
    ok thanks Graham. I take it you wired in a seperate air temp sensor. Where abouts did you locate this? Also I notice the megasquirt has a fuel pump pin to control the fuel pump relay. As far as I can tell the L-Jet system gounds the relay through the L-Jet ECU? Is this correct?
    Yes, seperate air temp sensor, I mounted this on the inlet manifold but will move it to the plastic intake pipe to reduce heat soak.
    The fuel pump on the L-Jet sytem works through the tachymetric relay, along with the ECU and injectors.
    All a bit too much when you add oxy sensor as well and this relay was getting quite hot!
    Eventually I got rid of the tachymetric relay and ran the ECU, injectors etc from a relay directly controlled from the ignition switch. I then ran another relay for the fuel pump, don't think there is a factory fitted pump relay but could be wrong, off the Megasquirt pump output, this is a switched ground.
    Graham

  9. #9
    1000+ Posts tekkie's Avatar
    Join Date
    Jun 2002
    Location
    Sydney
    Posts
    1,516

    Default

    how do you set up the initial tune.
    Other aftermarket ECU's have a basemap but it doesnt appear to be the case here.

    Do you just flood the injectors and back off until it runs while setting the timing to some basic like 8btdc?
    .
    1300cc's of jap buzzbox delivered the times below.

    EC 1:54.6 , Wakefield 1:13.15 , OP (short) 52.00 , OP GP 1:24.40


  10. #10
    VIP Sponsor
    Join Date
    Aug 2000
    Posts
    9,467

    Default

    Quote Originally Posted by tekkie
    how do you set up the initial tune.
    Other aftermarket ECU's have a basemap but it doesnt appear to be the case here.

    Do you just flood the injectors and back off until it runs while setting the timing to some basic like 8btdc?
    There is a program (on the MS web site) into which you put the characteristics of your engine. Then just play with the "required fuel" parameter until it runs.
    Graham

  11. #11
    Member Boldy's Avatar
    Join Date
    Jul 2005
    Location
    Auckland
    Posts
    47

    Default

    Wahoo! Just scored an old bmw 318 ecu for $10. Its got the same 25 pin connector and should make a good case for the MS.

    However the more I look into it and try to wire it up the more I realise it won't quite be the plug and play option I thought it would be. I think I'll put like a diary type thing up on a webpage for others that are interested in doing a similar conversion.

    Graham I'm interested to hear, as well as sorting out that wandering idle, how else has the MS improved your 1.9? Do you think there are some small HP/torque gains to be made there? I'm hoping that removing the AFM will free up the ability to rev a little.

  12. #12
    VIP Sponsor
    Join Date
    Aug 2000
    Posts
    9,467

    Default

    Quote Originally Posted by Boldy
    Wahoo! Just scored an old bmw 318 ecu for $10. Its got the same 25 pin connector and should make a good case for the MS.

    However the more I look into it and try to wire it up the more I realise it won't quite be the plug and play option I thought it would be. I think I'll put like a diary type thing up on a webpage for others that are interested in doing a similar conversion.

    Graham I'm interested to hear, as well as sorting out that wandering idle, how else has the MS improved your 1.9? Do you think there are some small HP/torque gains to be made there? I'm hoping that removing the AFM will free up the ability to rev a little.
    Yes, I used the connector of an old BX TRi ECU.
    A lot more drivable and the ability to adjust fuel mixture to compensate for injector wear etc. It does rev through to 7000 or so whereas previously it tended to tail off after 6000.
    Probably a brand new Jetronic system would be as good, the advantage of MS is for older systems and of course for when the engine is modified and the original set up is no longer relevant.
    Graham

  13. #13
    Fellow Frogger! casnell's Avatar
    Join Date
    May 2004
    Location
    Heidelberg/melbourne
    Posts
    912

    Default

    Quote Originally Posted by GRAHAM WALLIS
    Yes, I used the connector of an old BX TRi ECU.
    A lot more drivable and the ability to adjust fuel mixture to compensate for injector wear etc. It does rev through to 7000 or so whereas previously it tended to tail off after 6000.
    Probably a brand new Jetronic system would be as good, the advantage of MS is for older systems and of course for when the engine is modified and the original set up is no longer relevant.
    Graham
    Hey Graham, I think I need one of these, perhaps we can wheel and deal Billys/megasquirts?
    205gti

  14. #14
    VIP Sponsor
    Join Date
    Aug 2000
    Posts
    9,467

    Default

    Quote Originally Posted by casnell
    Hey Graham, I think I need one of these, perhaps we can wheel and deal Billys/megasquirts?
    Will you be at scrutiny tommorrow? (12-00pm) we can talk then.
    Graham

  15. #15
    Fellow Frogger! casnell's Avatar
    Join Date
    May 2004
    Location
    Heidelberg/melbourne
    Posts
    912

    Default

    Quote Originally Posted by GRAHAM WALLIS
    Will you be at scrutiny tommorrow? (12-00pm) we can talk then.
    Graham
    See you there! That spit roast sounds good...
    Picking up the DMS afterward at Jeff Beaumonts...
    Chris
    205gti

  16. #16
    Member
    Join Date
    Jan 2004
    Posts
    58

    Default

    Quote Originally Posted by GRAHAM WALLIS
    Will you be at scrutiny tommorrow? (12-00pm) we can talk then.
    Graham
    Hi Graham, I think I might have asked you this before but where did you source your Megasquirt was it glens garage ? and what was the total cost of the megasquirt landed here ?


    Cheers mate
    Tom

  17. #17
    VIP Sponsor
    Join Date
    Aug 2000
    Posts
    9,467

    Default

    Quote Originally Posted by tcns
    Hi Graham, I think I might have asked you this before but where did you source your Megasquirt was it glens garage ? and what was the total cost of the megasquirt landed here ?


    Cheers mate
    Tom
    Yes, and $200.
    You will need to buy Air Temp sensor, Throttle Position Sensor and O2 sensor on top of that.
    Graham

  18. #18
    Fellow Frogger! Cubits's Avatar
    Join Date
    Jan 2004
    Location
    Brisbane
    Posts
    555

    Default

    Quote Originally Posted by GRAHAM WALLIS
    The 205 has a cold air intake as standard, just behind the grill, can't do better than that.
    Graham
    Pity the intake runs across the engine, into a can heated by the head/manifold that it's attached to, then back over the end of the engine... :p

    I'm sure a cooler intake solution could be managed, especially with the battery out of the way.

    Back on topic, the megasquirt definitely will see an improvement in power as the standard ECU is a bit messy with it's AF ratio's at the best of times. I bet you'd get improved consumption too.
    1987 205 GTI - Graphite Grey - 206k km's
    1988 MR2 Supercharger - Mica Blue - 114k km's

  19. #19
    Member Boldy's Avatar
    Join Date
    Jul 2005
    Location
    Auckland
    Posts
    47

    Default

    Quote Originally Posted by Cubits
    Pity the intake runs across the engine, into a can heated by the head/manifold that it's attached to, then back over the end of the engine... :p
    Yeah have to say I've often wondering about sitting the air filter over the exhaust manifold can't be the coldest set up. I realise its not as simple as that and the peugeot engineers have put a lot of thought into getting the length right etc.

    I'm hoping the megasquirt will be the first step into getting some quad throttle bodies and a port and polish sorted out for the long term. Good to hear that I should be looking forward to increased driveability after my first step tho!
    Last edited by Boldy; 29th November 2005 at 06:22 AM.

  20. #20
    Fellow Frogger! Cubits's Avatar
    Join Date
    Jan 2004
    Location
    Brisbane
    Posts
    555

    Default

    I don't think the intake solution on the 205 was purely performance oriented. It looks like they put the air filter in the only place it would fit, then worked from there. There is nowhere else it could've gone!

    I strongly believe that it's one area that can be improved upon quite easily, but to do that you have to make some space. Once the battery is in the boot you have quite good room to put a cold-air box. It also removes the cluttery pipes from over the engine and frees up room for a strut brace.
    1987 205 GTI - Graphite Grey - 206k km's
    1988 MR2 Supercharger - Mica Blue - 114k km's

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •