MicroSquit Conversion, Giving this a try |
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MicroSquit Conversion, Giving this a try |
Mblizzard |
Oct 3 2016, 07:18 AM
Post
#1
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Advanced Member Group: Members Posts: 3,033 Joined: 28-January 13 From: Knoxville Tn Member No.: 15,438 Region Association: South East States |
I am pretty happy with my stock FI. But after seeing some of the setups at Okteenerfest, I thought this might be worth trying.
The stock system is not easy to modify and get things running correctly. I spent a lot of time making minor adjustments by trial and error. While I am not looking for huge HP gains or anything, it is pretty clear that the mods I have could potentially benefit from a bit more precise control. Going to start with fuel only at this point to get things going and see where it leads me. Any help or suggestions for set up would be appreciated. |
Dtjaden |
Oct 4 2016, 05:44 PM
Post
#2
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Member Group: Members Posts: 232 Joined: 25-May 13 From: Morgan Hill, CA Member No.: 15,915 Region Association: Northern California |
Some comments on my 2 year journey with Megasquirt:
1. Install a crank trigger while you have the engine out of the car. Mario at the DubShop sells the one I used at a very reasonable price. I believe McMark also sells one. While injection control could possibly work with less than a 36-1 trigger, ignition control would never be accurate enough. I am also concerned that a distributor based control would have too much trigger float because of the backlash in the distributor gears. 2. You can definitely use the existing injectors (2 liter), but have them rebuilt and flow tested. I used WitchHunter for this. You can also drive the injectors without resistor packs (which slow their response) by using a peak and hold driver board form JBPerf or DIYAutotune. You will need the flow rate of the injectors at the fuel pressure you decide on and the injector dead-time. I can give you those for my setup but yours may differ. They are not hard to calculate. 3. Once you decide to add ignition control it is almost trivial to get started with this. I used individual GM LS3 ignition coils which can be directly driven by the Megasquirt system. For a start at timing you can duplicate the the timing of the 914 advance curve and then go from there. 4. I tried using the stock CHT sensor - I went through 2 - and finally settled on the one sold by the DubShop. Its based of a GM sensor and is much more consistent. I had a lot of drift with the stock sensors. By the way, once the engine reaches normal operating temperature the CHT has little effect. 5. My throttle position sensor is a lightly used Bosch TPS that I adapted to the stock throttle body using a low tech aluminum plate. You can find this on numerous BMWs at your local junk yard or on ebay for around $30. 6. If you want reliable startup under varying temperatures you will need an idle control valve. I am again using a used Bosch ICV and as with the TPS this can be found on BMWs and others or ebay for $30 - 40. This is a PWM valve, not a stepper based valve. 7. To start tuning you can use the map that TunerStudio generates. You need to set the baseline tune with all TunerStudio Startup/Idle settings off and the engine fully warmed up. Set the idle using the idle adjustment screw on the throttle body. After that you can use the Startup/Idle settings to get a reliable cold start. If you don't do it this way you will chase your tale for weeks (ask me how I know). 8. If you want to do accurate tuning you will need a wide-band AFR meter. I use the Innovate Motorsports MTX-L for this. 9. I mounted the Megasquirt (not Microsquirt) in the rear trunk and have used WeatherPack connectors for all of the wiring. This includes two 22 pin bulkhead connectors into the engine compartment. I built my own mounting plate for the Megasquirt which includes a fuse panel, relays and breakout terminals for much of the wiring. I can build a 914 engine bay wiring harness for you using the Megasquirt standard wiring colors if you make a definite decision on the location of the Microsquirt/Megasquirt and the rest of the components that you will use. That's a quick summary. If you have questions let me know. By the way, on the drive to Medford and back I got near 40 MPG driving at 75 plus MPH. Darryl |
Mblizzard |
Oct 5 2016, 07:48 AM
Post
#3
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Advanced Member Group: Members Posts: 3,033 Joined: 28-January 13 From: Knoxville Tn Member No.: 15,438 Region Association: South East States |
Some comments on my 2 year journey with Megasquirt: 1. Install a crank trigger while you have the engine out of the car. Mario at the DubShop sells the one I used at a very reasonable price. I believe McMark also sells one. While injection control could possibly work with less than a 36-1 trigger, ignition control would never be accurate enough. I am also concerned that a distributor based control would have too much trigger float because of the backlash in the distributor gears. 2. You can definitely use the existing injectors (2 liter), but have them rebuilt and flow tested. I used WitchHunter for this. You can also drive the injectors without resistor packs (which slow their response) by using a peak and hold driver board form JBPerf or DIYAutotune. You will need the flow rate of the injectors at the fuel pressure you decide on and the injector dead-time. I can give you those for my setup but yours may differ. They are not hard to calculate. 3. Once you decide to add ignition control it is almost trivial to get started with this. I used individual GM LS3 ignition coils which can be directly driven by the Megasquirt system. For a start at timing you can duplicate the the timing of the 914 advance curve and then go from there. 4. I tried using the stock CHT sensor - I went through 2 - and finally settled on the one sold by the DubShop. Its based of a GM sensor and is much more consistent. I had a lot of drift with the stock sensors. By the way, once the engine reaches normal operating temperature the CHT has little effect. 5. My throttle position sensor is a lightly used Bosch TPS that I adapted to the stock throttle body using a low tech aluminum plate. You can find this on numerous BMWs at your local junk yard or on ebay for around $30. 6. If you want reliable startup under varying temperatures you will need an idle control valve. I am again using a used Bosch ICV and as with the TPS this can be found on BMWs and others or ebay for $30 - 40. This is a PWM valve, not a stepper based valve. 7. To start tuning you can use the map that TunerStudio generates. You need to set the baseline tune with all TunerStudio Startup/Idle settings off and the engine fully warmed up. Set the idle using the idle adjustment screw on the throttle body. After that you can use the Startup/Idle settings to get a reliable cold start. If you don't do it this way you will chase your tale for weeks (ask me how I know). 8. If you want to do accurate tuning you will need a wide-band AFR meter. I use the Innovate Motorsports MTX-L for this. 9. I mounted the Megasquirt (not Microsquirt) in the rear trunk and have used WeatherPack connectors for all of the wiring. This includes two 22 pin bulkhead connectors into the engine compartment. I built my own mounting plate for the Megasquirt which includes a fuse panel, relays and breakout terminals for much of the wiring. I can build a 914 engine bay wiring harness for you using the Megasquirt standard wiring colors if you make a definite decision on the location of the Microsquirt/Megasquirt and the rest of the components that you will use. That's a quick summary. If you have questions let me know. By the way, on the drive to Medford and back I got near 40 MPG driving at 75 plus MPH. Darryl Got TPS coming from McMark. Hoping to not go the crank trigger rout because I have AV. Looking at the Min Can Sync as an option. I have heard good and bad about use of the Stock CHT. Checking with Mario on the options. The GM NPT threading is not the same as the 10mm x1 stock threading so would you not need an adaptor for that? Like the idea of the peak and hold but I don't have the abilities to build the electronics and the prebuilt ones seem expensive. Had not considered idle control valve. I hoped that the warm up programing in the MicroSquirt would address those issues Seem like that was a wrong guess? Have wideband O2 already installed. As this will be a build in stages I am not sure I cam plan out the locations of everything in advance. But I would love to see some photos of your install for some ideas. Lots more questions to follow! Should be receiving my first batch of parts today. |
jd74914 |
Oct 5 2016, 10:21 AM
Post
#4
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Its alive Group: Members Posts: 4,776 Joined: 16-February 04 From: CT Member No.: 1,659 Region Association: North East States |
Hoping to not go the crank trigger rout because I have AV. Looking at the Min Can Sync as an option. What is AV? The Mini Cam Sync only gives you one pulse for determining engine phasing; for injection you really need to have more resolution. I guess you could technically use it (if the software allows), but you'd only get one trigger every 2 revolutions. Something like this is much better. Just like the mini sync it can be installed without removing the engine. The difference is that it has multiple teeth so you could use it as a replacement crank trigger. I have one and Jarred really did a nice job making it. http://www.914world.com/bbs2/index.php?sho...=247915&hl= |
Mueller |
Oct 6 2016, 10:51 AM
Post
#5
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914 Freak! Group: Members Posts: 17,146 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None |
Hoping to not go the crank trigger rout because I have AV. Looking at the Min Can Sync as an option. What is AV? The Mini Cam Sync only gives you one pulse for determining engine phasing; for injection you really need to have more resolution. I guess you could technically use it (if the software allows), but you'd only get one trigger every 2 revolutions. Something like this is much better. Just like the mini sync it can be installed without removing the engine. The difference is that it has multiple teeth so you could use it as a replacement crank trigger. I have one and Jarred really did a nice job making it. http://www.914world.com/bbs2/index.php?sho...=247915&hl= Wow, that thread brings back some memories! http://www.914world.com/bbs2/index.php?sho...c=24043&hl= If Jarred doesn't have anymore and has no interest in making more , i could whip a few out for you. |
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