MicroSquit Conversion, Giving this a try |
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MicroSquit Conversion, Giving this a try |
Mblizzard |
Oct 3 2016, 07:18 AM
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#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
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#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 |
Porschef |
Oct 4 2016, 07:13 PM
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#3
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How you doin' Group: Members Posts: 2,165 Joined: 7-September 10 From: LawnGuyland Member No.: 12,152 Region Association: North East States |
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Dtjaden |
Oct 4 2016, 08:38 PM
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#4
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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 |
I think you could contact Mario at the DubShop or Mark at Origional Customs. I believe both would provide turnkey systems for the type 4. But without controlling most of the engine parameters it's not easy. The 1.7, 1.8 and 2.0L engines are each different. Then add the variations of differing cams, ignition, intakes, extended engine sizes and 40+ year old parts. If you try to minimize variations by providing all of the components and parts that eliminate commercial risk I'm not sure that many 914 owners would pay for the system.
On a do it yourself basis I probably spent about $2,500 (maybe more). The packaging of the various components would add many hours of labor and support of customers many more so I can't see selling a turnkey system that would include FI and ignition control for under $4,500. On the Medford drive my CHT gauge was not working so I'm not sure of the head temps on that trip. My oil temps stayed in the range of 180 - 220 with the upper end during the drive through the passes on I5 between Redlands, CA and Ashland, OR. I can run on the lean side when not under load. For example light load in the 15's. Under load more like 13 - 13.5. P.S. - my engine is 2056 cc with about 9.2 cr and a Webcam #86 |
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