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> MicroSquit Conversion, Giving this a try
Mblizzard
post Oct 3 2016, 07:18 AM
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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.
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Dtjaden
post Oct 4 2016, 05:44 PM
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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
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Porschef
post Oct 4 2016, 07:13 PM
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QUOTE(Dtjaden @ Oct 4 2016, 07:44 PM) *



By the way, on the drive to Medford and back I got near 40 MPG driving at 75 plus MPH.

Darryl



BOOYAH!! Awesome. And there ain't a plug n' play for dummies like myself? BTW, how were your head temps?
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Posts in this topic
Mblizzard   MicroSquit Conversion   Oct 3 2016, 07:18 AM
76-914   :popcorn:   Oct 3 2016, 07:35 AM
GregAmy   I've been giving this a lot of thought. I...   Oct 3 2016, 08:01 AM
Mblizzard   I've been giving this a lot of thought. I...   Oct 3 2016, 08:08 AM
McMark   I have all the pieces I used on my car. Working o...   Oct 3 2016, 08:03 AM
Mblizzard   I have all the pieces I used on my car. Working ...   Oct 3 2016, 08:05 AM
McMark   :P Done!   Oct 3 2016, 08:07 AM
GregAmy   It will be easy to self wire. However, if you want...   Oct 3 2016, 08:18 AM
Mblizzard   It will be easy to self wire. However, if you wan...   Oct 3 2016, 08:38 AM
plays with cars   Mike, I think you're concern is justified abou...   Oct 3 2016, 09:34 AM
Mblizzard   Still asking questions. A number of people have c...   Oct 3 2016, 11:15 AM
jcd914   Still asking questions. A number of people have ...   Oct 3 2016, 04:50 PM
cgnj   Hi, I thought about about all of these issues whi...   Oct 4 2016, 04:30 AM
Mblizzard   Hi, I thought about about all of these issues wh...   Oct 4 2016, 06:05 AM
JamesM   All sorts of cool stuff http://www.thedubshop.net...   Oct 3 2016, 11:53 AM
jd74914   Does the Dakota CHT gauge have any analog (voltage...   Oct 4 2016, 06:19 AM
Mblizzard   Does the Dakota CHT gauge have any analog (voltag...   Oct 4 2016, 11:01 AM
McMark   CHT Group Buy from Mark Whitesell Never had a gro...   Oct 4 2016, 07:16 AM
Mblizzard   CHT Group Buy from Mark Whitesell Never had a gr...   Oct 4 2016, 08:18 AM
Mark Henry   If you use the stock 914 injectors (low impedance)...   Oct 4 2016, 03:20 PM
Mblizzard   If you use the stock 914 injectors (low impedance...   Oct 4 2016, 05:36 PM
Dtjaden   Some comments on my 2 year journey with Megasquirt...   Oct 4 2016, 05:44 PM
Porschef   By the way, on the drive to Medford and back I ...   Oct 4 2016, 07:13 PM
Dtjaden   I think you could contact Mario at the DubShop or ...   Oct 4 2016, 08:38 PM
Mblizzard   Some comments on my 2 year journey with Megasquir...   Oct 5 2016, 07:48 AM
Dtjaden   The DubShop CHT sensor is installed under one of t...   Oct 5 2016, 09:10 AM
Mblizzard   The DubShop CHT sensor is installed under one of ...   Oct 5 2016, 09:40 AM
JamesM   [quote name='Dtjaden' post='2407555' date='Oct 5 ...   Oct 7 2016, 02:17 PM
jd74914   Hoping to not go the crank trigger rout because I...   Oct 5 2016, 10:21 AM
Mblizzard   Hoping to not go the crank trigger rout because ...   Oct 5 2016, 10:58 AM
cgnj   [quote name='jd74914' post='2407580' date='Oct 5 ...   Oct 5 2016, 11:35 AM
N_Jay   . . . .Crank position sensor in distributor will...   Oct 5 2016, 12:11 PM
Mblizzard   Hoping to not go the crank trigger rout because ...   Oct 5 2016, 11:01 AM
Mueller   [quote name='Mblizzard' post='2407513' date='Oct ...   Oct 6 2016, 10:51 AM
Mblizzard   [quote name='Mblizzard' post='2407513' date='Oct...   Oct 6 2016, 11:25 AM
cgnj   9. I mounted the Megasquirt (not Microsquirt) in...   Oct 5 2016, 11:44 AM
porsche913b_sp   :popcorn:   Oct 4 2016, 06:18 PM
jd74914   Oops, just read your more recent post and saw that...   Oct 5 2016, 10:30 AM
Mark Henry   Oops, just read your more recent post and saw tha...   Oct 5 2016, 12:48 PM
Mblizzard   Oops, just read your more recent post and saw th...   Oct 5 2016, 01:13 PM
cgnj   This is the Dubshop cam position sensor $155....   Oct 5 2016, 02:04 PM
Mblizzard   This is the Dubshop cam position sensor $155...   Oct 5 2016, 02:27 PM
Dtjaden   [quote name='cgnj' post='2407689' date='Oct 5 201...   Oct 5 2016, 03:52 PM
Mark Henry   Yep, I'm just saying don't get hung up on ...   Oct 5 2016, 01:20 PM
Mblizzard   First box of goodies!   Oct 5 2016, 04:49 PM
Dtjaden   For anyone looking for a packaged solution for und...   Oct 5 2016, 11:33 PM
McMark   I don't think MicroSquirt does sequential inje...   Oct 6 2016, 07:37 AM
Mblizzard   I don't think MicroSquirt does sequential inj...   Oct 6 2016, 10:38 AM
aircooledtechguy   I own, run and have installed virtually every prod...   Oct 6 2016, 10:40 PM
Dtjaden   I own, run and have installed virtually every pro...   Oct 6 2016, 10:53 PM
Mblizzard   I own, run and have installed virtually every pro...   Oct 7 2016, 08:43 AM
N_Jay   I think the crank trigger would be better as well...   Oct 7 2016, 08:57 AM
Mblizzard   I think the crank trigger would be better as wel...   Oct 7 2016, 09:10 AM
cgnj   [quote name='N_Jay' post='2408476' date='Oct 7 20...   Oct 7 2016, 10:03 AM
cgnj   I think the crank trigger would be better as wel...   Oct 7 2016, 10:13 AM
Java2570   I've been talking to Mario @ Dubshop about doi...   Oct 7 2016, 07:44 AM
Mblizzard   Ok let’s be clear. I am not no wiring expert...   Oct 7 2016, 09:59 AM
N_Jay   Ok let’s be clear. I am not no wiring expert...   Oct 7 2016, 10:03 AM
Mblizzard   Ok let’s be clear. I am not no wiring expert...   Oct 7 2016, 11:32 AM
N_Jay   [quote name='N_Jay' post='2408496' date='Oct 7 20...   Oct 7 2016, 11:46 AM
Dtjaden   [quote name='Mblizzard' post='2408534' date='Oct ...   Oct 7 2016, 12:28 PM
N_Jay   [quote name='Mblizzard' post='2408534' date='Oct...   Oct 7 2016, 01:19 PM
Dtjaden   The crankshaft trigger wheel, either the DubShop...   Oct 7 2016, 11:13 AM
N_Jay   Maybe I am not picturing it correctly, but how doe...   Oct 7 2016, 11:20 AM
jd74914   Maybe I am not picturing it correctly, but how do...   Oct 7 2016, 11:26 AM
Mblizzard   Maybe I am not picturing it correctly, but how d...   Oct 7 2016, 11:31 AM
N_Jay   Maybe I am not picturing it correctly, but how d...   Oct 7 2016, 11:59 AM
cgnj   Maybe I am not picturing it correctly, but how do...   Oct 7 2016, 11:59 AM
jcd914   From a MegaSquirt manual: "Injectors are eith...   Oct 7 2016, 01:24 PM
Mblizzard   From a MegaSquirt manual: "Injectors are eit...   Oct 7 2016, 04:12 PM
Dtjaden   I appreciate all of the intelectual comments. I am...   Oct 7 2016, 02:12 PM
N_Jay   I appreciate all of the intelectual comments. I a...   Oct 7 2016, 02:57 PM
Mark Henry   I appreciate all of the intelectual comments. I ...   Oct 7 2016, 03:57 PM
N_Jay   I see where the manual talks about the resistors...   Oct 8 2016, 07:13 AM
Dtjaden   I appreciate all of the intelectual comments. I ...   Oct 7 2016, 05:10 PM
N_Jay   [quote name='N_Jay' post='2408588' date='Oct 7 20...   Oct 8 2016, 07:20 AM
Mblizzard   I appreciate all of the intelectual comments. I a...   Oct 7 2016, 04:54 PM
Dtjaden   I appreciate all of the intelectual comments. I ...   Oct 7 2016, 05:11 PM
Mblizzard   [quote name='Mblizzard' post='2408640' date='Oct ...   Oct 7 2016, 05:25 PM
Mblizzard   [quote name='Mblizzard' post='2408640' date='Oct...   Oct 8 2016, 06:41 AM
N_Jay   Ok still thinking about the placement of the res...   Oct 8 2016, 07:30 AM
Dtjaden   Blizzard - what are you doing for A/C on your car....   Oct 7 2016, 05:13 PM
Mblizzard   Blizzard - what are you doing for A/C on your car...   Oct 7 2016, 05:28 PM
Phoenix914   Since my engine is out, I'm thinking it would ...   Oct 8 2016, 08:37 AM
stugray   Since my engine is out, I'm thinking it would...   Oct 8 2016, 09:15 AM
Dtjaden   Since my engine is out, I'm thinking it woul...   Oct 8 2016, 09:31 AM
N_Jay   And having a capacitor installed across the coi...   Oct 8 2016, 01:12 PM
Phoenix914   Since my engine is out, I'm thinking it woul...   Oct 8 2016, 01:17 PM
Mark Henry   You guys are really over thinking this stuff....   Oct 8 2016, 09:19 AM
stugray   You guys are really over thinking this stuff.... ...   Oct 8 2016, 09:31 AM
Dtjaden   Good Job. I used to take my 914 on long trips re...   Oct 8 2016, 09:29 AM
McMark   Seriously. Low impedance injectors need a resisto...   Oct 8 2016, 10:56 AM
Mblizzard   Seriously. Low impedance injectors need a resist...   Oct 8 2016, 01:10 PM
Mblizzard   I know some of the discussion may seem trivial to ...   Oct 8 2016, 01:10 PM
jcd914   I know some of the discussion may seem trivial to...   Oct 8 2016, 03:08 PM
cgnj   Hi, waited till I had something of value to add.Gr...   Oct 10 2016, 11:50 AM
Mblizzard   Hi, waited till I had something of value to add.G...   Oct 10 2016, 12:23 PM
N_Jay   Is anyone using a MAF sensor or an O2 sensor with ...   Oct 10 2016, 04:54 PM
Mueller   Is anyone using a MAF sensor or an O2 sensor with...   Oct 10 2016, 10:04 PM
jd74914   [quote name='N_Jay' post='2409688' date='Oct 10 2...   Oct 11 2016, 05:57 AM
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