What brushless motors are being chosen?

If you have some interest in Fieros, check out the tech forum on Fiero.nl. Lots of interesting stuff.

I own four Fieros and am looking to downsize:
1984 - 1992 GM Quad 4 2.3L Quad 4 DOHC 190 HP
1986 - original 2.8L V-6
1988 - 1992 Cadillac 4.9L V-8 200 HP
1988 - 1994 Buick 3800 S/C M62 Eaton - 225 HP M62

For me supercharging the 1986 is more about a learning project. I like the torque at low-mid rpm that a roots blower gives. For me that's one of the attractions of the electric supercharger. DynoSim5 says that the 2.8L with 10 psi of boost at 2000 rpm makes less than 150 ft-lbs of torque and less than 250 ft-lbs at 5000 rpm. These don't seem like scary numbers. People have turboed the stock 2.8L with 10 psi of boost reliably. I don't see why I should be scared of low rpm boost? Is it getting the ignition timing map right? The fuel map should not be a problem.
 
I've blown up 2 APD ESCs and no MGM ESCs. And the VESC had major issues at high eRPM.
How about the Hobbywing Max4 ESC? Did you blow that up too or has that stood the test of time? Maybe I fell under the halo effect of the blog title "holy grail". Mine Hobbywing Max4 was just delivered yesterday and still has the plastic wrapper on it. Is it a good bet for delivering something in the Torqamp 5KW realm (paired with a Castle 1721)? That is the direction I am heading. Although I love the sounds of the LMT motor and MGM ESC, it is just soo pricey. I am hoping to put together a system in the $1000 realm.
If you could get 200hp n/a out of your engine
That is exactly what I am shooting for with my 4 cylinder 2 liter Opel GT!

you really don't need blow off valves…you can simply control the electric supercharger.
That is what I have been thinking and pondering. I built a modern fuel injection system for my car and have a fully programmable Holley Terminator X stand alone ECU. I may be able to add a table for boost as a function of RPM and have the Holley just pin out the appropriate PWM signal for boost. I that doesn't pan out, there is always aduino.
 
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For me supercharging the 1986 is more about a learning project. I like the torque at low-mid rpm that a roots blower gives. For me that's one of the attractions of the electric supercharger. And usually there is no replacement for displacement (of which I have little with 2.0 liter, originally 1.9 liter Opel 4 cylinder), unless you have boost to get more air and better breathing. So, I am all about more torque down low. In fact, I think that is the positioning of the TORQAMP. It seems more about torque down low than about increasing power at high RPMS. But maybe that is just an artifact of having only a single sized offering and the power systems being so expensive today.
I am after low RPM torque too. High RPM horsepower is about ability to sustain a high speed. For me torque is about acceleration
I don't see why I should be scared of low rpm boost? Is it getting the ignition timing map right? The fuel map should not be a problem.
I am planning to back off on my timing significantly at first and perhaps run a tad bit richer on my target Air Fuel Ratio. I will also reprogram my Holley Handheld touch screen to display boost in the center. Other than that, I am not planning on making many changes.
 
Low rpm boost will blow up pistons. I have a collection of pistons to prove it, and have even cracked a block (SBF) down the middle as a result. What will happen is your tuning window gets real small, because your cylinder pressure gets really high. RPM is easier on parts (up to a point, of course - but look at the redline of the new Z06). Also, most hybrids are going to smaller electric motors geared down more for similar reasons (well, there are other reasons too, but the trend is there).

Just for laughs:
PistonFailure.jpg

PistonCU.jpg
Crack1.jpg
Crack2.jpg
3Pistons.jpg
I have more, but you get the point. I just like looking at all the money I've wasted through the years by trying to outsmart myself.
 
Low rpm boost will blow up pistons. I have a collection of pistons to prove it, and have even cracked a block (SBF) down the middle as a result. What will happen is your tuning window gets real small, because your cylinder pressure gets really high.
Thanks for sharing, I’d like to understand the potential pitfalls better. So, how much boost did you have that blew up pistons? And what was the compression ratio of the engine? Folks who are building opel engines had similar problem when using mismatched camshaft. The cylinder pressures would build too fast leading to a lot of pre ignition which was the culprit that would break the ring lands off the pistons.

So do you thing the problem was pre ignition? If that is the case, I can just dial down the timing as a function of boost. Or do you think maybe it was extra heat from cramming in more air and fuel that cast pistons (vs forged or billet pistons) could not handle? Is that why you are going after methanol injection for more cooling to get more timing without pre ignition?

I currently have about 8.5:1 compression and want to run 7PSI or so of boost even at low RPMs (starting at maybe 2,000). On the engine I am building, I may custom grind the cam to avoid building pressure too fast.
 
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I did some runs with DynoSim5 to look at cylinder pressures. Mind you I made some assumptions on the cam specs to match a baseline N/A model to advertised HP for the Opel engine. Here are the gross indicated cylinder pressures in psig. These are the average for the compression and power strokes:

RPM N/A 7PSI boost
2000 161 229
3000 181 242
4000 179 228
5000 144 196

I don't know if the boosted values are reasonable for this engine. And maybe the average numbers don't tell the whole story. Could be that the peak to average number is greater at low RPM.

Wallace Racing has a dynamic compression ratio calculator including boost. The timing of intake valve closing ABDC is a critical value. Assuming 58 degrees, their calculator predicted an effective compression ratio with 7 psi of boost of 10.3:1. So probably need at least 93 octane gas and maybe some MMT octane booster. Alternatively there is E85. Some of the guys in the Fiero world are running E85 for high performance street engines.

If cam changes are being considered, I think that purchasing DynoSim5 would be very useful. It's only $70. I don't have extensive experience with it but I have been able to build models that seem to match the published specs for various engines.

I do have a 3800 supercharged engine with an Eaton M62 blower. It is 8.5:1 compression and is happy with 93 octane. It makes about 7 psi of boost at 3500 rpm.
 
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Running high boost at low RPM will not damage the engine if it is mapped correctly i.e both the ignition and fuelling are correct. When I used to map highly boosted rally engines many years ago I remember that the ignition timing was around TDC for borderline knock. If there is a possibility of knock then you really need a knock sensor correctly tuned (I currently use one on my engine and it runs in permanent closed loop knock control)
 
For a starting point on my GM 2.8L V-6, I am going to use the ECM from an 1989 GM 3.1 V-6 turbo. For comparison here is a comparison of timing for a 3.1 N/A at 100 kPa manifold pressure and a 3.1 turbo at 130 kPa (4.3 psi of boost):

RPM N/A Turbo
400 17.9 17.9
600 17.9 17.9
800 17.9 17.9
1000 17.9 17.9
1200 17.9 17.9
1400 17.9 9.8
1600 21.1 9.8
1800 21.1 12.0
2000 22.1 12.0
2200 23.9 12.0
2400 23.9 12.0
2800 23.9 14.1
3200 23.9 15.1
3600 23.9 15.1
4000 23.9 15.1
4400 23.9 15.1
4800 28.1 15.1

I think these don't include a few degrees of base timing from setting the distributor. With fast burn heads even less timing would be necessary to achieve best torque. The 3.1 turbo ECM does use a knock sensor with tunable knock retard.
 
Running high boost at low RPM will not damage the engine if it is mapped correctly i.e both the ignition and fuelling are correct. When I used to map highly boosted rally engines many years ago I remember that the ignition timing was around TDC for borderline knock. If there is a possibility of knock then you really need a knock sensor correctly tuned (I currently use one on my engine and it runs in permanent closed loop knock control)
Cool, did your engine come with a knock sensor or did you add one? If after market, do you have any guidance? I have a spot to plug it in on my Holley Terminator X and would love to enable the function for the ECU to be able to take out timing if there is any knock. Then I can use that timing correction data to map the new timing table.
 
GTHound, I have .bin files for 1989 GM 2.0L turbo (LT3), 1989 GM 3.1L turbo (LG5) and 1995 GM 3300 S/C (L67). The LT3 engine is a SOHC designed by Opel. I can scan in the 3D timing tables for these engines and either email or post them here. Let me know if you are interested.
 
Cool, did your engine come with a knock sensor or did you add one? If after market, do you have any guidance? I have a spot to plug it in on my Holley Terminator X and would love to enable the function for the ECU to be able to take out timing if there is any knock. Then I can use that timing correction data to map the new timing table.
I fitted my own one however the sensor itself will not do the job unless it is correctly calibrated to your engine using the code in the ecu you have. I would speak to the manufacturers of the ecu about what sensor they used to confirm the functionality of the code , if indeed they did at all. Fundamentally any OEM acoustic knock sensor will work if calibrated to your engine correctly.
 
From what I know about GM knock sensors some have standalone electronics and some have the electronics in the ECM/PCM. The electronics are engine specific.
 
From what I know about GM knock sensors some have standalone electronics and some have the electronics in the ECM/PCM. The electronics are engine specific.
I use something like this which is effectively a tuned accelerometer with no amplification or filtering. The ECU or additional knock control circuitry does the rest.
 
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