Hybrid SHO

[High on Ethanol]

Higher voltage is always better. 4160v motors barely pull any amps to make 500hp. I=E/R
Usually notice this with rc cars, higher voltage battery pack are faster but there are ways around this.

You can change the results by altering things you can control. Usually batteries are limited by size and weight. Same with motors. So it becomes a trade off of power vs time....

 

[stripSHO]

Awesome questions, something I'm working out right now. There are two versions of the Hyper9. One is 62v-132v and the other is 90v-180v. The HV motor likes higher volts back asks for less amps to produce the same output, supposedly. I'm looking to build a pack that is either 85.8-109.2V (93.6v nominal) for the LV motor. Or a pack that is 128.7-163.8V (140.4v nominal) for the HV. I have yet to find any resource from Netgain or any vendor that gives guidance on power output on reduced input voltage. The nominal for the LV is 120v, which I would be about 78ish% of that. For the HV version, the nominal desired is 144v, which my HV pack would be very close to. At 3S3P, on the HV motor, I calculated 2.5min on 500A draw. Help me if I mathed wrong.

Derp I missed the cell count so forget what I said about runtime.

As you contemplate this, just make sure you’re considering the tractive efforts of your rear assembly and the front engine as it relates to vehicle speed, not the torque curves of the motors relative to rpm as you mentioned earlier. One has a gear box, one doesn’t. Not sure of your goals, But you’re not going to accomplish any blistering acceleration gains without selecting a really short ring & pinion set and then you have to be very wary of the motor’s RPM limits. For reference, Tesla’s have a 9.23:1 gear reduction. But; the motors rev up to 18,000 rpm!

Contrary to what you said, I think you’re going to find that this electric motor won’t do much off the line but becomes much more significant as vehicle speed increases, especially if sticking with whatever the factory gear ratio is (please share btw).

Then also consider what the reduced available traction does to the engine’s ability to deliver torque. Might want to see what happens to your 60’ with the driveshaft pulled or rdu clutch disconnected to see what kind of ground the electric axle has to make up. Our engines are already capable of making much more torque off the line than the drivetrain can deliver, and I managed to one wheel peel to a 2.4s 60’ at the track when trying to truly go full send.

Lastly, don’t underestimate the complexity of making the two systems “play nice”. If the motor and engine aren’t relatively in sync then one is going to drag the other. WOT is simple, but great street driveability and efficiency seems like it would take a huge amount of effort.

Sorry for the ramble, I just find this really interesting so I was thinking a lot about it.

 

[skyshadow07]

****, don't apologize. This is the reason I posted it. I'm going to run into a lot of hurdles and I would rather a group help figure them out then just me.
As for the final ratio, I believe it's 4:1. I marked the diff and spun it to get the count but that was about 2 months ago. At 4:1 I would have a wheel speed of 26.55mph @1200rpm, 53.09mph@2400rpm, and 79.64mph@3600rpm. After seeing those numbers and checking the power consumption curve of the motor, I think I'm going to upgrade to a 6kwh battery pack. At that size, I can pull peak power for 4.35 minutes at 3600rpm. That sounds a lot better to account for real world heat/efficiency loss
I have built a few (3 bikes, 2 go karts) electric systems before this but small vehicles. They actually do hit hard at low rpm and dwindle away at high speed. All the projects where non-geared direct drive from motor to axle.
As for reduced traction, if the electric motor side spins then I'll consider a welded diff or a mini spool. If the front end spins and the rear can not help keep traction, I'm screwed.
You're totally right that they would be a nightmare to make sync up under half load or low load. I'm going to build it to be like a shot of nitrous. I just want the electric rear to help off the hit during a pull. In fact, I have considered having it go to half regen when the throttle is not pressed while the system is activated.

 

[High on Ethanol]

You should have peak torque at 1rpm, axle ratio is dangerous because of how fast the torque hits unless you are able ramp it slightly on launch. VFDs save parts in the industry. Lol I saw 2 500hp motors bring a building down from torque on a conveyer belt.

Overall this will be similar to nitrous I'd say

 

[skyshadow07]

I have looked at the controller manual and you can ramp up for traction control and to reduce that slamming effect on the diff and axles.

 

[Ecoboost_xsport]

Probably just a silly piece of input (this thread is making me realize just how dumb/simple I really am, LOL), but JMS makes a connector for our pedal to output that 0-5vdc signal.

https://www.jmschip.com/throttle-position-sensor-wiring-harness-p-gmp2-f-dcx-apps/

It's what I'm using for my BAP, but is a quick plug and play and might be a better 0-5v source vs throttle body or the MAP sensor, for a number of reasons...

But there may be something a bit more accurate you may be looking at as a 0-5v source...just throwing it out there...

 

[skyshadow07]

BRO! ^^ That is awesome! I wanted to pull directly from the pedal instead of the TB.

 

[Ecoboost_xsport]

BRO! ^^ That is awesome! I wanted to pull directly from the pedal instead of the TB.

And if you're curious, here's the actual voltage range of the pedal from AT REST to WOT:

 

[stripSHO]

You definitely don't want to use the TB for a command signal, at least not on a torque/load based ecu.

I get the torque curve of an all electric system. But I also bet none of those bikes or karts were geared for 160 mph. You really need to understand the influence of the transmission and total tractive effort of your current engine in order to manage your expectations and guide your application. I said a tune-only SHO in 1st gear puts out 7-8k lb-ft but that's not even factoring the torque converter, which probably makes it more like 16,000 lb-ft on the starting line. These are rough gross numbers before driveline losses, and hypothetical in the sense that (to my knowledge) nobody is even remotely close to leaving on full power, but you get the idea. Cut these figures in half and they still tower over the proposed ev motor.

So by comparison the gear-multiplied 692 lb-ft this rig would output has no significance. But fast forward to when you're in 4th gear and the trans is only putting out, idk, 1600 lb-ft or so. An extra 692 lb-ft or 120 hp is pretty huge at that point. The question becomes whether this makes economic sense for that sort of power gain. A person looking for something "like nitrous" might be inclined to save $5k-$10k and just get nitrous.

If I get time tonight I'll chart out the force produced vs mph with and without this motor to help everyone visualize what I'm talking about.

 

[High on Ethanol]

You definitely don't want to use the TB for a command signal, at least not on a torque/load based ecu.

I get the torque curve of an all electric system. But I also bet none of those bikes or karts were geared for 160 mph. You really need to understand the influence of the transmission and total tractive effort of your current engine in order to manage your expectations and guide your application. I said a tune-only SHO in 1st gear puts out 7-8k lb-ft but that's not even factoring the torque converter, which probably makes it more like 16,000 lb-ft on the starting line. These are rough gross numbers before driveline losses, and hypothetical in the sense that (to my knowledge) nobody is even remotely close to leaving on full power, but you get the idea. Cut these figures in half and they still tower over the proposed ev motor.

So by comparison the gear-multiplied 692 lb-ft this rig would output has no significance. But fast forward to when you're in 4th gear and the trans is only putting out, idk, 1600 lb-ft or so. An extra 692 lb-ft or 120 hp is pretty huge at that point. The question becomes whether this makes economic sense for that sort of power gain. A person looking for something "like nitrous" might be inclined to save $5k-$10k and just get nitrous.

If I get time tonight I'll chart out the force produced vs mph with and without this motor to help everyone visualize what I'm talking about.

So why tesla so quick without gears?


You are missing some key ingredients.

Electric power is best under load.
Electric has almost no power without load.
Electric is way faster off the line because of its power delivery. Electric is not as good at roll racing because of its power delivery.
Electric suffers almost no drivetrain loss by comparison due to less components.



Now do I think this is the setup to break the records? Most likely it will... Because of the way the stock AWD was limited.
Do I think that it's ideal? No.
Gotta start somewhere.
Personally I'd probably go raptor 3.5 with the custom AWD trans if I wanted to break platform records. Off the shelf parts would easily get you to 750hp at the wheels... Without much effort engine wise. The full time AWD would be amazing.... And the benefits of better gear spread would make it godlike.

But anyways back to the electrical idea.... As an off the line boost it should work but will require tons of trial and error and tuning.

 

[skyshadow07]

StripSHO, I get what you're saying but I think we're missing something. The Porsche 918 uses a electric motor to drive the front wheels that is actually pretty similar in power output to what I'm trying to do. They don't state what the gear ratio is but they do say the motor is single geared, direct drive to the front axle. I don't see Porsche wasting the R&D if the front motor doesn't do anything (relatively speaking). I will agree that maybe I need to increase the gear ratio. I wish I could find what the 918 front axle ratio is.

 

[skyshadow07]

Total cost is looking to be somewhere between $6890-7380.... That gofundme is sounding mighty fine right now haa

 

[stripSHO]

So why tesla so quick without gears?

Already answered. 9.23:1 gear reduction, 18,000 rpm power band. Oh and 960 lb-ft of torque sure as shit doesn't hurt either. It's becoming apparent that I'm the only one NOT missing the key ingredients. If you think this is the secret to a sub 1.5sec 60' you're dreaming.

 

[stripSHO]

StripSHO, I get what you're saying but I think we're missing something. The Porsche 918 uses a electric motor to drive the front wheels that is actually pretty similar in power output to what I'm trying to do. They don't state what the gear ratio is but they do say the motor is single geared, direct drive to the front axle. I don't see Porsche wasting the R&D if the front motor doesn't do anything (relatively speaking). I will agree that maybe I need to increase the gear ratio. I wish I could find what the 918 front axle ratio is.

Yeah, two of them actually. And using just the 281 hp electric powerplant nets a very underwhelming 7 second 0-60. They compliment a high revving naturally aspirated 600 hp primary engine that is undoubtedly an absolute dog at low rpm. That's not a great comparison to our cars that make peak torque at 3000 rpm. And again, what's the RPM range of Porsche's motors?

Look I'm not arguing that you need to put a gearbox on your electric motor. I'm just trying to share what I know because from my amateur perspective you've got it all backwards. This is not going to provide break-yo-neck launching or earth-shattering performance. Hope I'm wrong.

Here ya go:

 

[stripSHO]

Some clarifications on the chart-

rear axle is using Hyper9’s published 144v torque curve and 4:1 gearing.

front axle is using the ECU torque model from my C40 tune and PP 3.16:1 final drive.

The reason I started at 20 mph is because below that the torque converter is stalling and I didn’t want to fabricate torque values out of thin air. Follow the trend though. The hyper9 controller limits voltage at low speed for flat torque to 0 mph.

 

[High on Ethanol]

Already answered. 9.23:1 gear reduction, 18,000 rpm power band. Oh and 960 lb-ft of torque sure as shit doesn't hurt either. It's becoming apparent that I'm the only one NOT missing the key ingredients. If you think this is the secret to a sub 1.5sec 60' you're dreaming.

Never even mentioned 60ft times. So let's just swap to 9.23:1 in the SHO if it is all about the gear ratio.

Do you understand how electric motors work?

The only benefits I was suggesting was higher than factory torque at 1rpm. (the factory diff has clutch which is limited to 150ft lb or so) locked rotor torque is likely even higher than rated value.

Overall not the route I'd take due to cost and complexity.

But I will definitely watch someone else spend money and attempt it.

 

[Ecoboost_xsport]

.

I'm just here for the entertainment value at this point...



Sent from my SM-G965U1 using Tapatalk

 

[stripSHO]

Never even mentioned 60ft times. So let's just swap to 9.23:1 in the SHO if it is all about the gear ratio.

Do you understand how electric motors work?

The only benefits I was suggesting was higher than factory torque at 1rpm. (the factory diff has clutch which is limited to 150ft lb or so) locked rotor torque is likely even higher than rated value.

Overall not the route I'd take due to cost and complexity.

But I will definitely watch someone else spend money and attempt it.

First gear effective ratio in the PP sho is 14.17:1.

I have more practical hands-on experience with 3 phase induction motors than any electrician I know. You typically can't just throw full line voltage from a stop to a motor with a very large inertial load. This is why wye-delta starter panels are a thing. Ever tried using the default v/f pattern on a VFD applied to a very large low power fan? Good luck! You'll notice Hyper9 tapers voltage all the way until 3600 rpm

The "150 lb-ft" myth is just that. IIRC the factory tune asks for something like 550 lb-ft at launch. But that doesn't matter because you have to get past the open differential up front first. I'm quite sure all the tire chirping you hear comes strictly from the driver's front tire.

 

[skyshadow07]

ecoboost_xsport has a good point. Lets all calm down haa.
StripSHo has valid input that can/will be taken into account. I can add a simple 2:1 or 3:1 (whatever:1) reduction gearbox to the motor before the diff. It would require moving the motor up higher in the axle tube. I would say alter the differential ratio but I do not know of any company making ring or pinion gears for our platform. Some things to consider, the faster the motor spins, the more power it consumes... A lot more power. As well, the torque curve begins to fall after 3600rpms. The motor is rated to 8000rpm max but suggested to stay under 7200rpm. If I reduce it before the diff, here some numbers
>No reduction
-1200rpm, 692lb-ft, 29kw consumption, 26.5mph
-3600rpm, 692lb-ft, 59kw consumption, 79.6mph
-7200rpm, 392lb-ft, 101kw consumption, 159.2mph<- Would pull for a long time but not very hard

>2:1 reduction
-1200rpm, 1384lb-ft, 29kw consumption, 13.25mph
-3600rpm, 1384lb-ft, 59kw consumption, 39.8mph
-7200rpm, 784lb-ft, 101kw consumption, 79.6mph <--Pull medium to a semi high speed, must cut at 80mph

>3:1 reduction
-1200rpm, 2076lb-ft, 29kw consumption, 8.8mph
-3600rpm, 2076lb-ft, 59kw consumption, 26.5mph
-7200rpm, 1176lb-ft, 101kw consumption, 53.0mph <-- Pulls hard but has to shut off at 50mph or could over spin

>8.25:1 reduction (tesla model S)
-1200rpm, 5709lb-ft, 29kw consumption, 3.2mph
-3600rpm, 5709lb-ft, 59kw consumption, 9.64mph
-7200rpm, 3234lb-ft, 101kw consumption, 19.29mph <-- Impractical, essentially a tractor

The big thing to remember with gear reduction is you are going to consume more energy to rev higher and the higher it revs the less energy it outputs.

Performance sheet of the motor in the Voltage config close to what I plan is attached if you want ponder and play around with numbers.

 

[High on Ethanol]

Ok.... So I guess you are planning on keeping the gas engine.... Ah **** it I can't even be sarcastic... I'm on vacation all month and I just want to see something in action... I don't care what Lmao.

Someone with a spare rear axle test the clutch holding strength.... I'm not feeling like doing any research or calculations.

I'm a VFD whisperer. 390 motors in the plant, it's fun to mess with the settings and monitor the effects. I'm definitely on board with the Ford hybrids and full electrics.