Has Anybody Slammed their Prius, or Turbo'ed it? What is the freakiest Prius you have ever seen?

Yeah, if it was a Honda or a Subaru and the ECU was already hacked with piggy-back chips via an army of car mod nerds (make bacon & eggs taste better) then lots of things are possible. But a Prius doesn't cater to the racetrack types and the people who do mod their Prius have no ECU hacks other than spoofing. (making cereal taste better with Bacon & Egg improvements). It just doesn't make any sense. Prius have been so thoroughly optimized for fuel efficiency already, there's not much more you can do in terms of improving engine performance.

 

If the ECU is a really such a problem (I doubt that the Prius is an unhackable car) take it out and throw in a stand alone system. Getting +200V BLDC inverters will be a bit expensive, but it's all doable. I still think anyone that put their mind to hotrodding a Prius could figure out a way to get a custom tune without the car going into limp mode every minute.

That's totally incorrect. The fact that it is optimized for fuel efficiency means that there's a lot you can do for improving engine performance. Simply changing it from an Atkinson cycle to an Otto cycle would make a notable difference.

But I do think we can all agree that it doesn't make sense, not so much from a technical standpoint, but from a WHY-ON-EARTH-WOULD-YOU-DO-SUCH-A-THING!! standpoint.

 

I've been seriously thinking about lifting my Prius for a while. It's not easy driving through the hills I live around with a low bearing car, and I also love driving off road.

I do like the size of the second image. If I am successful at fixing the piston rings I'll likely be looking to do this next. I wonder how much a lift kit would affect the MPGs, because it would make for some great long distance trips out into the Nevada deserts. I'd be doing this is on a 2006 project car I bought to fix up and mess with. I'm currently a quarter way done with reconditioning the battery.

 

[it is the middle of the night and I am rambling.]

The mechanical gears in every Toyota/Lexus hybrid have the same ratio. 29% of the torque produced by the engine goes to make electricity on M/G1, 71% goes mechanically to the wheels to help M/G2 propel the car.

Torque helps your car be quick, HP helps it be fast. (in a Prius, top speed is mostly determined by these gear ratios, but if you have 'excess' HP you can fit larger diameter tires/different final drive to go faster.

Back to quick: M/G1 has to oppose the engine for it to add to the mechanical power, so tuning the car to make more torque than M/G1 can oppose * 29% is ineffective. Think of the Hybrid Synergy drive as a 29% tax on your tuning. if you make 10 more ft/lbs of torque only 7 ft/lbs are mechanically getting to the wheels.

And this is what the Australian I linked to discovered, you got a slight increase in performance but your traction battery charged all the time, as M/G1 suddenly was making much more electricity. One use of that electricity is to allow M/G2 to power the car more often, both because there is this M/G1 tax right now and because in the past the M/G1 tax was used to charge the battery.

So if you manage to tune the engine, you may wish to step up the Hybrid Synergy drive to have larger Motor/Generators so the engine power won't exceed M/G1's ability to oppose it, and so M/G2 can make more power, since M/G1 is making more electricity to use.

So perhaps the most effective 'hop up' Idea may be a engine/transaxle swap from a larger hybrid. Also since you plugged in a stock engine from some other Toyota, the stock ECU from it should work fine. Space will be an issue.

A Highlander swap would be 243 HP. 175 Ft/Lbs. 2.5 liter 4. (and 36 MPG)

 

Depends. The Highlander also has weight and aerodynamic disadvantages, so it could get a lot better than 36. If you're not using the peak power, it could be a lot closer to the mileage of a Prius.

 

I wonder how much the M/G2 is also underpowered. It may be possible to "tune it" to put out a bit more power than it does.

On the other hand, I wonder if this problem would lend itself to an electric supercharger. So instead of taxing the exhaust or crankshaft for power to turn the compressor, you'd be using at least part of that extra electricity generated by the M/G1.

Another solution would be to combine this problem with some sort of rear electric drive. Or maybe skirt the whole car and use the extra power to turn a sucker fan and get great traction on curvy tracks.

 

My (feeble) understanding is that M/C2 power output actually exceeds both the Battery and M/G1 electrical output, so M/G 2 is never the limit. Tuning can be done via the final drive. As an example the Gen 3 Prius does 115 MPH at redline, while the same engine/transaxle in a Prius v has a 103 MPH redline as they used different final drive gearing for more low end acceleration. The v is heavier and would have been quite a bit slower. Very few station wagon owners will want to exceed 103 MPH.

The Highlander (and RAV 4) is available with a rear drive unit M/GR.

21:10 minutes in, he admits it is a 67 HP motor, 96 Ft/lbs at the motor. 659 ft/lbs at the wheels.

I did not mention above but swapping a different engine/transaxle will need the matching battery.