Racing Prius?

[slvr_phoenix]

To start off, if you're not going to contribute positively to this thread, please don't post. I don't need to hear anything about why messing with the factory delivered setup is a crime against humanity or any such.

The concept: To show the world that a hybrid vehicle that still gets good gas mileage can also move. It'd start out in autocross racing because I think a Prius would do well there.

Of course I don't have a million dollars to drop into my Prius to do this all at once, but the plan goes as thus:

Step 1 ) This one is easy because I know what I need exists and will work. All of the Tom's stiffening mods. TRD Sportivo suspension mod. Motegi Traklite 17 inch rims (14lbs each) with 205 or 215 wide racing tires. This should give the Prius a lot better handling, maybe even enough to avoid the traction control dropout problems.

Step 2 ) Brakes! Can better disk brakes be put into a Prius? Does anyone know of any? With links? (No arguments about how regenerative braking makes it pointless as in a racing environment you're going to see the real brakes actually get used a lot more often.)

Step 3 ) Horsepower? The Prius with its high torque will do well in autocross, but to squeeze even more horsepower out of a Prius would be helpful. With such low horsepower in play, even a 5 or 10 hp addition could make a world of difference.

Step 4 ) Superbattery in the trunk to run 'in the green' for an extended period of time. There have been plenty of plug-in concepts that use this to improve the Prius fuel efficiency. But this should also improve the performance. I'd prefer not to use lead acid batteries for a number of reasons, but I'm not sure what a suitable better option would be as all of the new battery technologies never seem to come out. Has anyone heard of any real definitive deliverable yet?

Again, please keep this thread clean. It's not about your average drive for a Prius. (Though keeping it street-legal is still intended.) It's about showing the world that better economy doesn't have to mean bad performance. It's about getting people talking. Did you see that Prius race?! I was amazed! A Prius? And I hear it still gets 45MPG! You don't even have to win to get people's attention. So please help me. What can I do to make the best of it?

[hyo silver]

Hey, it's your car. If you're thinking of racing it, check out what modifications are allowed for whatever class the Prius fits into. Stiffening the chassis sounds like a good place to start. As for brakes, you could try stainless lines and see what fits from the Toyota or TRD catalogues in the way of bigger discs and calipers. The land speed record car used an Echo engine, so an engine swap may be the way to get more power. Adding extra batteries to the trunk shouldn't be a huge problem, though you may need to reprogram some software for everything to work smoothly. Good luck!

[jdenenberg]

<div class='quotetop'>QUOTE(Silver Phoenix @ Jul 4 2007, 02:59 PM) [snapback]473014[/snapback]</div>

[color=#FF0000]Step 3 ) Horsepower? The Prius with its high torque will do well in autocross, but to squeeze even more horsepower out of a Prius would be helpful. With such low horsepower in play, even a 5 or 10 hp addition could make a world of difference.

There was an article reporting the addition of a turbocharger to an early Prius. It helped and a 5 lb boost worked out (more can cause error flags). It was not an easy adaptation.

I also saw a remote install turbocharger (It can be mounted anywhere on the car) that may deal with the space limitations in your Prius engine compartment. Good luck.

JeffD

[bobdavisnpf]

Endless has Prius racing calipers in development:

Tom's has performance pads for the stock calipers, I think.

Tom's also has a performance muffler.

K&N has a new replacement air filter assembly:
http://www.knfilters.com/news/news.aspx?ID=526
They say it's a lifetime washable element and that it improves performance and mpg.

After adding all the Tom's braces and the TRD Sportivo suspension kit, you'll probably want to get in ot the group-buy for the all-around skirt package.

For tires & wheels you may want to go more aggressive than 205's. I think a set of 235's on 17/7.5 inch rims would be minimal. 245's on 18/8's would probably require 1/2" to 1" spacers but I think would give you much better racing stability. Going to racing slicks or to UHP summer tires is a must.

A magnetic oilpan plug would help keep the engine clean. A thinner oil and a fast-flow oil filter would help too. Finding a ATF radiator might be a good idea, along with checking out better transmission fluids for racing type operation.

Then, of course, there's always the turbocharger - don't know who has done this - and Nitrous Oxide...

[apriusfan]

Unless you are wanting to start some sort of green autocross category, you are going to have to compete against MINIs. Even the N.A. MINI is going to be a serious challenge to overcome. Things like lower overall weight, multi-link rear suspension, chassis rigidity, large selection of big brake options (up to 13 inch rotor diameter), all manner of handling options (shocks, springs, sway bars, etc.) and the like are what you are up against. Horses for courses....

[bobdavisnpf]

<div class='quotetop'>QUOTE(apriusfan @ Jul 4 2007, 10:35 PM) [snapback]473348[/snapback]</div>

Unless you are wanting to start some sort of green autocross category, you are going to have to compete against MINIs. Even the N.A. MINI is going to be a serious challenge to overcome. Things like lower overall weight, multi-link rear suspension, chassis rigidity, large selection of big brake options (up to 13 inch rotor diameter), all manner of handling options (shocks, springs, sway bars, etc.) and the like are what you are up against. Horses for courses....
[/b]

If the prius can make it onto the track at all, it'd be a win. Once we're on the track, we can start talk of a green category... maybe requiring a PZEV emissions threshold and test pre-race... I understand other races have pre-race inspections for all sorts of things, from wing and fender positions to fuel composition to exhaust manifold volumes...
Besides, even Nascar is tipping its hat to the environment: unleaded fuel is phased in as a requirement this year.

[apriusfan]

<div class='quotetop'>QUOTE(bobdavisnpf @ Jul 5 2007, 08:04 AM) [snapback]473454[/snapback]</div>

If the prius can make it onto the track at all, it'd be a win. Once we're on the track, we can start talk of a green category... maybe requiring a PZEV emissions threshold and test pre-race... I understand other races have pre-race inspections for all sorts of things, from wing and fender positions to fuel composition to exhaust manifold volumes...
Besides, even Nascar is tipping its hat to the environment: unleaded fuel is phased in as a requirement this year.
[/b]

That they do (have inspections for category conformance). It would be possible to tweak a Prius for competing against other Hybrids and personally, that would be an interesting race to watch. But a general autocrosser the Prius is not.

[subarutoo]

I autocross a Subaru Impreza that is modded to STS class. A couple of evasive highway moves in the Prius surprised me with the handling (in a good way). As for weight, the Impreza and Prius are about the same. Where the Prius has 295 ft.lbs. torque and oppressive traction control, the Impreza has 165 lbs torque and AWD. In straight line accel, I've beaten an Impreza similar to mine, at last up to legal speed limit. Off the line it's great. For autocross Prius needs more roll stiffness, less understeer, and more tire. It might be a fun project, but I wouldn't clear off the trophy case just yet. If there is enough interest for a Hybrid class, it might be worth it, but there are too many better suited cars out there now to be competitive. Don't sweat the brakes too much. I think the Prius brakes are just fine for autocross. I love my commuter Prius, and I love my autocross Impreza. Horses for courses.

[jweale]

I just recently noticed that Sigma Automotive's Prius page has a picture of a Prius labeled "Solo2 F Street." I would think running down the goods on that would be a good start. If you do, let me know - a quick google turned up nothing for me. I'd love to take a Prius (just ordered a touring model last weekend) autocrossing rather than my old '89 Porsche 944 turbo. I need all the excuses I can get...

A Honda Insight embarassed a lot of people in the SF Bay area region for a while. Very lightweight car and a good driver posted some decent times, as long as he started with a fully charged battery. It was really apparent when he ran out of amps during a run. Eventually the driver sold it and moved on, since while he did amazingly well it seemed the car couldn't crack the top ranks.

[Pinto Girl]

The Prius' simple suspension and high center of gravity will always work against you, especially in competition...I've considered going down just this road (do a search of previous topics).

Get rid of the Atkinson Cycle mill if you can. There was that turbo Classic but even the folks who built it said that it was a difficult project. There was also the Prius GT, that had more HP but, again, was an Otto. Again, I don't know how the top end of the engine was modified to work with the PSD, etc...but it was a factory effort.

Chassis-wise, there are all sorts of TOM's braces. Brake-wise, the Prius doesn't seem to use the stock brakes that much, even in aggressive driving; why you'd actually need those four-pot calipers designed to dissipate loads of additional energy, I honestly don't know.

The tires are also too small, as are the wheels; the discs are also of a small diameter...and of course, the rears are drums, so brake balance isn't so good. Then there's the feeling-less electric steering, and the traction control, which cuts engine power when a wheel even thinks about slipping...

I love my car, and I flog it at regular intervals (the TRD suspension and other things help a bit)...but it's no Porsche 993 (which I came out of) and never will be. Without its own category, I don't think it has a chance. Too many weird systems designed for economy, not performance.

Good luck to you. I think (but hope I'm wrong) that you'll find that this project will turn out to be more expensive than you'd suspect, and the returns might not be as substantial as you'd like.

Let us know how you do...at this point, I'd like to find a salvaged Pri, fire up the torch, and drop in a smallblock V8...