Wow good work!

 

 

Why not buy a proper light weight sports car like a Caterham ?

 

Caterham cars don't appeal to me at all.

I have always loved WRC, so the Toyota GR Yaris ticks a lot of boxes for me; it has a proper roof for starters, and it's four-wheel drive and, as such, fast in all weather; it was developed by Tommi Makinen and the Toyota WRC team. It also has a 10-year road and track day warranty, and clutch aside, it should be reliable.

 

From my perspective, Toyota designed the GR Yaris chassis primarily for motorsport, subsequently incorporating an audio system, rear seats, cupholders, and carpets to appeal to a broader audience.

By removing these everyday features, I can more fully appreciate the efforts of Tommi Makinen and the Toyota WRC team. Although it's £800,000 short of being a full-fledged WRC, the further I pare down the car, the deeper I can immerse myself in the WRC experience.

My plan is to remove or strip away non-essential features from the GR Yaris to get closer to the pure motorsport experience that the car was originally designed for.

 

Completely agree, have done similar. I’m 1193kg with 1/3rd tank of fuel. I agree the car feels light in the back, still stable however. I put an MT carbon wing, that fixed it, Ohlins also helped.
My Ti wheel nuts are 17 grams each, have saved 1020 grams, but conical nuts.
Have added GR Yaris under brace and Carbing Ti strut brace, RSI carbon rear tower brace. It’s worth it.
4th gear midrange feels like 3rd gear to me.
Eventuri and Yashio turbo back Ti. No tune as yet

 

Remember to have a Poo before you go back out on track. Every reduced gram of weight helps

Seriously though. That's dedication right there.

 

Remember to have a Poo before you go back out on track. Every reduced gram of weight helps helps

Seriously though. That's dedication right there.

Haha, that's some solid advice! I'll be sure to "lighten the load" before hitting the track. 🏎💨💩😂

On the topic of weight reduction, I'm currently 20 kg overweight, so there's definitely room for improvement there, but it's way more fun to strip the car down instead! 😂

 

Rally2 car would be fun..

 

Yes, it would be incredible; I believe the Rally 2 car will be approx £160K and worth every penny!

 

I think the best weight saving and performance mod, are a set of aftermarket brake discs. Saving of 1.8kg per wheel. Total 7.2kg of unsprung weight!!!!

 

This and a light weight battery.

 

How noticeable is the 80kg saving whilst driving? Have you taken it on track?

 

Yes, the car performs better in every aspect. Acceleration is quicker, braking is improved, and cornering feels more stable. I haven't had a chance to take it on the track yet since the weight reduction, but I plan to this summer. Although it's faster, the interior noise has increased significantly, which I personally enjoy. The turbo swoosh, for instance, is much more pronounced.

Around 10 kg has been removed from the roof alone. Removing the vinyl wrap (0.5 kg) and the shark antenna (0.3 kg) together accounted for almost a kilo of weight reduction at 0.8 kg.

During the carpet removal process, I had to remove the large plastic trim around the gear knob and handbrake, as well as the glove box and its mounting bracket. These parts together weighed around 10 kg. However, the buttons, USB ports, and 12v socket were left loose, and I missed having a glove box and cup holder, so I decided to reinstall them.

For track days, I plan to remove the 20 kg passenger seat along with the glove box and its bracket. This should result in a total weight reduction of approximately 100 kg.

To further reduce weight by another 45 kg, I might consider installing a titanium exhaust (-10 kg), a lightweight clutch and single mass flywheel (-10 kg), titanium wheel nuts (-1 kg), a Sparco seat without rails (-10 kg), a Sparco steering wheel (-3 kg), lightweight brake discs (-7.2 kg), a carbon fiber bonnet (-2 kg), and carbon fiber door cards (-2 kg).

I plan to add an FIA roll cage in the future, which will add approx 45 kg.


Standard Weight 1,280 kg Toyota GR Yaris:

European market:

Power: 257 hp (192 kW)
Weight: 1,280 kg (2,822 lbs)
Power-to-weight ratio: 257 hp / 1,280 kg ≈ 0.2008 hp/kg or 200.8 hp/tonne

Japanese market:

Power: 268 hp (200 kW)
Weight: 1,280 kg (2,822 lbs)
Power-to-weight ratio: 268 hp / 1,280 kg ≈ 0.2094 hp/kg or 209.4 hp/tonne

...

Toyota GR Yaris (-77 kg) 1,203 kg:

European market:

Original power-to-weight ratio: 200.8 hp/tonne
New power-to-weight ratio (77 kg reduction): 213.6 hp/tonne

Percentage increase: ((213.6 - 200.8) / 200.8) * 100 ≈ 6.38%

Japanese market:

Original power-to-weight ratio: 209.4 hp/tonne
New power-to-weight ratio (77 kg reduction): 222.8 hp/tonne

Percentage increase: ((222.8 - 209.4) / 209.4) * 100 ≈ 6.39%

With a 77 kg reduction in weight, the power-to-weight ratio increases by approximately 6.38% for the European market version and 6.39% for the Japanese market version.

...

Toyota GR Yaris (-100 kg) 1,180 kg:

European market:

Original power-to-weight ratio: 200.8 hp/tonne
New power-to-weight ratio (100 kg reduction): 217.8 hp/tonne

Percentage increase: ((217.8 - 200.8) / 200.8) * 100 ≈ 8.47%

Japanese market:

Original power-to-weight ratio: 209.4 hp/tonne
New power-to-weight ratio (100 kg reduction): 227.1 hp/tonne

Percentage increase: ((227.1 - 209.4) / 209.4) * 100 ≈ 8.45%

With a 100 kg reduction in weight, the power-to-weight ratio increases by approximately 8.47% for the European market version and 8.45% for the Japanese market version.

 

I don't think it would add up to 80kg. Would be interested to know some accurate weights, the rear seats certainly don't feel like 30kg but I've not measured them either.

 

You were right about the rear seats, so I have updated the total weight reduction to approximately 77 kg.

 

I just went for a set of Girodiscs.
Alloy centers hence 1.8 kg lighter.
I think EBC do a nice set now? I bought mine a while ago when there were little choices.

 

trackparts.ch weighed some of the parts they removed, so I will adjust the weights as follows to bring the estimated weight reduction to approx 77 kg:

1. Engine cover approx 1.5 kg
2. Battery replaced approx 18 kg (Replaced with 2 kg Deadweight Industries Tonge 200)
3. A, B, and C pillars approx 3 kg
4. Headlining approx 3 kg
5. Headlining wiring looms with lights, microphones, and alarm senor approx 1.5 kg
6. Audio system - head unit; amplifier; front speakers; brackets; bolts; and plastic trim pieces approx 3.6 kg
7. Rear seats; rear seatbelts; seat mounting brackets; rear speakers and brackets; bolts; parcel shelf; boot floor; polystyrene floor molds; tow eyes; breakdown kit; tyre repair kit 33.1 kg
8. Floor mat set approx 1.5 kg
9. Capet approx 3 kg
10. Carpet sound deadening approx 3 kg
11. Carbon vinyl roof wrap and shark fin antenna 0.8 kg
12. Misilanous trim pieces, brackets, and bolts approx 5 kg

GR Yaris Tracktool Umbau

GR Yaris Felgen, GR Yaris Recaro, GR Yaris Bremsen, GR Yaris Tuning

trackparts.ch

 

I wonder if we will ever get any clarity with Japan getting 10bhp extra on their standard mapped cars... it's odd they didn't make them all the same!

 

Isn't it because they don't fit an OPF in the Japanese spec car?

 

On track tyre noise increases quite a bit with the standard car one you get some pick up on the tyres. Stripped out it must get really loud.

 

That's why I deleted the audio system as it's pretty pointless now with all of the noise the car makes 😂

 

Yes, identical part from opf/gpf, however you choose to name it.

Do you think the GR Corolla engine is different? Sure it has some different exhaust valve springs and a few part number differences but it's rated 300hp because it's also always "opf delete" config (not sold in the EU which is the only market worldwide with petrol particulate filters) and turbo pressure of 1.5 bar stock = there's the 300hp on any car.

 

Yep rumor has it that this standard engine has about 10% more boost (hence your 1.5 bar), no OPF/GPF, and at a certain RPM the gasses flow more thru the center pipe adding to more free flow, stiffer exhaust springs (also read somewhere bigger exhaust valves) and on top of a bigger oilcooler to make sure the added heat is somewhat countered.

In short; I agree that it’s most likely the added boost together with an OPF/GPF delete makes up for the 300hp

The other mods most probably add to the reliability of this engine.

 

@Track Lover after i removed my seats , and added a lighter battery in (11kg vs 17kg) , stock springs and dampers

I feel the rear of the car is extremely light and barely has any loading on it and it genuinely makes me feel unsafe when cornering at the limit , especially at higher speeds. So much that i make sure to always leave ESC on because i can't really feel what is going on in the rear of the car and is also part of the reason i have gone with wider tyres (245/40/18) to combat this particularly.

What are your thoughts on this? , and have you done anything to address this or you just don't see this as an issue and you just remain flat-out on the throttle to combat lift-off oversteer and ride out on the balance of whatever luck/time you have left on this planet what have you

 

Personally, I drive with traction control and all driver-assist systems completely off, come rain or shine, or even during Scotland's bone-chilling -9 weather in December. I always set my tyre pressures to 30 psi for that perfect balance of grip and compliance.

The first time I shed some weight off the car was when I replaced the battery, dropping a whopping 18 kg. Within the first 20 meters, the rear end felt as light as a feather (which I enjoyed), but eventually, I got used to the driving characteristics.

While driving through the Scottish Highlands, my car was particularly unbalanced, with no rear seats, rear speakers, rear plastic trim, or heavy battery. It was as unevenly balanced as a tipsy unicyclist, but somehow it didn't feel compromised at all. In fact, it handled like a dream, as if it were dancing a ballet on ice.

I have now shifted focus to the front of the car (engine cover, carpets, sound deadening, audio system, etc.), to make it more balanced. And now, with my second clutch slipping, it's time for an upgrade to a lighter aftermarket competition clutch and single mass flywheel setup to further balance this track day warrior.

At this point, if I were to hop into a stock GR lugging around an extra 80 kg, I reckon it would feel about as swift and graceful as a sumo wrestler in a potato sack race.

 

Yeah I bet the back can get incredibly light and sketchy if you're pushing it at high speed with no rear seats and a lighter battery for example!

 

Hmm, I thought I read that a Rally 2 car was one-fifth the cost of a Rally 1 car at £850k.

 

1 Million Euro WRC hybrid cars 'too expensive', says Malcolm Wilson
RALLY NEWS

JANUARY 10TH 2020- LAST UPDATED: JANUARY 20TH 2020

Upcoming drivers face being priced out of WRC, with 2022 hybrid cars set to cost €1m, says Malcolm Wilson

€1m in the Argentinian dust
Motorsport Images
AUTHOR

Dominic Tobin

The cost of new hybrid WRC cars threatens to price young drivers out of the top of the sport, Malcolm Wilson has warned.

As it stands, each of the new generation of cars will cost around €1m (£850,000); five times that of a feeder series WRC2 car, according to the M-Sport boss.
“The cars are going to be too expensive,” said Wilson. “Personally, I think that goes against the DNA of what rallying is about.

“It’s crazy to be running around in €1m cars crashing through a gravel road in the depths of Argentina. I think that we can still create the same spectacle for the fan [for less], which is important.

“The WRC2 cars are price-capped at around €190,000 (£160,000). What really concerns me is rallying going forward. You’re broadening the gap so much for any young aspiring drivers.

“I’ve always tried to create a ladder of opportunity right through to WRC. What’s happened is the gap to WRC 2 and WRC 1 has become so great.”

Malcolm Wilson
Motorsport Images

Wilson said that it’s not just the hybrid system making WRC cars more expensive, but increasing costs all round.

“The current WRC cars are still very expensive,” he said, speaking at the Motorsport Industry Association’s energy-efficient motorsport conference. “Historically we have sold eight to 14 WRC cars a year but for the current generation car, we have sold five in three years.”

The regulations for the 2022 season are still being thrashed out but will include hybrid power, with a 100kW motor providing extra performance on stages, as well as electric-only running in towns and the service park.

A move away from cars based on production shells to a tubular chassis looks likely, which could bring closer competition and allow manufacturers to race a greater range of models.

However, Wilson said that there were alternatives: “The current cars look aggressive and sexy and fast. We can still do that, probably with an R5-based car [used in WRC 2] with some bigger wings and a hybrid system.”

The introduction of hybrid cars to WRC could help to reverse the decline in sponsorship revenue, partly driven by the need of manufacturers to sell more eco-friendly cars to meet EU emissions targets.

“Another thing we’re facing at the moment is that because WRC doesn’t have any green credentials, the sponsors are all going to series like Formula E,” said Wilson.

 

Has anyone removed the weight on the gear selector mechanism at the gearbox end? Looks like it just bolts on but you’ll probably make it feel a bit more mechanical. There’s also a weight on the rear diff bracket, I suspect it’s to stop a particular vibration frequency but I’m not sure you’d notice that now @Track Lover

 

.

 

I tried removing the weight on the gear selector as I noticed the HKS car has it removed. I didn’t like it though, the extra inertia helps selects the gears and feels smoother for road use.

 

OP - Which Battery did you replace it with, and how are you finding it?

 

I recommend adding about 100 grams.