GR Yaris Questions about my upcoming tuning/modification

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Wubziz

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Greetings everyone,

I'm new here and I hope that I post this thread in the correct diectory.
If not, I apologize profusely.

I am coming from germany and own a 2022 Toyota GR Yaris with the additional high performance package and the pearl white color.
I was directed here by the reddit user u/masterventris since I made a new post in the r/GRYaris community with questions about my upcoming tunings/modifications that I would like to do to the car.
He said my questions would be best asked here because here is a broader and more experienced community.

My current tuning plan consists of the following:
  • prior design aerodynamic body kit (excluding the rear wing spoiler. About the frontal wings on each side I am VERY unsure. Don‘t want too much downforce on the front and too little on the back and the other way around)
  • giacuzzo rear wing spoiler
  • milltek exhaust with titan tips
  • hjs downpipe
  • eventuri mat carbon intake
  • wagner intercooler
  • KW suspension (maybe)
  • strut bars front & back (maybe)

Everything needs to be 100% legal.

The car is my first newly bought car and see's daily-, mountain road- and b-road usage with a little bit of track days in the summer months.
I would like to modify it to my liking since it is a collectible for me. I will never ever sell it. It has it's permanent place in the garage beneath the house.
My questions don't have the moneywise "is it worth it?" in it. My questions are purely "will I benefit from this modification? If yes, small, medium or largely?"

My original question was: "Strut bar(s) worth it?" but after I got some responses/hints/ideas from users inside the r/GRYaris community other questions also arose, that's why I am going to reorganize them.
  • Is a strut bar in the front (& back) worth it? Example oem toyota or from dna racing components in carbon.
  • Some users told me to opt for track wheels & tyres to get better handling & grip.
    Since I don't do track days frequently often, it would be a waste of money for me (even tho money is no problem).
    What kind of compromise could I do, that gives me more handling & grip on the track and on the day to day road?
    Some users told me that I could buy 235/40 tyres for my oem toyota bbs forged 18 wheels and call it a day and some users told me 9x18 wheels + tyres and some users even told me to opt for 17 wheels and some even for bigger wheel sizes and "to not use the oem toyota bbs forged wheels" for whatever reason. I know they are expensive since they are forged but they are so lightweight and so good looking (and made in japan)!
    Nonetheless as I said, I am open for a compromise. If bigger wheels means better handling & grip, I would like to go for it. I could still use the OEM ones for the winter (or whatever).
    You probably can see that I am very lost here.
    I would call myself a car guy but when it comes to wheel sizes with 8x18 or 8,5x19 or 9x18 (whatever) or ET45/42/40/39/36/... and what tyres would fit on them I am seriously lost! Like literally! I. need. help.
  • I was told that its better not to opt for a aftermarket suspension, since the OEM is good enough and with the aftermarket ones I will have a hard time driving over bumpy roads, speed bumps & whatever since it will get uncomfortable very quickly.
    Disclaimer: With the oem high performance package suspension I have no butt, back (or whatever) pain when driving over bumpy roads, speed bumps and even after a 8 hour long drive. Yes, you read that correctly. I am doing frequent road trips over the year to visit family that is living in the south of germany.
    Is it true that I cannot achieve the same comfortable driving with an aftermarket suspension?
    Also, will it be a problem to drive over speed bumps (or any other kind of obstacles) with a lowered car + the aerodynamic body kit I have planned? That is what is most concerning to me. I don't want to scrape the body kit off the car when I am driving over obstacles or the entry to the house.
    Is it true that IF I am going for a bigger wheel size, then the ground tolerance will go up and will "vanish" the problem? But then I think I also have to get bigger wheels for the winter?
  • I was also told to ask about the bodykit I have planned. Is it really aerodynamically beneficial to the car or is it just a show off?
    The manufacturer claims it is.
    Maybe you guys know more about it (maybe one of you guys are using it?) and if not, then could recommend other body kits that are proven to be beneficial to the aerodynamics of the car.
  • Same with the rear wing spoiler from giacuzzo.

If more questions from my side arise, then I will put them in the comments.

I am gladful for any help that I am getting, may it be small, medium or largely. It will help me tremendously.

I hope that my english is fairly understandable.

If you guys have any questions whatsoever feel free to leave a comment. I even beg you for your opinion/comment :)
I will try to answer as quickly as possible. If I am at work, then I think I dont have enough free time to answer to your comments, but I will take care of it as soon as I come home.

Thank you very much!
 
@Wubziz, at first welcome to GR-Zoo. As a first recommendatiom I'd like to make you having a closer look into the forum. Most of your questions were asked and answered before. Personally I stopped modifying after fitting a dome strut (it's worth) and a DTUK tuning box, so I can't answer ,ost of your questions. But I'm sure you'll find the information you are looking for.

Bye for now Fred

PS: Where are you located? Maybe you are not too far away to pop in for a coffee ;-)
 
@AP756 Hey Fred, thank you for your kind welcome to GR-Zoo.

Tomorrow I will take a closer look at the forum.
Did not have a lot of time today but wanted to write this "essay" of my chest :LOL:

Currently I am located in 21629 Neu Wulmstorf in northern germany and traveling to friends and family in the close neighbourhood of 74523 Schwäbisch Hall.
In 4-5 years me and my fiancee will move back from northern germany to southern germany.

If it's in close proximity to you, then we'll maybe can arrange a meeting the next time we're there!

Good night,
Marcel
 
After reading your questions, my first question to you is: is this a tarmac/track car or a year round rally car for the road?

With that body kit, it would look more in style with a lowering and wider wheels. But that would make the car pretty useless for winter use and for bad roads due to ground/snow clearance. Body kits are much about personal taste, I would say that aerodynamically such bodykits make not much improvements (and often make fuel economy worse), they are style over function mostly and nothing wrong with that if it makes you happy.

Next question, what is better handling? More grip and speed? Then KW and wider tyres will do that. On the other hand, for me and some others too, this car already has too high grip to be fun in summer if you like to play with the cars balance and like to feel the car move around at less then neck braking speeds. Also wider tyres tend to feel more inert and even more grip can remove grip feel and make the chassis feel soft, starting a spiral of chassis and suspension upgrades. And power upgrades if you want to challenge the higher grip just a little.

Stock suspension is good, aftermarket can be better as dampers are more sophisticated in secondary ride but need good set-up. Downside (as above) most are made for lowering which could be an issue.

The chassis as is, is epic fun in winter and on winter tyres in snow but also in wet. To that end, I would say just keep the stock wheels and tyres as you seem to like them, they are a good compromise for summer. Or go even lighter wheels and maybe explore lower grip tyre options if the winter fun should continue somewhat into summer. Or if you like stance and stock handling, get slightly wider 8,5" wheels with 235 proper tyres and slightly lower et (35-40 instead of oem 45), these improve stance yet don't change much to the original handling/grip and are similar to the JDM GRMN version.
Can't really recommend 17" wheels generally (I only run 17"...), only very few fit and while there are benefits, tyre choice often makes a bigger difference. And roads are pretty good in Germany generally.

The other mods, strut bar (not sure they do much though but looks nice, I think front axle lower subframe reinforcements at the front are probably most effective), HJS (improved response and some power), Milltek (sound check), Wagner (better hot weather performance, more power but some increased lag), Eventuri (much liked mod) are all common and well documented here and mostly well liked.

In the end, do the taste/aesthetic mods that make you happy. Performance wise best is not listen too much to others, just improve things that YOU find lacking in YOUR driving, instead of solving perceived by others problems that could very well make the car worse for you if you have a different approach to the car... Being happy with the car is a blessing, and the closer that is to stock, the easier life is with less worries, waiting times, planning, assembly, tweaking as one performance mod affect more things then you first expected etc,
Instead of just enjoy the car...only mod if you personally feel it's necessary to remain content with the car.

Also, mods will typically add no value to the car, so important you like them and if not, you typically can recuperate at most 50% of it taking in account costs for assembly/disassembly.

Good luck
 
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Onehp said:
After reading your questions, my first question to you is: is this a tarmac/track car or a year round rally car for the road?

With that body kit, it would look more in style with a lowering and wider wheels. But that would make the car pretty useless for winter use and for bad roads due to ground/snow clearance. Body kits are much about personal taste, I would say that aerodynamically such bodykits make not much improvements (and often make fuel economy worse), they are style over function mostly and nothing wrong with that if it makes you happy.

Next question, what is better handling? More grip and speed? Then KW and wider tyres will do that. On the other hand, for me and some others too, this car already has too high grip to be fun in summer if you like to play with the cars balance and like to feel the car move around at less then neck braking speeds. Also wider tyres tend to feel more inert and even more grip can remove grip feel and make the chassis feel soft, starting a spiral of chassis and suspension upgrades. And power upgrades of you want to challenge the higher grip just a little.

Stock suspension is good, aftermarket can be better as dampers are more sophisticated in secondary ride but need good set-up. Downside (as above) most are made for lowering which could be an issue.

The chassis as is, is epic fun in winter and on winter tyres in snow but also in wet. To that end, I would say just keep the stock wheels and tyres as you seem to like them, they are a good compromise for summer. Or go even lighter wheels and maybe explore lower grip tyre options if the winter fun should continue somewhat into summer. Or if you like stance and stock handling, get slightly wider 8,5" wheels with 235 proper tyres and slightly lower et (35-40 instead of oem 45), these improve stance yet don't change much to the original handling/grip and are similar to the JDM GRMN version.
Can't really recommend 17" wheels generally (I only run 17"...), only very few fit and while there are benefits, tyre choice often makes a bigger difference. And roads are pretty good in Germany generally.

The other mods, strut bar (not sure they do much though but looks nice, I think front axle lower subframe reinforcements at the front are probably most effective), HJS (improved response and some power), Milltek (sound check), Wagner (better hot weather performance, more power but some increased lag), Eventuri (much liked mod) are all common and well documented here and mostly well liked.

In the end, do the taste mods that make you happy, Performance wise best is not listen too much to others, just improve things that YOU find lacking in YOUR driving, instead of solving perceived by others problems that could very well make the car worse for you if you have a different approach to the car... Being happy with the car is a blessing, and the closer that is to stock, the easier life is with less worries, waiting times, planning, assembly, tweaking as one performance mod affect more things then you first expected etc,
Instead of just enjoy the car...only mod if you personally feel it's necessary to remain content with the car.

Also, mods will typically add no value to the car, so important you like them and if not, you typically can recuperate at most 50% of it taking accounts costs for assembly/disassembly.

Good luck
Click to expand...
Excellent and well considered advice.
 
Absolutely agree with #Onehp if you aren't tracking the car then stock suspension is fine though again with a body kit a little lowering helps the aesthetics. My MSA reds dropped my lap times maybe 2 seconds in 60 but the ride is a bit harsher and the car lower which can be problematic on gravel. The rest of the bits, inlet, exhaust etc are personal preference unless you are looking for a lot more power in which case cams and valve springs etc come into the equation.
 
Start off with small modifications, even if the temptation is to go with the bigger ones first. Just a few ergonomic changes can transform the feel of the car.

Adjusting your seating position, your controls (pedal extension, alcantara or steering wheel swap/extension, gearshift modifications) and your view (mirror riser) can bring more out of you as a driver.
 
Welcome aboard!
Choose your chassis setup per tyres you are using. Sounds that you like the stock setup so wouldn't go too stiff with suspension if you decide to upgrade. Stiffness kills easily the road handling especially if roads are not silky smooth (as they seldom are, nowadays). There is also coilovers near stock spring rates if you decide to update them.

- IC is a no brainer if you drive the car any harder, especially on track.
- HJS DP or similar also recommended, make sure DP has proper additional mounting braket or you can othervise brake stuff from turbo end (due to exhaust movement).

Regarding engine:
I have improved the breathing on inlet side with better airfeed to stock box (wanted to keep filtering stock), larger turbo inlet, IC pipes and manifold. mid range response is now rather sweet and wouldn't like it any other way. Depends really what you're after. I was not after top peak hp but driveability and good response, so engine works rather well now.
But as said 10yr warranty is quite golden to have, so it is not really a bad choice to keep engine stock. its quite good package from the factory.

The stock car excels on road and is really fun to drive on smaller roads. I think its the one brilliance of this car, versatile and quite good all rounder.
Hope you will have nice rides with your GR!
 
Greetings everyone,

first of all I would like to thank all of you for your comments.
You provided me with a lot of help, ideas & advices already.

I would like to prodivde some answers to your questions, while also asking some more questions.

I'll start with @Onehp
my first question to you is: is this a tarmac/track car or a year round rally car for the road?
Click to expand...
It's a year round rally car for the road.
That's why I can only opt for modifications that are ok for the german TÜV.
Otherwise the police could shutdown my car and take it into custody.

Next question, what is better handling? More grip and speed?
Click to expand...
To me, its more grip & speed in corners, yes.
I just love to drive my GR very fast around corners on public roads (within speed limits ofc) and on tracks.
When going into the corner fast while maybe even accelerating and pushing out of the corner puts such a huge smile on my face, that I always have to think about "god do I f***ing love this car!".
Atleast that is my take on the "fun".
Then KW and wider tyres will do that.
Click to expand...
Okay :)

With that body kit, it would look more in style with a lowering and wider wheels. But that would make the car pretty useless for winter use and for bad roads due to ground/snow clearance. Body kits are much about personal taste, I would say that aerodynamically such bodykits make not much improvements (and often make fuel economy worse), they are style over function mostly and nothing wrong with that if it makes you happy. ...

... To that end, I would say just keep the stock wheels and tyres as you seem to like them, they are a good compromise for summer. Or go even lighter wheels and maybe explore lower grip tyre options if the winter fun should continue somewhat into summer. Or if you like stance and stock handling, get slightly wider 8,5" wheels with 235 proper tyres and slightly lower et (35-40 instead of oem 45), these improve stance yet don't change much to the original handling/grip and are similar to the JDM GRMN version.
Click to expand...
What I actually forgot to write down is that I would like to transform my GR Yaris on the outside that it looks like the JDM GRMN version.

There are many body kits on the market that don't really fit my taste, but the one from prior design does & it looks (more or less ofc) than the JDM GRMN version.
The bodykit Toyota put on the JDM GRMN version is not really that much to my liking but I very much like the overall design from the outside.
I also will order the GRMN Yaris shifting knob from japan.

Here comes my first question:
You wrote about lighter wheels, wider wheels, wider tyres to make my GR Yaris look more like the JDM GRMN version.

I have found a wheel that I am very interested in (I love the looks!). I could use the new ones for the summer and the OEM toyota bbs forged wheels for the winter since I am most sporty in the summer.
Link: WedsWheels Europe

What wheel size would be most suited here for me?
For 8,5" there are 2 options. One with ET43 and one with ET32.
What tyres would you recommend here? Pilot Sport 4S in 235?

The other mods, strut bar (not sure they do much though but looks nice, I think front axle lower subframe reinforcements at the front are probably most effective), HJS (improved response and some power), Milltek (sound check), Wagner (better hot weather performance, more power but some increased lag), Eventuri (much liked mod) are all common and well documented here and mostly well liked.
Click to expand...
Thank you for that input. I'll maybe drop the strut bar(s) and will definitely take a look at "axle lower subframe reinforcements at the front".

In the end, do the taste/aesthetic mods that make you happy. Performance wise best is not listen too much to others, just improve things that YOU find lacking in YOUR driving, instead of solving perceived by others problems that could very well make the car worse for you if you have a different approach to the car...
Click to expand...
Thank you, I will go for the prior design bodykit + the rear wing spoiler and after that is done I'll take a look at how much ground clearence I have left and then I will decide if I want to go for a KW or not.
If you have nothing bad to say about the WedsWheels I definitely will also get those!!

Being happy with the car is a blessing
Click to expand...
Yes it really is, I love mine soooo much :love::love::love:

Also, mods will typically add no value to the car, so important you like them and if not, you typically can recuperate at most 50% of it taking in account costs for assembly/disassembly.
Click to expand...
Don't worry about that.
I wrote that I will never ever sell the car in my lifetime. It has a permanent place with me. So that is nothing that I will worry about at all.

Good luck
Click to expand...
Thank you very much!

-
Now off to @Michael Knight
Sounds that you like the stock setup so wouldn't go too stiff with suspension if you decide to upgrade. Stiffness kills easily the road handling especially if roads are not silky smooth (as they seldom are, nowadays). There is also coilovers near stock spring rates if you decide to update them.
Click to expand...
Yes, I will take a very good look at if I want to do any suspension/coilover upgrades or not in the end.
Which coilovers are you talking about if I may ask?

But as said 10yr warranty is quite golden to have, so it is not really a bad choice to keep engine stock. its quite good package from the factory.
Click to expand...
Dont worry, the engine will stay 100% stock due to the 10yr warranty.

Hope you will have nice rides with your GR!
Click to expand...
Thank you, you too!
 
Wubziz said:
Greetings everyone,

first of all I would like to thank all of you for your comments.
You provided me with a lot of help, ideas & advices already.

I would like to prodivde some answers to your questions, while also asking some more questions.

I'll start with @Onehp

It's a year round rally car for the road.
That's why I can only opt for modifications that are ok for the german TÜV.
Otherwise the police could shutdown my car and take it into custody.


To me, its more grip & speed in corners, yes.
I just love to drive my GR very fast around corners on public roads (within speed limits ofc) and on tracks.
When going into the corner fast while maybe even accelerating and pushing out of the corner puts such a huge smile on my face, that I always have to think about "god do I f***ing love this car!".
Atleast that is my take on the "fun".

Okay :)


What I actually forgot to write down is that I would like to transform my GR Yaris on the outside that it looks like the JDM GRMN version.

There are many body kits on the market that don't really fit my taste, but the one from prior design does & it looks (more or less ofc) than the JDM GRMN version.
The bodykit Toyota put on the JDM GRMN version is not really that much to my liking but I very much like the overall design from the outside.
I also will order the GRMN Yaris shifting knob from japan.

Here comes my first question:
You wrote about lighter wheels, wider wheels, wider tyres to make my GR Yaris look more like the JDM GRMN version.

I have found a wheel that I am very interested in (I love the looks!). I could use the new ones for the summer and the OEM toyota bbs forged wheels for the winter since I am most sporty in the summer.
Link: WedsWheels Europe

What wheel size would be most suited here for me?
For 8,5" there are 2 options. One with ET43 and one with ET32.
What tyres would you recommend here? Pilot Sport 4S in 235?


Thank you for that input. I'll maybe drop the strut bar(s) and will definitely take a look at "axle lower subframe reinforcements at the front".


Thank you, I will go for the prior design bodykit + the rear wing spoiler and after that is done I'll take a look at how much ground clearence I have left and then I will decide if I want to go for a KW or not.
If you have nothing bad to say about the WedsWheels I definitely will also get those!!


Yes it really is, I love mine soooo much :love::love::love:


Don't worry about that.
I wrote that I will never ever sell the car in my lifetime. It has a permanent place with me. So that is nothing that I will worry about at all.


Thank you very much!

-
Now off to @Michael Knight

Yes, I will take a very good look at if I want to do any suspension/coilover upgrades or not in the end.
Which coilovers are you talking about if I may ask?


Dont worry, the engine will stay 100% stock due to the 10yr warranty.


Thank you, you too!
Click to expand...
Some coilovers have near stock spring rates - I collected the data on one thread that is on this forum.
BOS is likely softest of the pack, BIGEM you also can get as custom spring rates valved to your liking.

Thread 'Coilovers'
https://www.gr-zoo.com/threads/coilovers.2341/
 
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Weds are among the very best possible aftermarket wheel choice there is and if anything, more upmarket then BBS... ET43 or ET32 is a matter of philosophy and looks. ET 32 will have that stance to go with the bodykit but will look decidely aftermarket, ET43 can pass as OEM+ GRMN lookalike and will keep the cleanest steering feel due to less torque/brake steer.

Tyres, 235/40 and pick among the best sport tyres (PS4S, F1 Supersport, Sport contact 7 or v107 - read tests here and on tyrereviews.co.uk). For your objectives, I would also consider Yokohama Advan AD09 as a very direct and very grippy tyre cost no issue, with some minor possible downsides that go with such a thread design (aquaplaning and noise).
 
Michael Knight said:
Some coilovers have near stock spring rates - I collected the data on one thread that is on this forum.
BOS is likely softest of the pack, BIGEM you also can get as custom spring rates valved to your liking.

Thread 'Coilovers'
https://www.gr-zoo.com/threads/coilovers.2341/
Click to expand...
I would also like to have the BOS suspensions, but there are no TÜV papers... I think the same problem applies to BIGEM.
 
Greetings everyone,

thank you all for your answers again.

@Onehp
Then the WedsSport TC105x FORGED in ET43 18x8,5 5H-114.3 are set in stone!
I will buy those with Continental SportContact 7 or PS4S in 235/40.
I bet the WedsSport come without wheel Nuts and the center cap/piece?
In the description there is no information about if these are included with each wheel or have to be bought seperately.
I have seen that the shop also sells the center cap/piece so I guess these are not included.
What about the wheel nuts? The shop also sells these. Which can I use here? There are many to choose from and I have no idea which would be the likely fit…

After I bought the WedsSport wheels the Toyota OEM BBS forged wheels will become my new winter wheels.
I currently have 225/40 winter tyres. Are these good enough for the winter or should I also go with 235/40 tyres here?
In the winter I don’t drive sporty and I also don’t track.


@Michael Knight
In germany only H&K and KW (as far as I know) have TÜV papers so I can only pick between those two.
KW seems to be the best you can get and this will lower my car about 25mm front & back minimum.
I will worry about the KW after I got everything else done. Then I see how much ground clearence I have left.

Thanks again!
 
I believe Bilstein B16 PSS10 also come with TUV papers, but not many reviews available.
 
Wedssport do hubcentric centre caps for the TC105X but they're quite expensive. Nice touch though, as then you don't need to use separate spigot rings.

You'll need 60 degree tapered wheel nuts. Shaft nuts don't tend to fit Japanese wheels (I have struggled to find any) as the diameter of the holes is usually smaller than 14mm. You should get 8-9 turns, which is a minimum for M12 x 1.5. I'm going to fit extended studs all round when I change pads, but most I've found are especially long, so I'm going to have them machined down a bit to save some weight...going to try some aluminum wheel nuts too, about 40% of the weight of the stock wheel nuts.

The 8.5J in ET43 is pound for pound the best wheel out there, about 700-800 grams lighter than the stock BBS in 8J. ET32 changes the scrub radius by just a bit too much for my liking, I wish it was available in ET38-40 just for that compromise between stance and performance. But then as my ex said, that extra few mm always makes a difference...
 
Greetings everyone,

I am very sorry that I have not posted another answer of mine for quite some time.
First, I would thank all of you again for your comments!


In the meantime, I have spoken with the german TÜV about my plans to use WedsSport wheels, which went very unpleasantly to say the least.
  • The CH documents don’t count for germany or the EU in general. (That I already thought)
  • Need to get a viability report (TÜV does that) for the wheels so I have the load capacity on TÜV papers (costs 1500€ + 2 wheels will be destroyed). Load capacity values "from the manufacturer punched into the rim or available online" dont count.
  • A certificate from a comparison rim with the same dimensions & materials used (if not, a driving test will be needed which costs 250€)
  • After all of that, I can do a individual acceptance for the wheels & my car which costs minimum 100€

That is why I opted for the “Borbet DB8GT2” wheels now. They are 8.5X18 ET40 5x114.3 72.5 and have TÜV for my car.
I wanted to use them with 235/40 R18 tyres but this does not seem to work (also according to TÜV).

In germany its allowed that the speedometer display shows more speed than you are really driving (after a change to bigger wheels/tyres than OEM), but not less speed than you are really driving.

The combination of the Borbet wheels with 235/40 tyres will result in -1,2% less real driving speed.
Meaning, at 100 real km/h my speedometer will show 98,8km/h.
This deviation is too much for german laws & TÜV (max -0% is allowed).

I could however put 245/35 R18 tyres on these Borbet wheels, but according to this spreadsheet its better to use 245/35 tyres only with 9.0 wheels & when you are tracking the car.


You probably can see the new problem that I am facing here.
I need help again please. What should I do in this situation?

Stay on 18 inch wheels and go with 18x9.0 or use 245/35 on the Borbet 18x8.5 wheels (don’t forget, its my daily car with infrequent track days & I would like to achieve better grip) or go one inch up to 19?

I do must say that I really like the design of the Borbet wheel, it’s the design some Japanese wheels have (it reminds me of the R34/R35 GTR which I really love - ofc I also love the Supra!).
 
Wubziz said:
The combination of the Borbet wheels with 235/40 tyres will result in -1,2% less real driving speed.
Meaning, at 100 real km/h my speedometer will show 98,8km/h.
Click to expand...
This is incorrect. The change is 1,2% but the OE speedo reads maybe 2-3% too high so you have some margin to reduce that overread. So it will be OK if they really check speedo vs GPS speed. But not if they assume speedo on OEM tyres is 100% correct (it is not)...
 
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