AVO BRZ: 1000km at the track
 

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You'd expect a little exaggeration when seeing a title like this, but literally, besides driving to and from the track, that's exactly how the AVO BRZ has been, and is being, broken in. It hasn't happened overnight, we got the first BRZ sold to the public in Japan 3 months ago. Since then it's spent an equal amount of time on the lift being used for R&D or at the track being use for R&D.

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This is mainly a writeup about what we've learnt from being at the track. To start with, it's been modified from early on. The car we ordered was a RA edition. We corner weighed the car, and boy is it light at a 1172kg (2585lbs). We also threw it on the dyno so that we'd have a baseline to judge all power modifications against.

http://www.avoturboworld.com/images/...z_dyno_001.JPG

It came from the factory with steel wheels and rubber that would probably be used as a spare tire on other cars. This was a simple economical decision, we knew both that the car would mainly see track duty, and that whatever standard wheels would be on the car would be quickly be binned. And so the steelies were, with 18 x 8 WORK wheels and 225/40 Bridgestone RE11 tires fitted soon after. We had literally gotten the car two days before the Hyper Meet, so we had to rush to fit the DAMD rear wing in time for the event. We also had the graphics done within those two days as well. This setup went straight to the track, and Ross recorded a 1m14.3sec lap at Tsukuba Circuit during the Hyper Meeting BRZ 5 Lap Race. During this 5 Lap Race he was doing 145km/h at the end of the back straight. This was to be our base line.

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Soon after that we fitted the coilovers that we are working on in conjunction with Spirit. These are high-end track specification coilovers, they'd feel a bit stiff on the street, but are quite good on the track. Our lapping times went well with 1m13.1sec laps, though we felt the coilovers still needed fine tuning on the spring rates. Speed didn't go up, we were still doing a 146km/h at the end of the back straight. We also tested some 700 degree (celcius) brake pads which were a definite improvement over the stock pads, which we will release soon in the future after we finish our testing. The overall impression was still excellent, with great response at the track and clearly superior cornering compared to, say, an STI. Light weight and an ideal balance will do that for you.

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A little time was taken off from the track to get into the R&D. The panel filter was sent off to the factory so we could make a high flow version, and the exhaust was taken apart so we could start on that as well. In both cases, it's not that neither is that bad from the factory, but of course we found areas to improve. We also got the revised springs from Spirit. Finally, we fitted our front lower control arm bushings, the ones at the front, and at the rear our CAB (Caster Adjustment Bushings). They provided a tremendous improvement in turn-in and stability at the front end, and we felt we could push it a lot further at the track.

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So that's what we did, took it back to Tsukuba. We had a host of changes for this run. Front LCA bushings, 800 degree brake pads, newly revised springs, new panel filter and some new exhaust pieces. And around the track, it certainly felt a lot more stable. Ross was able to take it deeper and deeper into the corners before standing on the brakes and bringing it on through under power, with a bit of kick out at the exit. Lap times were very consistent, and it was quite easy to bring the lap times down from the previous best. In fact, by the end of the session, over 3 seconds had been knocked off from the last time, a huge improvement at a short track like Tsukuba Circuit. Our final best time was 1m10.8 seconds at 149.7km/h at the end of the back straight.

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Being able to go much harder than before also returned some very valuable data on the mechanical reliability of the car. It's one thing for Subaru to say it'll be a good track car, it's another to actually test it. And this certainly did test it to the limit, and beyond some limits.

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One of the first area's we found some issues with were the front brakes. Admittedly, not everybody is going to spend their first 1000km standing on the brakes at the track, but we did, and they didn't last quite as long as we'd have liked. The front rotors were shot after our last lapping session - no real surprise there - but the brake calipers also had some issues. As you can see in the photo, the rubber boots on the pistons tore, not something we had expected to see quite so soon.

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The other area of concern was the front lower control arms. Installing the new LCA bushings front and rear took a lot of slop out of the arm, reducing unwanted movement tremendously. It also showed that Subaru got the car as light as it is by using as little metal as possible anywhere it could. With less flex in the bushings, the arms now showed more effectively how lightweight they were designed. They were literally flexing when we applied physical pressure to them by hand. This has raised enough worries about long term effects of racing that we sent them out to our factory to get reinforced.

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In response to the issues with the front brake calipers and rotors, we removed them completely from the picture and installed our 330mm Big Brake Kit, which utilizes DBA slotted brake rotors with the kangaroo paw design for vastly improved longevity and performance at the track. Fitted to these were our 4-pot calipers, which fit easily under the wheels and use a Porsche 911 size brake pad, which increased the swept area of the pads by a huge percentage. Due to the increase in size and venting of the new rotors, we have gone to a 500 degree brake pad, as this will be a better match.

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For the next track session, we will be testing the Big Brake Kit and the DBW throttle controller. Even on these newest Subaru's, they still suffer from the initial throttle hesitation that Subaru designs in to all of their drive by wire cars. The throttle controller cures this issue and as a big bonus also gives it a quicker, torquier response. We have fitted our Lap Timer to keep track of our times even better. We might test swaybars at this time as well. We are debating changing them out to balance with the springs on the coilovers better.

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Muffler details?

:thanks:

I love, love, love when tuning houses have data, dyno or track times, to back up changes that they make.

I'm also loving being at the ground level of whats happening with this car.

Man that's light wish they offered it here...same as the WRX STi I doubt we will see it.

Thinner than 02 WRX cast LCA?

Yes, thinner/lighter. There's a certain logic about it - the car is lighter, so they feel they can make the components lighter. But if you are going to be tracking the car heavily like we are, we don't have confidence they'll hold up to the stresses of traction generated by bigger, stickier rubber.

Paul Hansen
www.avoturboworld.com
www.facebook.com/BRZSportsCarClub

It's a prototype, hand polished stainless steel, 4" diameter on the exhaust tips. Still testing to make sure it's the optimal design.

Paul Hansen

great to see your R&D efforts and testing of stock components. What else besides the brakes and control arms do you see as limiting factors during extended track usage? Has the engine/transmission performed adequately? Curious to see results of repeated abuse on those components...

Have you had issues with the power steering shutting down like element tuning had?

We've had no issues with the power steering as of yet.

At this point, the biggest issue Ross has is with the standard seats, probably because it corners so well now, he's sliding all over the place. He's probably going to weld up some brackets and mount a racing seat soon.

As far as the rest of the car, everything else has held up quite well. Of course, we are only in the first 1000km, have to see how the next 19,000km go.

I like how this car is coming along. Can't wait to see your products up and running for the BRZ. :thumbsup:

Excellent thread.

This was very enjoyable to read-- like an article in Grassroots Motorsports. I enjoyed the combination of photos and great detail. I'm very excited to see this car evolve. And going from 1m14s to 1m10s is great for Tsukuba-- that's a very technical and tricky track. I'm looking forward to updates.

Temporary solution till the race seat is fitted:

http://sphotos.xx.fbcdn.net/hphotos-...38845459_n.jpg

...you could get the control arms to flex with your hands?

And great writeup; thank you.

great read! id like to see a video of the control arm flex by hand. surely they cant be that weak? thats disappointing about the brakes too, particularly the calipers.

Any thoughts on brake ducting? Perhaps that could help the stock brake system (obviously with track pads, fluids, lines).

The drop looks perfect. How low did you guys go?

Thank you for this great information. If owners put on bigger, stickier rubber for street use (e.g. 235 tires or larger), do you think the thinness of the LCA could be an issue, even when the car is not tracked? I was planning to use this car as a DD, but wanted to upgrade the tires a little. Cheers.

I believe the final drop was 50mm.

I don't think it's an issue at all with normal street duty. We are at the extreme end of possible BRZ/FRS owner, with nearly 100% track duty planned for the short term, and looking at times when we'll be putting S tires or even slicks on the car. Neither of which are street legal. Normal street rubber won't put the same stresses on the suspension. And to be honest, at the track you are doing high-speed corners at the limit 85% of the time, on the street you do very little high-speed cornering. At least, I hope not!

i can see why subaru went with lightweight LCA. they wanted the mass ratio of the sprung mass with the unsprung mass to be as high as possible for better ride quality. being really lightweight as it is, they had to go to further lengths to keep the unsprung mass as low as possible.

i wouldn't be surprised if the LCAs bent during extended track use. i'm curious to know how you reinforced them. was it simply a weld job and weld in additional 'walls' in the stamped sections of the LCAs?

I believe for now they are just doing that, but they are sending a spare set off to the factory to engineer something a bit better in the future.

Updates from the Option 2 magazine event, with Orido driving:

We fitted our 18mm solid rear bar halfway through to see how that would affect the handling. Unfortunately, not in a good way - it was nearly a second slower than with the standard rear bar. Orido said it was initially quite entertaining, the rear end would drift through nearly any sort of corner, but also quite twitchy, and ultimately harder to get through the course fast.

What we found so far is that, with the perfect 50/50 balance of the car from the factory, putting on a larger rear bar only, or a larger front bar only, will just upset that balance. Subaru/Toyota really did a good job of setting up the car out the door. Any swaybar upgrades need to be very carefully balanced front to rear, or you'll upset the balance, and ultimately, grip.

http://www.avoturboworld.com/images/...gazine_015.JPG

What about other suspension components or their connection points to the frame? Are you seeing stress or wear that could cause failure or replacement? Replacing a control arm is relatively easy, but what about the hardpoints where the arm meets the frame? Would stiffer bushings only make the problem worse?

Fantastic write up. Great work and thanks for sharing here. What is your opinion about this car for very occasional track use in stock setup? After I get an FR-S I want to take it to a track a few times a year, otherwise it will be my weekend and once or twice a week to work car.

- J

good read, any details on that wing? i'm in love lol

Oh, it's a fantastic car for that, probably nothing better in the price range.

DBW throttle controller
 

Can you give any more info on this? Better 0-60 times or does it just feel better sitting in the drivers seat?

Fantastic read! I plan on switching out the bushings as well. Mine will be a DD with occassional (no more than a dozen times a year) track use for the first 3-4 years of ownership but eventually it'll be relagated to track duty only. I'm concerned over those LCA's however, once the new bushings go in with them being so pliable. For those track days I'd like to avoid as many nightmare experiences as possible :(

Don't make any mistake here, it doesn't add an ounce of power. It just reworks the throttle mapping (via voltage) for far better response (or far less if you use the "inclement conditions" settings). The main benefit is to get rid of that initial hesitation, and to give the throttle a quicker, more linear feel.

Great write up, Thanks so much - Subscribed!

Can u please share how and where u mounted the harness?

Thanks

The best thread I have come across in regards of tuning experiences!
THANK YOU!
Please share future findings and information! :)

Nice to see you here Paul! I had a few your your products on my LGT...

Gasp!

I can't wait to test drive one!

What will be the goal of this car? Will it be a fully stripped down track car or something that could also be used on daily driving? Which is your targeted tsukuba time? Dyno of the stock car?

iThank you for the answer and great post!

That's good to know. Car is crazy light for RWD, but a little weight in the form of beefier components sounds like a good idea.

While it's mostly going to see track duty, we aren't going to strip the interior out - going to keep it DD enough to drive to and from the track. It's a R&D platform for our parts development, and developing parts that only work in a race environment would leave out 90% of the market.