You’ve probably seen the World Time Attack Audi R8 from team R8 1:1 in Finland on social media by now. It has become quite a hit due to its huge aero and the incredible suspension system that has been designed into it. We had to find out more so organised an interview with the team manager of Team R8 1:1; Mikko Ahola.
Our Q and A below covers everything from the impressive large parts right down to the intricate suspension design and assembly and the answer to the most asked question on our social media …. What is the third damper for?
What made you decide upon the Audi R8 as the car of choice for your build?
Opportunity. Sami has always liked VAG products, he´s been doing track driving with his TTRS and a fully built Seat Leon and wished to have something more in every way. They came across a track day Audi R8 in Germany and decided to go and get it.
How many years has the car been in development?
The car was bought in 2015 and did one track session that autumn in Finland. Then it was disassembled and built as a 5.0 Twin Turbo for the second half of the 2016 season. The 5.0 engine soon let go and a 5.2 was brought in to replace it which meant some extensive modification of several things to make it fit. The suspension was slowly developed on the side using partly GT3 parts and partly modified OEM parts. 2017 was the first year for WTAC so that season was mainly prepping for the Aussie trip. In 2018 after the Aussie trip we did some weight reduction and refining of the existing package but soon realized that the chassis and suspension will not cope with what we have and Sami also wanted to have a second go at the WTAC Pro Am crown.
How much does the car weigh?
At the moment we don´t have the final weight as some of the aero parts are still being made but our WTAC minimum without driver is 1200kg and we are very close to that. So with driver it will be below 1300kg. 2017 race weight with driver was 1440kg.
What are the main things you have done to lose so much weight?
Pretty much everything we can. From the chassis side the main thing is to get rid of the original front and rear crash structures as we are not required to do crash tests so the construction is not ideal for race use. We were lucky to get good sponsorship deals for very high quality materials like Docol high strength tubes from SSAB and Imacro steel from Ovako Metals. The main thing with weight is that you try not to just throw stuff on the car but think about where the parts need to be etc.
What is the weight distribution like across all 4 wheels?
Around 58% rear. That has stayed pretty much where it is now all the time. But we managed to get the car balanced sideways for this season as before the engine has been more left because of the 4WD output and as in our case the driver is on the left as well so it made the left side significantly heavier before.
What have you done or moved to achieve this weight distribution?
Front to back it’s pretty much the same but weight is more in the centre so dynamics should be better. Sideways we moved the engine and gearbox to the right to get it close to the centre.
What have you done to reduce the unsprung mass of the car?
Unsprung is dictated by brakes and wheels. We might have shaved a kilo or two with the a-arms but it’s pretty much the same as before. But you need to also remember that this suspension is able to handle the new increased loads plus we have much more freedom to adjust it where we want it to be with the current design so overall the package is much better than before.
Your aero is obviously a major area of the car so how much downforce does the aero package generate in full attack mode?
Yes, aero was one of the major developments for this season as Eastern Creek is a very aero rewarding track. We already had all the power so aero development was fairly straight forward with goals. The numbers ended up showing that we are looking at close to 5000kg of downforce when doing full speed which should be just below 300kph. Dr. Sammy Diasinos and his company Dynamic Aero Solutions made an awesome job on the aero with the challenges of the wide frame and large power unit that we have.
How much power/torque does the engine produce?
Measured on a chassis dyno with some wheel spin we made 1287hp at 7700rpm and 1267Nm at 6500rpm. Those are at rear wheels and 1,5bars of boost. It has more than 1000Nm of torque from around 4500rpm to almost 8000rpm.
What engine is it using and how have you achieved so much horsepower?
It’s the Audi/Lambo 5.2 litre V10. We´ve added two Garret GTX3582R turbos and made few internal modifications to allow us to achieve the power that we have. We´ve used the same basic idea for the engine concept for the last 4 years but for this season we installed stronger Arrow con rods than before and lowered the compression with custom JE pistons. The compression is dropped from stock 12.4:1 to around 9:1. This has helped with heat management a lot and now we can dial in all the timings (cams and ignition) so that the engine is working a lot more efficient and is more responsive. It does like its ethanol, on full demand we use about 13.5L of E85 a minute. Other than that we have only changed valve springs; everything else is stock.
Now Let’s Talk Suspension
What brand of coilovers are you using?
The main dampers are Öhlins TTX40 with our own damping curves. 3rd dampers are from Tractive Suspension and are specially built for our specification.
What is your suspension system called?
The suspension type is parallel double a-arm with pushrods on both axles. Main focus in the suspension design was to have wide range of adjustments with good serviceability and easy manufacturing. Suspension geometry design and vehicle dynamics simulations have been done with MSC Software Adams/Car by Toni Ristolainen from Ristolainen Engineering.
How does the electronic system work?
The main dampers are normal 4 way adjustable passive dampers but the 3rd dampers are controlled by their own control unit. There are various parameters either directly or via CAN communication from, for example, MoTeC. The damper has a patented electronic DDA valve that is opened and closed at a maximum rate of 180Hz which allows for heave damper rate adjustments. So only damping rate can be changed, not spring stiffness or height.
What format of suspension system have you chosen and why?
We have gone with pushrod actuated mainly to get the freedom of motion ratios and to have the parts at the centre of the car and available for adjustment.
This suspension type also offers almost free reign to design ideal suspension geometries and position all suspension components freely. Also all the loads transferred from suspension to chassis are easier to handle making the subframe structure rigid but lightweight.
Why do you have 3 dampers at the front and 3 dampers at the back?
Due to the high aero loads applied from the new aero package it became necessary to have something to control the ride height. The easiest way is to add bump rubbers to main dampers but that effectively disables suspension in high speed so the ride becomes very harsh and while not damped at all the tires can suffer. Quite early we decided that a rocker operated 3rd spring will be added and later we chose to use the active damped version as we came to the conclusion with Dr Dejan Ninic, director of TT Suspension that the system that we are thinking will work. The main idea with the 3rd spring or element is that you remove some of the loads created by the heave motion and support those with the 3rd element connecting the 2 rockers together. So a well-designed system works so that if you remove the main dampers and spring and the ARB the car is free to roll. Of course in heave motion the main dampers/springs will take some of the heave load as well so it’s not a fully separated system but when we are on the ride height limit we still have bump travel left on single wheel.
Another advantage with damped and especially actively damped 3rd elements is that we don´t need to run any anti-geometry in the a-arm setups. We did run before with a lot of anti-dive and especially anti-squat at the rear and our feeling is that the rear geometry caused some unexpected behaviour as when using the anti-geometry you transfer undamped loads through the suspension members which can cause binding and force oscillations.
Do your dampers work when at full speed with full aero or does the car sit on bump stops?
We do run bump stops on all of the main dampers and on the 3rd elements as well. Also there is an internal hydraulic bump stop inside the Tractive damper so if the system is set correct we have a nice progressive bump stop which is very good for overload situations such as high speed bumps. The systems work at all speeds so at lower speeds the 3rd dampers are mainly used for attitude control.
What anti-roll bars is the car using?
We have torsion bar type anti-roll bars operated via drop links from the rockers both front and rear.
How many points of adjustment do the roll bars have?
The cantilevers have 3 holes per side which equates to 6 different settings in total. Roughly +-30% of adjustment from the nominal bar stiffness on the mid-point of the linkage. And of course we can change the diameter or effective length of the bars so the range is close to unlimited.
What key areas of geometry were considered when making the custom billet uprights?
In the front the challenge is that the top a-arm rear point is mounted to the original chassis so there is not much room to play with the position which dictated the length of the top a-arm so everything is done around that. The stock upright was not stiff enough for the setup we are running now and there were no camber adjustment possibilities so we decided to do that. We were running the LMS ultra billet uprights at the rear before but they did not suite the rocker setup and the toe control on them was poor.
What areas of geometry are available to adjust on the front and rear suspension systems?
We can modify the suspension hard points by different bushings or by rotating the inner brackets. This allows us to change almost all the geometries as an example roll centre heights, camber change, bump steer, motion ratios, anti-effects etc. By adding shims between suspension brackets and chassis we can correct the manufacturing uncertainties. With different spring/ARB options we can modify the roll balance of the car and this way affect the dynamic behaviour of the car.
What tyres are you using?
For WTAC we need to use Yokohama A050 semi-slicks. Our max size is 295/35-18. The car is very much designed around that tire.
What is your favourite area of the car personally?
Honestly I haven´t had the time to sit down and think about it yet but I´m very happy on the manufacturing side of the chassis and suspension. When we first lowered the car on the scales the front side-to-side weight difference was less than 1kg and rear was within 8kg or so which shows that everything is where they are supposed to be.
Are there any special thanks you would like to give?
Special thanks goes to Toni Ristolainen from Ristolainen Engineering for the awesome work with the suspension geometries as well as Dejan from TT Suspension for hanging on with the spec that we proposed as well as helping with the setting up of the systems.
We would like to wish Mikko and the team the best of luck competing this year with such an incredible car in the World Time Attack series.