Sneak Peek: The Mighty Tilton Evo

by Mike Kojima

As the 2015 WTAC has just ended with the Titlon Evo piloted by Garth Walden setting another world record by lapping Eastern Creek at a blistering 1:23.777 pace, let's take a close look at the world's fastest unibody car, the winner of the 2015 WTAC and overall world record holder, the mighty Tilton Evo.  Currently the Tilton Evo is the epitome of time attack state of the art and showcases just what can be done when maintaining the standard unibody to a car built nearly to the fullest extent of the rules with almost no expense spared. 

The Tilton Evo is fascinating with a level of construction, typical of WTAC cars that makes our efforts at doing the same thing here (in the USA) look silly in comparison. Unlike the controversial Nemo Evo the Tilton Evo is built with the chassis in a very safe conventional interpretation of the rules.  Thus the Tilton Evo is a more conventional car which bears some semblance to its street going brethren. 

For interests sake, take a look at the Nemo Evo and compare and contrast the two radically different cars.

Finding Nemo

Part 1

Part 2

My personal preference is for cars more like the Tilton Evo which I consider to be built in the spirit of what I feel time attack should be.  Not to take anything away from the amazing Nemo Evo but just my own personal opinion.  Let's now take a look inside this marvellous monster.


The Tilton Evo's 4G63 engine is quite a powerhouse pushing the limits of what the basic engine architecture is capable of.  The engine is stroked with a Cosworth crank and rods to gain another 200cc of displacement for 2200cc total.  ACL bearings are used as well as CP forged pistons. The cylinder head is CNC ported and features 1mm oversize valves actuated by Kelford cams with Cosworth springs and titanium retainers.  To keep things lubricated the engine uses a Peterson dry sump system.  The engine retains the stock Evo IX variable intake timing but has an HKS adjustable exhaust gear.
A Hypertune stainless tubular pulse converter exhaust manifold is used with dual Turbosmart 45mm Hypergates one for each pair of cylinders to control the boost.
Note the generous use of swirl pots and surge tanks to keep air out of the cooling system.  Also note the generous crankcase ventilation for the drysump system.  A Turbosmart Race Port BOV handles surge prevention duties. Hypertune also fabricated all of the charge piping.
A Hypertune intake manifold and throttle body are used.  You can see the direct fire coils for the MoTeC CDI unit that take the place of the stock lost spark parts. A Turbosmart fuel pressure regulator and large injectors are needed for the E85 fuel. 
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Sunday, October 18, 2015 11:38 PM
A little surprised I'm not seeing any active aero on the car. Is there a rule that prohibits it?

A good point about the 'exhaust blown diffuser', as it is fairly easy to setup and has proven results in F1, although you may have to adapt your driving style to take full advantage of an EBD.

Considering all that drag the front end makes, I'd love to have some of those canards fold up under positive acceleration for the straights, and deploy under negative acceleration braking.

Strange, I see a hugely fast car like this, and all I can think of are the ways it could go even faster! Ugh!
Mike Kojima
Mike Kojimalink
Monday, October 19, 2015 12:30 AM
Active aero and moveable aero surfaces are not legal.
Dan DeRosia
Dan DeRosialink
Monday, October 19, 2015 4:00 AM
Regarding the EBD, from hearing designers of prototype and F1 cars back in the day of few underbody aero restrictions, blown diffusers weren't universally liked. Yeah, it's potentially a little bit more aero efficiency but it's engine dependent, and on a highly boosted 4-banger you have to imagine the exhaust flow is going to vary quite a bit. Also, a lot of the exhaust energy is getting used to run the turbo in the first place.
Monday, October 19, 2015 5:27 AM
Where was the ARK GT-R this year? Surely you all haven't given up on it after so much time and effort.

How would the Tilton EVO compare with the NEMO EVO? I know the NEMO is outlawed due to the updated rules, but it would be interesting to see how the two stack up.
Monday, October 19, 2015 5:48 AM
2nd picture on 3rd page says that "A non adjustable Whiteline front sway bar is used." - that's not quite true, isn't it? because (if I see correctly) sway bar links lower mount has 4 holes to be attached to.
Monday, October 19, 2015 7:12 AM
Think about how much faster they might have been if they put the front rotors on the right way round!

Continuing the pedantic observations, a rear diffuser does not create downforce, in fact it makes lift. However when integrated into a properly designed under-car floor what it does do is allow the throat of the venturi to make far more low pressure than without said properly designed diffuser. It's a case of net downforce.
Monday, October 19, 2015 7:48 AM
I heard the Tilton car is now retired after 3 WTAC wins. The team is supposedly returning in 2 years with something else.

Very interested to hear an update on the ARK car, you guys should run it in something like Global Time Attack or Redline or something, don't let it go to waste!
Mike Kojima
Mike Kojimalink
Monday, October 19, 2015 8:52 AM
The bar is not adjustable but the arm is although with the link used it isn't.
Monday, October 19, 2015 10:19 AM
Would be nice to have a Team USA entry that didn't fall apart on the first lap. Lyfe Motorsports 1:32 lap times for how much they spent on the car is not exactly flying. R35 I guess is just too heavy of a platform. 3000lb car even with 1200hp is just not competitive.

Not sure any team other than AUS teams will win anymore due to access to the race track and tons of testing. Tilton was there like 5-6 times this year testing the car.
Micah McMahan
Micah McMahanlink
Monday, October 19, 2015 11:59 AM
@Kaane, right there with you!! I've long since track testing to be a huge limit to any of the international competitors. Heck, Under Suzuki actually ran slower with his new set up than what he'd posted last year (although I don't know the full story from this year).

@Matt, in regards to the ARK car, I'd love to see Global Time Attack unify the unlimited class with what they have for WTAC, as far as chassis and aero at least. That way you could design a car for both at the same time. If we build to US rules strictly, you're at a disadvantage when going to WTAC.

...with that being said, I'd still LOVE to see the ARK car go around Buttonwillow, our US standard, in anger!!

Also super bummed that Andy Forrest broke his trans and wasn't able to get a spare sorted out with MRT. Would have been very interesting to see how it did.
Monday, October 19, 2015 12:06 PM
Thanks Micah, interesting that the rules are different, I agree that makes no sense. Does the car fit into NASA TTU?

The Lyfe car wasn't running 1200hp, they blew their engine on the first lap (bad injector), so they swapped in a stock engine for the rest of the event. They shipped an unfinished untested car to Oz so it was not surprising to see what happened to them. Boggles my mind you would spend that much money building the car and shipping it down there without any testing.
Mike Kojima
Mike Kojimalink
Monday, October 19, 2015 12:12 PM
I personally would like to have some rules limiting aero, like perhaps the front splitter cannot extend past the track width and extend more than 6" forward. Also aero devices be limited in their complexity. This idea may or may not be popular but if not implemented Time Attack will go the way of open wheel racing where it is largely a battle of aero budgets.
J NOLOlink
Monday, October 19, 2015 3:52 PM
Was this aero designed by Andrew Brilliant? Spoiler, doors, hood and front undertray look similar to Nemo.
Monday, October 19, 2015 4:07 PM
@mikekojima That is why there is different class? Having unlimited aero rulebook pushes innovation however do agree with the cheque book tuning, but isn't that the case with most motorsport

Under suzuki didn't post a faster lap time this year as the weather condition was not ideal, it was 35C on Friday and there were forecast of rain on the shootout on Saturday so everyone dial the boost up to try set a record on Friday evening and unfortunately under suzuki was one of the many cars that blown their engine, replacement engine didn't work right on Saturday and didn't even last a whole lap, hopefully next year the weather is cooler
Monday, October 19, 2015 5:59 PM
I know life R35 wasn't running 1200hp, but even with 600-800hp it should of been faster than 1:32. The car was just too heavy and aero was untested. More aero = need more power to overcome the drag, so heavy cars are disadvantaged from the get go, especially that they don't get wider tires.
Der Bruce
Der Brucelink
Monday, October 19, 2015 9:09 PM
I'm okay, to an extant, with the crazy aero in unlimited. BUT if they're going to let things spiral so far from even a production silhouette and gut the chassis, then they might as well allow a kit car. Project 818c, here we come!!
Tuesday, October 20, 2015 8:19 AM
The belt routing is something you always see in Euro race cars. I don't know why they eschew a horizontal bar right behind the driver seat to shorten the belts and also to strengthen the middle of the car in side impacts. Ah well time attack, same reason the backwards front rotors don't matter. Incredible car though, and they did a great job keeping a lot of the stock unibody.

Any idea of the weight with driver?
Tuesday, October 20, 2015 7:46 PM
The Tilton Evo is roughly 1200-1300kg wet without driver.

Garth weights around 85kg pending how much beers he drinks leading up to the event. :)
Mike Kojima
Mike Kojimalink
Tuesday, October 20, 2015 9:10 PM
The belt thing really puzzles me.
Wednesday, October 21, 2015 12:58 PM
are pits so rushed at time attack that they can't spare a few minutes to jack up the car instead of using air jacks? I mean air jacks are cool and all, but if your an extra minute in the pit isn't gonna cost you a win, why put the extra weight in the car?
Mike Kojima
Mike Kojimalink
Wednesday, October 21, 2015 1:14 PM
Hahaha you never tried to actually jack up a car with a flat bottom and extensive aero!
Wednesday, October 21, 2015 1:19 PM
you don't know me! haha j/k, you're right
Monday, November 30, 2015 10:54 AM
Great write up!
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