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Sneak Peak-Tanner Foust's 2015 VW Passat Formula Drift Machine! 

by Mike Kojima

The start of every Formula D season is always pretty cool for the tech head enthusiast.  New cars are being introduced and old favorites are getting overhauled and updated.  Pro drift cars are always interesting because drifting is one of the last forms of Motorsport with a fairly open rule set that allows for technical diversity.  The competition is pretty tight in the higher levels of drifting thanks to a good and stable rule set and the wide diversity of cars is quite fascinating.  Hey Indy Car are you listening?  No one wants to see a bunch of cookie cutter spec racer deluxes motoring around body kits or not. Take a hint from drifting and bring back some creativity!

2015 marks the return of 2 time champion Tanner Foust to the Formula D arena.  Tanner left drifting after the 2010 season due to a full calendar with his GRC schedule and shooting commitments for Top Gear USA. As fans we really missed Tanner with his aggressive yet precise driving style and we are super stoked to see him back behind the wheel. We are also happy to see him reunited with his former crew chief, Steph Papadakis. 

Tanner is returning to Formula D and he bringing his GRC sponsors VW and Rockstar energy drinks with him. Unfortunately, Tanner is only going to be at selected events on the FD schedule that don't conflict with his other professional commitments.  Tanner's return to drifting is also significant as he is  teamed up with Star Driver Fredric Aasbo making a Rockstar dream team of drifting.

We recently got to take a good long look at the Tanner Foust Racing VW Passat and found it to be a well engineered and beautifully built machine with a good deal of technical innovation.  Check it out and we will take you on a technical tour of its insides.

 
Turning a 2015 Passat into a pro drift car means a lot of work which involves a very typical for drifting engine swap.  Modern Pro Drifting is a very power intensive sport.  The cost of entry is currently around 800 hp.  Besides a lot of power, drifting requires a ton of torque, a super wide powerband, fast throttle response and steady reliability.  Nowadays that almost universally means an engine swap to a big displacement V8 engine.  New generation domestic V8 engines are typically used as they put a lot of torque and power producing displacement into a small package.  This compact size is a direct result of their OHV valvetrain which makes for a much smaller cylinder head than a DOHC 4 valve head. A modern domestic V8 like a Chevy LS is compact and lightweight compared to a much more complex import DOHC V8.  Believe it or not, an LS engine is often lighter than an import turbo 4 cylinder.
The Tanner Foust Racing Passat features a modified LS7 engine.  The LS7 displaces 450 cubic inches (7.4 liters) or rougly 4 Honda engines. It is bored slightly to 4.130" and stroked to 4.200" up from the stock bore and stroke of 4.125". Looking at this picture you can see perhaps the most interesting part about the car: its amazing 8-1 header.  As you can see the LS is a pretty compact engine and there is plenty of room in the engine compartment for it.  The FWD Passat has been converted to RWD but adheres to all FD rules regarding crossmember configuration, suspension layout, engine set back and firewall configuration. There are AWD Passat variants in other markets so the Passat is allowed.
The engine uses a basically stock LS7 valvetrain as running too radical of a cam and the hardware needed to support it tends to cause the rocker pedestals to crack into the intake port. The stock LS7 valvetrain stuff is pretty stout and supports a pretty high redline anyway.  The engine sports a high 13.6:1 compression ratio for good torque and throttle response. The engine is run on E85 fuel to support the compression ratio.  The engine is set back in the chassis to the limit of FD rules and the firewall opening is also designed exactly to the limit of FD rules.
A FAST intake manifold with a 102mm drive by wire throttle body is used for good hood clearance. Some peak power is being sacrificed here over a more race oriented manifold but no hood bulge is required by the team.  The 8-1 header is stepped in the primary runners starting at 1 7/8" and progressing to 2" inches at the header's mid point.  The stock LS7 ignition coils are used.  The cross bar near the firewall is not a chassis brace, but an anti sway bar.  By having the bar here where it is easy to reach, it is easy to adjust quickly.  The high mount front swaybar is a cool innovation.
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Comments
8695Beaters
8695Beaterslink
Monday, April 27, 2015 6:28 AM
I don't care that this isn't a "JDM home built drift car yo." This is an awesome piece of machinery. The level of detail in today's drift cars is mind boggling, even more than their power levels. I love how Papadakis left the uprights unpainted; show off that weld porn! I'm curious, with these new mega-power engines, how long are teams going between engine rebuilds? I remember a few years ago Dai's S13 could go the entire season on a motor. Is this still the case, or have the power wars brought back some unreliability?

Also curious if that mega header induces heat soak in the intake since it's sitting right next to the air filter.
Van_1986
Van_1986link
Monday, April 27, 2015 10:29 AM
Nice build, Ross Petty's S15 had a similar 8-1 setup a few years back. The collector was a work of art. Very unique sound to them as well, more like a flat plane V8.
Mike Kojima
Mike Kojimalink
Monday, April 27, 2015 11:26 AM
We generally tear down and inspect the motor after the east coast events and before Seattle. The motor gets a leak down and compression check after every round. Generally the motor is fine when we inspect but we change the bearings, valve springs and rings just to be safe since we are in there.
warmmilk
warmmilklink
Monday, April 27, 2015 4:08 PM
Is the Embee header coating more effective than header wrap? I was under the impression that header wrap is still the best insulator for that kinda thing... also, would there be any reason to not do both, the ceramic coating and wrap?
Mike Kojima
Mike Kojimalink
Monday, April 27, 2015 8:20 PM
Some coatings are pretty effective. I have measured a surface temp of 270 degrees F on a coated header during a dyno pull for instance. I am probably going to do a coating and a wrap on our car to reduce underhood heat.
Burninator
Burninatorlink
Tuesday, April 28, 2015 8:27 AM
Mike, since the Falken team is no longer together who are you working with? From your comments I'm assuming you're still with an FD team. Still with Dai?
Mike Kojima
Mike Kojimalink
Tuesday, April 28, 2015 8:29 AM
I am doing engineering support for Team Dai.
buzzboy
buzzboylink
Tuesday, April 28, 2015 11:11 AM
You've got to love working on a 4 door car. My road racer is a 4 door and it's great to hop in the back seat to work on the harness or wiring.
Rockwood
Rockwoodlink
Monday, May 04, 2015 12:54 PM
8-1 headers sound epic.

@ buzzboy: except working on anything in the "back seat" of a racecar with roll cage is terrible, 2 or 4 doors. 4 doors just help you get into the general area, once there you're still playing on the monkey bars and contorting to do anything. Fuel pumps go from a simple job to a WTF!? session as soon as the x-braces go in... :)
econobox
econoboxlink
Thursday, May 07, 2015 2:04 PM
Beautiful fabrication!
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