Block Buster, Inside Ken Block’s Monster Gymkhana Killer

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 Block Buster, Inside Ken Block's Monster Gymkhana Killer
The engine uses a Jenvey ITB intake system with an OMSE custom machined intake manifold plenum.  ITB’s offer superior throttle response and bottom end power. If you are wondering what all those braided steel lines do, they’re a vacuum manifold.  ITB’s have the throttle plates in the intake runners instead of at the opening of the plenum.  Thus there is no vacuum in the plenum only in the runners behind the throttle plates.  So intake vacuum must be taken from each runner to feed things like fuel pressure regulators, MAP sensors and anti lag systems.  This  blow off valve is bypassed when the antilag is used.  When the throttles close, the vacuum opens the anti lag valve which sends boost pressure straight to the exhaust manifold.  The ECU then makes the injectors run rich and retards the timing.  This causes fuel to ignite in the exhaust manifold which helps drive the turbo, pre spooling it, eliminating or reducing lag.

Ultra Motors modified the engine’s block, enlarging the cooling and oiling passages for more flow.  Most noticeably you can see the external water passages to help ensure a good amount of coolant flow in the cylinder head.  A custom Arrow crankshaft with an 84mm stroke machined from billet was selected.  Arrow is a supplier to many F1 teams and makes really high quality cranks. Carrillo rods and JE 88mm forged, lightweight strut type pistons were also used for a final displacement of 2044 cc.  The JE pistons use a fairly high compression ratio of 10:1.  ARP fasteners are used throughout the bottom end to ensure reliability.

 Block Buster, Inside Ken Block's Monster Gymkhana Killer
This shot shows the 900cc shower type injectors.  Shower injectors are often used on racing engines because of their superior atomization.  Because shower injectors introduce the fuel a long way back by spraying into the bell of the intake stack, much of the fuel vaporizes when going down the runner.  The fuel’s latent heat of vaporization cools the intake charge causing it to shrink and increase in density.  More charge can be ingested improving volumetric efficiency.

To ensure lubrication in the violent high G maneuvers that rallycross and Gymkhana create, a dry sump lubrication system is used.  A custom OMSE casting is used for the cylinder head.  The OMSE head has improved cooling and has a stiffer deck for improved sealing under extreme boost pressure.  OMSE ported the head and fortified it with Ferrea valves, lightweight titanium on the intake and heat resisting inconel on the exhaust side. Ferrea valve springs and titanium retainers are used. Ultra Motors camshafts were chosen to activate the valves.

Block Buster, Inside Ken Block's Monster Gymkhana Killer
At 60 psi of boost there is not much margin for error so with the rev limiter pounding and anti lag popping going on a pop off valve is added for safety to the intake manifold plenum just in case you have a turbo sneeze and a hiccup at the same time if you know what we mean.
 Block Buster, Inside Ken Block's Monster Gymkhana Killer
 It was very difficult to get a good shot of the Garrett TR30 turbo due to all of the intricate plumbing around the engine compartment.  Here you can see its not for public consumption thinwall magnesium compressor housing.

To seal the head to the block under extreme conditions, the block deck is grooved and exotic inconel gas filled o-rings are fitted. These work to provide an active seal against combustion pressure.  An MLS gasket backs up the o-rings as does the thick deck OMSE head casting.  ARP studs help keep the head from lifting.

 Block Buster, Inside Ken Block's Monster Gymkhana Killer

 A single Tial 44mm wastegate controls boost pressure.  You can see the thin heat shielded investment cast stainless exhaust housing and big 90mm downpipe. The 90 degree wastegate discharge into the downpipe could be better as Jeff pointed out as over 40% of the exhaust flow comes thru the wastegate.

 

On the exhaust side a divided OMSE tubular manifold is used with one of Garrett’s unobtanium TR30 turbos.  A divided manifold pairs cylinders 1-4 and 2-3 together feeding them individually into a divided twin scroll turbine housing.  This phases the exhaust pulses exactly 180 degrees apart and takes full advantage of the pulse energy to help spool the turbo.  Divided systems improve turbine efficiency by about 15% which is significant as it can reduce turbo lag by over 20%.  Divided systems usually have better volumetric efficiency as well by reducing reversion.  Since turbo engines by nature have more backpressure, having a divided system helps reduce the amount of reversion or exhaust blow back into the cylinders.  In a log manifold, an adjacent cylinder on the exhaust stroke can blow into a cylinder on the intake stroke contaminating and heating the charge.  A divided system makes this much more difficult.  This facilitates the use of more aggressive cam profiles.

 Block Buster, Inside Ken Block's Monster Gymkhana Killer
Charge piping leading to and from the intercooler uses quick release aerospace Wiggins clamps allowing them to be removed in seconds.

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