IRL eyes Grand-Am engines

UPDATE #3 This AutoWeek article talks more about the IRL's 2007 engines. Rest assured that if the IRL switches to Grand-Am engines the series will most assuredly fail. Open wheel race fans have no interest in dumbed down formulas. 05/12/05 A reader writes, Dear AutoRacing1.com, Look for confirmation shortly of the IRL going to a Grand Am (Daytona Prototypes) engine spec as you report. I work for a Grand-Am team, and we have had some contact from a few of the 'Marquee' teams in the IRL about builders, engine sources, etc. The spec will require a change to the current IRL chassis as the Grand-Am engines are non stressed members. The IRL wants to spin this in a positive light, by showing that they have true 'international' participation in their engine program if teams opt for BMW, Lexus and Infiniti engines, even if they won't really be 'factory' programs, rather off the shelf Grand-Am packages. Adrian, Florida 05/12/05 A little research reveals that the Grand Am engines are rev limited well below their potential, intake size is limited, etc. It would be relatively easy for the Grand Am engine builders to make those engines put out a lot more horsepower than they currently do. The Grand Am cars do have real-time telemetry between the car and the pits… everything from fuel mixture to suspension, steering and braking functions. 05/12/05 Rumors in the Indy paddock are that the IRL may very well switch to the production based Grand-Am prototype engines starting in 2007. The rumors say Honda and Toyota are definitely gone and the series is looking to make it cheap to go racing, i.e. as in dumbing down the formula and prestige of the series further. Since the Grand-Am series is so popular with the fans as evidenced by the huge throngs of spectators that show up at their races (not) the IRL must think adopting the Grand-Am formula will win over some of the many Grand-Am fans.

We sit here writing what we heard and can only shake our head in amazement. This can't be true, can it? It may explain why the IRL has postponed their engine announcement until after Indy. If it is true, here are the current approved Grand-Am engines that make about 500 HP and 400 ft-lb of torque.

The following engines have been approved for competition in Daytona Prototypes.
BMW S62-B50 32 valve 5.0L V-8
Bore: 3.701″ Stroke: 3.502″ Minimum crank weight: 40 lbs
Maximum compression ratio: 11:1
Cylinder heads and intake cannot be ported.
Intake valve: 1.377″ Exhaust valve: 1.200″
Piston, rings, pin and connecting rod: 936 gm minimum
Maximum camshaft lift @ retainer with zero lash: .445″
Maximum cam duration: 250 ° @ .050″ lift
Induction: 8 individual butterflies @ 1.965″
Twin intake air restrictors of 1.875-inch diameter opening into the approved air box.
Must use OEM intake manifold
RPM limit: 6800
FORD 5.0L V8
Bore: 3.705″ Stroke: 3.543″ Minimum crank weight: 38 lbs
Maximum compression ratio: 11:1
Unported OEM cylinder head.
Intake valve: 1.496″ Exhaust valve: 1.260″
Piston, rings, pin and connecting rod: 1100 gm minimum
Maximum camshaft lift @ retainer with zero lash: .498″
Maximum cam duration: 214° @ .050″ lift
Induction: two butterflies @ 2.250″ diameter
RPM limit: 6900
INFINITI 4.35L V8
Cylinder bore: 3.661″ Stroke: 3.149″
Minimum crank weight: 34 lbs
Maximum compression ratio: 11:1
Cylinder head intake runner maximum volume: 196 cc’s
Cylinder head exhaust runner maximum volume: 83 cc’s
Intake valve: 1.424″ Exhaust valve: 1.237″
Piston w/rings, pin and connecting rod: 1000 gm minimum
Maximum camshaft lift @ retainer with zero lash: .492″
Maximum cam duration: 282°in/320°ex degrees @.050″lift
Intake manifold as approved.
Throttle body: Ron’s four hole throttle body w/1.875″ butterflies and 2.5″ inch spacer.
RPM limit: 7700
LEXUS (TRD) 4.3L V8
Bore : 3.545″ Stroke: 3.300″ Minimum crank weight: 38 lbs
Maximum compression ratio: 11:1
Cylinder head intake runner maximum volume: 139 cc’s
Cylinder head exhaust runner maximum volume: 81 cc’s
Intake valve: 1.356″ Exhaust valve: 1.147″
Piston w/rings, pin and connecting rod: 1053 gm minimum
Maximum camshaft lift @ retainer with zero lash: .478″
Maximum cam duration: 260° @.050″ lift
Rons 4 hole throttle body with 1.875″ diameter butterflies.
Intake manifold TRD (as approved)
RPM limit: 8100
PORSCHE 3.99L GT3R Flat 6
Up to 3.99 liter displacement with unlimited components.
PONTIAC 5.0L V8
*Can also be branded as Cadillac or Chevrolet
Standard Bore LS6 engine block: 3.900″ Stroke: 3.185″
Minimum crank weight: 38 lbs
Maximum compression ratio: 11:1
Cylinder heads must be OEM LS6. Intake and exhaust ports cannot be modified.
Cylinder head intake runner maximum volume: 230 cc’s
Cylinder head exhaust runner maximum volume: 87 cc’s
Intake valve: 2.000″ Exhaust valve: 1.550″
Piston w/rings, pin and connecting rod: 1000 gm minimum
May use titanium wrist pin.
Maximum camshaft lift @ retainer with zero lash: .590″
Maximum cam duration: 260° @.050″ lift
Must use with no modifications: OEM LS6 Corvette part number 88894339 intake.
OEM Camaro throttle body with 2.950″ butterfly part number 17113647
Maximum RPM: 7100