Alpine951

I know the Brumos car ran the six last year with the higher allowed rpm than the V8's. Same this year? What about the other Porsche DP? The Cayenne V8 looks like it's still allowed.

ilko

It's a Cayenne V8, correct.

srf506

All but the Brumos car I believe are running the Cayenne V-8 derivative built by the Lozano Bros. Brumos has the only flat-six running in a DP.

brendo

not sure about the brumos car but others are running the V8

Meister Fahrer

Go Brumos, go Flat 6, less is more!

Blackness

The Brumos car is the 4.0L flat-six. Not sure of the RPM limits this year. The #9 and #90 are cayenne V8's.

Alpine951

Max rpm on the six is 9600
DAYTONA PROTOTYPES ENGINE ELIGIBILITY AND APPROVAL LIST as of 1/19/10
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: .500″ Maximum cam duration: 260 ° @ .050″ lift Induction: 8 individual butterflies @ 1.965″ Must use OEM intake manifold. Air intake to be sealed to 11 x 9 9/16 hole in top of OE intake manifold. Must use approved air box. Cam profile on file cannot be changed RPM limit: 7000 Maximum fuel pressure 5 bar ( 72.5 psi)
FERRARI 4.5L V8
Bore: 3.70” Stroke: 3.185” Minimum crank weight 36.2 lbs. Maximum compression ratio:12.8:1. Cylinder heads and intake cannot be ported. Cylinder head intake port volume: 75.4cc. Cylinder head exhaust port volume: 142cc. Intake valve: 1.486”. Exhaust valve: 1.215”. Piston, rings, pin and connecting rod: 920 gm. Minimum. Maximum camshaft lift at retainer with zero lash: .520”. Maximum cam duration: 225oin/216oex @.050” lift. Induction: two throttle bodies @ 82mm. RPM limit: 8200. Maximum fuel pressure 5 bar ( 72.5 psi)
FORD 5.0L V8
Bore: 3.705″ Stroke: 3.543″ Minimum crank weight: 38 lbs, Maximum compression ratio: 11:1 OEM GT40 cylinder head with production intake ports. . Maximum intake runner volume: 251cc, maximum exhaust runner volume: 115 cc Intake valve: 1.496″ Exhaust valve: 1.260″ Piston, rings, pin and connecting rod: 1000 gm minimum Maximum camshaft lift @ retainer with zero lash: .498″ Maximum cam duration: 254° @ .050″ lift Induction: two butterflies @ 2.250″ diameter. Intake manifold by RYRE / Ford Racing, RPM limit: 7000 Maximum fuel pressure 5.0 bar ( 72.5 psi) Cam profile on file cannot be changed
HONDA 3.8L V6
Bore: 3.54” Stroke: 3.70” Minimum crank weight 35 lbs. Individual runner throttle bodies (2.370”) Maximum fuel pressure 5 bar (72.5 psi)
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 Maximum fuel pressure 5.5 bar ( 80 psi)
LEXUS ( TRD) 5.0L V8
Cylinder bore: 3.720″ Stroke: 3.500″ Minimum crank weight: 38 lbs. Maximum compression ratio: 11:1 Cylinder head intake runner maximum volume: 145 cc’s Cylinder head exhaust runner maximum volume: 81 cc’s Intake Valve: 1.458″ Exhaust valve: 1.178″ Piston w/rings, pin and connecting rod: 1000 gm minimum. Maximum
camshaft lift @ retainer with zero lash: .510″ Maximum cam duration 260° @ .050″ lift. TRD intake #17112-GA008 top, # 17110-GA008 bottom, Toyota Throttle body # 22030-0F010 Maximum fuel pressure 5 bar ( 75.4psi) Maximum rpm : 7000; minimum crankshaft weight: 38 lbs. Cam profile on file cannot be changed
PORSCHE 3.99L GT3R Flat 6
Up to 3.99 liter displacement. Engine to Transaxle adaptor with 24/25 or 24/23 (Xtrac only) drop gear ratio permitted allowed approved supplier TBA. Maximum RPM: 9600. Maximum fuel pressure 5.2 bar (75.4 psi) Cars electing to use this engine must weigh 2275 lbs. Six speed transaxle is permitted.
CAYENNE based 5.0L V8
( by Lozano Bros. Porting)
Cylinder Bore: 3.701 Stroke 3.543 ,Minimum crank weight :38 lbs .Maximum compression ratio: 11:1. Cylinder head intake runner volume 156 cc’s. Cylinder head exhaust runner volume: 121 cc’s . Intake valve:1.464.Exhaust valve: 1.282.Piston w/rings ,pin and connecting rod 1000gm minimum .Maximum cam duration 260°@.050 lift .Maximum cam lift w /zero lash: 500. Throttle body : 3.159 ID.( Lozano Bros.) Ma body : 3.159 ID.( Lozano Bros.) Maximum fuel pressure 5 bar ( 72.5 psi). Maximum rpm 7300. PONTIAC 5.0L V8
*Can also be branded as Cadillac or Chevrolet. Standard Bore LS6 or sleeved LS2 engine block: 3.900″ Stroke: 3.185″ Minimum crank weight: 38 lbs Maximum compression ratio: 11.5:1 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 Maximum RPM: 7100 Maximum fuel pressure 5 bar ( 72.5 psi)
PN 54042 LSRXT Intake Manifold, PN 54009-9 LS6-type port gasket replacement seal set and # PAX – 0649 throttle body available through GM - charles.vancamp@gm.com.

Land Jet

Thanks for this info. The TV people use to give this info at the beginning of the broadcast but for a number of years now, they don't.

APKhaos

Looks like the 4L GT3R also gets a minumum weight benefit.
- Anyone happen to know how much lighter this 2275# is vs the others?
- Are all other DPs at the same weight?

Alpine951

http://admin.grand-am.com/assets/dprulesforweb2.pdf

Just noticed under 4.0 liters doesn't have any limitation on compression or throttle body size.


SECTION 3 - WEIGHT
3-1 Minimum Weight - Minimum car weight, per engine displacement, less fuel and driver race ready.
Minimum weight for cars 4.0 liters or more, 2275 lbs
Minimum weight for cars under 4.0 liters, 2225 lbs
3-1.1 GRAND-AM reserves the right to adjust the weight of any car.
3-1.2 The use of titanium is prohibited except for engine valves and valve spring retainers.
3-1.3 The use of magnesium is prohibited.

JustinL

Being under 4.5L also allows them to use a 6 speed instead of 5.

IcemanG17

I would imagine the Porsche V8 from the ALMS P2 cars would work out nicely in this application??

Larry Herman

Allowing the Flat 6 to run a 6 speed again is a big help. The 5 speed trans was killing them coming off of corners.

APKhaos

So......The 3.99L [aka <4L] Porsche 6 cylinder gets PENALTY weight added to the 2225# for <4L engines?

MUSSBERGER

Didn't Brumos get penalized for being under weight after a race?