Welcome to the @Porsche911UK website. Register a free account today to become a member! Sign up is quick and easy, then you can view, participate in topics and posts across the site that covers all things Porsche.
Already registered and looking to recovery your account, select 'login in' and then the 'forget your password' option.
Bigfra said:As title chaps, fancied the parr 3.9 conversion but 450 bhp doesn't sound much if I'm honest. Any other options besides sending the engine to the states ?
Bigfra said:As title chaps, fancied the parr 3.9 conversion but 450 bhp doesn't sound much if I'm honest. Any other options besides sending the engine to the states ?
NXI20 said:Power figures sell cars, torque wins races.
Bore and stroke on the 3.6-litre engine is 100mm x 76.4mm; on the 3.8 they changed it to 102.7mm x 76.4mm. On the 4.0, they kept the same piston size of 102.7mm and increased the stroke by 4mm to 80.4mm
According to Andreas Preuninger, Porsche motorsport manager for high-performance cars: "We have finally really reached the bore limit with this engine. This is the maximum before we need to create a new engine blueprint." Wall thickness between bores is in fact so thin now that steel cylinder liners have been added for durability as with the GT3 RSR racecars.
In my experience of doing a 3.9 conversion (using 104mm pistons) but retaining the standard crank & rods, going over the 102.7mm bore of the 3.8 results in the piston flopping around inside the cylinder because they have to allow for the piston to expand and the cylinder expands much less than the piston; the greater the diameter, the more the piston expands when hot and this larger cold clearance increases wear. Not to mention sounding like a bag of nails until fully up to temperature. I don't have that engine any more due to piston / ring failure after 42K miles. There's a reason that Porsche don't use a larger piston & chose a longer stroke for the 4.0 ...
AFAIK, nobody has made a N/A Mezger engine of over 4.0 produce reliable big power for hundreds of hours on a track. Claims of 50K miles on the road in big bore cars are out there but that's not really stressing the engine. Just because it's possible doesn't automatically mean it's a good idea...
nick w said:Nice concise summary...and anyone out there thinking of investing in a 3.9
conversion i'd take real heed. If you're in need of more power for your 997,
your best bet is find yourself a nice gen 2 car, that has a useful edge of extra
bhp and a better and slightly fuller torque curve.
The other remedy.....a 997 RS 4.0...maybe not !. :roll:
tonymac3 said:How about this conversion for FVD
997 GT3 / RS 3.6L ( to 4,1L ) Level 3 (485HP/354TQ)
FVD 997 100 83B
8.995 €
Add to cart
SRP: 9.748 €
11.600,12 €
FVD 997 GT3 4.1 Level 3 Kit
- Max. Power - 485 HP (357 kW) @ 8100 rpm
- Max. Torque - 354 lb ft (480 Nm) @ 5650 rpm
- Max. Speed - 198 mph (320 kph)
- Max. RPM - 8600 rpm
- Acceleration 0-100 kph (0-62 mph)* - 3.7s
* Based on German tests done with kph. 100 kph = 62.137 mph
The FVD conversion kit includes:
MAHLE Piston & Cylinder set 4.1 L (106mm), 997.1 & 997.2 GT3/RS x 1
FVD Software upgrade for 3.6 L to 4.1L with My Genius Flash tool x 1
BMC sport air filter for 997.1 GT3 x 1
Intake manifold 4.0 L x 1
Engine gasket set 997 GT3 x 1
Cylinder head gaskets for 4.1 L FVD conversion x 2
Cylinder base gasket for 4.1 L FVD conversion x 2
Intermediate shaft bearings x 2
Intermediate shaft thrust bearings x 2
Connecting rod bearing shell x 12
Spark plug GT3 x 6
Crankshaft pulley washer 997.1 GT3 x1
O-ring for thermostat housing x 1
Pan head screw x 2
Hexagon head bolts x 2
Washers x 2
Screw x 2
O-rings for actuators (small) x 2
O-rings for actuators (large) x 2
O-ring for oil tube x 1
Gaskets for exhaust manifold x 2
Further additional parts/work required:
- Connection rods (22mm pin) FVD10397520
- Modification of the customer's original water housing - 2 Qty.Needed (Right and Left) FVD10303905WKA
- Modification of the customer's original crankcase FVD10303905MG
- Modification of the customer's original crankcase to 2 oil jets (or purchase 3.8 crankcase)
We recommend the use of an M&M Exhaust System BES99701260S with 200 sport catalytic.
The labor for the engine conversion is approximately 65 hours.
TàœV-Approval is only possible for vehicles converted by us and equipped with a valved exhaust system.
TonyMac.
Bigfra said:tonymac3 said:How about this conversion for FVD
997 GT3 / RS 3.6L ( to 4,1L ) Level 3 (485HP/354TQ)
FVD 997 100 83B
8.995 €
Add to cart
SRP: 9.748 €
11.600,12 €
FVD 997 GT3 4.1 Level 3 Kit
- Max. Power - 485 HP (357 kW) @ 8100 rpm
- Max. Torque - 354 lb ft (480 Nm) @ 5650 rpm
- Max. Speed - 198 mph (320 kph)
- Max. RPM - 8600 rpm
- Acceleration 0-100 kph (0-62 mph)* - 3.7s
* Based on German tests done with kph. 100 kph = 62.137 mph
The FVD conversion kit includes:
MAHLE Piston & Cylinder set 4.1 L (106mm), 997.1 & 997.2 GT3/RS x 1
FVD Software upgrade for 3.6 L to 4.1L with My Genius Flash tool x 1
BMC sport air filter for 997.1 GT3 x 1
Intake manifold 4.0 L x 1
Engine gasket set 997 GT3 x 1
Cylinder head gaskets for 4.1 L FVD conversion x 2
Cylinder base gasket for 4.1 L FVD conversion x 2
Intermediate shaft bearings x 2
Intermediate shaft thrust bearings x 2
Connecting rod bearing shell x 12
Spark plug GT3 x 6
Crankshaft pulley washer 997.1 GT3 x1
O-ring for thermostat housing x 1
Pan head screw x 2
Hexagon head bolts x 2
Washers x 2
Screw x 2
O-rings for actuators (small) x 2
O-rings for actuators (large) x 2
O-ring for oil tube x 1
Gaskets for exhaust manifold x 2
Further additional parts/work required:
- Connection rods (22mm pin) FVD10397520
- Modification of the customer's original water housing - 2 Qty.Needed (Right and Left) FVD10303905WKA
- Modification of the customer's original crankcase FVD10303905MG
- Modification of the customer's original crankcase to 2 oil jets (or purchase 3.8 crankcase)
We recommend the use of an M&M Exhaust System BES99701260S with 200 sport catalytic.
The labor for the engine conversion is approximately 65 hours.
TàœV-Approval is only possible for vehicles converted by us and equipped with a valved exhaust system.
TonyMac.
I would be concerned about reliability with this. Been speaking to Matt at Fear sport after Nick's advice so let's see what happens over the next few months. A gen 2 car would be ideal as well but no CS spec cars about at the moment