email: chris@cjsracing.co.uk tel: 07594 342279
« Back 998 155bhp FastPhil
Phill Issac was a previous Japanese bike owner. He decided one day to purchase a Ducati 998 which he loved very much but was dissatisfied with the straight line performance compared to his old gsxr.
Phill had his heart set on getting 150 hp from the 998s with big midrange power. After a long chat at the CJS workshop Chris said he could make this possible.
In order to get this sort of power from a 998 and keep the engine reliable the engine had to be blueprinted using a balanced crankshaft/flywheel assembly with pankil conrods and pistol 13.1 pistons. The crankshaft balance is critical for high rpm smoothness and prolongs engine life.
As usual the bottom end was shimmed to spec assembled with squish set to the optimum but safe distance for 11.000rpm use.
In standard trim the cylnder heads are only good for 139hp with a big exhaust system. To reach 150hp it needed serious revision especially to the short side radius, throat size and valve angles. Chris re-worked the ports on the flow bench to make the desired shape and installed some 2mm larger flat nail intake valves using the PEG multi angle seat cutter. As chris knew full well that Phil is a member of the DSC and this bike would be in the public eye he ran several more than usual flow tests to establish a better valve and seat combination for more airflow. The heads were also skimmed a little more than usual.
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The new port shape with colsibro race guides.
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New combustion chamber shape with oversize inlet valves.
The new re-worked heads were shimmed using the standard cams which were degree'd to a tried and tested spec to boost the midrange power.
After the engine was installed back into the bike a full 57mm Leovince exhaust system was added along with a powercommander 3.
On dyno day we all smiled and jumped around as the bike made 150hp on its first run.
AWAITING DYNO CHART
Phill was also worried about how reliable a 155hp tune would be. In actual fact the engine is now stronger and more reliable then ducati ever made it . The peak power is now produced at a lower rpm than originally intended prolonging service, valve and rocker life !!
Article included with permission of Fastphil
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