 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| August 2006 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Testarosso or MBP 4 valve Red Heads | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| After several months of waiting (seven and a half month) I finally received the heads for my 984 monster S4. Guy Martin at MBP did the following job. Bigger valves 37/31mm, new guides, new valve seats, and a serious porting job. He also installed the MBP Valve Retaining System instead of the normal half rings, polished the cams and adjusted the valves | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
 |
||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||
| The main goal with this engine is to give a lot of useful and reliable and power that does not require continues maintenance. The power goal for this engine is 130hp on the Dyno bench that I am using. On this bench the standard 916 /MS4 engine produced 99hp. With slipons, open airbox, timed cams and PC3 with custom map she made 106hp. With 996SPS cams, ST4 (45mm instead of 40mm) exhaust it was 114hp. To reach my goal with 130hp I will use 955 (96mm bore) cylinders with omega HC pistons, 900ss crank shaft (68mm stroke), Termigioni 45/50 spaghetti system. To keep it all in one piece I will use Carrillo steel rods and the rev limiter will be at 10000RPM. The only thing that I can see today that will prevent me from getting 130hp is the exhaust and the standard throttle bodies. I am not sure how much power the Termigioni 45/50 system can handle. A tapered Acrapovic would be perfect but they do not make a system for the monster. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
 |
 |
 |
||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||
| It does not look like it is a lot of difference between the Pre mod and Post mod heads on the pictures but when you have them in the hands and look closely it is a big difference. The ports are a bit bigger but the big difference is the shape of the ports in the valve area and the shape of the valves. As you might have figure out the red heads are the MBP modified ones. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
 |
||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
 |
||||||||||||||||||||||||||||||||||||||||||||||||||||||
| The exhaust looks a bit different too but not easy to see on pictures. | Foggy is checking out my heads | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Polished 996 SPS cams | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
 |
 |
|||||||||||||||||||||||||||||||||||||||||||||||||||||
| The actual combustion chamber (I guess that it is not the correct name on a piston engine) is just slightly modified. It also looks like the heads has been machined a few tenth of a millimeters to increase compression | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| MBP Valve Retaining System | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Go to Building the Testarosso 984 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Back to S4 main page | |||||||||||||||||||||||||||||||||||||||||||||||||||||||