My 3 Yr Dilemma is Over!!
03-18-2006, 08:33 AM
#1
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My 3 Yr Dilemma is Over!!
For the past three seasons I have been trying to get my engine to pull higher RPMs than 4800 and figure out why it seemed to be low on HP. The first dyno run indicated only 550 HP, significantly lower than the 648 HP it showed after the rebuild in '03. Many people have offered advice and suggestions, unfortunately to no avail, but I certainly appreciated the input.
This week after, seven days on the dyno, I am happy to say the gremlins are all gone. The issues we found and corrected are:
The cam was a little light on duration and lobe seperation for a blower engine. Bob Madera at Marine Kinetics designed a better cam profile and helped the engine breath better. This helped immensly.
The rev limiter in the ECU had been set at 5600, but for some reason started shutting down the injectors at 4800 RPM. Thats why it would never go beyond the 4800 RPM regardless of the prop I ran. We moved the rev limiter up to 6100 RPM and the issue is gone. I use a soft touch rev limiter at 5800 to protect the engine.
The blower belt was slipping at the higher RPMs and this was never noticable in the boat with the little/cheap gauge. We now have 5# of boost up to the rev limiter.
And finally the fuel map was all over the place, rich on the bottom, lean in the mid range and rich on top. We were able to adjust the pulse width at every RPM range to achieve an air/fuel ratio of 12.5 across the board. This helped with the HP, a little economy and less sooty transom.
We ended up picking up 88 HP and 1200 RPM. The engine produced 652 Ft. Lbs of torque at 4300 RPM and 638 HP at 5400 RPM and was still high on HP up to 6000 RPM.
I would like to thank Bob at Marine Kinetics and everyone at Ateco Engine and Dyno shop http://www.atecoengines.com/
without these guys I'd still be chasing my tail!
Thank you very much,
Kirk
Pantera638HP
This week after, seven days on the dyno, I am happy to say the gremlins are all gone. The issues we found and corrected are:
The cam was a little light on duration and lobe seperation for a blower engine. Bob Madera at Marine Kinetics designed a better cam profile and helped the engine breath better. This helped immensly.
The rev limiter in the ECU had been set at 5600, but for some reason started shutting down the injectors at 4800 RPM. Thats why it would never go beyond the 4800 RPM regardless of the prop I ran. We moved the rev limiter up to 6100 RPM and the issue is gone. I use a soft touch rev limiter at 5800 to protect the engine.
The blower belt was slipping at the higher RPMs and this was never noticable in the boat with the little/cheap gauge. We now have 5# of boost up to the rev limiter.
And finally the fuel map was all over the place, rich on the bottom, lean in the mid range and rich on top. We were able to adjust the pulse width at every RPM range to achieve an air/fuel ratio of 12.5 across the board. This helped with the HP, a little economy and less sooty transom.
We ended up picking up 88 HP and 1200 RPM. The engine produced 652 Ft. Lbs of torque at 4300 RPM and 638 HP at 5400 RPM and was still high on HP up to 6000 RPM.
I would like to thank Bob at Marine Kinetics and everyone at Ateco Engine and Dyno shop http://www.atecoengines.com/
without these guys I'd still be chasing my tail!
Thank you very much,
Kirk
Pantera638HP
Charter Member
03-21-2006, 04:59 PM
#5
MarineKinetics
Platinum Member
Re: My 3 Yr Dilemma is Over!!
Kirk,
Congratulations on making the numbers you targeted. Running down multiple gremlins can be frustrating, nice job from Bill and Jeff @ Ateco on the dyno work. Have a great summer on the water!
Regards,
Bob
Congratulations on making the numbers you targeted. Running down multiple gremlins can be frustrating, nice job from Bill and Jeff @ Ateco on the dyno work. Have a great summer on the water!
Regards,
Bob
