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496 & Raylar questions

Old 09-11-2007, 10:59 AM
  #11  
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The intake will not benefit from a larger throttle body on a stock block motor with the 525HP 103 kit. we've tested them many times. this larger throttlebody is required only when we build a HO600 engine where the larger cam and breathing requirements require the larger throttlebody. You are correct as we instruct. You always set fuel pressure with the vac. line disconnected. Your fuel pressure setting should be set a 50psi and you don't need any addtional pressure than that. Your fuel pressure at 3500 rpms under load will probably be around 47-48 psi. Your air fuel settings are just fine. In all the 103 kit equipped motors we measure about 12.8 to 13.2 in that 3000-4000rpm range which is right where Mercury sets them to run on a stock 496. You will see that the air fuel ratios will drop between 4000-5000rpms into the 12.4 to 12.8 range which is right where they should be for a balance between power and slightly safe side. The problem you seemed to have at #3 cylinder was not one of to lean a mixture in the engine overall, since cylinders 1, 7, 2,& 8 are the first ones to lean out under load when the fuel pressure is to low. We know this from our dyno testing where we have exhaust gas temperature sensors on each exhaust during dyno testing. Remember also the air fuel meter guage you are using is not a highly calibrated dyno type we use for our testing and we find they all tend to read a little on the lean side in actual testing. Your numbers on air fuel are just fine and there are hundreds of Raylar 103 kits out there running those same numbers for over three years now with not one engine damaged from a lean condtion. The injectors are just fine and these are the same injectors the factory F-1 race teams used in 2001-2003 for the 525HP engines. Also be advised I believe it is actually Coast Guard illegal to run a fuel line to your dashboard for fuel pressure. Use a claibrated electric guage and sensor for saftey and realize that a fuel pressure line that long from engine to dash would most likely have a pressure drop due to the volume and distance involved. If your stock boost pump, fuel water seperator and primary fuel pump and injectors are operating properly and the fuel delivery system is not impeded you should be having no problems. Also you might want to check the fuel line size from your fuel tank to the boost pump or fuel water seperator and make sure its at least 3/8" size as a restriction in line size here will affect the fuel systems flow at higher demands.
Hope this information helps with your examinations.

Best Regards,
Ray @ Raylar
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Old 09-11-2007, 02:42 PM
  #12  
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Originally Posted by Raylar
Also be advised I believe it is actually Coast Guard illegal to run a fuel line to your dashboard for fuel pressure. Use a claibrated electric guage and sensor for saftey and realize that a fuel pressure line that long from engine to dash would most likely have a pressure drop due to the volume and distance involved.

Ray @ Raylar
Ray is being nice, running a line with 50psi fuel pressure to your dash or windshield is foolish. No sanctioning body would allow this and no doubt your insurance would void your coverage. The technology exists to do this safely. If the gauge or line fails or even loosens you will be instantly inundated with fuel looking for an ignition source, of which there are plenty in most boats.
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Old 09-11-2007, 05:27 PM
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Thanks guys, I appreciate the feedback. I ended up installing the fuel pressure gauge near the floor and on the far starboard side with the line tucked out of sight which would make it very difficult to tamper with. This location is not near the dash or windshield. However, you bring up interesting points and concerns about safety and legal issues. The line I'm using to measure the fuel pressure is much stronger than the factory lines and the thought of it failing didn't cross my mind. I'll look into an alternate this winter.

Ray, I will say she now runs smoother than I ever expected. I don't know if it's the 103 kit or the fact it's a true and balanced hand-built motor, or what...but she runs much better than before and the throttle response is great!
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Old 09-12-2007, 01:06 PM
  #14  
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Ray,
RE: "Remember also the air fuel meter guage you are using is not a highly calibrated dyno type we use for our testing and we find they all tend to read a little on the lean side in actual testing. " Can you share the amount that the hand held A/F meter (Innovate Technology Model LM-1 or similar) reads leaner than the dynamometer unit? What is a make and model of a typical dynamometer A/F recording unit?

Originally Posted by Raylar
The intake will not benefit from a larger throttle body on a stock block motor with the 525HP 103 kit. we've tested them many times. this larger throttlebody is required only when we build a HO600 engine where the larger cam and breathing requirements require the larger throttlebody. You are correct as we instruct. You always set fuel pressure with the vac. line disconnected. Your fuel pressure setting should be set a 50psi and you don't need any addtional pressure than that. Your fuel pressure at 3500 rpms under load will probably be around 47-48 psi. Your air fuel settings are just fine. In all the 103 kit equipped motors we measure about 12.8 to 13.2 in that 3000-4000rpm range which is right where Mercury sets them to run on a stock 496. You will see that the air fuel ratios will drop between 4000-5000rpms into the 12.4 to 12.8 range which is right where they should be for a balance between power and slightly safe side. The problem you seemed to have at #3 cylinder was not one of to lean a mixture in the engine overall, since cylinders 1, 7, 2,& 8 are the first ones to lean out under load when the fuel pressure is to low. We know this from our dyno testing where we have exhaust gas temperature sensors on each exhaust during dyno testing. Remember also the air fuel meter guage you are using is not a highly calibrated dyno type we use for our testing and we find they all tend to read a little on the lean side in actual testing. Your numbers on air fuel are just fine and there are hundreds of Raylar 103 kits out there running those same numbers for over three years now with not one engine damaged from a lean condtion. The injectors are just fine and these are the same injectors the factory F-1 race teams used in 2001-2003 for the 525HP engines. Also be advised I believe it is actually Coast Guard illegal to run a fuel line to your dashboard for fuel pressure. Use a claibrated electric guage and sensor for saftey and realize that a fuel pressure line that long from engine to dash would most likely have a pressure drop due to the volume and distance involved. If your stock boost pump, fuel water seperator and primary fuel pump and injectors are operating properly and the fuel delivery system is not impeded you should be having no problems. Also you might want to check the fuel line size from your fuel tank to the boost pump or fuel water seperator and make sure its at least 3/8" size as a restriction in line size here will affect the fuel systems flow at higher demands.
Hope this information helps with your examinations.

Best Regards,
Ray @ Raylar
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Old 09-13-2007, 11:56 AM
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Its a wide band gas analizer unit which costs over $3000 and its calibrated to be about +- 1% on O2 readings which we take cylinder to cylinder on the dyno.

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Ray @ Raylar
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