1971 Trojan F31 Hardtop - Twin 1971 Chrysler 318's
Posted: Fri Mar 29, 2024 5:05 pm
Hello to all,
I'm new to the forum and would like to ask some questions about a boat that I'm looking to purchase, (on subject line), and the performance of the engines based on BSFC and it's relationship to RPM, Speed and GPH consumed.
I have put together a simple spreadsheet that includes RPM, HP, Torque, and calculates GPH, MPG and Range but I don't have the GPS speed for corresponding RPM's in order to solve for MPG and Range. So basically, I would like to find out if anyone has GPS speed information they can share for the following RPM's on a Trojan F31 w/ twin 318 Chryslers. It is strictly BSFC for the engines so not concerned about any other variables unless you read GPS while being towed.
RPM
700/ 1000/ 1500/ 2000/ 2500/ 3000/ 3500/ 4000/ 4020/ 4400.
Why 4020 RPM's? Well, the manufacturer has the specifics on the 1971 318's as follows: 230HP @ 4400 RPM and 320Ft-lb torque @ 2000RPM's.
As I was calculating the relationship for torque & HP published, there was a variance. My calculations produced 230HP at 4020 RPM for 300.5Ft-lb to match the manufacturers published T & HP. At 4400 RPM's the calculation produced 251.8 HP for the same torque. So since it may be that their published numbers may be eschewed, I figured I use my calculations instead. For confirmation, I will recalculate with their results once I have reached received the GPS speeds.
Any help would be greatly appreciated and yes, I am positive that there will be many questions to follow.
Thanks
I'm new to the forum and would like to ask some questions about a boat that I'm looking to purchase, (on subject line), and the performance of the engines based on BSFC and it's relationship to RPM, Speed and GPH consumed.
I have put together a simple spreadsheet that includes RPM, HP, Torque, and calculates GPH, MPG and Range but I don't have the GPS speed for corresponding RPM's in order to solve for MPG and Range. So basically, I would like to find out if anyone has GPS speed information they can share for the following RPM's on a Trojan F31 w/ twin 318 Chryslers. It is strictly BSFC for the engines so not concerned about any other variables unless you read GPS while being towed.
RPM
700/ 1000/ 1500/ 2000/ 2500/ 3000/ 3500/ 4000/ 4020/ 4400.
Why 4020 RPM's? Well, the manufacturer has the specifics on the 1971 318's as follows: 230HP @ 4400 RPM and 320Ft-lb torque @ 2000RPM's.
As I was calculating the relationship for torque & HP published, there was a variance. My calculations produced 230HP at 4020 RPM for 300.5Ft-lb to match the manufacturers published T & HP. At 4400 RPM's the calculation produced 251.8 HP for the same torque. So since it may be that their published numbers may be eschewed, I figured I use my calculations instead. For confirmation, I will recalculate with their results once I have reached received the GPS speeds.
Any help would be greatly appreciated and yes, I am positive that there will be many questions to follow.
Thanks