Top speed run with B1 26 pitch
06-03-2023, 09:30 AM
#11
Registered
I noticed that the rpm was down on that engine too. I am aware that there are several factors that could cause one engine to have a different rpm but the props not being a "matched set" is definitely one reason.
I am going to try the Spinelli's next week. I am a little worried that they will be worse than the B1 28's only because I looked on the hub and it says 29". I understand that different manufactures props don't align with the others and these could run like a smaller pitch B1. Either way, I'll let you know.
As far as the "labbed 28's" I would like to try them just out of curiosity however, I'm not sure why if they are still a 28 pitch why I would be able to get more rpm and speed? I already ran 28's and don't have the hp to run them.
As far as trimmed out, yes I was however opinions vary on what is enough. I trimmed till the boat stopped making speed. This "measurement" is obviously not exact, but on my mechanical indicator, I was very close to "5" on the scale. This is a new addition to the boat and I am still looking for the correct setting. I have posted before that I "feel" like the bow should come up more however, I don't have a pic or video of the boat running so maybe not?
As a side note, the mid range from cruise to WOT with the new power is awesome! Even with the 28's it pulled hard. The 24' s were ridiculous!
I will get with you next week about the props. Thanks again for your help.
I am going to try the Spinelli's next week. I am a little worried that they will be worse than the B1 28's only because I looked on the hub and it says 29". I understand that different manufactures props don't align with the others and these could run like a smaller pitch B1. Either way, I'll let you know.
As far as the "labbed 28's" I would like to try them just out of curiosity however, I'm not sure why if they are still a 28 pitch why I would be able to get more rpm and speed? I already ran 28's and don't have the hp to run them.
As far as trimmed out, yes I was however opinions vary on what is enough. I trimmed till the boat stopped making speed. This "measurement" is obviously not exact, but on my mechanical indicator, I was very close to "5" on the scale. This is a new addition to the boat and I am still looking for the correct setting. I have posted before that I "feel" like the bow should come up more however, I don't have a pic or video of the boat running so maybe not?
As a side note, the mid range from cruise to WOT with the new power is awesome! Even with the 28's it pulled hard. The 24' s were ridiculous!
I will get with you next week about the props. Thanks again for your help.
The Spinellis spin rpm's closer to a Bravo 26/27. They have less surface area and carry the bow better than the Bravo's. My boat seems to be less wetted with them and a better overall prop (personal opinion) and they look cool.
The labbed 28's are 28 pitch, but blades thinned and worked to bring RPM's up. They feel slippery in the water. I actually would like you to try the 28's they act weird on my boat and you could confirm if it is my boat or the props.
The following 2 users liked this post by Rookie:
Brad Christy (06-05-2023), PQ290Enticer (06-03-2023)
The following users liked this post:
PQ290Enticer (06-03-2023)
08-06-2023, 02:54 PM
#13
Registered
Thread Starter
I switched out the factory mufflers (I think someone said they were from Corsa) for straight through 4" tips and picked up some speed. The old mufflers started at 4" then shrunk down to 3" then back up to 4" for the muffler. Anyway, I hit 76 mph at 5300 rpm using the B1's @ 26" pitch. That's up about 200 rpm. I will admit that I trimmed it out a little further than my original top speed run so I am sure that is part of the increase. Also I had about 5/8 of a tank of gas vs a full tank.
Just to ask the question, if I put the 28's back on and the rpm at WOT climbs to 4600-4700 would that be okay? The max torque for my engines was about 520 ft lbs at 4400. How far away from this number is considered safe? I don't live at WOT and the longest run I think so far has been less than a couple minutes. I do lots of cruising at 3500 rpm and unfortunately a lot of "No Wake" idle speed on the river. When I tried the 28's before, the boat got on plane easily and the acceleration was crazy. That is the greatest feeling when you accelerate from a cruise speed at 3500 rpm to top speed. It really pulls hard! Night and day from stock. The top speed with the 28's was 75 mph vs at the time 74 mph with the 26's.
Thanks for your help and comments.
Just to ask the question, if I put the 28's back on and the rpm at WOT climbs to 4600-4700 would that be okay? The max torque for my engines was about 520 ft lbs at 4400. How far away from this number is considered safe? I don't live at WOT and the longest run I think so far has been less than a couple minutes. I do lots of cruising at 3500 rpm and unfortunately a lot of "No Wake" idle speed on the river. When I tried the 28's before, the boat got on plane easily and the acceleration was crazy. That is the greatest feeling when you accelerate from a cruise speed at 3500 rpm to top speed. It really pulls hard! Night and day from stock. The top speed with the 28's was 75 mph vs at the time 74 mph with the 26's.
Thanks for your help and comments.
09-10-2023, 04:08 PM
#14
Registered
Thread Starter
So like many or all of you I was suppose to "happy" reaching my original goal of running in the 70's. I am so close to 80 mph that it's become my new goal. I'm going to swap the borrowed B1 26's for the borrowed B1 28's and see if I can get it there. It was a little faster with those when I ran them at the beginning of the season but the rpm wasn't great. Anyway, with a little less fuel and now that I'm trimming the drives higher, I am pretty sure it will make it. I'm calling this 78mph in this video and for what it's worth, I was running against the current. My brother took a vid of me going by at WOT so I could see how it's riding and it's riding higher than I thought. It does feel real loose at WOT. Different topic all together but I think I may owe boatnt an apology. Long ago we were talking about the turned down chine on a 290 affecting chine walk etc. and I said at WOT that part of the boat is not in the water so how can it affect the ride? Hard to see in the vid but I think it may be in the water. Live and learn. If you're interested, please take a look.
The following 6 users liked this post by PQ290Enticer:
1983ScarabIII (09-11-2023), CheckmateScarab (10-01-2023), miller high life (10-05-2023), pasquesi (10-02-2023), swellcraftman (09-10-2023), thegoodson (09-10-2023)
09-10-2023, 05:29 PM
#15
Registered
Port is easily 2 or 3 hundred rpms lower. I think its got 2 or 3 mph left in it with better props. Also if you have a way to raise hatch 1 or 2 inches with it flying off it sometimes gives the motors more air and can get 1 or 2 mph. Its boat dependent. Sure looks like 80 going by.
Chris
Chris
The following users liked this post:
PQ290Enticer (09-10-2023)
09-11-2023, 03:55 PM
#16
Registered
Video on the river looks great. You have done a good job on it.
09-11-2023, 04:19 PM
#17
Registered
Thread Starter
The following 2 users liked this post by PQ290Enticer:
1983ScarabIII (09-11-2023), liberator221 (09-11-2023)
Platinum Member
The following users liked this post:
PQ290Enticer (09-11-2023)
09-13-2023, 08:39 PM
#19
VIP Member
VIP Member
The curse of hot rodders. Just 2 more mph right? 😅
enjoy the process
enjoy the process
__________________
Formula 353
Merc Racing 540s
Formula 353
Merc Racing 540s
The following users liked this post:
PQ290Enticer (09-14-2023)
09-30-2023, 05:42 PM
#20
Registered
Thread Starter
Found out that one engine is not operating at 100%. I'm in the process of fixing that and it brought up a question in my mind. The starboard engine runs about 5300 rpm and the port was about 5100 rpm. If I get the port to run equally with the other that maybe the overall rpm of both would go up? Does that make sense? I am thinking that the starboard engine could only reach 5300 because it's being held back by the other? If they both are running the same could I expect that both of them may turn 54-5500 rpm? I ask mainly because over the winter I will be ordering my props. I also really want to run 80 mph. I could do with the 26's if the rpm would come up. The info above is using 26's. Thanks for your help and comments.
