|
177 swap to 250 on 525SC
I've caught a few post on this topic but never really came to a conclusion myself. Wanted to make a little more steam in a triple 525 Black Thunder 43 flat deck. With considering the height of a 71 series blower and having to chop the boat up I'm stuck on the 250. With a single 1150 on E85 what kind of mph should I see with 7 psi over the 177. Thanks for any info |
IMHO, I would think you would see minimal gains for the money/time it would take. |
I’m assuming since your concerned about engine height that you are not running intercoolers? |
[QUOTE=dykstra;4614736] I’m assuming since your concerned about engine height that you are not running intercoolers? [/QUOTE Yes I'm more concerned with the sale down the road. Speed is nice but so is function and form. I'm thinking E85 should help and maybe meth injection after 3 pounds to cool it off. I've never seen a post stating someone took off the 177's added 250's and said what the outcome was. It's a easy swap and really the only swap if height is a factor and you can't afford W blowers lol. I have this formula at 5150rpm 17% prop slip 7#'s of boost I'm at 87mph not sure if I brought the motors up 75 horse each what mph gain I would see 5-10mph? I've heard every 25hp is a mph in a 40' boat not sure how accurate that is. |
That will take about 25hp per engine per 1mph gain.
Going from 177's to 250's at the same boost might gain you 25hp per engine. |
Originally Posted by dykstra
(Post 4614736)
I’m assuming since your concerned about engine height that you are not running intercoolers? |
I have a Weiand 174 blower on a 454 with meth (29% methanol, so I am using it for cooling only, not additional fuel) that comes on at 3.5 lbs boost. The intake temp drops from 195 to 110 immediately when the meth comes on. The temp sensor is installed in one of the intake runners below the blower.
Your results might be slightly less, because I need to back off on the nozzle size, as it is a bit strong. I have no experience with an intercooler, because my spark arrester barely clears the stock hatch as it is. I would have to think that dropping the intake temp 85 degrees is significant. Just noticed that I am shown as just joining in Nov 2017, and this is my first post. Odd. I originally signed up at least 10 years ago. Things that make you go hmmmm..... |
Originally Posted by thisistank
(Post 4614812)
That's what I was thinking. Intercoolers would prob give as much HP gain and even improve reliability over changing to larger blowers.
Isnt it Mild who has run just about every size blower you can think of on a 454 ? I may be wrong but I think I remember him saying that he picked up speed every time he went to a bigger blower even at the same boost level. |
Originally Posted by phragle
(Post 4614824)
Im kinda thinking the opposite... the 177 is small for a bbc...A cooler is a restriction,so now you spin a small blower even harder, making more heat to compensate for a cooler. A bigger blower wont have to work as hard to make the same boost, so it would run cooler to begin with.
Isnt it Mild who has run just about every size blower you can think of on a 454 ? I may be wrong but I think I remember him saying that he picked up speed every time he went to a bigger blower even at the same boost level. |
Originally Posted by thisistank
(Post 4614826)
I was under the impression a chiller gives more power even with a smaller blower. Many people (me included) have run chillers on those stock 525SC Merc motors with great results = more speed.
|
| All times are GMT -5. The time now is 07:41 AM. |
Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.