Go Back  Offshoreonly.com > General Discussion > General Boating Discussion
"Dyno Exploring the 502 EFI" from Hot Boat >

"Dyno Exploring the 502 EFI" from Hot Boat

Notices
General Boating Discussion

"Dyno Exploring the 502 EFI" from Hot Boat

Thread Tools
 
Old 03-16-2011 | 08:46 AM
  #1  
Thread Starter
Registered
 
Joined: Oct 2005
Posts: 5,825
Likes: 612
From: Clarkston, Michigan
Default "Dyno Exploring the 502 EFI" from Hot Boat

This is the four part series as printed in Hot Boat magazine from Jan to April, 1997. I'll start with part 1:






thirdchildhood is offline  
Reply
Old 03-16-2011 | 09:02 AM
  #2  
Thread Starter
Registered
 
Joined: Oct 2005
Posts: 5,825
Likes: 612
From: Clarkston, Michigan
Default

dbkski, if you'd like I could e-mail these to you in higher resolution and more printer friendly format. I thought this might be of interest to others here though. I'll do part two ASAP.
thirdchildhood is offline  
Reply
Old 03-16-2011 | 09:34 AM
  #3  
Dean Ferry's Avatar
Charter Member
20 Year Member
Charter Member
 
Joined: Nov 2000
Posts: 7,213
Likes: 395
From: Merritt Is. Fl. USA
Default

I remember that article, i think I remember that the old KE headers, (back then were PF Marine headers) were the best of the bunch. I'm installing SM manifolds on my 2000 502 EFI's right now. Good article.
Dean
__________________
Everything is for sale @ a certain $$
Dean Ferry is offline  
Reply
Old 03-16-2011 | 10:14 AM
  #4  
Thread Starter
Registered
 
Joined: Oct 2005
Posts: 5,825
Likes: 612
From: Clarkston, Michigan
Default

Originally Posted by Dean Ferry
I remember that article, i think I remember that the old KE headers, (back then were PF Marine headers) were the best of the bunch. I'm installing SM manifolds on my 2000 502 EFI's right now. Good article.
Dean
Yup, good stuff. I'm posting it on request. Here is part 2:







thirdchildhood is offline  
Reply
Old 03-16-2011 | 11:48 AM
  #5  
JasonSmith's Avatar
Registered
20 Year Member
 
Joined: Feb 2005
Posts: 4,333
Likes: 5
From: USA
Default

Nice find. I remember when Hot Boat magazine was the best one out there.
JasonSmith is offline  
Reply
Old 03-16-2011 | 01:39 PM
  #6  
Thread Starter
Registered
 
Joined: Oct 2005
Posts: 5,825
Likes: 612
From: Clarkston, Michigan
Default

Originally Posted by JasonSmith
Nice find. I remember when Hot Boat magazine was the best one out there.
Yup, it was the best, at least as long as it was owned by Flynt. Part 3:










thirdchildhood is offline  
Reply
Old 03-16-2011 | 02:23 PM
  #7  
Thread Starter
Registered
 
Joined: Oct 2005
Posts: 5,825
Likes: 612
From: Clarkston, Michigan
Default

Fourth and final part:








Last edited by thirdchildhood; 03-16-2011 at 02:25 PM.
thirdchildhood is offline  
Reply
Old 03-16-2011 | 05:09 PM
  #8  
ZXXX Donzi's Avatar
Registered
 
Joined: Jun 2004
Posts: 834
Likes: 2
From: Tennessee
Default

Nice article Carl. Thanks for posting
ZXXX Donzi is offline  
Reply
Old 03-16-2011 | 06:55 PM
  #9  
Thread Starter
Registered
 
Joined: Oct 2005
Posts: 5,825
Likes: 612
From: Clarkston, Michigan
Default

I studied the entire article and what they ended up with is very close to a 525 EFI. They installed CMI headers, modified and ported the intake, did the same to the throttle body and did a lot of head work. Then they installed a roller cam with specs nearly the same as a 525 cam. They ended up with 543 hp @ 5,400 RPM. That happens to be where the rev limiter starts to hit on a 525 and is where I run my 525 on the top end. I've often read that the 525 actually puts out closer to 540 hp. The project engine made 594 Lb-ft torque @ 4,000 RPM where the 525 specs at 570 Ft-lb torque @ 3,800 RPM. The project engine was held to just a slight compression increase of the stock 8.75:1 which is the same as the 525. They also confirmed that with the lower compression ratio the engine runs best on 87 octane fuel and lost power with 92 octane. I will always run 87 octane in my 525 from now on unless I'm topping off old fuel.
thirdchildhood is offline  
Reply
Old 03-16-2011 | 07:32 PM
  #10  
Registered
20 Year Member
 
Joined: Dec 2003
Posts: 187
Likes: 0
Default

I did a few projects with Jeff Koerner back then in the early days of MEFI 1 very nice to work with. Marine efi has come a long way since then. Great power from that manifold mod still works today.
CAL MAN is offline  
Reply


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.