Go Back  Offshoreonly.com > Technical > General Q & A
502 EFI Intake Limitations >

502 EFI Intake Limitations

Notices

502 EFI Intake Limitations

Thread Tools
 
Old 03-08-2006 | 02:08 PM
  #21  
Kanookstr's Avatar
32' SUNSATION
 
Joined: Feb 2001
Posts: 1,143
Likes: 0
From: MA
Default Re: 502 EFI Intake Limitations

Originally Posted by Pantera28-650HP

I would still be circulating fuel with the regulator so chances are it would heat up a little.
Brett at Aeromotive said you should not return the fuel to the fuel filter/separator (the way mercruser does) that's what heats up the fuel thus needing a fuel cooler. Returning the fuel to the tank directly eliminates the need for a fuel cooler. It also helps in preventing fuel pump cavitation.
Kanookstr is offline  
Reply
Old 03-08-2006 | 07:44 PM
  #22  
Elite Marine's Avatar
Thread Starter
Banned
 
Joined: Aug 2002
Posts: 5,658
Likes: 1
From: IL
Default Re: 502 EFI Intake Limitations

My fuel fill is in the front of the boat, so returning to the tank is not a real good option.

Smitty, where did you get the cooler from and how does it mount (engine or stringer mount)?
Elite Marine is offline  
Reply
Old 03-08-2006 | 08:14 PM
  #23  
articfriends's Avatar
Platinum Member
20 Year Member
Platinum Member
 
Joined: Jun 2004
Posts: 7,318
Likes: 1,037
From: frankenmuth michigan
Default Re: 502 EFI Intake Limitations

Originally Posted by Pantera28-650HP
My fuel fill is in the front of the boat, so returning to the tank is not a real good option.

Smitty, where did you get the cooler from and how does it mount (engine or stringer mount)?
I bought the cooler from Tyler Crockett for around 100$,I think I saw one in cp perf catalog for same price too.I have cooler mounted in the discharge hose from raw water pump on left hand side of motor (as you face it from the front) near the motor mount. I am also returning fuel to a tee before the suction side fuel filter (between it and the suction from gas tank),everyone says its not "ideal" BUT there is no good way on my boat to return extra fuel to the tank and I have no fuel pressure issuse even at the 950 hp level,Smitty
articfriends is offline  
Reply
Old 03-08-2006 | 09:26 PM
  #24  
Kanookstr's Avatar
32' SUNSATION
 
Joined: Feb 2001
Posts: 1,143
Likes: 0
From: MA
Default Re: 502 EFI Intake Limitations

Originally Posted by Pantera28-650HP
My fuel fill is in the front of the boat, so returning to the tank is not a real good option.

Smitty, where did you get the cooler from and how does it mount (engine or stringer mount)?
Mine is in the front as well. If you look where your pickup is coming out of the tank in the back you'll notice an extra plug where you can put your return. A "T" before the suction side of the pump will guaranty premature pump failure. And that always results in a piston melting... Been there done that..
correct Pressure doesn't mean you have correct volume. learned that the hard way too. I increased my draw tube to 5/8" and got rid of the "T" and returned to the tank. There is really no easy way to go around this problem, sure The "T" works, but it will fail eventually. I got about 80 hrs on mine before it happened.

Last edited by Kanookstr; 03-08-2006 at 09:34 PM.
Kanookstr is offline  
Reply
Old 03-08-2006 | 09:36 PM
  #25  
Kanookstr's Avatar
32' SUNSATION
 
Joined: Feb 2001
Posts: 1,143
Likes: 0
From: MA
Default Re: 502 EFI Intake Limitations

Here is another post that talks about kinda the same thing.
It also has links to how some of the guys returned there fuel to the tank. OSO post
Kanookstr is offline  
Reply
Old 03-08-2006 | 09:44 PM
  #26  
Kanookstr's Avatar
32' SUNSATION
 
Joined: Feb 2001
Posts: 1,143
Likes: 0
From: MA
Default Re: 502 EFI Intake Limitations

Another post.
.
.
fuel pump plumbing
Kanookstr is offline  
Reply
Old 03-09-2006 | 03:49 AM
  #27  
articfriends's Avatar
Platinum Member
20 Year Member
Platinum Member
 
Joined: Jun 2004
Posts: 7,318
Likes: 1,037
From: frankenmuth michigan
Default Re: 502 EFI Intake Limitations

Originally Posted by Kanookstr
Mine is in the front as well. If you look where your pickup is coming out of the tank in the back you'll notice an extra plug where you can put your return. A "T" before the suction side of the pump will guaranty premature pump failure. And that always results in a piston melting... Been there done that..
correct Pressure doesn't mean you have correct volume. learned that the hard way too. I increased my draw tube to 5/8" and got rid of the "T" and returned to the tank. There is really no easy way to go around this problem, sure The "T" works, but it will fail eventually. I got about 80 hrs on mine before it happened.
I know what your saying but my fuel tank has no extra fitting and getting to the filler neck to cut in a return tee is also nearly impossible without removing top half of my hull.I have a fuel filter that holds 1 qt of fuel between the suction side of my pump and the tee where my fuel returns. I'm also running two regulators back to back,one holds the base pressure,the other overtakes the first when boost referencing,and I'm reading fuel pressure off the excess in the charged loop returning the extra fuel from the rail to first regulator. If there wasn't enough volume the pressure wouldn't be there or regulator would close down more,its not ideal but it works and my fuel pump longevity has never been a issue. I been using this set-up for about 350 hours with no problems and I'm currently supporting 950 hp,Smitty
Attached Thumbnails 502 EFI Intake Limitations-dsc02974.jpg   502 EFI Intake Limitations-fuel-regulator-016.jpg   502 EFI Intake Limitations-fuel-regulator-017.jpg  

articfriends is offline  
Reply
Old 03-09-2006 | 10:34 AM
  #28  
Kanookstr's Avatar
32' SUNSATION
 
Joined: Feb 2001
Posts: 1,143
Likes: 0
From: MA
Default Re: 502 EFI Intake Limitations

Sounds like you got it work out for your app.

My main point is that you have to be careful and not think that having the right fuel pressure means you have the right volume of fuel. They don't work hand in hand.
For example if you have a 1/4" fuel line with 50 lbs of pressure, And a 5/8" fuel line with 50 lbs of pressure.
Sure the pressure is the same, but the volume of fuel coming out of the 5/8" line will be a lot more than the 1/4" line with the same pressure.
With a regulator you will always get the pressure in the line to be whatever you set it at because that's what it does, but it doesn't mean it's suppling the volume of fuel needed.
Kanookstr is offline  
Reply
Old 03-09-2006 | 04:36 PM
  #29  
articfriends's Avatar
Platinum Member
20 Year Member
Platinum Member
 
Joined: Jun 2004
Posts: 7,318
Likes: 1,037
From: frankenmuth michigan
Default Re: 502 EFI Intake Limitations

Kanookstar,I saw your thread on making a bigger pickup tube with a bulkhead fitting,excellent idea, plus a return fitting could be plumbed to the original pick-up at same time. If I get ambitious this spring I may follow your advice,Smitty
articfriends is offline  
Reply
Old 03-09-2006 | 06:06 PM
  #30  
Kanookstr's Avatar
32' SUNSATION
 
Joined: Feb 2001
Posts: 1,143
Likes: 0
From: MA
Default Re: 502 EFI Intake Limitations

Just too bad I did that after melting #6 piston.. My home waters are kinda small, so the high speed runs were short and quick. It was when I went on a big lake with room to spare did I run just long enough to starve the engine of fuel Volume and .... well we know the ending of that story.
Summer is almost here.
Kanookstr is offline  
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Elite Marine
Swap Shop
0
09-20-2008 08:51 AM
Rocko C
General Q & A
4
07-24-2007 11:41 AM
Smitty
General Q & A
2
08-20-2004 06:04 PM
ursus
General Q & A
2
03-17-2002 09:28 AM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



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.