Thread: 2.8 MFI dyno
View Single Post
356RS 356RS is online now
Registered User
 
356RS's Avatar
 
Join Date: May 2003
Location: Bend, Oregon
Posts: 2,221
Garage
Quote:
Originally Posted by Neil Harvey View Post
I don't have any real experience with these early mechanical injected engines. What work what doesn't. However, if we were to get involved with building one of these mechanical injected engines, I would want to know a few things about the pump. How many crank degrees is it on and how many off. I could calculate the start of the Injection, or the end or the middle. Then, I would look at the cam spec's the dome of the piston and consider if I needed to include a bowl in the piston dome then figuring out of the pistons are suitable without. Injection timing plays a huge role here too. I cannot see how you can consider a cam profile or its settings without first knowing the injection timing.

Great point Neil. These are the 2 standard MFI pump timing specs.
Stock MFI pump: Set @ 40 degrees after overlap. #1 plunger starts to rise @ 85* after #1 TDC.
@ 295* ATDC #1 plunger is at 50% of travel.
@ 115* after overlap #1 plunger is fully compressed. Total plunger travel is 6.90mm.

For the RSR's: Set @ 14* before overlap. #1 plunger starts to rise @ 34* ATDC.
@ 243* ATDC #1 plunger is at 50% of travel.
@ 55* after overlap #1 plunger is fully compressed. Total plunger travel 6.90mm.

Hope this helps.
__________________
Mark Jung
Bend, OR
MFI Werks.com
Old 07-22-2020, 06:58 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #42 (permalink)