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neuropel · 01-28-2008

Gary,
I've had a similar goal in mind for a long time (with a manta) but haven't made much progress other than accumulating parts (I keep getting sidetracked with other projects). I can't help but believe that going to a modern, fully tunable EFI system would make a big contribution. I'm planning the Sentra SER throttle body/Opel EFI plenum setup with a megasquirt, and try to tune the engine for economy. Several years ago when I dumped a 4 speed and installed a 5 speed in a GT I was getting 30+ MPG using a well-tuned Weber 32/36. I could never break 25 mpg with the 4 speed, but my commute was all highway. My experience with the automatic has been even worse gas mileage. I'm wondering if there are strategies to porting an Opel head that would improve economy? Certainly skinny tires help, along with a good ignition system and appropriate exhaust. It'll be interesting to see how others may have approached this challenge. I'd like to see just how high the mileage could go with the 1.9L.

Todd K.

Edit - Also, what about cam profile? That's a pretty cheap way to drastically alter an engine's performance, but I've never heard us mention optimal profiles for economy.

01-28-2008	#3 (permalink)
neuropel Rice Cooker Join Date: May 2002 Location: Spring Church, PA Posts: 1,787	Gary, I've had a similar goal in mind for a long time (with a manta) but haven't made much progress other than accumulating parts (I keep getting sidetracked with other projects). I can't help but believe that going to a modern, fully tunable EFI system would make a big contribution. I'm planning the Sentra SER throttle body/Opel EFI plenum setup with a megasquirt, and try to tune the engine for economy. Several years ago when I dumped a 4 speed and installed a 5 speed in a GT I was getting 30+ MPG using a well-tuned Weber 32/36. I could never break 25 mpg with the 4 speed, but my commute was all highway. My experience with the automatic has been even worse gas mileage. I'm wondering if there are strategies to porting an Opel head that would improve economy? Certainly skinny tires help, along with a good ignition system and appropriate exhaust. It'll be interesting to see how others may have approached this challenge. I'd like to see just how high the mileage could go with the 1.9L. Todd K. Edit - Also, what about cam profile? That's a pretty cheap way to drastically alter an engine's performance, but I've never heard us mention optimal profiles for economy. __________________ "In the end, it's not the years in your life that count. It's the life in your years." -Abraham Lincoln ________________ 1972 GT 2.4L 1974 Manta GT/E 2.2L 1973 Manta Rallye 2.5L Last edited by neuropel; 01-28-2008 at 12:35 AM.