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stock fuel injection vs carb

2K views 8 replies 3 participants last post by  davegt27 
Joe, do you have any more specs on the cam? If you can provide the duration @ .050", and the lobe separation angle, that would help out. Stock Opel EFI doesn't like a lot of overlap and duration. I've found that it's usually better to keep the duration @ .050" below 220 degrees or so, after that the air flow meter tends to bounce around due to pulsations in the inlet tract, and off-idle performance is will be bad.

I don't see anything else with that combo that would hurt the usage of EFI, in fact the larger displacement will help to keep the idle vacuum decent.

Bob
 
Joe, are there any numbers engraved into the front of the cam? If you could find out who used to grind the cams for Opel Parts and Service, any numbers might ID the cam for you. Do you still keep in touch with Toby Thevenin? I believe Charles Goin said he still spoke with him on occasion.

HTH
Bob
 
jpavlack said:
I will try to reach Toby about the specs on the cam. If it were compatible, would you pick fuel injection over 38 dgas? All things equal, which would perform better?
My personal picks....

1) Programmable EFI, using stock Opel EFI intake, but no air flow meter used. Best overall for power/torque, and tunability. Limited to about 160 hp with stock injectors.
2) 38 DGAS on ported intake. Easiest to setup. Easiest to service. Good power still, but not as much as the programmable EFI.
3) Stock Opel L-Jetronic fuel injection. Can be problematic, if a part 'lets go' on a road trip, finding a way home may be difficult! Will have good power in the mid-range, but off-idle performance with a big cam can be shaky at best, and top end power may suffer due to leaning out of air-fuel mixture. Limited tuning capabilities. Usually, any mods that affect one area of the power band will affect all areas of the power band. Make it richer at 6000 rpm, it'll also be rich at 4000 rpm, at 2000, etc.

Your results may vary....

Bob
 
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