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dyerkes dyerkes is offline
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Join Date: Oct 2000
Location: South Riding, VA, USA
Posts: 692
With regards to tuning either systems...leave it to the experts with the proper equipment. Too lean for only a few seconds and you're doing a rebuild.

The potential for an EFI system is totally dependent on so many other variables (exhaust system, turbo, cams, heads, fuel injectors, etc.). The EFI system relieves the mechanical limitations of the CIS system, and allows for precise delivery of fuel, and if you also have crank fire ignition, a more accurrate delivery of spark. The only way to take advantage of EFI's potential, is to have all of the components of a system perfectly matched, such that the least efficient device becomes your limitation for HP.

Speaking from experience (I'm right in the midst of my conversion to EFI), the best approach is to determine a budget and a desired HP. Than you can enlist the help of both a professional builder, and tuner in order to determine what modifications will be necessary in order to achieve your goal, and from the parts list alone, determine if you are within budget alone. Cost aside, your best choice would be to enroll the services of the professionals to take care of all of the details and trials and tribulations. This board is full of professionals in the industry and DYIers that can assist in supplying an endless amount of information and experience. The purchase cost of the EFI system ($3k to $10k) is the cheapest part of the conversion. The first issue is, whether you're do for a bottom-end rebuild or not, replacement of your rod bolts (which are limited to 450HP at the crank), followed by upgrading the "other" HP limiting items mentioned above in order to achieve your HP goal. Assuming that you can do all the mechanical work yourself, you'll still need to take your car to a tuner that is expert with the EFI system you installed. Since I'm currently still on that slippery slope, I can definitely say that you shouldn't even ponder going EFI unless you have a bare-bone budget of at least $10k. Will you meet your budget, no way. If for no other reason, you'll run into at least one "while you're in there you might as well...".

Good luck on your decision,
186 911 Turbo
David Yerkes
1987 911 Targa - GP White
Old 07-12-2007, 06:06 AM
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