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Old 08-01-2020, 10:10 PM
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eschaider eschaider is offline
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Join Date: Feb 2006
Location: Gilroy, CA
Cobra Make, Engine: SPF 2291, Whipple Blown & Injected 4V ModMotor
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+1^ on what Tony said but I would go a bit farther and say the individual who told you that either did not know anything about what they were talking about or had some other agenda that wanted you in a carbureted version of the car.

You should know from first hand experience that fuel injected engines do not behave that way. There are lots of high powered daily drivers at or over 500 HP, available from many of the manufacturers, that do not behave like that. If anything they can be controlled as well or better than carbureted engines at any engine speed because of the programmable digital fuel injection and sensors to monitor and correct for actual vs commanded engine operation.

If the car was 'drive(ing) forward on its own'. chances are the idle was set too high and/or the converter had too low a stall speed selected for the converter. You should be able to get a fuel injected automatic transmission equipped car to behave indistinguishably from your daily driver with the one exception the acceleration will be stunningly better.

A properly built and tuned engine with EFI and an AODE will make for a very satisfying driving experience. The operative words here are properly built and tuned. Use a cam with tight lobe centers advance it a couple of degrees and you will get a lumpy surging idle that will not smooth out until you get somewhere between 1500 and 2000 rpm. That will produce an unhappy driving experience. A higher stall converter will help but the real problem is the lumpy low speed operation of the engine. With a 5 speed manual this is not as big a problem because you just drop down a gear to get out of the lumpy rpm range that makes the car buck and fart. With an auto this is not as easy — the higher stall converter will help but it will not eliminate the problem.

If you go to a wider lobe separation angle (LSA) on the cam put it closer to straight up you will get a smoother idle, good vacuum and you will loose the lumpy 60's competition Cobra idle so many people like. What you will get is a stunningly fast car with excellent driving manners — so good your wife or daughter would have little difficulty driving the car.

An item you did not speak to (and most of us ignored when building/getting our cars) is the exhaust. Nothing looks sexier or sounds better than the side pipes. What most first timers do not realize is that exhaust outlet is 24 inches from your left ear — all the time. On anything but short trips (and probably even those) you will need ear plugs to protect your ears. At highway speeds they are mandatory. The fix is under car exhausts. Virtually all the replica manufacturers offer them, all you have to do is ask for them.

Don't get BS'ed by the anti EFI rhetoric of whoever gave you that guidance. It is not real world. FWIW my engine makes a little north of 770 FWHP and 645 RWHP out of 289 cubic inches, so it is in a relatively high state of tune. It idles like a Singer sewing machine at 750 rpm essentially the same as my BMW daily driver. It does not produce the lumpy 60's competition Cobra idle but it is frightenly fast and gets 25 mpg on the highway. You do have to be a bit careful passing. On the highway at 70 mph in fourth gear if you roll into the throttle too quickly, with the traction control turned off, the car will begin to black track with a corresponding increase in vehicle control issues.

Don't worry about drivability with EFI and an automatic. They will go together like peanut butter and jelly — although you might occasionally miss the fun of changing gears manually.


Ed
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Last edited by eschaider; 08-01-2020 at 10:13 PM.. Reason: Spelling & Grammar
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