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Join Date: Dec 1999
Location: bakersfield CA.
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rev lemiter

I was wondering if anyone knows a way to byepass the rev-limiter on the l-jet fuel injection system. I want to be able to get more revs and i cant do that with the rev-limiter and dont want to put carbs on.I would be thankful if anyone could help.
Old 12-04-1999, 08:00 PM
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There are two possible kinds of rev-limiter that I've heard about. One of them may or may not apply to the L-jet FI system.

That one is an extra gizmo that plugs into the FI wiring harness near the battery. Some of the late D-jet cars have a gizmo on there that cuts off fuel when the revs get to a certain point. I have not heard explicitly that any of the L-jet cars have this; they may not. It can supposedly be completely disarmed by unplugging the gizmo.

The other rev-limiter that the early cars have is a distributor rotor that has a spring-loaded weight in it. When the revs get fast enough, the centrifugal force on the weight overcomes the spring force and the weight shorts out the spark.

You disable that rev limiter by replacing the rotor with the version without the rev limiter. Which is usually a lot cheaper anyway.

In general, the 914 motor is very much on the down side of the power curve by the time you get to the rev limiter. With a stock motor, you are unlikely to gain anything by over-revving the motor.

Except for added stress and wear on the motor, of course.

--DD
Old 12-05-1999, 01:45 AM
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I am not running a stock motor at all.I know that the distrubuter rotor does not apply in this case. I will look for the gizmo on the wiring harnes. thanks for the help.
Old 12-05-1999, 09:10 AM
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What is your "not" stock motor?
Old 12-05-1999, 09:41 PM
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I have a 1.7l with big bore kit 1.8l heads with 2.0l valves. Bulliet aluminum rods. lightend flywheel. the heads are ported and polished to a mirror shin. heavy duity valve springs.
Old 12-06-1999, 11:41 AM
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You did not say what you are trying to rev to? If it is much over 6000 RPM you might just have to go to carbs as the stock FI system either D-Jet or L-Jet can only pass enough to go slightly over that at full throttle accelaration. Seems as though this is a little safety factor to keep from blowing up the engines although there are some that rev to 7000 or so. My Porsche 914 mentor has said that as you go over 6000, even with heavy or dual springs, light valves, light push rods, forged conn rods, this is still a push rod engine and life expectancy will go down. I try to limit the revs in the race car to 6000 and even have the shift light set at 5800 as a safety factor. The electronic rev limiter is usually like the MSD soft rev limiter or there are a number of others. Look around the coil primary wires for a little box. 914 rev limiters of any kind are a little dangerous since they kill the spark, but the fuel injectors will keep right on injecting and when spark comes back, bang. Besides most overrev conditions happen at downshifts! But this can be as controversial a subject as prop valves.....

[This message has been edited by john rogers (edited 12-06-1999).]
Old 12-06-1999, 01:45 PM
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