Hits rev limiter before auto shifts - boosted car
03-30-2010, 12:03 PM
#16
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With the bowden cable slacked off 1/4" past the ball the car will shift at WOT now. Really shifts short during normal driving but I can live with that. Probably the best solution is to raise the rev limiter like Brett said.
03-30-2010, 01:00 PM
#17
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There is an adjustment for the hydraulic upshift point, but it's at the front of the valve body. (I've never tried adjusting it.)
03-30-2010, 11:15 PM
#19
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The kickdown relay gets an RPM signal input into it. When the RPM point that the kickdown relay's internal electronics are set for is reached, the relay opens. That has the same effect as lifting off of the gas pedal and opening the kickdown switch that's located under it, and an upshift occurs.
As has been mentioned, when the supercharger is put on, the RPMs increase so much faster that the operation of the upshift system doesn't react fast enough, and the rev limiter is hit before the shift occurs. The same thing was happening on the '87 Murf A/T car, and on A/T Murf customer's cars as well. It's been very typical for the same thing to happen to the 5-speed customers too initially after they've installed the supercharger kit. The RPMs increase so much faster than they're used to, that they hit the rev limiter before completing the shift to the next higher gear. It would take them a little while to get used to the new, faster increasing engine RPMs, and shift accordingly to avoid hitting the rev limiter.
The chips that are now supplied with the Murf kits have the rev limit increased slightly, which eliminates the problem with the A/T equipped cars, and makes it a little easier for the 5-speed guys to get used to shifting in time to avoid the rev limiter. The rev limit isn't raised very much with the supplied chips, but it's enough to make a difference when it comes to hitting the rev limiter.
As has been mentioned, when the supercharger is put on, the RPMs increase so much faster that the operation of the upshift system doesn't react fast enough, and the rev limiter is hit before the shift occurs. The same thing was happening on the '87 Murf A/T car, and on A/T Murf customer's cars as well. It's been very typical for the same thing to happen to the 5-speed customers too initially after they've installed the supercharger kit. The RPMs increase so much faster than they're used to, that they hit the rev limiter before completing the shift to the next higher gear. It would take them a little while to get used to the new, faster increasing engine RPMs, and shift accordingly to avoid hitting the rev limiter.
The chips that are now supplied with the Murf kits have the rev limit increased slightly, which eliminates the problem with the A/T equipped cars, and makes it a little easier for the 5-speed guys to get used to shifting in time to avoid the rev limiter. The rev limit isn't raised very much with the supplied chips, but it's enough to make a difference when it comes to hitting the rev limiter.
03-31-2010, 11:16 AM
#20
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Thread Starter
Thanks Z, Tim is going to be sending me a clone of Shane's EZF chip, so it should have the rev limit increased and that should cure the problem
The kickdown relay gets an RPM signal input into it. When the RPM point that the kickdown relay's internal electronics are set for is reached, the relay opens. That has the same effect as lifting off of the gas pedal and opening the kickdown switch that's located under it, and an upshift occurs.
As has been mentioned, when the supercharger is put on, the RPMs increase so much faster that the operation of the upshift system doesn't react fast enough, and the rev limiter is hit before the shift occurs. The same thing was happening on the '87 Murf A/T car, and on A/T Murf customer's cars as well. It's been very typical for the same thing to happen to the 5-speed customers too initially after they've installed the supercharger kit. The RPMs increase so much faster than they're used to, that they hit the rev limiter before completing the shift to the next higher gear. It would take them a little while to get used to the new, faster increasing engine RPMs, and shift accordingly to avoid hitting the rev limiter.
The chips that are now supplied with the Murf kits have the rev limit increased slightly, which eliminates the problem with the A/T equipped cars, and makes it a little easier for the 5-speed guys to get used to shifting in time to avoid the rev limiter. The rev limit isn't raised very much with the supplied chips, but it's enough to make a difference when it comes to hitting the rev limiter.
As has been mentioned, when the supercharger is put on, the RPMs increase so much faster that the operation of the upshift system doesn't react fast enough, and the rev limiter is hit before the shift occurs. The same thing was happening on the '87 Murf A/T car, and on A/T Murf customer's cars as well. It's been very typical for the same thing to happen to the 5-speed customers too initially after they've installed the supercharger kit. The RPMs increase so much faster than they're used to, that they hit the rev limiter before completing the shift to the next higher gear. It would take them a little while to get used to the new, faster increasing engine RPMs, and shift accordingly to avoid hitting the rev limiter.
The chips that are now supplied with the Murf kits have the rev limit increased slightly, which eliminates the problem with the A/T equipped cars, and makes it a little easier for the 5-speed guys to get used to shifting in time to avoid the rev limiter. The rev limit isn't raised very much with the supplied chips, but it's enough to make a difference when it comes to hitting the rev limiter.
03-31-2010, 12:28 PM
#21
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Over the limit, and it opens the fuel pump relay, which also powers the fuel injectors (+ O2 sensor heater).
