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tdw6974
09-15-2003, 09:31 PM
Is it possible to simply remove the chip from the rev limiter? We are trying to diagnosis High speed break down and suspect maybe the rev limiters are cutting in too soon. We have a Mazda RX-7 using 2 limiters and 2 MSD boxes and the Vibration proof coils. As a dditional has anyone used the 8995 tool for checking boxes and how expesive are they? T weaver

msdtech1
09-15-2003, 09:52 PM
You can remove the rev limiter module and the rev limit function will no longer be active. The engine (if allowed) will rev as high as it can go. Have the MSD units been modified for a specific cylinder count? Which coils are the MSD units hooked to, the trailing or the leading? I take it that you are working with a 2 rotor engine. The easiest way to check the rev limiter on a rotary engine is to put a 3000 rpm module in it and then rev the engine until it hits the limiter. Look at the tach and see if it is limiting at 3000 rpm. If it limits at half the rpm then you have the units cylinder count set wrong. You can use the MSD PN 8998 (PN 8995 is no longer available) to check and set the rev limiter as well. They run around $175 retail.

MSD Tech1

tdw6974
09-16-2003, 05:54 AM
Yes, We are using the 12a 2 rotor. There are a seperate box(6446) and rev limiter (8738) to the coils (master blaster epoxy filled) ie one for the leading and one for the trailing. Thanks T weaver

msdtech2
09-16-2003, 10:26 AM
If using 2 separate boxes with separate limiters, the PN 8738 is the box that will have the loops to cut for cylinder select. The best way is to install a test chip and rev the motor to see where the engine is cutting out and look at the tach.
Thanks,
msdtech2