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  #1 (permalink)  
Old 10-02-2009, 09:42 AM
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Default Rev Limiters

Not long ago, I over-rev'd my engine. Luckily, no damage, or at least not that I can tell. I see a lot of mention in this site on rev-limiters. I take it a lot of them work in conjunction with a computer igntion system like MSD.

I originally had a dual points system, but have converted to a Pertronix module. Either way, it appears I need a "stand alone" limiter.

I found this one, the Pertronix 600



Seems to me that cutting ignition (even randomly to various cylinders) and then lighting it back up is asking for trouble with an engine loaded at high rpms.

What can I expect to happen when the rev-limiter comes on (other than not revving higher)? Is it sort of smooth, or does it sound like the engine is very unhappy.....like a lot of nasty misfires, etc.
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Old 10-02-2009, 10:17 AM
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You can buy the StreetFire from MSD it uses the same plugins that the Ford box does it has about 3 chips in it just pick the amount of revs you wanna rev to. Go to MSD.com an check it out
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Old 10-02-2009, 11:10 AM
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Yes, the MSD starts to cut out at the limit. Not really a misfire but more like no fire. Your foot will detect it instantly. The car will just stop pushing at that point.

John
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Old 10-02-2009, 11:11 AM
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Quote:
What can I expect to happen when the rev-limiter comes on (other than not revving higher)? Is it sort of smooth, or does it sound like the engine is very unhappy.....like a lot of nasty misfires, etc.
With the MSD, it just acts like a very bad miss. You know instantly what you've done and it's time to get off the gas or shift.
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Old 10-02-2009, 11:53 AM
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Quote:
Originally Posted by Argess View Post
What can I expect to happen when the rev-limiter comes on (other than not revving higher)?
You can't miss it, and you instantly raise your foot -- no explosions out the pipes, or anything like that. I looked for the specs on that rev limiter and it says it's adjustable -- that's good. I have an adjustable rev limiter mounted in the back of my glove box. Heaven forbid you should ever allow someone to drive your Cobra you can turn the rev limiter all the way down as far as it will go before you hand over the keys.
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Old 10-02-2009, 12:07 PM
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That's one of the things I liked about this Pertronix unit. It's small, so I should be able to wire it in under the dash right to the tach wire from the coil (-) terminal, if that's how it hooks up. Getting to it for adjustment wouldn't be that easy, but it keeps my engine bay from looking too sci-fi.

I didn't want a big MSD-type CI unit in there, so I went to the Pertronix Ignitor in place of points and all looks 60's style once the dist cap is on.

I was concerned because I once melted a piston in a Mercury 70 outboard due to igntion cutting out and then coming back in. Maybe a 2-stroke loads up with fuel during a no-spark condition where a 4-stroke doesn't.

As far as a red-line goes, I'm sure I hit about 6800 rpm once with my 428 caast crank, and that bothered me a bit as I know I could have gone higher yet. Seems to me setting this unit for 6000 rpm would be a good place to start.

I could test it out at say 3000, just to make sure it works. Nice little dials on it for adj.

If anyone actually has one, I would appreciate their view on it.

Thank-you for the replies. All good information to know.

Last edited by Argess; 10-02-2009 at 12:09 PM..
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Old 10-02-2009, 12:08 PM
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Originally Posted by patrickt View Post
I have an adjustable rev limiter mounted in the back of my glove box. Heaven forbid you should ever allow someone to drive your Cobra you can turn the rev limiter all the way down as far as it will go before you hand over the keys.
That's classic. Sounds like something a lawyer would think of......
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Old 10-02-2009, 12:10 PM
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Quote:
Originally Posted by Argess View Post
That's one of the things I liked about this Pertronix unit. It's small, so I should be able to wire it in under the dash right to the tach wire from the coil (-) terminal, if that's how it hooks up. Getting to it for adjustment wouldn't be that easy, but it keeps my engine bay from looking to sci-fi.

If anyone actually has one, I wold appreciate their view on it.

Thank-you for the replies. All good information to know.
Let us know how this works out. I might consider this as an option too.
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Old 10-02-2009, 02:53 PM
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Can you use one of these rev. limiters on an EFI motor?
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Old 10-02-2009, 03:04 PM
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Seagull81 you might check your EFI system as mine (Imagine Injection) has a rev limiter built into the program that you can set on the computer.

Dick
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Old 10-02-2009, 03:04 PM
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Quote:
Originally Posted by Seagull81 View Post
Can you use one of these rev. limiters on an EFI motor?
Yes........
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Old 10-02-2009, 03:18 PM
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Mine is just a stock Mustang computer. I would love to have that over rev. protection. You never know when it might come in handy.
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Old 10-02-2009, 03:21 PM
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I have had several EFI motors with MSD limiters on them.
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Old 10-02-2009, 03:29 PM
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Quote:
Originally Posted by lamaluv View Post
Seagull81 you might check your EFI system as mine (Imagine Injection) has a rev limiter built into the program that you can set on the computer.

Dick
The Accel DFI system has rev limiter built in. It is programmable with the USB dongle/software.
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