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Discussion Starter · #1 ·
Hey guys, so this is my first post on this account. Used to be on the V6 forums a few years ago but finally made a good call and bought a V8. My question is regarding the rev limiter. I'm aware that it cuts fuel, and not spark. The problem is that I'm running a 2.1 KB on my car, and don't want fuel to disappear if/when I hit the rev limit and melt pistons. Is there any way to make the rev limiter cut spark instead of fuel? Sorry if this question has been asked before..... Thanks for the help!
 

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Too Soon, Junior!
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The most common options are the MSD ignition rev limiter and the WOT Box. Either one has a rev limiter option that cuts spark rather than fuel. This also has the fun effect of shooting flames out of your exhaust when you do hit the limiter. You'll also want to disable the stock limiter with a tune once you install either one of those options.
 

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The msd is for a 2-step not for the rev limiter. Hiting the rev limiter won't melt pistons.
Have the rev limiter raised with a tune and learn to drive your car....
The sct sofrware has a 2-step feature that cuts fuel. I never had an issue using it..
 

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Too Soon, Junior!
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All MSD 6AL Ignition Control systems have a rev limiter for the high range as well as a 2 step, such as this: MSD Digital Programmable 6AL-2 - 6530

Cutting the fuel at high RPMs is pretty bad for your engine if it's done for a prolonged period of time. Fuel has a cooling effect, which is one of the factors that keeps the pistons from melting, or the valves from welding themselves onto the heads, though neither happens very often in the 4.6L 2V. Learning the car is important, but having a backup doesn't hurt. Using the 2-step function on your SCT is not good for your FI engine, as the cylinder pressures are already higher than normal.
 

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Discussion Starter · #5 ·
The msd is for a 2-step not for the rev limiter. Hiting the rev limiter won't melt pistons.
Have the rev limiter raised with a tune and learn to drive your car....
The sct sofrware has a 2-step feature that cuts fuel. I never had an issue using it..
Yeah of course I don't regularly bounce of the rev limiter or anything..... Just a safety precaution
 

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no fuel=nothing to burn
Using the sct 2-step wont hurt the engine.
I've bounced off the rev limiter with 18psi at 7000rpm plenty of times at the track without issue.
 

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Too Soon, Junior!
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Your pistons are still hot even if the combustion process isn't occurring. Is your engine still spinning? At higher RPMs near the rev limit, the mean piston speed is much higher than normal.

Higher MPS = more friction
More friction = more heat
No fuel = more heat

And because heat is the mortal enemy of all mechanical components, I'm going to stick with the novel idea that that cutting fuel as a rev limiter isn't too great for a performance engine.
 

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Too Soon, Junior!
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Sorry if I came off as hostile in the above post, I'm not trying to be rude, just stating the factors that engineers have to consider when designing a high performance engine, and those factors are the same ones to consider when dealing with a heavily modified street car.
 

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while i don't disagree with any of these posts, i'm wondering how often and consistently you plan to drive while above the "rev limited" RPM. As y2K02 mentioned, i've also hit my rev limiter plenty of times at the road course, but you do learn the sound of the engine when you approach the limit. The first couple tours around the track ends up in hitting the limit a few times. but by the end of the day, your senses tell you when you're nearing the limit.

as i said, i think your question has merit, but i'm not aware of anyone who has had the issue you're worried about. i'd be interested if anyone else has.
 

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Discussion Starter · #11 ·
while i don't disagree with any of these posts, i'm wondering how often and consistently you plan to drive while above the "rev limited" RPM. As y2K02 mentioned, i've also hit my rev limiter plenty of times at the road course, but you do learn the sound of the engine when you approach the limit. The first couple tours around the track ends up in hitting the limit a few times. but by the end of the day, your senses tell you when you're nearing the limit.

as i said, i think your question has merit, but i'm not aware of anyone who has had the issue you're worried about. i'd be interested if anyone else has.
Yeah like I said before, I rarely get up there, and have yet to actually hit the rev limiter on the street as far as I can remember. I was just thinking about it yesterday and realized that leaning out at full boost CANNOT be good for the car at all. Just wanted to see what the options were. I want this motor to be as safe as possible. It's a street car after all.....
 

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i also agree. i like these types of questions as they keep me thinking in directions i normally wouldn't. and i throw my opinions out for others to take them for what they're worth too. hopefully they have the same value for you.
have a great day!!
 

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ur not suppose to hit the rev limiter?? how else am I suppose to know when to shift? /joke :)
 

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You can hear me on the rev limiter in second gear. It was set at 7000rpm.
 
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