Rev Limiter
 

I currently have a 502 mag mpi thats bumped to 509 with a M3 Pro Charger 730 hp. My rev limiter seems to be set at 4700/4800 rpm"s. i thought it was my bravo 30 prop but after a few trial size props its stays the same. i even put a new throttle position sensor in it, and still same rpm's. How do i reset my rev limiter to higher rpm's ? thanks

You will have to have the computer flashed by whipple or another company like that. I thought the factory setting was higher than that but not by much. Maybe thats all you can turn with that motor/prop combo. Have you tried a 28p. A stock merc 30 is pretty hard to tun. I run around 750hp and had to race lab a 30p to run it.

Yes i ran a 26 and 28 it made no diffrence in the rpm"s the motor is all new. just not sure why they would set it at such a low rpm. Its a 98 Baja Boss 27. The set up now is a drive breaker.I really need more rpms to take the load off the drive.

The rev limiter is in the ECM, you'll need to have it reflashed.

do you know who set up the tune that's in it now?

Precision Marine, My build sheet says custom calibrated for cam and blower 5600 rev limiter ( 750 ) idle timing set at 8 degrees with COMPUTER LOCKED. Not sure why i only see 47-4800 rpms max, no matter what i do.

There's a noticeable feeling when you bump the rev limiter. Im under propped with 23" 3 blade mirage plus. I hit it between 51 and 5200. Totally stock 502s. You sure your tachs are correct?

I have bumped it in other boats. Im nowhere near it in the Baja.

I'd get with Precision and see if they would be willing to read it and confirm the setting

If your hitting the limiter go up in props not down. 32" would have better results. Never heard much good about 34" Bravos but maybe it's changed now. Also make sure your running labbed.

If he increase pitch you are correct he might not hit limiter. But he'll still only get 4700 or 4800 rpm. Maybe less if he can't quite turn them properly. What is the factory redline on 502's?

This just doesn't sound right. Are you hitting the limiter or can you just not turn more than 4700/4800 RPM's? Does the engine climb to 4700 really fast?

I learn a little constantly so maybe I'm wrong but..... More rpm won't be easier on your drive. Smaller props would be easier on them. It must be in the ECM and you'll need that reprogrammed. Unless your losing spark at that rpm or starving for fuel and it seems like a rev limiter.

Actually more RPM is better on motor not on drive.
Has the drive been serviced? Anyway the gear ratio was changed by accident? That happened too me. You will lose a bunch of RPM with same prop. Does that motor have knock sensors? Are they going off because of the blower?
My old motor did this as well and it was because that was all it would pull cam wise.

We would be more than happy to take a look, But I dont think we did this calibration.
Mark

Bill Schumaker built the engine, and they said the computer was programed by Mark Boos at precision Marine. The boat runs awsome 85 mph on gps. I think the bravo 30 is preventing higher rpms. or maybe my tach is off. I never see more than 4800. I have never hit the limiter.but my build sheet says limiter set at 5600.

good lord thats flying in a 27 Baja! Bravo 30p stock is very hard to turn. I have a labbed 28 you can try. We boat in your area a lot and I have a bunch of props and a lot of exp in what your doing. Again congrats on that speed. What does it handle like?

Very nice of you Poker Run. I bet you get him figured out. If the rpm stays the same with a labbed 28, then that's a problem. Obviously

The stock rev limiter is higher than that. Are you having a detonation problem?

Poker~N~Run, Thank You for the offer on the prop. I do have a 28 hydromotive and a Bravo 28 avail to trial out as i remember the rpms stayed the same running the 28, I lost top end also, This could be my tach, But even so i still have never bumped limiter. My boat runs like a bat out of hell, Light weight and handles very well. Full Imco steering dual steering.The problem i have is keeping drives together on it.

I have never had a problem with detonation. My marina has non ethenol 92 octain fuel. I always thought of it as a safety feature not spinning high rpm's. But Mr Gadget says higher rpms are easier on the drive. " big prop not lugging drive"

I would put boat in water and see what it will free rev to. If it bangs limited at 4800 ok there you go if it keeps on going than you know the answer. I had this same prob on a cat of mine I went all the way down to a 22p from a 28p and gained only a couple hundred with crazy rooster tail(; it ended up being my cam/timing combo and heads. The motor would only pull what it would. Cam timing moved my trq hp curve to 4800. If you look at your hp and 85mph on a 272 boss u r moving hoss. You are in a very small group who have got that speed out of that boat. I had one and loved it but only saw 63 with a 502 mpi. Some phucker stole it. Miss that boat. Beautiful lines.