Rev Limiter?

Jake · #1 (**permalink**) 03-03-2003, 10:02 AM

I am thinking about putting a rev limiter on my S.V.O. 460. because it tends to really want to spool up between 5500-7000r.p.m. Unless I am watching the tach. it is really easy to rev the engine higher than I would like. I was told that every time I take it to 7000r.p.m. that I am halfing the engine life. However, I could run the engine at 6000r.p.m. all day and it would not hurt it. This came from a S.V.T. service tech.
My thought is to put a rev limiter on and set it at 6300rpm...just to play it safe. If anyone has any suggestions as to what is a good choice or clean set-up please respond. Also I would like to know what is involved in hooking the limiter up.
Thanks, Jake

Excaliber · #2 (**permalink**) 03-03-2003, 10:18 AM

MSD-6AL ignition unit features various rpm limiting "chips" you can simply plug in to change the range. The unit, about $260 comes with 4 or 5 "chips" that may not be the exact rpm you want. Additional chips cost about $50 for a set of 4 or 5 in different ranges.

Ernie

Tongue Pirate · #3 (**permalink**) 03-03-2003, 10:48 AM

If you can follow intructions the 6AL is a snap to install & small enough to hide away if that is your intention. A "Must Have" in my opinion!

sparks · #4 (**permalink**) 03-03-2003, 10:50 AM

I also have a 460 built by perf. eng., they installed the msd-6AL w/adjustable rev. limiting chips. Your max h.p. and tq should be below 6k rpm. I keep the 6k chip in until I get used to the car. I'll put the 7k in after break-in. A good BB should be able to hit 7k now and then w/o a problem, but you really shouldnt need to go above 6-6.5k unless u miss a shift.(oops)!

Mr.Fixit · #5 (**permalink**) 03-03-2003, 11:55 AM

Not just for missing shifts. When your tires lose traction, the first thing that will tell you is hitting the rev limiter.

Jake · #6 (**permalink**) 03-03-2003, 12:04 PM

Wow, thanks for the quick response! If I go with the msd unit, do I need to change the intire ignition? If so, is there a unit that will just hook up to my coil.....like a tach. with a limiter?

excelguru · #7 (**permalink**) 03-03-2003, 02:22 PM

It might also help to put your car on a chassis dyno to find out when the torque starts dropping off. Mine starts dropping off around 5600 RPM, so there's no sense in spinning it much beyond 5800. The engine sounds awesome at 6000 or even 7000, but what's the point? I can shift sooner, cause less wear and tear, and achieve faster acceleration. You may find the same scenario with your engine.

Keith

Mr.Fixit · #8 (**permalink**) 03-03-2003, 02:29 PM

The MSD 6AL will work with points, electronic, every popular style of ignition. Very easy to install, well worth the time and money.

excelguru, sometimes you want to wring the motor out a little past where power starts declining, cause you want to maximise torque at the shift recovery RPM. Lets not get carried away with RPM, unless your bottom end and valvetrain was built to stay alive at that RPM

petek · #9 (**permalink**) 03-03-2003, 02:31 PM

"The engine sounds awesome at 6000 or even 7000, but what's the point?"

Oh come on now Keith ... part of the point IS the sound

excelguru · #10 (**permalink**) 03-03-2003, 02:42 PM

Petek - Okay... you got me there.

Mr. Fixit - Good point! I made the assumption of a loooong flat torque curve. I can shift at 5800 in any gear and have well over 400 ft-lbs at the rear wheels in the next gear (which is both fun and scary). This would vary with the engine and tranny, so your point is quite valid.

Keith

Carroll DeWeese · #11 (**permalink**) 03-03-2003, 03:56 PM

Jake Greger,

You are smart to get a rev limiter. It is a must have item. It will protect you shifting up through gears but it will not protect you shifting down through gears. It is very easy to over rev an engine when rpm are still high and you shift to a lower gear. The drive train will force the engine to rev higher to keep up the speed. Use it to protect our up side but do not get complacent on the downside.

agro1 · #12 (**permalink**) 03-03-2003, 06:39 PM

I would have blown my motor the first day without the 6AL - the soft touch rev control is great...it'll stay on redline (wherever you set it) and still produce power...I would go with all MSD stuff if your gonna change it, MSD Blaster coil and Pro Billet distributor...Can't beat that setup.

Jake · #13 (**permalink**) 03-03-2003, 08:00 PM

Carroll DeWeese, That is interesting. I would have thought it would have worked on the down shifts as well. Even though that is not to big of deal....it's still good to know. As I said earlier, my big concearn is not over revving and I would much rather watch the road in front of me than have to focus 90% of my attention on the tach. With as fast as you can shift through the gears it can get a little CRAZY! Not to mention, thowing it down a gear to pass on a two lane hwy. Thanks for the response, Jake

Ikestaa · #14 (**permalink**) 03-03-2003, 08:38 PM

One quick question. Does it matter which direction the chip goes in?

petek · #15 (**permalink**) 03-03-2003, 08:56 PM

Jake ... on down shifts the engine won't fire, but it WILL overspin (driven by the rear wheels through the gearbox).

Ikestaa ... if I remember correctly the thing that sets the max rpm is a resistor so it shouldn't matter which way the thing is inserted. However, I have a Holley box and not the MSD box. Then again, if it mattered which way the "chip" went in and the engineer didn't design it to have a polarized plug / socket, then the engineer should be made to drive a Yugo!

Ikestaa · #16 (**permalink**) 03-03-2003, 08:58 PM

Petek...I figured it was a resistor. Thank you for your help.

Hal Copple · #17 (**permalink**) 03-03-2003, 09:46 PM

well, i too think a rev limiter is vital. But it only electonically protects against increasing revs, it does not as mentioned before keep the engine from mechanically over-reving. You can blip the throttle, and over spin the engine by it's crankshaft intertia (or momentum?) , momentarily.

On a related point, i think a shift lite is equally important. I personally don't think an engine at redline is happy nor safe with "dropping" alternating ignition to one then another cylinder, it would seem to me to be placing erratic stresses on an already highly stressed motor. The alternation of cylinder "dropping" is only to keep from loading up the cylinder with unburnt gas, i thas to be painful for any motor to endure sitting at redline on a revlimiter.

I have studied my engines torque curve, and decided to keep my engine at 6K rpm limited, but i have my MSD shift lite set for 5800 rpm, so i can shift before i get on the rev limiter, and stress my motor. I try very hard to stay off off my engine's rev limiter. I have seen Replica's that toss a rod, and it is not pretty or cheap.

Pete C · #18 (**permalink**) 03-03-2003, 10:24 PM

Jake,

The MSD is a great ignition system but the rev limiter is a must. I had the 6A and finally went to the 6AL two rocker shafts, one lifter, 8 push rods and a rebuild too late! You just cant run that much shrapnel through an FE! If you open track the car it is easy to over rev with someone in your cross hairs. It is also great missed shift insurance!

Randy,

Damn, don’t tell me it is even faster! Do I need a blower?

Cheers, Pete