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From: Michigan in the summer, Florida the rest of the time
St. Jude Donor '08-'09-'11
Re: LT4- Rev limiter? (Glock'94)
You're lucky if your water pump going is all you have wrong when you peg the rev limiter all the time.
Why's that? I thought the only thing the rev limiter did was alter the timing to detune the engine and force back the throttle cable. Doesn't sound like that would harm the engine...
Well, the rev limiter of the LT4 is 6300.. and I've always thought of a rev limiter as an absolute maximum for a car. Yes, it'll run a little higher than that (stock), but it's not necessarily safe. Just my opinion...
LT4 revlimiter is set at 6400 stock. Redline is 6300 rpm.
I run the end of my quarter mile runs on the rev limiter in third gear ~110 mph.
It cuts the fuel, but is not like hitting a wall. Is it hard on a car...well it is hard on a car to run it to redline...so hardly any more hard on it than hitting redline in my opinion.
Engines are pretty durable-mine has 73,000 miles-not cruizer ones either.
I hit the rev limiter all the time autocrossing. Small courses are frequently faster when you just stay in 1st gear. The LT4's higher rev limit means more usable engine range within a given gear.
It's programmed to protect the engine. (And avoid warranty claims)
If the engine would be hurt by pegging the rev limiter, G.M. would have set it even lower than it is. :seeya
I have mine reprogrammed (Hypertech).
I try to shift at 200 RPM's below the limiter. Usually it works great without hitting the limit. :yesnod:
You should be fine. It's really all about your valve springs more than anything. The story goes with the LT1 anyway that if you hit the rev limiter about twice you just ruined your springs. Rumor has it that they are shot after 50,000 miles. Anyway worn out springs will cost you HP and your valves will float in the higher RPM's. I've hit the limiter on mine since I've done the cam several times, being that the tach doesn't read that high. Anyway the springs are good for more than that, hell people with stock bottom ends will turn 7k. I don't think I want to, but it can be done.
If it really worries you I would buy an MSD box or something just so you have a better rev limiter. These can be set to whatever you want and they drop the spark rather than fuel, which is much better on the motor. Just set it about 100 rpms before the factory limit.
Gee what's that knocking noise?. The motor blew right at the finish line of an autocross event in the middle of nowhere Michigan. Of course right at the height of race season and one day after I had just spent big bucks on 4.09 gears. I broke my vette and Al Murrel, a fellow competitor, hauled me home. Thanks Al! You have an invitation to co-drive my car! Also, I owe thanks to John & Debbie Fessler, and Paul Wines for hauling my tire trailer home.
A word of warning, 6200 RPM is the Limit for a stock LT1. I set my rev limiter to 6400 RPM against the advice of Justin Vandersall (Superman Vette Mechanic). The motor lasted for maybe 10 revs at that limit. The LT1 rod caps can not take high RPMs. The cap on the number six cylinder stretched. The piston began to slap against the head when down revving. As soon as the engine cooled the bearing spun.