simple question---no answer
Thread Starter
Le Mans Master
Joined: Oct 2003
Posts: 8,862
Likes: 85
From: PA
St. Jude Donor '08
simple question---no answer
hitting the rev limiter will cut injector and cause lean condition.
question one is ... does the spark get cut too to that injector?
question two is.... if it doenst, is that a bad lean condition or is it no big as no fuel no combustion therefor no problem.
thank you
question one is ... does the spark get cut too to that injector?
question two is.... if it doenst, is that a bad lean condition or is it no big as no fuel no combustion therefor no problem.
thank you
Melting Slicks
Joined: Mar 2002
Posts: 2,931
Likes: 2
From: Tx
Originally Posted by NICK YOSKIN
hitting the rev limiter will cut injector and cause lean condition.
question one is ... does the spark get cut too to that injector?
question two is.... if it doenst, is that a bad lean condition or is it no big as no fuel no combustion therefor no problem.
thank you
question one is ... does the spark get cut too to that injector?
question two is.... if it doenst, is that a bad lean condition or is it no big as no fuel no combustion therefor no problem.
thank you
Right, no fuel no combustion, but what happens if you are spraying fuel with another source besides the injectors (n20 fuel noid/alky).
I have bounced on the rev limiter many times and it sure seems like it cuts spark to me. I've never had a problem and I have been on the rev limiter more than I want to admit.
It is impossible to see what the AF ratio is under those conditions since some of the cylinders get no fuel. You would have to have a sensor on each cylinder.
Burning Brakes
Joined: Jul 2004
Posts: 759
Likes: 12
From: Tampa Fl
With Alky or NOS hitting the rev limiter is not a good thing. The limiter should be set where you wont hit it unless a severe overshoot.
With mild systems, there's been no reports of issues hitting limiters. With aggressive systems.. then there have been issues. Aggressive as in twin nozzles at 200 PSI pressure on 4 cyl motors.
Reasons are pre-ignition issues. My understanding is the PCM pulls fuel typically.. but shutting down a motor under a lot of boost at high RPM's=trouble... remember when a cylinder doesnt fire, the crank yanks the piston down. And if you look at the bottoms of pistons..there's not a lot of material there under the pin area.
Bottom line.. careful when you race the motor..
With mild systems, there's been no reports of issues hitting limiters. With aggressive systems.. then there have been issues. Aggressive as in twin nozzles at 200 PSI pressure on 4 cyl motors.
Reasons are pre-ignition issues. My understanding is the PCM pulls fuel typically.. but shutting down a motor under a lot of boost at high RPM's=trouble... remember when a cylinder doesnt fire, the crank yanks the piston down. And if you look at the bottoms of pistons..there's not a lot of material there under the pin area.
Bottom line.. careful when you race the motor..
Team Owner
Joined: Mar 1999
Posts: 28,753
Likes: 9
From: San Jose/Bear Valley CA
CA Events Coordinator
Originally Posted by Julio
With Alky or NOS hitting the rev limiter is not a good thing. The limiter should be set where you wont hit it unless a severe overshoot.
With mild systems, there's been no reports of issues hitting limiters. With aggressive systems.. then there have been issues. Aggressive as in twin nozzles at 200 PSI pressure on 4 cyl motors.
Reasons are pre-ignition issues. My understanding is the PCM pulls fuel typically.. but shutting down a motor under a lot of boost at high RPM's=trouble... remember when a cylinder doesnt fire, the crank yanks the piston down. And if you look at the bottoms of pistons..there's not a lot of material there under the pin area.
Bottom line.. careful when you race the motor..
With mild systems, there's been no reports of issues hitting limiters. With aggressive systems.. then there have been issues. Aggressive as in twin nozzles at 200 PSI pressure on 4 cyl motors.
Reasons are pre-ignition issues. My understanding is the PCM pulls fuel typically.. but shutting down a motor under a lot of boost at high RPM's=trouble... remember when a cylinder doesnt fire, the crank yanks the piston down. And if you look at the bottoms of pistons..there's not a lot of material there under the pin area.
Bottom line.. careful when you race the motor..
VR
Melting Slicks
Joined: Mar 2002
Posts: 2,931
Likes: 2
From: Tx
remember when a cylinder doesnt fire, the crank yanks the piston down. And if you look at the bottoms of pistons..there's not a lot of material there under the pin area.
It is really hard to stay off the limiter on a high hp street setup. The tires let go and you are on it before you can react.
Le Mans Master
Joined: Sep 2000
Posts: 6,976
Likes: 527
From: Clouds Over California
Originally Posted by NICK YOSKIN
hitting the rev limiter will cut injector and cause lean condition.
question one is ... does the spark get cut too to that injector?
question two is.... if it doenst, is that a bad lean condition or is it no big as no fuel no combustion therefor no problem.
thank you
question one is ... does the spark get cut too to that injector?
question two is.... if it doenst, is that a bad lean condition or is it no big as no fuel no combustion therefor no problem.
thank you
It is my understanding that the rev limiter retards the timing and cuts the fuel.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
Melting Slicks
Joined: Mar 2002
Posts: 2,931
Likes: 2
From: Tx
Originally Posted by AMERICAN_HP
The guys at efi-live have been modifying the os code to enable a 2 step... they mentioned that the rev limiter routines do not mess with spark, but it is still possible that there is a something deep inside the code that they missed. There could also be something that is not software (could be hardware) that causes spark to cut without a fuel pulse.
Burning Brakes
Joined: Feb 2004
Posts: 1,108
Likes: 0
From: over the water Cali
It pulls fuel only. Then if other conditions are met then timing and traction control, like wheel spin beyond normal conditions ( in ls1 edit this is detectedd in the delta change for acceleration xmph/sec). I changed mine to allow for 30mph per sec. not exactly real world right. I think the stock is 10mph/sec limit. Again if timing is retarded its likely a subsystem.
Burning Brakes
Joined: May 2000
Posts: 1,160
Likes: 10
From: Nashville TN
Originally Posted by Julio
With Alky or NOS hitting the rev limiter is not a good thing. The limiter should be set where you wont hit it unless a severe overshoot.
With mild systems, there's been no reports of issues hitting limiters. With aggressive systems.. then there have been issues. Aggressive as in twin nozzles at 200 PSI pressure on 4 cyl motors.
Reasons are pre-ignition issues. My understanding is the PCM pulls fuel typically.. but shutting down a motor under a lot of boost at high RPM's=trouble... remember when a cylinder doesnt fire, the crank yanks the piston down. And if you look at the bottoms of pistons..there's not a lot of material there under the pin area.
Bottom line.. careful when you race the motor..
With mild systems, there's been no reports of issues hitting limiters. With aggressive systems.. then there have been issues. Aggressive as in twin nozzles at 200 PSI pressure on 4 cyl motors.
Reasons are pre-ignition issues. My understanding is the PCM pulls fuel typically.. but shutting down a motor under a lot of boost at high RPM's=trouble... remember when a cylinder doesnt fire, the crank yanks the piston down. And if you look at the bottoms of pistons..there's not a lot of material there under the pin area.
Bottom line.. careful when you race the motor..
Safety Car
Joined: Apr 2000
Posts: 4,326
Likes: 140
From: Weatherford, TX
Hitting the Rev Limiter with N20 has happened to me many times while spraying and it never caused a problem. It's usually just kissing the limiter and not a long event. Anyone else that races with N20 has surely done it too. I don't use a window switch. So we can rule out instant death for that scenario.