AEM Users - Rev limit settings?

[KiDyNomiTe]

All you AEM users, what do you have as your rev limiter settings, as in fuel cut, spark cut, when, ignition retard, etc.

And how often are you sitting on limiter, I guess this is more for drifters.

Reason I ask, throwing rockers, blaming the harsh limiter, sounds cool and all, but not trying to do all that anymore.

I have an Infinity in particular, let me know which you have.

[Jorgs_7]

Sub'd for more info.

Im running AEM v2, currently have ignition cut at 6000 with fuel cut at 6100 RPM (under 7 MPH). Just trying things for now. Seems to be a lot of good info regarding 2 step, anti lag and rev limiters on Supra forums using AEM EMS.

[[email protected]]

Sub'd for more info.

Im running AEM v2, currently have ignition cut at 6000 with fuel cut at 6100 RPM (under 7 MPH). Just trying things for now. Seems to be a lot of good info regarding 2 step, anti lag and rev limiters on Supra forums using AEM EMS.

You'll basically want to do a spark cut first, then 100 RPM above that do fuel cut. the factory rev limiter is based strictly on fuel cut (and throttle angle on DBW cars) problem with that is keeping the spark after fuel is turned off can sometimes burn a lean mixture that didn't completely burn off on the first cycle and cause a lean melt down. (extremely unlikely but can happen) so the way I was taught and feel comfortable is to cut the spark first and the fuel later. this will also contribute to awesome fireballs out back.

[///M3LVIN]

You'll basically want to do a spark cut first, then 100 RPM above that do fuel cut. the factory rev limiter is based strictly on fuel cut (and throttle angle on DBW cars) problem with that is keeping the spark after fuel is turned off can sometimes burn a lean mixture that didn't completely burn off on the first cycle and cause a lean melt down. (extremely unlikely but can happen) so the way I was taught and feel comfortable is to cut the spark first and the fuel later. this will also contribute to awesome fireballs out back.

That's what I've heard most all people do for rev limit. What I am seeing is that the awesome fireballs are causing valves to close against their will which in turn causes the rocker to be thrown. Does that kind of make any sense? lol. I may be way off on my research but I'm also trying to learn this as well.

[derass]

I've also heard that ignition cut can cause SR's to throw rockers. I too wanted fireballs and loud noises, but it's not worth losing the motor. For that reason, my Haltech is set to do a hard fuel cut at 7500 RPM.

[KiDyNomiTe]

On Haltech I had it set to spark cut (E6X), it had no customization to it, just a choice spark vs fuel. That limit was very soft though, there was no harsh bangs or fireballs. Sat on limiter plenty of times, never an issue with rockers.

Switched to AEM, had it setup the way Juan mentioned, sounded amazing, but hit the limiter maybe 3 times in a row mid drift, rocker snapped.

Currently I have just switched to a fuel cut first that starts 75 RPM before, then a spark cut 100 rpm past that. Still not sure if I should just skip the spark cut completely. Hit limiter once, definitely softer sounding, but still pretty "harsh"

[guiheju]

it's not worth losing the motor. For that reason, my Haltech is set to do a hard fuel cut at 7500 RPM.http://www.miya.us/e/images/28.gif

[brndck]

Sub'd for more info.

Im running AEM v2, currently have ignition cut at 6000 with fuel cut at 6100 RPM (under 7 MPH). Just trying things for now. Seems to be a lot of good info regarding 2 step, anti lag and rev limiters on Supra forums using AEM EMS.

what engine are you running that your rev limit is 6k?

[Jorgs_7]

You'll basically want to do a spark cut first, then 100 RPM above that do fuel cut. the factory rev limiter is based strictly on fuel cut (and throttle angle on DBW cars) problem with that is keeping the spark after fuel is turned off can sometimes burn a lean mixture that didn't completely burn off on the first cycle and cause a lean melt down. (extremely unlikely but can happen) so the way I was taught and feel comfortable is to cut the spark first and the fuel later. this will also contribute to awesome fireballs out back.

Sure, on platforms that don't have rocker arms just sitting under cam shafts.

what engine are you running that your rev limit is 6k?

SR20DET

Sorry, should have clarified,

My settings were like that for driving on jack stands. Wanted to a brief shake down before hitting the road.

Anyways, Ill be setting fuel cut before ignition around 7400 RPM.

What I am seeing is that the awesome fireballs are causing valves to close against their will which in turn causes the rocker to be thrown. Does that kind of make any sense?

It does make sense, and that is likely the reason(s) why rocker arms "fall" off.

[Kingtal0n]

Fuel cut, only. No spark cut.

Spark cut is dangerous for multiple reasons, mainly you never want fuel to just "go where it wants". If you have fuel puddle problems, where fuel clings to walls/ports and causes an issue when the injector is turned off, then you solve those problems separately. (rougher ports, more turbulence, higher temperatures (partial pressure of fuel)), etc

spark cut has applications for building boost/building exhaust temperature energy, and is hard on the engine/turbo, not recommended for beginners or daily drivers (it is for race cars with multiple engines to spare) as some have mentioned, the energy of fuel reacting in the exhaust system can apply force to the valves, popping them open or bending them, as the valve loses contact with the camshaft lobe, then bounces back on to it, hard, at a random position. You never want the valve to lose contact with the lobe/lifter, as when you over-rev the engine.

I had a discussion with myself about this a while back
http://aemelectronics.com/?q=forum/spark-cut-or-fuel-cut-final-word-both

[Kingtal0n]

what engine are you running that your rev limit is 6k?

On stock sr20det engines with high mileage (150k+) I like to keep the RPM limit around 5800-6400rpm for daily drivers using the OEM fuel cut. This lets you "let loose" you can miss shifts / drive it hard and never worry about spinning a bearing or losing the valvetrain from over-revving the engine, especially with tired worn out components. The OEM turbo doesnt do much past that point anyways.

Also remember to watch the oil pressure, as a cold, high oil pressure (first 20~ minutes of driving) also contributes to rpm-related bearing failure (let the engine's oil warm up first, and pressure will drop notably before running the engine hard).

if you take the car to the track or need to race, you can temporarily raise the redline to whatever you want. After that, pull it back down for safety. No reason to run around the streets in a daily always set to kill. Same thing with boost, I run 2-5psi around town and raise it to whatever when I need it.

[Kylepaschke]

What type of lifter/cam setup do you have Simba? Dual guide? Solid lifters? Hydraulic stock setup that is shimmed?


edit: my setup - redtop sr, aem v2, dual guide conversion, tomei 260 lash type with the hydraulic lifters, BC springs/retainers. Oversized valves.

[KiDyNomiTe]

I am on poncams, stock lifters, stock rockers, stock shims/guides, oversized valves, RAS, BC retainers and springs.

Pretty much what I have always run, minus oversized valves and different cams.

Looks like going with fuel cut only is best.

The fun part is the PID settings in the Infinity, not sure if anyone has any good settings for that. It's currently on the default setting, but I know modifying it can reduce the "harshness" even moreso.

[TheRealSy90]

My Sr probably has almost 200k at this point and I've always revved it to 7500 lol. But now with the new AEM Series 2 setup I'll probably have to switch to fuel cut only whenever I get it tuned. I'm also going to do dual rocker guides and roller rocker sr20de lifters so it shoudn't even be possible to throw the rockers anyways.


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