Rev Limiter ( throttle shut - Spark Cut - Fuel Cut )

[Leg_Twitch_7.0L]

Hi i need some help please iv searched the forums for an answer or some explanation on the RPM cutoff or rev limiter now as far as i no is that Hemi 6.1 NGC 4 approaches this subject in a number of ways, in the PCM side it does that by shutting the throttle when u hit the limit and shuts or reduces the fuel till it shifts and in TCM it also has a Rev limiter which is overrides the PCM which means even if you set your RPM limit to say 7000 but the TCM limiter is set to 6200 It will not allow the you to pass that and in most cases it will go into limp mode.
The thing that i am facing difficulties with is how to change the way the PCM limits the RPM is you see in the Cutoff section at the bottom there is an option of using spark for RPM Rev Limiter TQ Management so basically if you enable it it should use spark in its operation but the thing is it never does no matter what i do in could not change that it shuts the throttle every time the car hits the Rev limiter i disabled all TQ Management in the PCM - zeroed out the TQ Management in the Cutoff section and so on but nothing worked if someone can shed a light on this issue would be highly appreciated.
There is one thing that i have noticed which led me to believe that there is a missing table because i have seen on some Dodge Challenger (not sure of the year) and Jeep Wranglers in the cutoff section the have RPM cutoff option were you put whatever RPM you desire but in The NGC 4 2008 jeep SRT8 file that option is not there only Autostick 1st gear Cutoff and then the tables for the RPM in Gear and P/N

[Leg_Twitch_7.0L]

Guys some help would be highly appreciated i am at a dead end here couldn?t figure out why it is shutting the throttle and reducing the fuel but the spark is untouched Please look at the log attached of a run at WOT.

Thanks

MohammadJeep SRT8 Run 14.02.2021.hpl

[pointofview_365]

Yep, spark isn't being used... The log only confirms what you' re saying... If you post the tune file, then someone who is familiar with these controllers might be able to help...

[Leg_Twitch_7.0L]

Thanks buddy for the reply i have attached at copy of my current tune for anyone out there who is familiar with these controllers then hopefully the matter will be resolved.
Appreciate your help, be safe.

Mohammad

{60419) Jeep SRT8 PCM-TCM 02.2021 {3}.hpt

[uarperformance]

Drive cutoff is your cutoff and not sure why you would want to go past that. U
nless its a stout NA motor

[Leg_Twitch_7.0L]

well its not really about the cutoff exactly thats one part of it, for example i can theoretically max RPM limit to something which ill never reach unless i want to blow it, so in that way i can shift anytime and it will never cut fuel and throttle but that's pointless because i would loose power ny doing that and risk blowing it up, that's not the idea.

What i want to achieve is first engine protection i don't want it to to keep firing the cylinders while at the same time reducing fuel and air, i rather reduce spark the other thing is the amount of power you loose say you over shoot your target shit which happens quite often the car feel like its chocking it self during that short period till the gear shift happens which will make the shift unnecessarily ruff on the trans and at the same time your RPM takes a huge dip plus as a bonus it would just sound way better than that dull sound it makes now.

it is a strong built NA which i used to rev it up to 7000 RPM almost daily for a long time no complains so i am not worried about the stresses.

Mohammad

[Leg_Twitch_7.0L]

there is one more thing i just noticed i changed the Drive RPM limit to 6325 and then i tried flooring it in second gear to reach the limit quick so what i have noticed is that the throttle begins to close at RPM 6029 and within 2 seconds all the changes that happened blew my mind, first the spark table sifted from the WOT table to part throttle table my guess is due to the reduction in MAP reading so the spark advance kept on increasing till it reached 32 degree at 6300 RPM!!! Torque drops about 65%, Inj Duty Cycle drop from 34% to 11%, Power Enrichment stops and the list goes on and on and on all that in just 2 seconds. could someone please explain to me wtf is the logic behind this because i cant make sense out of it at all

[white1]

there is one more thing i just noticed i changed the Drive RPM limit to 6325 and then i tried flooring it in second gear to reach the limit quick so what i have noticed is that the throttle begins to close at RPM 6029 and within 2 seconds all the changes that happened blew my mind, first the spark table sifted from the WOT table to part throttle table my guess is due to the reduction in MAP reading so the spark advance kept on increasing till it reached 32 degree at 6300 RPM!!! Torque drops about 65%, Inj Duty Cycle drop from 34% to 11%, Power Enrichment stops and the list goes on and on and on all that in just 2 seconds. could someone please explain to me wtf is the logic behind this because i cant make sense out of it at all

Traction control will close the throttle blade as well. I didnt dig into your tune but I did glance at it. try turning traction control off and seeing if the problem persist

[Leg_Twitch_7.0L]

Traction control will close the throttle blade as well. I didnt dig into your tune but I did glance at it. try turning traction control off and seeing if the problem persist

Thanks for your reply, it is off the entire time i changed the displacement number in the Tune to disable ESP/TC instead of using the Special Function option in the scanner also disabled everything in Engine Torque Management plus i dont think it has to do with TC because it spins the wheels at low speeds if you floor it easily without any TC kicking in at all ( All wheel system is permanently disabled )

[GeForce1986]

هi got the same model as you and still looking for a way to make the car riv sporty like the late srts but it will always feel like it shocked in the rpm i set and funny thing is it riv good if am not at wot!! i mean if i use 95% throttle pull it riv cool somehow but it will shock and lag if am at 100%
is there any one could make this models riv like it should yet ?

[Leg_Twitch_7.0L]

هi got the same model as you and still looking for a way to make the car riv sporty like the late srts but it will always feel like it shocked in the rpm i set and funny thing is it riv good if am not at wot!! i mean if i use 95% throttle pull it riv cool somehow but it will shock and lag if am at 100%
is there any one could make this models riv like it should yet ?

Well there is a way but not through Hp Tuners you have to use CMR then you could do it and much more, i opened my old file which was originally programed using CMR and my God what a huge deference when is comes to the variety of tables available, like for example the issue i mentioned above using HP Tuners i guess there are probably 4 maybe 5 tables to adjust but they wont make much deference because there are key tables missing that overwrite what ever changes you do so its pointless but by using CMR you would gain almost complete control on the process because of the options available to you like Torque Reduction, Spark Control, Throttle Control ect the list is huge my wish is that HP Tuners would add those tables to the platform i requested this addition a while back but nothing really happened and you know the funny part is i found the exact missing tables in the Jeep Wrangler platform anyways good luck buddy hope this would help

[al7nfi]

No Any way to tune rev limit cutoff on jeep 2008 Wrangler dear?