Rev limit...WOT

[SRT8Tech]

ESP was OFF. I guess I could have just crept up on it but its more fun to just go ahead and hit it from a roll. Gets sideways and all that good stuff. The ESP was in the 3rd position. On, OFF, and REALLY off. Hold the button for 10 seconds. But, if you really want it totally off hold the key in the start position WHILE MOVING for 3-6 seconds and it turns ABS, and ESP totally off.

[Quick]

ESP was OFF. I guess I could have just crept up on it but its more fun to just go ahead and hit it from a roll. Gets sideways and all that good stuff. The ESP was in the 3rd position. On, OFF, and REALLY off. Hold the button for 10 seconds. But, if you really want it totally off hold the key in the start position WHILE MOVING for 3-6 seconds and it turns ABS, and ESP totally off.

Yes, definitely more fun but maybe not so good for information gathering. The predator has a sample rate for logging and you have to poll the DCx cars a bit slower than some others. You could have missed seeing some rpms between samples or lost a response although I can't imagine it would be on that scale of rpm difference. If your readings are correct the implication might be that setting the rev limiter is independent of raised shift points. Might be something like +200 (over stock) brings you to 6400 but the raised shift points already has it set at 6500 so there is no effect. maybe something like that?

[Illss1]

What does the REV limit in "D" do if the the trans has its own shift points ? If i'm at wot and the trans has its own limits then what good is the rev limit ? Maybe since at wot the high rpms prevents a normal clean shift therefore in case it wont shift the rev limit in "D" catches it from over revving the motor and creating a disaster ? Sorry guys maybe i shouldn't be adjusting anything with my predator but i'm trying to figure out why the adjustment i was told to make isn't working .

[Illss1]

Guess it'll never get fixed then an i wont understand but thanks to those who replied .

[Illss1]

???????

[Quick]

What does the REV limit in "D" do if the the trans has its own shift points ? If i'm at wot and the trans has its own limits then what good is the rev limit ? Maybe since at wot the high rpms prevents a normal clean shift therefore in case it wont shift the rev limit in "D" catches it from over revving the motor and creating a disaster ? Sorry guys maybe i shouldn't be adjusting anything with my predator but i'm trying to figure out why the adjustment i was told to make isn't working .

I think maybe every car with an ECM these days has a rev limiter. It's sort of a fail safe. With an automatic transmission that will always upshift at the shift point you should never see the rev limiter. I bought my srt8 in 2006. At that time you could put the car in autostick mode and the car would hold the gear until you manually upshifted. If you didn't upshift it would bounce off the rev limiter repeatedly. The rev limiters are set for what the factory thinks is sufficient or safe (sufficient may be lower than safe). Lots of things go into that decision like duty cycle as well as the physical and electronic components, public safety, etc. When they came out with the srt8 many people were bumping the rev limiter in "D" on the 1-2 shift and some even on the 2-3 shift. Turns out that it was a programming oversight. They used the same algorithm as the 5.7L. The srt8's would rev up faster and so the overshoot was a bit more while the transmission was shifting. They came out with a TSB to fix that. The TSB also changed the behavior. The transmission would force an upshift at the upper end of a gear even if in auto stick mode. The TSB was to be applied for any customer that complained about bumping the rev limiter. It wasn't a recall or something to be applied to every car coming through service. There are still many srt8s out there that will hold a gear to the rev limiter. You'd have to ask a SRT Engineer if there are ANY corner case set of conditions where a car with the TSB (or new version) might get past the transmission shift point and hit the rev limiter. No one will know that here. I think the TSB may have bumped the rev limiter 50 rpm and/or initiates the shift sooner. Note that before the TSB some cars exhibited the problem and some didn't. Every car is a little different.

In your first 2 posts you implied you wanted to be SAFE. The only way to be SAFE is remain 100% stock. Even then you're not as safe as your regular car but it will be under warranty. The SRT team designed and made these cars to perform as well as possible within the constraint of a 100K mile duty cycle. They did a really good job. If you want to get more performance out of any car there is a tradeoff. First there is economy and emissions and most often there is some cost in longevity. How much is a guess and no one is going to be able to give you an exact answer on that. You WILL void your waranty if they show that something you changed contributed to the particular failure. What rpm do the valves float? No one will be able to tell you that exactly. Some people with a lot of experience and familiarity with these components and engines could give you a good guess. Some other people who experienced valve float might be able to tell you at what rpm their's floated. If they happened to be logging it at the time and it wasn't just a bad component. Even then every car is a little bit different. Is 6500 too high? is 6600 too high? is 6700 too high? It depends. It depends on how much risk you're willing to take and if it buys you anything (there's not a lot of power to be had up there with a stock motor).

On my car, with the r20 CAI 91 oct perf tune and raised shift points, will shift at 6400 give or take a few rpm. I know that because I logged it. What's the rev limiter at? I don't know because I've never hit it. It could be very close. Your car may be a little different. So your car should be initiating a shift that should complete within 50 rpm of 6400. Is it? Have you logged this to verify? Same for hitting the rev limiter. Is it actually hitting the rev limiter? have you logged this? There would be a fairly distinctive set of parameters that would indicate hitting the rev limiter. Is there any possibility that you think you're hitting the rev limiter and it's something else? You probably could find where your rev limiter is set by disabling auto upshift, holding a gear and creeping up on the limiter. Risk? certainly. How much? depends. If you sneezed violently while doing this and the rev limiter was very high it could be bad right?

If you raised the rev limiter to say 6700 and leave automatic upshift enabled you SHOULD never see the rev limiter. No one will guarantee you won't or if you do that nothing bad will happen. Apparently it was suggested that you raise the rev limiter 2-300 rpm to resolve your issue and you were asking if it was safe. The response was that if you're not comfortable doing that then the other resolution would be not to use raised shift points. What is the answer you're looking for?

Also in your first post it didn't sound like you tried the solution and wanted to know if it was safe first. In this last post it sounds like you tried the suggested solution and it didn't work?

[Illss1]

Again thanks for breaking it down so i can get an understanding and i guess i will give this another go again...... I was browsing a forum searching on rev limits and came across a thread an i read a post where this guy was saying he would'nt raise the rev limiter because it could damage the stock valve train BUT its the only thread i read about it an am NO longer worried about that issue becuase i havent heard anybody having problems like that so i'm dropping that . As far as being safe i understand that its always safer to leave it stock which i don't care to do an will mod more plus i have no warranty and i'm believing that i need to 1) datalog my car 2) figure out why it seems (sounds/rpm needle bounces) my car is hitting some kind of limiter (although its not doing it so much now an the weather is nicer the tires are sticking so i'm starting to think the cold weather an it spinning off the line at wot has smt to do with the issue . I guess just answer me this ....... rev in "d" is at 6750 right now , raised shift points , on 93 oct cai tune is all i've set so i'm ok right ? So far i havent hit it yet since the weather being better .

[SRT8Tech]

If you have raised shift points and you have the limitter at 6750 then you souldnt hit the limitter ever. I have the raised shift points and it shifts at 6400 give or take 30 rpms + or -. I have the rev limit at +150 and thats it. I bounced off the rev limit on purpose to see what it was with the limit set a +200 and it was at 6538 at the most 6600. And that was with a datalog. Shifting at 6400 is perfectly safe.