Diablosport Forums

This question hasn't gotten a answer from anyone from Diablo, so I'm going to try one last time.

-2006 300C SRT8 6.1
-Running 8r18 (at least it shifts well) - 93CAI canned tune.
-Airhammer, Cats, Corsa, 180 etc. No cam/heads (yet).

When I raise my shift points in Drive with my Predator, I am prompted to 'raise rev limits'. When I go to the screen that allows me to do that, I see that the RPM is ALREADY SET TO 6600.
So I follow it's advice and raise it on a few separate occasions between 50-200 rpm higher.

WOT run... whoa... hit the limiter. Some kind of reciprocating hesitation at WOT. Nice.

So I go back in to the Predator (on people's advice here) and reset the tune, raise my shift points, but THIS time I LEAVE THE RPM LEVELS IN DRIVE AT 6600. (Again... that's what the Predator has as my default. Some people here and on various forums say 'whoa that's high', but who am I to argue with the manufacturer?).

WOT run... hit the limiter. Same feeling. Nice.

So now I'm back to STOCK shift points and STOCK rpm limits in Drive. Am I supposed to understand that I cannot ever raise my shift points then?

I got my 06 TCM flash done from Chrysler to alleviate my Autostick issues... and now this.

Anyone from Diablosport, please feel free to chime in. I've tried to explain things so there's no mystery behind anything. Thanks.

Put on a newer software version and see if it still happens. The version you're using is like 6 versions old.

Didn't you go back to an even older version (16a) because the new one was sluggish?

johanness wrote:Didn't you go back to an even older version (16a) because the new one was sluggish?

DOooooohhhhhh!!

He he.
This is a common issue with the DCX cars, most people end up raising the rev limiter until it does not happen anymore.
The pred tunes do raise the rev limiter by default to 6600 on the srt8's, might need to raise it to 6800, some guys raise it to 7000 it varies from vehicle to vehicle.

johanness wrote:Didn't you go back to an even older version (16a) because the new one was sluggish?

Yes, but I'm back to 9r04 now. A tweaked 9r04, but the newest version none the less.

Plus, I haven't had this issue with any of the older versions. I've hit the rev limiter and thrown it into limp mode twice, and both times were my own fault.

Johan, Mike... thank you. So I'm not going to float or blow anything by raising it to 6800-7000? Sounds SUPER high, but if you say it's a safe setting, I will gladly raise it. Our gauge read high anyways doesn't it?
Mike, limp mode because you held the gear manually too long or?

Cheers

The motor shouldn't rev to the limiter. It will only rev until the shift point, so the key is to get the limiter higher then the shift point. Thats why I try to discourage turning off the Autosticks self-shifting, because if it doesn't shift, and the valves float, then you've got a major problem.

I got into limp mode by power braking the car and spinning the tires too fast. Motor revved sky high, but tranny wouldn't shift because the road speed was too low. So it hit the limiter, went into limp mode and threw a code.

Hey Johan... isn't this a holiday weekend in the USA? (I live in Canada and our holiday was last Monday). I didn't realize it or else I would have waited until Tuesday for the "Tester" Tune. Do you want any log files or is the e-mail explanation I sent to you last night sufficient?

Anyway, thanks again and Happy Memorial Day!

Yup, today is a national holiday

Mike_Levy wrote:I got into limp mode by power braking the car and spinning the tires too fast. Motor revved sky high, but tranny wouldn't shift because the road speed was too low. So it hit the limiter, went into limp mode and threw a code.

I suspect there was some other reason. I don't think road speed is measured off the wheels?

johanness wrote:Johan, Mike... thank you. So I'm not going to float or blow anything by raising it to 6800-7000? Sounds SUPER high, but if you say it's a safe setting, I will gladly raise it. Our gauge read high anyways doesn't it?

I don't believe anyone said it's a safe setting.

Like Mike_Levy said, the rev limiter is a "fail safe" and you really don't want to hit it. I also think auto upshift should be left enabled. You want to set your shift points at something reasonable and your rev limiter closer to the edge of doing damage in case you somehow manage to go over the shift point.

If you plan on hitting the rev limiter then you would want to set that where you think it's going to be safe. I don't think DiabloSport has tested the limits of our valve springs. I could be wrong. I heard of one 6.1L that failed a motor at or just above 6700. It may have been due to a broken spring rather than floating the valve. I don't think you're going to get any gaurantees.

Quick wrote: I suspect there was some other reason. I don't think road speed is measured off the wheels?

Exactly. Thats why when the tires spin, the tranny won't shift, because while the tires may be spinning at a certain speed, high enough for a shift, the car isn't.

Mike_Levy wrote:

Quick wrote: I suspect there was some other reason. I don't think road speed is measured off the wheels?

Exactly. Thats why when the tires spin, the tranny won't shift, because while the tires may be spinning at a certain speed, high enough for a shift, the car isn't.

Where is road speed measured, then? If the rear wheels are spinning that means that the tranny, driveshaft, and rear end are also in motion. Is the vehicle speed measured off of the front wheels? Or by the GPS unit?

I believe it is measured from the fronts.