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Re: Tip Stepdown issue on Modded TT's
Quote:
tortesq1 said:
Did any tuner ever resolve the stepdown issue for modded tip cars ? Haven't heard anything about this in a while. I know that US tuner EVOMS had uncovered the issue, but I don't think they found a solution to the problem.
"Stepdown" issue???
Aug 22, 2007 2:24:45 PM
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Nick_Athens
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Reply to:
RC
Re: Tip Stepdown issue on Modded TT's
RC,
As you have a tip, I'm surprised that you haven't seen the issue in Europe. Nick described the issue which is a MAJOR problem in modding tips. I know that EVOMS was experimenting with the gas pedal and transmission/electronic brains to see if there was a reason for the power cutoff in the modded tip cars when at full throttle. I'm not a member, but 6speedonline had a couple of threads on this critical issue a while back. I'm still waiting for a solution - maybe the RUF 550 package has the issue resolved ???
As you have a tip, I'm surprised that you haven't seen the issue in Europe. Nick described the issue which is a MAJOR problem in modding tips. I know that EVOMS was experimenting with the gas pedal and transmission/electronic brains to see if there was a reason for the power cutoff in the modded tip cars when at full throttle. I'm not a member, but 6speedonline had a couple of threads on this critical issue a while back. I'm still waiting for a solution - maybe the RUF 550 package has the issue resolved ???
Re: Tip Stepdown issue on Modded TT's
Quote:
tortesq1 said:
RC,
As you have a tip, I'm surprised that you haven't seen the issue in Europe. Nick described the issue which is a MAJOR problem in modding tips. I know that EVOMS was experimenting with the gas pedal and transmission/electronic brains to see if there was a reason for the power cutoff in the modded tip cars when at full throttle. I'm not a member, but 6speedonline had a couple of threads on this critical issue a while back. I'm still waiting for a solution - maybe the RUF 550 package has the issue resolved ???
OK, guys, I'm not sure if I understand this correctly.
The 997 Turbo, like other automatic transmission cars, has a "kickdown" function which is activated as soon as you go past a certain "resistance" point with the throttle pedal.
The "kickdown" is a great feature because it suddenly shifts down as much as possible and you get full acceleration. Unfortunately the kickdown also has a downside, meaning that there is sometimes a certain lag in throttle response if the car is in the lower rev range.
So are you referring to this? The solution is pretty simple, step down throttle til the mentioned "resistance" point in the throttle pedal and then SLOWLY move your foot further until you floor the throttle pedal. If you floor the pedal immediately, there is a lag.
Not sure if this is the issue like I said before.
RUF's 550 HP kit has apparently an issue too regarding the top speed. Despite the 550 HP kit, a Tiptronic equipped 997 Turbo doesn't go faster (Vmax) than the stock car.
The reason seems to lie in the Tiptronic software which apparently triggers a safety switch which shuts down power when the rev figure goes over 6600 or 6800 rpm. Since RUF raised the rev limiter in the 5th gear, so the 997 Turbo does real 330 kph (Tiptronic), the Tiptronic cuts off power at a certain rev range, limiting the Vmax of the tuned car. Funny thing. RUF promised that I could review another car as soon as a fix is available but I wouldn't really care about this too much because there aren't many occasions where you can drive at speeds over 310 kph.
IF tuners raised the rev limiter in ANY gear, this is a huge problem because the Tiptronic won't allow the engine to rev over 6400 or 6600 rpm (Chrono Sport) or was it 6600 and 6800. Like I said before, this is some sort of "safety switch" from the Tiptronic and there is no solutio right now. I suppose the only solution would be to modify the Tiptronic software too but this isn't too easy, simply because nobody seems to have done it yet.
Since this is a Mercedes automatic tranny, there may be a solution available sooner or later because companies like Brabus or Lorinser have a lot of experience with Mercedes. The question is if these companies would supply Porsche tuners or their software developers with the necessary information.
Aug 24, 2007 6:17:21 PM
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Nick_Athens
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Re: Tip Stepdown issue on Modded TT's
Quote:
SSBP said:
Call David @ ProtoTech. There is not a step down issue with his program. I had the program in my 997TT (recently sold) and I will be putting same in my TT Cab when it arrives in October (hopefully).
Had you also raised the rev limiter or not ?!
Aug 25, 2007 2:31:33 AM
- SSBP
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Re: Tip Stepdown issue on Modded TT's
Rev Limiter was not raised.
Quote:
Nick_Athens said:Quote:
SSBP said:
Call David @ ProtoTech. There is not a step down issue with his program. I had the program in my 997TT (recently sold) and I will be putting same in my TT Cab when it arrives in October (hopefully).
Had you also raised the rev limiter or not ?!
Re: Tip Stepdown issue on Modded TT's
Quote:
SSBP said:
Rev Limiter was not raised.Quote:
Nick_Athens said:Quote:
SSBP said:
Call David @ ProtoTech. There is not a step down issue with his program. I had the program in my 997TT (recently sold) and I will be putting same in my TT Cab when it arrives in October (hopefully).
Had you also raised the rev limiter or not ?!
Prototech uses the Protomotive program which in the manual includes a raised rev limiter (7300) and a removed speed limiter.
Must be a reason why they didn't do it on the TIP
Aug 25, 2007 7:34:19 AM
- WhiteKnight
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Aug 25, 2007 8:30:39 AM
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Nick_Athens
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Aug 25, 2007 1:22:50 PM
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RC
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Re: Tip Stepdown issue on Modded TT's
Quote:
WhiteKnight said:
I heard that TIP tranny gets confused if the rev limiter raised in 1-2-3-4th gears.
There isnt a problem in the 5th gear because there isnt a higher gear than 5 to get confused.
You don't seem to understand, guys: we're talking about Tiptronic ONLY and there IS a problem, simply because the Tiptronic software doesn't allow more than a certain rev figure due to "working safety" reasons. Meaning: if a Tuner raises the rev limit to 7200 rpm in the 5th gear, it doesn't help at all, the engine will still shut off power at the stock rev limiter, simply because the Tiptronic software has priority (to make sure the Tiptronic isn't "harmed"). Meaning: it is impossible to make a Tiptronic equipped Turbo faster than stock for the time being. I already know that tuners work on a modded Tiptronic software or at least on a way to try to "remove" the software switch from the motronic programming but right now, nobody seems to have a solution.
Understood? Fine.
Re: Tip Stepdown issue on Modded TT's
Quote:
RC said:Quote:
WhiteKnight said:
I heard that TIP tranny gets confused if the rev limiter raised in 1-2-3-4th gears.
There isnt a problem in the 5th gear because there isnt a higher gear than 5 to get confused.
You don't seem to understand, guys: we're talking about Tiptronic ONLY and there IS a problem, simply because the Tiptronic software doesn't allow more than a certain rev figure due to "working safety" reasons. Meaning: if a Tuner raises the rev limit to 7200 rpm in the 5th gear, it doesn't help at all, the engine will still shut off power at the stock rev limiter, simply because the Tiptronic software has priority (to make sure the Tiptronic isn't "harmed"). Meaning: it is impossible to make a Tiptronic equipped Turbo faster than stock for the time being. I already know that tuners work on a modded Tiptronic software or at least on a way to try to "remove" the software switch from the motronic programming but right now, nobody seems to have a solution.
Understood? Fine.
There are 2 problems:
1) the stepdown issue which seems to be a non-issue with the right programmer;
2) the redline issue - which seems yet to have a solution.
Don't mean to state the obvious, but to avoid any confusions...
Aug 25, 2007 7:34:16 PM
- WhiteKnight
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RC
Re: Tip Stepdown issue on Modded TT's
Quote:
RC said:Quote:
WhiteKnight said:
I heard that TIP tranny gets confused if the rev limiter raised in 1-2-3-4th gears.
There isnt a problem in the 5th gear because there isnt a higher gear than 5 to get confused.
You don't seem to understand, guys: we're talking about Tiptronic ONLY and there IS a problem, simply because the Tiptronic software doesn't allow more than a certain rev figure due to "working safety" reasons. Meaning: if a Tuner raises the rev limit to 7200 rpm in the 5th gear, it doesn't help at all, the engine will still shut off power at the stock rev limiter, simply because the Tiptronic software has priority (to make sure the Tiptronic isn't "harmed"). Meaning: it is impossible to make a Tiptronic equipped Turbo faster than stock for the time being. I already know that tuners work on a modded Tiptronic software or at least on a way to try to "remove" the software switch from the motronic programming but right now, nobody seems to have a solution.
Understood? Fine.
RC,
I know this problem since may, and i have tried raised rev-limiter ecu and it doesnt cut the power all the time as you say, it is a bit more complicated than that.
I have tried 7000-7100 rpm rev limit and it is actually fine when you are going with %100 throttle, the problem is when you are going below 100 percent throttle. When you hit the revlimit with TP below 100% tranny puts it self in N position and you cant change any gears, you have to stop and restart the engine.
I hope i gave a little bit more explanation to the rev-limit problem.
Aug 25, 2007 8:58:05 PM
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RC
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Re: Tip Stepdown issue on Modded TT's
Quote:
WhiteKnight said:
I have tried 7000-7100 rpm rev limit and it is actually fine when you are going with %100 throttle, the problem is when you are going below 100 percent throttle. When you hit the revlimit with TP below 100% tranny puts it self in N position and you cant change any gears, you have to stop and restart the engine.
I hope i gave a little bit more explanation to the rev-limit problem.
The rev limiter raise is ONLY necessary in the 5th gear, not in the lower gears. You certainly don't want to raise the rev limit in the lower gears for various reasons I can't elaborate now. It IS necessary in the 5th gear because otherwise the car runs the stock 310 kph, maybe up to 312 kph only (real speed, not speedo, speedo shows up to 327 kph at stock top speed).
Raising the rev limit in the 5th gear causes the Tiptronic "software switch" to jump in and to cut off power very suddenly, resulting in a very "ugly" power cut off at around 310-312 kph. The stock cars have a very smooth cut-off, simply because the rev limiter is stock and all the power cut-off is controlled by the motronic. The Tiptronic cut-off is more of an emergency power cut-off to avoid possible damage.
I know this stuff is very confusing.
Regarding the "stepdown" issue: I'm still not sure I understand the problem. Like I said, you should NEVER floor the throttle pedal, simply because the kickdown is activated, resulting in a short "gap" in throttle response, mostly at lower rev figures. To achieve a satisfactory power distribution/throttle response, it is necessary to use a "linear" style of throttle usage, meaning to smoothly fully accelerate until the first "stop" of the pedal way and THEN to press the pedal further to activate the kickdown (and overboost).
Sorry if my English isn't good enough to explain it better.
Regarding the rev limiter problem: I really hope that somebody finds a solution because right now, there isn't much optimism. Changing the Tiptronic software mapping may be the only solution but it would be the toughest one. A more simple solution would be to turn off the "software emergency switch" in the Tiptronic software or to actually lead this software "signal" to the motronic into nothing, meaning that it has no effect. Unfortunately this also could be very harmful to the Tiptronic if there is a very high rev figure, even for a very short time.
I'm curious to see the solution. Anyway: the power output of the RUF kit is impressive, performance is very good for such a kit and thanks god, it doesn't involve any major hardware changes, making it very easy to reverse it.
Re: Tip Stepdown issue on Modded TT's
Not sure if raising the rev limit is the proper solution, the tip box was sourced fom MB and when it was used in the AMG applications, the engines that it was mated to wasn't high revving ones. It could be that the tip/mb autobox wasn't design for high rpm applications, it maybe bulletproof in handling power, but it's not when being asked to spin at 7k+ rpm.
For a safer was to raise top speed, final gear ratio change would be the better choice.
For a safer was to raise top speed, final gear ratio change would be the better choice.
Aug 29, 2007 8:57:05 AM
- Freak997Turbo
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Aug 29, 2007 4:04:28 PM
- tortesq1
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Re: Tip Stepdown issue on Modded TT's
Freak997Turbo,
The stepdown issue we are referencing is primarily for modded turbos only. The lag with our tips is generally heightened when the tip is modded. Of course, the lag is most pronounced when starting out (not torque/power braking). With modded tips there appears to be a "power cutoff" when literally flooring the cars gas petal. One solution is to simply not floor the petal and to feed the power slowly (as RC mentioned). In any event, we are really talking about fractions of a second with the lag. Truth is who wants to mod your tip with 550 plus hp (in some cases it will eventually be 700-800) only to be hamstrung with this stepdown issue ?
The stepdown issue we are referencing is primarily for modded turbos only. The lag with our tips is generally heightened when the tip is modded. Of course, the lag is most pronounced when starting out (not torque/power braking). With modded tips there appears to be a "power cutoff" when literally flooring the cars gas petal. One solution is to simply not floor the petal and to feed the power slowly (as RC mentioned). In any event, we are really talking about fractions of a second with the lag. Truth is who wants to mod your tip with 550 plus hp (in some cases it will eventually be 700-800) only to be hamstrung with this stepdown issue ?
Re: Tip Stepdown issue on Modded TT's
Quote:
tortesq1 said:
Freak997Turbo,
The stepdown issue we are referencing is primarily for modded turbos only. The lag with our tips is generally heightened when the tip is modded. Of course, the lag is most pronounced when starting out (not torque/power braking). With modded tips there appears to be a "power cutoff" when literally flooring the cars gas petal. One solution is to simply not floor the petal and to feed the power slowly (as RC mentioned). In any event, we are really talking about fractions of a second with the lag. Truth is who wants to mod your tip with 550 plus hp (in some cases it will eventually be 700-800) only to be hamstrung with this stepdown issue ?
if I am not mistaken freak997tt has a protomotive tuned tiptronic and so far I have not read about that problem with this specific tuner.
Freak, do you feel the car has less acceleration when you floor it all the way versus 95% of the way?
Re: Tip Stepdown issue on Modded TT's
AAHTT,
That is a damn good question !!! Seems like protomotive guys are very loyal (as they should be), but I don't believe that ANY aftermarket manufacturer has eliminated the stepdown issue 100%. I'll be interested to see how a legit 700-800 hp plus (at the engine not at the wheels) tip handles this issue. We will likely know by the end of 08 when aftermarket tuners are "into" the 997 TT full swing.
That is a damn good question !!! Seems like protomotive guys are very loyal (as they should be), but I don't believe that ANY aftermarket manufacturer has eliminated the stepdown issue 100%. I'll be interested to see how a legit 700-800 hp plus (at the engine not at the wheels) tip handles this issue. We will likely know by the end of 08 when aftermarket tuners are "into" the 997 TT full swing.
Sep 1, 2007 5:07:58 AM
- Freak997Turbo
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Re: Tip Stepdown issue on Modded TT's
Again...The car pulls hard from 1,2,3 and on 4th the rpm needle jump quick until 4200rpm it like hitting a wall it become slower..is that normal? it maybe kickdown issue as RC mention or maybe the speedo confuse as i heard not sure.
Regarding the stepdown im still not sure what's that issue exactly... the car didn't pull hard on all gears or what ?
Proto raise the rev limiter on 1 to 4 to 6900 and to 7200-7300 on 5th.
Once i floor it hit 7000rpm after that it hit the redline normally.
Regarding the stepdown im still not sure what's that issue exactly... the car didn't pull hard on all gears or what ?
Proto raise the rev limiter on 1 to 4 to 6900 and to 7200-7300 on 5th.
Once i floor it hit 7000rpm after that it hit the redline normally.
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