Tricky time Launching this car..Tip?

[vegasgtr]

Launch control generates 4.2 and me coming off 3k rpms with a little slip generates 3.9 0-60. That is prob around 2.2 60ft time which sucks.

Car has 2700 miles and every time I get on it with little clutch slip it has a bad clutch smell.. anyone else noticed the smell after aggressive acceleration from a stop?

All Launches are done in ESC ON.

[ViperPete]

When I tracked my car I used traction control off. I think the best 60 foot I could muster was like a 2.6

Apparently the only way to launch a Viper and get a low 60 ft time is to slip the clutch.

[Steve M]

Apparently the only way to launch a Viper and get a low 60 ft time is to slip the clutch.

With a looooooooooong first gear and a lightweight clutch/flywheel combo, that's about all you can do.

[Nine Ball]

With the Gen 5, you'll need a lot of rpm and have to slip the clutch out a lot. In order to achieve my 1.6 60' times (19" drag radials) I had to launch around 4500-4700 rpm and slip the clutch out. Otherwise it would bog the nose. The stock clutch is pretty awful for drag racing, it will die after about 30 hard launches. Ask me how I know. :)

Here is how it sounds outside the car. That smoke is clutch, not tires or exhaust.


https://www.youtube.com/watch?v=K4prnJgB3uk

Oh, and turn ESC off.

[vegasgtr]

With the Gen 5, you'll need a lot of rpm and have to slip the clutch out a lot. In order to achieve my 1.6 60' times (19" drag radials) I had to launch around 4500-4700 rpm and slip the clutch out. Otherwise it would bog the nose. The stock clutch is pretty awful for drag racing, it will die after about 30 hard launches. Ask me how I know. :)

Here is how it sounds outside the car. That smoke is clutch, not tires or exhaust.





https://www.youtube.com/watch?v=K4prnJgB3uk

Oh, and turn ESC off.



30 launches and bye bye clutch? screw that shit. was it covered under warranty?sounds weak.

[Nine Ball]

30 launches and bye bye clutch? screw that shit. was it covered under warranty?sounds weak.

Clutches, brake pads, tires. All wearable items. None of that gets covered under warranty for use.

30 very HARD launches. Not that baby 1.8 60' stuff. :)

[vegasgtr]

Clutches, brake pads, tires. All wearable items. None of that gets covered under warranty for use.

30 very HARD launches. Not that baby 1.8 60' stuff. :)

so they give you a car with LC and 30 times you are done? or does LC have zero wear on the clutch due to the instant release? If thats the case i would just LC every time , not worth the bill. BTW how much was it to replace it ?

[Dman]

LC is there to save the clutch. Dumping at 4k+ rpm with this kind of trq and slipping the clutch is asking a lot of any factory unit.

There are stronger alternatives. But not using LC, aka going faster and harder, 30 abuses isn't abnormal. But like a GT500 I think if you kept esc and LC on, you can launch all day long and be fine, albeit a little slower than you could manage on your own.

[Steve M]

30 launches and bye bye clutch? screw that shit. was it covered under warranty?sounds weak.

Not really weak, more of a design compromise. Based on the cars you've owned previously, I'm guessing you already know what a stiff, sticky clutch feels like driving around town. I went through many different clutches on my previous car (2002 Camaro), and none of them were as nice to drive around town as the stock clutch. I got close on my last attempt (RPS Carbon/Carbon twin), but even that wasn't the most street friendly clutch (it really liked to chatter in reverse).

Due to my previous experience, I have no plans to run anything other than an OEM clutch in my Viper. They are good for what they are, especially since mine spends 99.9% of its life being driven on public roads.

[Nine Ball]

so they give you a car with LC and 30 times you are done? or does LC have zero wear on the clutch due to the instant release? If thats the case i would just LC every time , not worth the bill. BTW how much was it to replace it ?

It is the slipping out of the clutch (controlled by your foot) that wears out the friction material the fastest. Launch Control is much less aggressive, since you engage the clutch instantly, at lower rpm. LC accounts for the tires to spin, not the clutch. LC also sucks at the drag strip, any halfway decent driver can achieve better 60' times by being more aggressive and slipping the clutch out.

Clutches aren't that expensive. I believe you can even swap in a Gen 4 clutch, which some say work better for these hard launches.

The main problem? Our terrible transmission 1st gear ratio. They put a very, very long 1st gear in this car, so that the silly magazine racers could brag about the 0-60 time without having to shift into 2nd. The trade-off is that it made the car more difficult to launch from a stop. I couldn't care less for 0-60 stuff, since nobody I know only races to 60 mph. I'd be more interested in 0-100 or 0-150, and if those were the trend we'd certainly see a different 1st gear being used, requiring a shift.

[1.8t]

^ What clutch did you end up replacing your stocker with and were you able to flat foot shift with it as well?

[Roddy]

^ What clutch did you end up replacing your stocker with and were you able to flat foot shift with it as well?

+1.

[Nine Ball]

^ What clutch did you end up replacing your stocker with and were you able to flat foot shift with it as well?

I put the Bad Boyzz dual-disk in the last car. No problems shifting it. Never made it back to the drag strip though, I was waiting for someone to beat my stock ET first. ;)

Almost 2 years now, still hasn't happened...

[vegasgtr]

I guess ill just get on it from a roll... speaking of roll 60-130 was 9.1 DA 6600. It feels quicker than that damn.. Maybe ill order the E-tune until then. I have a feeling the car is pulling timing IATs were 111

[Steve M]

I guess ill just get on it from a roll... speaking of roll 60-130 was 9.1 DA 6600. It feels quicker than that damn.. Maybe ill order the E-tune until then. I have a feeling the car is pulling timing IATs were 111

With IATs like that, it is pulling 7.5-8° of timing.

[vegasgtr]

With IATs like that, it is pulling 7.5-8° of timing.

Will the Tune via Hptuners help with that?

[viper04]

Will the Tune via Hptuners help with that?
Yes! You can change at what point the car pulls timing for IAT. Here is a write up Steve M did about the HP tuner.
http://driveviper.com/forums/threads/4774-HPTuners-Info-%28Gen-4%29

[Nine Ball]

The computer pulls timing for safety reasons. If I were in +6600 ft DA weather, I'm not so sure I'd want to make the tune more aggressive. Anything above 89F pulls timing.

[vegasgtr]

The computer pulls timing for safety reasons. If I were in +6600 ft DA weather, I'm not so sure I'd want to make the tune more aggressive. Anything above 89F pulls timing.

I was thinking the same thing. For 25hp i would hate to eat the motor. Lets see when D3 and AC shop come up with a blower kit..

[Steve M]

I was thinking the same thing. For 25hp i would hate to eat the motor. Lets see when D3 and AC shop come up with a blower kit..

It's not quite that dire. Below is the infamous IAT timing modifier table:

http://i305.photobucket.com/albums/nn227/meentss02/HPTuners%20Viper/Gen%205%20IAT%20Timing%20Table_zpswj9kobim.jpg

As you can see, the PCM pulls 3° starting at 86°F. Based on the Arrow heads/cam thread Andy (FLATOUT) started in this section, I was able to confirm what I had suspected - the PCM does a linear interpolation between discrete points, so timing actually starts being pulled at 77° (the next cell down). It would pull 1° at 80°F, 2° at 83°F, etc.

Now, I also know that Arrow left at least some of those protections in place on their performance-oriented PCM for the Gen 4/5 crowd. How much? Don't know...they ain't saying, and I don't have an Arrow PCM to figure it out myself. What I do know is that they also increased the main spark timing (which accounts for a lot of the power gain in the midrange), so keeping these safeguards in place is probably smart, especially considering that they had to make sure this tune could handle the worst case scenario: a Viper tearing ass around a road course on a triple digit day. Given that, it makes sense that they would tune on the conservative side. What that also means is that you are leaving at least something on the table when driving the car under less stressing conditions, like on the street. How much? Again, hard to say.

Don't forget that the fueling on these cars is MAF-based (two of them actually), so the less dense air is something actually measured by the PCM as it is calculating fuel and spark. Incidentally, the thinner the air, the more timing you can get away with in general.

That said, I've done a lot of experimenting on my own car with HPTuners, and there's definitely some room to play within the safety margins established by Dodge. I think pdv25's car is probably the best example of just what a good tune can do for you on a Gen 5 - I can make a pretty good guess as to what his IAT timing modifier table looks like (because Torrie likely set up my base tune similarly), and I can assure you, it is not even close to the stock values. His car runs hard as shit in South FL...hot and humid is a bit more stressing than high and dry when it comes to timing values.

The nice thing about HPTuners is that you can set this any way you choose. Leave it stock, make it more conservative, make it more aggressive...you can alter it to suit the conditions and what you are doing. I've said it before and I'll say it again - the tune I run on the street is more aggressive than what I'd run on a road course.

Just something to think about. Both the Arrow PCM and HPTuners with a custom tune are a good bang for the buck when it comes to getting the most out of these cars. The factory calibration is pretty conservative...some of that because of powertrain warranty concerns, but also some due to needing to make sure the catalytic converters live through the federally mandated 8yr/80,000 mile warranty. Arrow washes their hands of this by making their PCM off-road use only (which is why it won't pass a plug-in emissions test)...same with their heads/cam package.

[vegasgtr]

It's not quite that dire. Below is the infamous IAT timing modifier table:

http://i305.photobucket.com/albums/nn227/meentss02/HPTuners%20Viper/Gen%205%20IAT%20Timing%20Table_zpswj9kobim.jpg

As you can see, the PCM pulls 3° starting at 86°F. Based on the Arrow heads/cam thread Andy (FLATOUT) started in this section, I was able to confirm what I had suspected - the PCM does a linear interpolation between discrete points, so timing actually starts being pulled at 77° (the next cell down). It would pull 1° at 80°F, 2° at 83°F, etc.

Now, I also know that Arrow left at least some of those protections in place on their performance-oriented PCM for the Gen 4/5 crowd. How much? Don't know...they ain't saying, and I don't have an Arrow PCM to figure it out myself. What I do know is that they also increased the main spark timing (which accounts for a lot of the power gain in the midrange), so keeping these safeguards in place is probably smart, especially considering that they had to make sure this tune could handle the worst case scenario: a Viper tearing ass around a road course on a triple digit day. Given that, it makes sense that they would tune on the conservative side. What that also means is that you are leaving at least something on the table when driving the car under less stressing conditions, like on the street. How much? Again, hard to say.

Don't forget that the fueling on these cars is MAF-based (two of them actually), so the less dense air is something actually measured by the PCM as it is calculating fuel and spark. Incidentally, the thinner the air, the more timing you can get away with in general.

That said, I've done a lot of experimenting on my own car with HPTuners, and there's definitely some room to play within the safety margins established by Dodge. I think pdv25's car is probably the best example of just what a good tune can do for you on a Gen 5 - I can make a pretty good guess as to what his IAT timing modifier table looks like (because Torrie likely set up my base tune similarly), and I can assure you, it is not even close to the stock values. His car runs hard as shit in South FL...hot and humid is a bit more stressing than high and dry when it comes to timing values.

The nice thing about HPTuners is that you can set this any way you choose. Leave it stock, make it more conservative, make it more aggressive...you can alter it to suit the conditions and what you are doing. I've said it before and I'll say it again - the tune I run on the street is more aggressive than what I'd run on a road course.

Just something to think about. Both the Arrow PCM and HPTuners with a custom tune are a good bang for the buck when it comes to getting the most out of these cars. The factory calibration is pretty conservative...some of that because of powertrain warranty concerns, but also some due to needing to make sure the catalytic converters live through the federally mandated 8yr/80,000 mile warranty. Arrow washes their hands of this by making their PCM off-road use only (which is why it won't pass a plug-in emissions test)...same with their heads/cam package.

Thanks for the Info Steve! In the winter it will run hard as i will say IAT's will be around 75-80 here in vegas. I might give Torrie a call monday and have him give me mid-agressive tune. With a tune did you notice better throttle response from 1200rpms -2500.. thats were the car feels a little weak of the line..

[Steve M]

I'm not sure what Torrie has been able to do for the Gen 5 crowd - for the Gen 4 guys, increasing throttle response with HPTuners has been a sticking point. If you mess with any of the throttle response related tables, you are eventually greeted with the car going into limp mode. There are things you can do to affect the throttle response besides messing with those tables (fueling, spark, exhaust cam changes), but we're still waiting on a work-around for the meat and potatoes of the issue. The Gen 5 is supposed to have better throttle response than the Gen 4s (wouldn't know, never driven one)...it's very subjective. Compared to my old Camaro with a 30-lb flywheel/clutch combo and a cable driven throttle body, my Gen 4 sucks balls. It can be driven around to an extent, but still...executing a heel-toe downshift in my Camaro was almost too easy.

[Ninjazx71]

Clutches aren't that expensive. I believe you can even swap in a Gen 4 clutch, which some say work better for these hard launches.


Thought the Gen4/Gen5 clutches were the same, no? Any details on the differences between the 2?

[Steve M]

Thought the Gen4/Gen5 clutches were the same, no? Any details on the differences between the 2?

Gen 5 uses a lightweight flywheel...not sure if there are any differences in pressure plate design or friction materials. From what I've seen, the Gen 5 clutch is also a lot more expensive than the OEM Gen 4.

Sorta clutch related, but worth noting: the slave cylinder on the Gen 5 does not have a bleeder screw. It also shares hydraulic fluid with the brake master cylinder apparently.

[Jack B]

The light flywheel with the high 1st gear would make any clutch worry.


UOTE=Steve M;150365]Gen 5 uses a lightweight flywheel...not sure if there are any differences in pressure plflight late design or friction materials. From what I've seen, the Gen 5 clutch is also a lot more expensive than the OEM Gen 4.

Sorta clutch related, but worth noting: the slave cylinder on the Gen 5 does not have a bleeder screw. It also shares hydraulic fluid with the brake master cylinder apparently.[/QUOTE]

[ViperGeorge]

Launch control generates 4.2 and me coming off 3k rpms with a little slip generates 3.9 0-60. That is prob around 2.2 60ft time which sucks.

Car has 2700 miles and every time I get on it with little clutch slip it has a bad clutch smell.. anyone else noticed the smell after aggressive acceleration from a stop?

All Launches are done in ESC ON.

I've spoken with the SRT engineer that designed the Launch Control for the Gen 5. It was not designed for a prepped drag strip. It was designed for the street (no VHT). He does not recommend using it on a VHT prepared drag strip. Oh, and turn ESC off. If you leave it on the car will not allow the tires to spin and you will be much slower.

[vegasgtr]

I've spoken with the SRT engineer that designed the Launch Control for the Gen 5. It was not designed for a prepped drag strip. It was designed for the street (no VHT). He does not recommend using it on a VHT prepared drag strip. Oh, and turn ESC off. If you leave it on the car will not allow the tires to spin and you will be much slower.

After talking to Paul.. I think i will chill with the Launches. I will Just roll race .These vipers were designed for 60ft times..

[G37Sam]

Agreed, learnt the hard way haha

http://driveviper.com/forums/threads/8252-How-on-earth-do-you-launch-these-cars-!-Sucked-on-the-drag-strip-yesterday!

[Jack B]

My 13 has a best of 1.69.


After talking to Paul.. I think i will chill with the Launches. I will Just roll race .These vipers were designed for 60ft times..

[pdv25]

My 13 has a best of 1.69.

Was that on the factory trans or the 2010 trans?

[Nine Ball]

1.67 here, on 19" Nitto NT05R drag radials, stock wheels.

http://i466.photobucket.com/albums/rr29/ynotdv8/2013%20Viper/DSC06677.jpg (http://s466.photobucket.com/user/ynotdv8/media/2013%20Viper/DSC06677.jpg.html)

It took a while to figure out just the right launch. These Gen 5's are a pain in the ass to launch hard. The clutch has less traction than the tires do.

http://i466.photobucket.com/albums/rr29/ynotdv8/2013%20Viper/DSC06693.jpg (http://s466.photobucket.com/user/ynotdv8/media/2013%20Viper/DSC06693.jpg.html)

[FLATOUT]

I really want to drag race the snot out of these cars this fall and winter to see how deep we can push them with boltons and the heads and cam packages.

[vegasgtr]

what is the world record for Gen V viper in the 1/4 ?

[GTSilver]

what is the world record for Gen V viper in the 1/4 ?

I think Andy (FLATOUT) has the fastest time for a gen v in his black TA. Hopefully this time slip will be broken with his blue H/C gen v viper.

[GTSilver]

http://driveviper.com/forums/threads/7240-***Gen-V-Viper-1-4-Mile-FAST-LIST***?highlight=quarter+mile

[vegasgtr]

http://driveviper.com/forums/threads/7240-***Gen-V-Viper-1-4-Mile-FAST-LIST***?highlight=quarter+mile
wow not much of a list.. guess no one really runs the 1/4 with these cars..

[Jack B]

Andy and I ran almost identical times. Both OK times, mine was done at +1000 DA and Flatout's was done with a -1000 DA. For information purpose, a 1000 DA less is approx + 2.5% hp.

=GTSilver;150636]I think Andy (FLATOUT) has the fastest time for a gen v in his black TA. Hopefully this time slip will be broken with his blue H/C gen v viper.[/QUOTE]

[darbgnik]

wow not much of a list.. guess no one really runs the 1/4 with these cars..

Most guys I know with Vipers use them on the roadcourse, like I do, surprisingly. But they are mostly all in my track group, so my sample might be skewed.... lol

I did try a few quarter mile passes in my last Viper after a track event(Race City in Calgary had a quarter mile strip set up on its front straight), and it's a lot harder than it looks. It was fun, but I wouldn't drive the few hundred miles just to do it. I'll leave it to the pros like the guys in this thread, and continue trying to improve my lap times.

[Nine Ball]

Road course is certainly more fun. Running 10s in a manual car with independent rear axle is more challenging than most people give credit for, however. I know quite a few Gen 5 owners that have gone to the drag strip, but didn't get the results they hoped for. So, info doesn't get shared.

If 10s were easy, everyone would be doing it. Right?

[Jack B]

Tony

I have the MT drag radials mounted on the new 18" wheels, they road force balanced perfect. I don't think anyone will notice they are not oem

QUOTE=Nine Ball;150822]Road course is certainly more fun. Running 10s in a manual car with independent rear axle is more challenging than most people give credit for, however. I know quite a few Gen 5 owners that have gone to the drag strip, but didn't get the results they hoped for. So, info doesn't get shared.

If 10s were easy, everyone would be doing it. Right?[/QUOTE]

[98intrigue]

I'll be giving it a go this "winter" in FL, but with IATs around 110 it just doesn't make sense to do so now.