Today's Standing Mile Results for My SRTC

[dtenney]

In Gen 4 Vipers I would expect shifting from 4th to 5th around 165mph to 170mph depending on rear tire selection and assuming you run up to 6400rpm. Given the 585 hp, 133mph 1/4 mile, and knowing how well Gen IV motors perform on road course tracks, I would assume 190mph is reasonable. Comparing times from Texas to FL can be challenging though.

I know on boosted cars that I track regularly, the temp, humidity, and driver style can vary the results greatly. I have data showing that if I lift between shifts (causing the boost to fall) that between 60-140mph my car is slower to the equivalent of loosing 50 hp, on a car that dynos 350hp(world Challenge spec SRT-4). This loss of boost between gear changes can add up over the distance of 1 mile. However, not lifting to shift will shorten the life of transmission synchros.

I would assume that you might want to do a combination of gear swap/tune/nitrous/charge cooler. Also might want to look into a device or programming that can hold boost between gears, in my car the boost is held for 3 seconds when clutch is depressed as long as you keep the pedal to the floor.

-David

 

[Viperless]

Bob,

I thought Viperless was running a 3.55 rear ratio (maybe I'm wrong, he can confirm).

That would help overcome the 5th gear issue a little. With 3.55's and a modded 5th gear, I'd think your hp would put you at 190 no problem.

Also, it is hard to compare speeds from different dates and locations. Track conditions and weather plays a big effect on high hp cars. My buddy did the fall Texas mile in his Ford GT and the temps killed his speed.

I think the standing mile is going to be a very popular motorsports event, we finally had our first one on the West Coast last month in Mojave, Calif.

Good luck on your next event, I do think that if you're doing 5th gear you might as well make 6th gear usable too. 5th gear will have a dramatic effect to your acceleration goals.

Cheers,
George

Stock gearing.

 

[Bobpantax]

Also might want to look into a device or programming that can hold boost between gears, in my car the boost is held for 3 seconds when clutch is depressed as long as you keep the pedal to the floor.

Interesting. How does this work? I do not see how this can happen considering the supercharger is belt driven. Please explain. Who sells this? But, even if it held there, once the shift is complete the .74 will trash the revs and take the supercharger out of its performance zone. I think the best my car would do if the supercharger stayed in play during fifth would be about 185-187. I base this on the amount of power the cars that made more speed were running. I would love to think I could get to 190 but I doubt it. I think it would take about 750 HP to the rear wheels. The twin turbo C5 Z06 that ran 203MPH in March was running 840 HP to the rear wheels at the time. So, with cooler weather, a fifth gear change and assuming I ran 685 HP to the rear wheels, maybe 185-187 MPH but I would be very surprised if that power level was enough to get me to 190 MPH in the standing mile.

 

[RTTTTed]

I'm guessing that dtenney has a TT and he's referring to the Blow Off Valve? My Paxton doesn't have a BOV and therefor the boost doesn't get "blown off" when I lift to shift. At the base power levels I havn't noticed any shifting difficulties as with my Turbo cars (which need the BOV to dump the boost to protect the Turbos).

Paxton being belt driven lowers it's own boost when the engine slows. You're correct Bob. The boost also picks up as fast as the engine's rpms whereas the Turbos are exh. temp driven. Different.

Turbos would make the power sooner at lower rpms.

Ted

 

[TrackAire]

Thanks for correcting me Keith, I couldn't remember for sure on the gearing when we discussed trans ratios after your Texas mile run.

I don't think a dyno figure can always be counted on to give an exact result in a standing mile. As you found out, banging through the gears the mile comes up real quick. When putting a car on the dyno, everything is optimized for a 4th gear pull. As stated in the other post, boost drops don't happen on a dyno pull.

There has got to be some math formula showing different time to speed differences with different trans ratios out there.

Cheers,
George

 

[plumcrazy]

Ted. Your paxton has a BOV. Its just not so noticeable. You can change it out for a louder one if you like. You just can't control boost with it.

Same as bobs setup.

The BOV on my car came off an SRT. It used to be fast and furious loud with the one that was on it.

 

[dtenney]

I believe superchargers have an internal bypass, so I think you are correct in assuming that you are not losing boost except due to rpm loss from the gear change. Shifting into fifth is a difficult shift to make quickly, so there maybe some time/rpm loss there. So I still believe you could benefit from some devices like these:

1. N2MB - wot box - with 2 step and no lift shifting - I wonder if they make an app that will work on the Viper??wotbox (www2)

2. Racelogic traction control - combined with the N2MB type box and you should be fast out of the gate, then hold pedal to the floor and flat shift, letting the N2MB cut power between shifts and the Racelogic keep you from blowing the tires.

3. Add 50 to 100 shot of Nitrous to help compensate for boost loss during shifts and also help cool the charged air entering the motor.

4. 5th gear swap to make the 4th to 5th jump reasonable as EPA regs apparently made 5th a fuel economy gear.

The racelogic may not be necessary in your application.

-David

 

[Bobpantax]

I have the Racelogic system. I will probably proceed with the gear swap after doing a bit more research on the subject.

 

[RTTTTed]

Ted. Your paxton has a BOV. Its just not so noticeable. You can change it out for a louder one if you like. You just can't control boost with it.

Same as bobs setup.

The BOV on my car came off an SRT. It used to be fast and furious loud with the one that was on it.

BOV? After being told that I DO have one I checked again and found it bolted to the bottom of the Intercooler. Never heard it while driving and can't hear it in the video we made. I'll check the vacuum lines and see if mine is working (no boost guage). Thanks for that bit of info.

Ted

 

[Bobpantax]

I just looked at the actual results from yesterday. They are at the Mile Marker 1 web site. When compared to the rest of the field, I actually did much better than I thought. I was a bit naive about the amount of BS that goes on at these events both with regard to understating mods ( including a little hidden NOS) and that one or more people may have ****** stated a speed when asked that they did not actually attain. In any event, I am more pleased than I was yesterday. Live and learn. I am still probably going to cahnge out fifth and sixth. It won't hurt and it might help quite a bit.

 

[RTTTTed]

What? You're ruining a great thread Bob. I learned something because of this thread. Now you're happy? Sheesh

 

[pteam]

My opinion is keep your 3.07 and swap out 5th , or 5th and 6th, although 6th wont be used for the mile run. Supercharged cars are a handle to keep traction in 1st and you probably wouldnt want to up that gear, sometimes 2nd gear to. Swap out 5th and your 14 seconds faster as the 09s are. Changing out 5th should be a NO BRAINER for you if you want to run mile events, there is no decision, change it out!

Also you should take your car to a dyno just to make sure everything is running ok, you never know...

 

[Marv S]

did anyone of you fold in your side mirrors before the runs to give that smooth air?

At what speed did you notice the side mirrors POP?

What other things did you pick up on as the speed went north of 150? pay attention

 

[Marv S]

Congrats You will get there and it will be a rush.

Drag the front brakes too lignt for too long on a few of those runs and the wheel will turn light gold

 

[plumcrazy]

i have been over 150 too many times to count. i never noticed anything happen with my side mirrors. i will have to look this weekend at them. now im curious.

Bob, whats it take to swap out those gears ? is it much cost ? time ?

 

[GONABITE]

did anyone of you fold in your side mirrors before the runs to give that smooth air?

At what speed did you notice the side mirrors POP?

What other things did you pick up on as the speed went north of 150? pay attention

I have been over 200 mph in my 98 GTS and over 185 in my SRT coupe and have never encountered any " mirror popping ". This is a new one on me.

 

[dtenney]

When compared to the rest of the field, I actually did much better than I thought.

I think that is the best comparison to make, same track same day. I am in agreement with everyone else that if you want your car to perform well above 160mph you need the 5th gear swap.

-David

 

[britospeed]

Bob, before changing gears it would be good to data log your runs. Get a REAL look at whats going on with timing, IAT's ect.. Do the next event and gather some good data. After you'll be able to make an exact plan as to what is needed to accomplish your goals.

 

[SquadX]

i have been over 150 too many times to count. i never noticed anything happen with my side mirrors. i will have to look this weekend at them. now im curious.

Bob, whats it take to swap out those gears ? is it much cost ? time ?

I looked into this as well and may pull the trigger. Price was around $2500 for 5th and 6th gear swap. Not sure if thats a fair price or not.

 

[Viperless]

did anyone of you fold in your side mirrors before the runs to give that smooth air?

At what speed did you notice the side mirrors POP?

What other things did you pick up on as the speed went north of 150? pay attention

I did not. I noticed some folded them back but the overwhelming majority left them alone. I saw a few cars that had them removed.

I didn't notice any "popping".

 

[Bobpantax]

What? You're ruining a great thread Bob. I learned something because of this thread. Now you're happy? Sheesh

Not happy. Just more pleased. I am going to do the gear change in the near future. It will not cure the whole problem but it will reduce the RPM drop by 10%. I will be without the car for at least ten days. This means that I may exhibit acceleration addiction withdrawal symptoms but I am hoping my supercharged Jeep and my modded Lightning used in the right doses will hold me over. It's too bad someone has not perfected a durable and reliable roots or twin screw kit for the Viper. Since its power comes in at 1800 RPM, I do not think the same problem would occur on the shift to fifth but there might be a different problem. With the Paxton, the power keeps surging all the way up to redline. I do not think that this is the case with the other two types. Has anyone with a Gen II and a Roe supercharger done a standing mile event? If so, what happened when you shifted to fifth?

 

[plumcrazy]

what rpm did you shift at ?

im assuming you shift at or close to 6K ?

 

[Paul Hawker]

Marv.

Don't know about mirror pop, but on gen II Coupes the side windows would pop out of their channels about 145mph. Makes lots of wind noise, but not too distracting with helmets on.

I have also seen the glass mirrors sucked out of their cowls at high speeds. The glue just gives way.

In addition, at sustained high speeds, the valve stems can be pushed in by centripital forces and bleed your air pressure when you need it the highest. Using a valve stem cap with a rubber O ring can stop this loss of pressure.

Lots of neat things happen above 150 MPH!

 

[Marv S]

Paul,
Spoken like a veteran of the 318.

Yes, in the GTS we would notice the wind noise change a lot, and quickly, as the side windows popped out. On some high speed runs we would fold in the mirrors (side windows up) in and noticed they were back in normal position when we stopped. So we watched for it and could hear them pop from the folded back position to normal position at about 165 or so.

 

[Bobpantax]

1. The car was stable as a rock. No side effects.

2. I shifted a microsecond before the red light went on or just as it went on. But that is not the issue. The issue is the rev drop when I shift to fifth. It takes the Paxton out of the best RPM zone.

3. If this is Viperless's run, all I can say is he got an exceptional result and congrats!! The fellow in the video mentions a tail wind. Was he joking or was there a strong tail wind that day? Here is the link. I do not understand how the physics allowed the result but the video says it all.

YouTube - Dodge Viper 190.0 mph Texas Mile

 

[shooter_t1]

Stock gearing.

If that was your car in the video, you do NOT have stock gearing. In the vid, you shifted from 4th to 5th at 148 mph @ 6100 rpm. Not stock gearing!. More like the 3.55 someone else mentioned was in your car.

Last night, I took my stock 09 car to 160 in 4th without hitting the limiter.

 

[shooter_t1]

1. The car was stable as a rock. No side effects.

2. I shifted a microsecond before the red light went on or just as it went on. But that is not the issue. The issue is the rev drop when I shift to fifth. It takes the Paxton out of the best RPM zone.

3. If this is Viperless's run, all I can say is he got an exceptional result and congrats!! The fellow in the video mentions a tail wind. Was he joking or was there a strong tail wind that day? Here is the link. I do not understand how the physics allowed the result but the video says it all.

YouTube - Dodge Viper 190.0 mph Texas Mile

Watch @ 14 seconds into the run Bob. That car does not have the stock 3.07 gears.

 

[Viperless]

1. The car was stable as a rock. No side effects.

2. I shifted a microsecond before the red light went on or just as it went on. But that is not the issue. The issue is the rev drop when I shift to fifth. It takes the Paxton out of the best RPM zone.

3. If this is Viperless's run, all I can say is he got an exceptional result and congrats!! The fellow in the video mentions a tail wind. Was he joking or was there a strong tail wind that day? Here is the link. I do not understand how the physics allowed the result but the video says it all.

YouTube - Dodge Viper 190.0 mph Texas Mile

That's my video. The winds were out of the north at 8mph. Max wind speed was 20mph. Temp was 74. We ran on runway 10. 10 means 100 degrees so 10 degrees past due east. A bit of a tailwind but mostly a crosswind.

 

[Viperless]

If that was your car in the video, you do NOT have stock gearing. In the vid, you shifted from 4th to 5th at 148 mph @ 6100 rpm. Not stock gearing!. More like the 3.55 someone else mentioned was in your car.

Last night, I took my stock 09 car to 160 in 4th without hitting the limiter.

You guys are unbelievable. My car has the stock 3.07 factory installed rear end. That goes for the rest of the drive line as well. It has NOT been touched. I was running BFG drag radials which are nearly 1.5" shorter than the 345/30-19's.

I just love how other people think they know more about my car than I do.

 

[dtenney]

That's my video.

Nice run, great job showing what the Gen IV is capable of with basic mods. I am impressed.

-David