Drag strip questions

[Reaper]

Im going to take my car to our local 1000' drag strip this weekend and have a couple questions for those that have done this. Should I turn off the ESC? Also, has anyone used ethanol free gas? I found a station by me that has ethanol free 93. I know there is more BTUs in pure gas over ethanol gas. Im wondering if this will give me a little more power. I do have the Arrow PCM as my only mod so the octane is good. Also, what launch technique should I go with? Im thinking a quick release of the clutch, not sidestepping it, at maybe 2500 and maybe work my way up to 2800 if results work. I have the stock Corsas on my car so they should be pretty sticky. Ive drag raced before in my mustangs, however this will be first time in the Viper. Thanks all

[Jack B]

Your launch rpm will depend on the track grip and the track/tire temps. Because of the long first gear you will have probably have to slip the clutch. You are not going gain much with 93, the Arrow controller is designed for 91. Turn ESC off.



Im going to take my car to our local 1000' drag strip this weekend and have a couple questions for those that have done this. Should I turn off the ESC? Also, has anyone used ethanol free gas? I found a station by me that has ethanol free 93. I know there is more BTUs in pure gas over ethanol gas. Im wondering if this will give me a little more power. I do have the Arrow PCM as my only mod so the octane is good. Also, what launch technique should I go with? Im thinking a quick release of the clutch, not sidestepping it, at maybe 2500 and maybe work my way up to 2800 if results work. I have the stock Corsas on my car so they should be pretty sticky. Ive drag raced before in my mustangs, however this will be first time in the Viper. Thanks all

[SilveRT8]

Always tought the Arrow PCM was tuned for 93 octane ?

[Jack B]

Always tought the Arrow PCM was tuned for 93 octane ?

Half the country is limited to 91, that has to be the tune base.

[swexlin]

Reaper, let me know how you do, as you and I have the same car. So I'm interested!

[Reaper]

Reaper, let me know how you do, as you and I have the same car. So I'm interested!

Scott, will do! Im going to race either my buddies 2013 launch edition or his supercharged Challenger so it should be fun either way.

[EvilWon]

Like others have stated it's really going to come down to track prep. This car is a lot trickier to launch then the corvettes I've had in the past.

I would suggest slipping the clutch some and start your first launch around 3k rpm. If you don't slip it enough and hook you'll bog. If you release the clutch to fast and spin you're going wheel hop. These things don't seem to transfer weight all that well from my experience.

On a drag radial the car is much much easier to drive but requires a lot of rpm and slip to get a good launch and the stock clutch isn't going to be very happy. That's the main reason I've only taken my car to the track a handful of times.

Good luck!

[Ninjakris]

I recently took two trips to the 1/4 strip. First was on old/hard Corsa tires. I had to almost leave the line off idle since I would just spin or wheel hop. I ran a best of 11.8 A couple weeks later I went back with new tires (R888's) and it was a huge difference. With sticky tires I was able to leave the line around 3500 with just a little clutch slip. I ran a best of 11.2@131 I realize my MPH indicates I could be faster, but like others have pointed out, its not easy to launch these cars. I turned traction control off for all runs.

What did I learn at the track? Track prep and tire conditions play a huge factor in your technique. I think you have a good plan and just adjust it as you go.

[ViperSRT]

Half the country is limited to 91, that has to be the tune base.

Tell me again why, given that there is a knock detection system to retard/add fuel if detonation exists. Seems like the base program needs to be aligned with best fuel and not worst if the knock detection system is capable.

[Rare Snake]

On my first hard pass I smelled clutch like crazy to get traction. But my local track is well known for being awful for street tires and I've never done any better than high 11's in the 1/4, which isn't that great for these cars.

Also, I confused spectators with the typical brake light flash on shifts, track guys thought I was sandbagging and told me I was allowed to go faster lol.

I look forward to seeing how this goes for you, if the track prep is good, you will have a lot of fun!

Dason

[Jack B]

Tell me again why, given that there is a knock detection system to retard/add fuel if detonation exists. Seems like the base program needs to be aligned with best fuel and not worst if the knock detection system is capable.

Why not tune it for 105 octane? Even with kr you are going in and out of detonation.

[ViperGeorge]

Why not tune it for 105 octane? Even with kr you are going in and out of detonation.

I was under the impression (from Mark Jorgensen I think) that the Arrow controller would increase power up to about 98 octane. While it will run on 91 as long as it doesn't detect knock it won't subtract timing with higher octane. I seem to remember that on 91 octane it didn't add too much power. I'm probably wrong but maybe Mark could chime in.

[Jack B]

I was under the impression (from Mark Jorgensen I think) that the Arrow controller would increase power up to about 98 octane. While it will run on 91 as long as it doesn't detect knock it won't subtract timing with higher octane. I seem to remember that on 91 octane it didn't add too much power. I'm probably wrong but maybe Mark could chime in.

The pcm is going to start a with base timing map, then, pull timing from that base scheme. All the learning is done in closed loop (part throttle). It is too dangerous to have an alternate timing map for a change in octane, though, not impossible. I have multiple logs with the stage 2 arrow pcm where I mixed 105 and there is no increase in timing, however, there are multiple things influencing total timing.

[The_Ruski_Driver]

I am glad you posted this because I'm going for the first time in my car this weekend as well. I'm not an experienced dig racer so I'd be happy to break under 11.5 with the 4 year old stock tires. I will do a pass with the launch control, just to see how it does. I've tried it on the street and it just spins.

[EvilWon]

I am glad you posted this because I'm going for the first time in my car this weekend as well. I'm not an experienced dig racer so I'd be happy to break under 11.5 with the 4 year old stock tires. I will do a pass with the launch control, just to see how it does. I've tried it on the street and it just spins.

They actually advise against using it on a prepped surface.

[Jack B]

They actually advise against using it on a prepped surface.

What rpm does yours settle at during prelaunch

[Bruce H.]

Half the country is limited to 91, that has to be the tune base.

It actually is a 93 tune. I discussed this with Ralph and at length with Dick. They both recommended that I not use it on 91, with 93 or higher not readily available in my particular area. They said it would likely be fine for normal street driving where load is lighter, but didn't recommend it for tracking where certain conditions could be a risk. I asked Dick why the knock response system wouldn't manage knock under all conditions, and although I can't recall the specifics, the clear answer was that in some cases it might/would not.

[EvilWon]

I am glad you posted this because I'm going for the first time in my car this weekend as well. I'm not an experienced dig racer so I'd be happy to break under 11.5 with the 4 year old stock tires. I will do a pass with the launch control, just to see how it does. I've tried it on the street and it just spins.


What rpm does yours settle at during prelaunch

I've only used it once but if memory serves around 6k. The whole point is for it to initially break traction and then dial it back based on the amount of wheel spin. Long story short i wasn't impressed.

[ViperGeorge]

I spoke with the engineer that developed the ESC/Traction/Launch system for the Gen 5. He said it was configured for a non-prepped surface. He said not to use it on a prepped drag strip.

[Jack B]

It was easy to solve, the Arrow website says 93 octane, I stand corrected. They actually made the statement in bold type, whereas, the rest of the text was not bold.



It actually is a 93 tune. I discussed this with Ralph and at length with Dick. They both recommended that I not use it on 91, with 93 or higher not readily available in my particular area. They said it would likely be fine for normal street driving where load is lighter, but didn't recommend it for tracking where certain conditions could be a risk. I asked Dick why the knock response system wouldn't manage knock under all conditions, and although I can't recall the specifics, the clear answer was that in some cases it might/would not.

[Reaper]

Drag racing a Viper was an experience but fun. The Corsa tires are super sticky, like any drag radial Ive used on mustangs in the past. Its the tall first gear thats tricky. I tried bumping my launch rpm up from 2500 to closer to 3000 and it seemed to help but I wasnt good enough of a driver to break below a 2.0 60" I ended up running a best of a 9.90 in the 1000' and had a best trap speed of nearly 119 mph. The car pulls like crazy on the top end. I gained 21 mph from the 1/8 to the 1000' mark! I was getting wheel hop on the 1-2 shift and chirping into 3rd. I made a few runs against my buddies bone stock 2013 launch edition but his highest trap was 115. I think my Arrow PCM really showed a big difference here. Later on a C7 Z06 auto made a run and he did a 9.50ish pass at 116 mph. I know my viper is a easy low to mid 9s in the 1000' car, its just my driving holding it back some. It was fun but I dont know if/when I'll take it back to the track again. Tonight proves this car wasnt made to be a dragstrip terror but instead its a road ripping, corner carving, road car.

[swexlin]

Great feedback! Sounds like you had fun!