Hello,

Recently picked up a 17 F-Type SVR, I simply love it! The sound, the drama, the speed. Certainly the fastest car I have owned to date. I picked up the Dragy and took it out to the drag strip to get a baseline before I start to go down the path of mods, drag strip sits at 2300ft elevation. I did 5 runs, dynamic mode, S gear, used launch control, some runs with and without traction control. Very consistent times, attached a video. However I have seen better times stock. Is it just my elevation that is limiting or something else I am missing?

11.91s@118.8 0-60 3.87s
11.90s@119 0-60 4.08s
11.83s@119.2 0-60 3.76s
11.91s@119.2. 0-60 3.89s
11.83@119.31. 0-60 3.81s

 

I found this info which should be helpful:

The NHRA uses a correction factor to compensate for altitude for stock/super stock classes. To accurately convert your ET, find your altitude with the chart below and convert your quarter mile ET and MPH to sea level times.

Here's how you do it: Simply multiply the elapsed time factor below times your ET or MPH.

ET Example: 16.1 x .9692 = 15.60412 corrected ET
MPH Example: 84 x 1.0325 = 86.73 corrected MPH

To find the elevation of the track where you drag race, check out the Geographical Nameserver. Enter the city, state and the server will find the info for you.

and the altitude converters:
Altitude(ft) ETFactor MPHFactor
1200 .9874 1.0129
1300 .9861 1.0143
1400 .9848 1.0157
1500 .9835 1.0171
1600 .9822 1.0185
1700 .9809 1.0199
1800 .9796 1.0213
1900 .9783 1.0227
2000 .9770 1.0241
2100 .9757 1.0255
2200 .9744 1.0269
2300 .9731 1.0283
2400 .9718 1.0297
2500 .9705 1.0311

Your 2300' elevation run of 11.83@119.31 would convert to 11.51@122.68 at sea level. That seems pretty reasonable for a stock SVR. Nice job!

*An Important Update* - In my haste to try to be helpful, I grabbed correction factors for a normally aspirated engine. With our F-Types being supercharged, elevation (or density altitude, more accurately), has much less impact. Here is a good website where you can calculate corrected 1/4 mile times and speeds for different conditions and different types of engines - https://www.dragtimes.com/da-density...calculator.php. Scroll to the bottom to enter your original data and see corrected results. Use the last option (Extensively Modified Supercharged and Turbocharged Engines) for an F-Type. Also, if you have an Android phone, you can use the app Drag Racing Weather Station (https://play.google.com/store/search...=apps&hl=en_US) to pull in live weather data for most drag strips and use the Density Altitude for your corrections.

From my personal experience, ambient temperature has a significant impact on performance for our F-Types due to hotter IATs. At higher elevations, the supercharger has to work harder to hit target boost, which will likely further increase IATs. I have not found a good method to correct 1/4 mile times for this effect.

 

That is super helpful, thanks for this! Help with my thoughts of it not performing to spec. I feel then once it is off the all seasons it came with and it is on some semi-slicks should grab another tenth.

 

I have updated my original reply to include the following:

*An Important Update* - In my haste to try to be helpful, I grabbed correction factors for a normally aspirated engine. With our F-Types being supercharged, elevation (or density altitude, more accurately), has much less impact. Here is a good website where you can calculate corrected 1/4 mile times and speeds for different conditions and different types of engines - https://www.dragtimes.com/da-density...calculator.php. Scroll to the bottom to enter your original data and see corrected results. Use the last option (Extensively Modified Supercharged and Turbocharged Engines) for an F-Type. Also, if you have an Android phone, you can use the app Drag Racing Weather Station (https://play.google.com/store/search...=apps&hl=en_US) to pull in live weather data for most drag strips and use the Density Altitude for your corrections.

 

Hmm, based on that likely not much of a difference. Maybe the tires then.

 

What were your 60-foot times from the drag strip? That is your best indication of traction limitations and launch technique.

For comparison, here are the time slips from a couple of my passes earlier this year. Note that I am VAP Stage 3. There was a pretty decent headwind the night I ran these times, so trap speed was lower than expected.

 

Here is a couple from the night. I am car 561. Similar 60' times, 1.77 and 1.84.

 

Those times look very respectable for a stock SVR. Also, I'm jealous of the digital time slip with the Density Altitude included at the bottom. I run at Indianapolis Raceway Park, home of the US Nationals, and we just get old-school paper time slips.

I dug up my stock time slips and here is one for comparison. IRP runs around 1000' DA most of the time.