Heat Soak & Race Gas's Effects On My GIAC Stage 2 991 Turbo S 1/4 Mile ET/Trap Speed
 

This is a follow up post to my thread with the Youtube videos of several of my runs on June 8, 2015 at Albuquerque Dragway during goldRush Rally 7: https://www.6speedonline.com/forums/...dragstrip.html.

In this post, I analyze, based on the time slips, the effects of heat soak power loss and then the addition of top shelf race gas (Torco 108 -- the Torco equivalent of VP's MS109) paired with the GIAC Stage 2 race gas tune subfile.

Here are the pictures of my time slips. My best run was, of course, on race gas with the GIAC Stage 2 race gas tune file activated. It was an ET of 11.2743 with a trap speed of 124.10. According to the dragtimes.com density attitude correction calculator, the DA at the time of this run (6:53 pm local time) was 7,721 feet (the track elevation is 4943 feet and at the time of this run the air temp was 82 degrees F, the barometric pressure was 29.87 inches and relative humidity was 31%).

Running that through the correction calculator yields at sea level ET and trap speed of 10.796 at 129.377 mph. See http://www.dragtimes.com/da-density-...ect+ET+and+MPH

The result would have been a lot faster if the car were cool and running race gas.

These time slips show the brutal effect of heat soak on the performance. I am car number 52 in the slips. The car's performance mods: GIAC Stage 2, Europipe exhaust with 100 cell cats, IPD Plenum, BMC filter and Champion Race Diverter Valves. Tires were Michelin Pilot Super Sports in OEM sizes riding on ADV005 track spec CS wheels with titanium fasteners in OEM sizes (ADV1's top of the line and lightest wheel with a retail price of about $15,000). Car has no suspension mods.

All runs were using launch control with spoilers retracted and the PDCC button off to allow for the most weight transfer on launch to the rear wheels. The car was emptied of any luggage or extra weight. The AC was off and everything electrical that could be turned off was turned off. Windows were closed and, to minimize drag, I did not mount GoPros or anything else on the outside of the car.

The first five runs were on pump gas.

The first run, when the car was cool, was a 11.3751 seconds at 121.95 mph.

In the second run, the numbers worsened to 11.5352 seconds at 119.94 seconds.

In the third run, the numbers worsened more to 11.7259 seconds at 11.7259 seconds at 120.42 mph.

The fourth run was the worst of the day: 11.9387 seconds at 117.65 mph. This is just massive soak power loss -- an ET .5636 seconds higher and 4.3 mph slower than the first run -- both on pump gas.

The fifth run wasn't much better: 11.7330 seconds at 118.67 mph.

Then I added the Torco 108 race gas, switched to the race tune file and things got much faster.

The 6th run (1st on race gas): 11.3079 seconds at 121.49 mph -- a run even better than when the car was cold on pump gas. This run also had my best 60 foot time of the event -- 1.6847 seconds.

The 7th run (2nd on race gas): 11.3568 seconds at 122.78 mph.

The 8th run (3rd on race gas): 11.3752 seconds at 122.88 mph.

The 9th run (4th on race gas): 11.3296 seconds at 122.55 mph.

The 10th run (5th on race gas) was my fastest: 11.2743 seconds at 124.10 mph.

What this showed me is that the race gas essentially restored the power than I lost to heat soak. Unfortunately, I never got to run the car on race gas when it was cool. Had I been able to do so (the race gas only got delivered to the dragstrip halfway through the event) the car would certainly have broken into the 10s.

Good stuff brother. A way to combat heat soak is to bring a water sprayer and put some water and ice and spray down your intercoolers in between runs. They don't get heat soaked because you are racing...they get heat soaked because in between runs you are sitting on the Tarmac with no airflow and because the intercoolers are right next to the engine they start getting hot.

I did that two weekends ago it was like 90 degrees with high DA (not as high as yours) and it worked great. Did a 10.28 @ 134.4 uphill 1% incline Fontana (horrible track).

The stock Porsche 991 Turbo S was the other car in the slip at 6:12 pm, running at 12.37 seconds. My ET was 11.30 -- a full 1.07 second faster than the stock 991 Turbo S -- virtually all of the gain occurred in the first 1/8 mile.

The Huracan was the other car in the slip at 6:40 pm, running at 12.53 seconds. My ET was 11.37 seconds -- 1.16 seconds faster.

The 12c was the other car in the slip at 6:46 pm, running at 12.61 seconds. My ET was 11.32 seconds -- 1.29 seconds faster.

Ha! I have to go with you to a meet!

Need to get you down to a lower elevation track in the wintertime. How about coming out west for one of our Airstrip Events and then off to Famoso for a try at a 680-foot elevation drag strip?

Heat Soak & Race Gas's Effects On My GIAC Stage 2 991 Turbo S 1/4 Mile ET/Trap Speed
 

I live in the NYC area so shipping my car cross country for a meet won't happen because it is at least a $4000 round trip proposition enclosed.

We are doing a private dragstrip event at Atco New Jersey on October 7 which is invitation only. Atco is about at sea level and produces some of the fastest times in the country. We're going to have some of the fastest German sedans and Porsches in the New York area there including 2 Weistec turbo upgrade CLS63s, the fastest RS7 in the U.S., an 2015 AMS tuned vs Renntech tuned E63 S battle, the fastest stock turbo F10 M5 in the NYC area (all bolt on mods and Aquamist water-meth injection) and others. We are limiting the event to 20 cars so everything can get unlimited runs and participants will be splitting the track rental pro rata is this is a no profit event

Sounds epic. Sorry thought your last drag race was New Mexico not New York lol. Anyway you will get a great trap at ATCO. Out here in SoCal we are definitely jealous of that track, it's prep and the DA it gets.

Heat Soak & Race Gas's Effects On My GIAC Stage 2 991 Turbo S 1/4 Mile ET/Trap Speed
 

Thanks. I'm hoping for some good numbers and cool air

Heat Soak & Race Gas's Effects On My GIAC Stage 2 991 Turbo S 1/4 Mile ET/Trap Speed
 

Wow, this sounds like a great event to be a spectator as well!!!

Sure is although the purpose of the event is simply to battle the fastest German cars against each other.

If any 6speed member with a 911 Turbo or Turbo S is interested in participating, PM me. Should be about $200 per car (pro rata split of track rental among 20 cars). We have kept it private because we are limiting it to only the really fast German coupes and sedans.

If I ever get my car back I would love to join :rolleyes:. I'll pm you either way because even if I don't, it would be a cool thing to watch.

wut up with your car?

Heat Soak & Race Gas's Effects On My GIAC Stage 2 991 Turbo S 1/4 Mile ET/Trap Speed
 

See my PM re an invite

Ninjas kidnapped it and won't give it back hilarious


Thank you sir, I'll be in touch