KPG

Jean , you have a point... I just checked my slope on my 60-130 1 shift and 2 shift and it was 1.4% and 1.3% respectively... Now I dont think scotty slc's 4 % changes the fact he has a great running car, especially since his best run of 8.76 was a 2% slope,but where should the line be drawn? What percent slope will affect the times to the point they are not valid indicators of vehicle performance? Later, Kevin

scotty slc

In an effort to try to clear up the slope over the ~1300ft. I tried to do some pulls the opposite direction on the same highway.... Basically I recorded a 8.9 and a 8.7... I sent the data over to KPG. hopefully this will either confirm 2% slope has little effect, or at least that my car is in the high 8's low 9's....

Theese pulls were on 19" HRE wheels max boost was .9 bar I am very happy with the current setup on my car....

KPG

Scott congrats on trying again...but there is good news and bad. Your 2 latest runs improved on time and decreased slope as well,but still remained downhill
Run 1 8.66 sec 60-130 in 1272.5ft with a 24 ft downhill run for a 1.88% slope... this was a 1 shift run.
Run 2 8.88 sec 60-130 in 1288.6 with a 30ft downhill run for a 2.30% slope...this was 2 shift
You really cleaned up your shifting on the 2 shift run....great time.You lowered your times and slope percentages but you need to find a BIG uphill slope for this experiment Kevin I cant post the run log because I am on my laptop and I recently reinstalled my os and forgot to put Adobe or Word back on.

Dock

There is no question that slope will affect acceleration times.

KPG

Of course it will...just how much is what we are trying to figure out. Kevin

scotty slc

It seems my faster runs are with less slope.... I do need to find an uphill to see some even better #'s .....

KPG

Scott, check your mail and get back to me Kevin

Jean

This makes sense, his previous run had an issue with the second shift and lost time. As I mentioned, around a 9s is more likely due to the issue with the shift.

KPG, as long as we can identify the slope if it can have an impact on the numbers then it is fine, if the run has a 4% slope which might represent 2-3/10s, we just keep it in mind.... personally I am not looking at these numbers as a bench race (you neither I know), I am interested at how HP is relating to performance and weight.

For instance if I were to see a 700HP claimed car perform like a 550-600HP then I would like to understand more, if I see something strange with long Gs, I try to understand why, etc..

An 8.9 or 9s is the same in my books, which on a flat would prbably be 9.1-9.2s and both are strong times for a 4WD 510HP TT. Does the car have stock weight?

Thanks Scott for sharing the numbers and your car is gorgeous. Thanks KPG.

Kiko

This is slightly off-topic but if anyone has one of this devices in Europe and is interested to see how an RS Tuning 508 performes, I'm more than willing to pay the shipping costs.

P.S.: If all goes as planned in a few months I'll be able to supply data for a 542bhp as well...

TB993tt

Scotty
Thanks for sharing the numbers - and for attempting to nullify the slope issue, it is no big deal its just good to get conditions as close as possible for all runs. Having said that I waited for a nice cold damp day to get my best run

Dock

I can tell you that an aircraft's takeoff performance, in terms of the actual takeoff distance (and therefore it's acceleration rate), is increased by 0.5% for each +0.1% of slope. So if an aircraft required 3000 feet of runway to reach liftoff speed on a runway with 0% slope, it would require 3600 feet to reach liftoff speed on a runway with 4% slope...so that's an additional 600 feet to accelerate to the same speed.

scotty slc

Kevin.... I am going to try to get to a weighting station later today..... I think I should be in the 3600-3700 weight...

Jean.... Thanks for all of your insight.... I have always enjoyed reading your posts....

TB... I fully understand.... Basically I want the #'s to be as accurate as possible for my own knowledge... If I spend 10-20K on my car I want to know it was for a reason..... Sort of makes it easier to spend the money I never really realized how many elevation changes there are around me....

Jean

Scotty, thanks for your words.

Dock, it is interesting to know about the airplanes and distance required to take-off, thanks.
I have not spent time doing the calculations, but it would not be very difficult to get an accurate result. Of course I am no expert in the aeronautics field, but I know that my car would have an advantage of 0.19 seconds approximately, and about 25+ feet as a result of a 4% slope, which I just simulated on my program.

I have this data from an acceleration program that I have fine tuned specifically to my car with very high precision, with the help of the program designer.

For a slower car such as a 996GT2 I am seeing about 0.22 s and circa 50feet, but in this case the parameters are not as accurately formulated as with my car, which was done with the help of my datalogger and a lot of trial and error.

It would be interesting to spend sometime on this. Isincerely think that 600feet is very unlikely in this case but I do not have any solid data at this point to debate it.

KPG

Well, in the interest of full disclosure here is the slope data on all the runs I have in my files...Scotty slc you already know from the above post.
KPG UMW Stg2 ZC
0-130 12.53 sec -12ft/1427.68 = .84% neg slope
60-130 1 shift 7.93sec -18.2/1166.54 = 1.56% neg slope
60-130 2 shift 8.59sec -14.5/1241.20 = 1.16% neg slope

9Eleven GT2
0-130 12.59sec -53.8/1410.98 = 3.81% neg slope
60-130 1 shift 8.10sec -53.2/1187.21 = 4.48% neg slope
60-130 2 shift 8.42sec -41.5/1223.84 = 3.39% neg slope

Revo X50
0-130 9.56 -6.8/1410.29 = .48% neg slope
60-130 9.56 3 shift -9.3/1595.86 = .58% neg slope

Thought these numbers might make interesting viewing.I will post slope with all forthcoming data. Looks like the X50 has the best area to run. BTW, the X50 will be running the GPS again and should have some numbers mid week, and I assume with 2 shifts only his 60-130 will be much lower. He will try a 1 shift run as well. Kevin

Dock

Once you get everyone running on similar slopes, you can start working on incorporating the impact of headwinds and tailwinds into acceleration numbers...