It's Official, SLR Vbox times

the E.T. could probably be improved but I dont know about the trapspeed. The SLR's E.T. could be improved more than the LP640s, IMO.

 

Aaron

 

This is your second run no? The vbox pic shows the quarter mile @109.9mph in 11.5 seconds on your first run. The first results might be wrong, because you would need a much better 60ft time to have the same ET in both runs. The huge difference in trap speeds is puzzling.

 

Great trap speed on the second pass. Congrats!!

 

No that was the first run, the reason for the trap speed being 109 is because I was slowing down (from over 120) when I reached the end of the quarter mile. The fact that I still ran an 11.5 shows that there is a lot of improvement to be made in the E.T.

 

Aaron

 

No that was the first run, the reason for the trap speed being 109 is because I was slowing down (from over 120) when I reached the end of the quarter mile. The fact that I still ran an 11.5 shows that there is a lot of improvement to be made in the E.T.

 

Aaron

 

Gotcha, what was your 60ft time for both runs?

what do you think the LP640's ET would have been had you not hit the rev limiter? it seems the LP640 could really do with the LP560's LC system.

Just a note: I believe these 1/4 mile trap speed from VBOX will always be faster than these reported on drag strip tracks because on the drag strip the trap speed is averaged over the last 66' before the finish line. So they are not comparable.

Just a note: I believe these 1/4 mile trap speed from VBOX will always be faster than these reported on drag strip tracks because on the drag strip the trap speed is averaged over the last 66' before the finish line. So they are not comparable.

Actually we ran 11.5 @and 11.6 @128.7 at the dragstrip in AZ.

so they are comparible?

 

also interesting that all the times achieved by Aaron in either the LP640 or SLR are BETTER than the magazine's results.

Gotcha, what was your 60ft time for both runs?

 

Both were 2.1 seconds, although the SLR loses traction (and traction control cuts power) all the way up to like 50 mph. 2.0 is the best 60ft I have managed so far. With warmer temps I think I can get a 1.9.

 

Aaron

 

what do you think the LP640's ET would have been had you not hit the rev limiter? it seems the LP640 could really do with the LP560's LC system.

 

maybe 11.1-11.2 if I had the exact perfect launch with the exact perfect shifts, and the exact perfect temperature and conditions. Keep in mind that the LP does well when using the launch control, but no one is going to ever use that in a street race. I believe my best 0-100mph in the LP without using the launch control was 7.9 seconds. and the best 0-60 was I believe 3.7 seconds. The 11.9 quarter I ran without launch control was on a 2.7% decline (not huge, but helps nonetheless), so with a standard launch an egear LP would probably not crack 12 seconds.

 

Aaron

 

well you would if your going up against an SLR!

so they are comparible?

 

also interesting that all the times achieved by Aaron in either the LP640 or SLR are BETTER than the magazine's results.

 

not all my results are better, just my best results.

 

Aaron

 

well you would if your going up against an SLR!

 

And the SLR would have drag radials on if it was going against a launch controlled awd Lp640, so whats your point?

 

Aaron

 

Just a note: I believe these 1/4 mile trap speed from VBOX will always be faster than these reported on drag strip tracks because on the drag strip the trap speed is averaged over the last 66' before the finish line. So they are not comparable.

 

I found this:

 

Specifically there are 3 sets of photocells/lights at the end of a drag strip. There is the set at the actual finish line 1/4 mile (1320 feet) from the start line (and itsphotocell/light). That wouldn't be enough to measure speed across the finish line. There is a photocell/light 66 feet before and 66 feet after the finish line so that the amount of time it takes to travel 132 feet can be measured. From that, speed can be calculated. That means one needs to keep "on the gas" 66 feet past the finish line if they want the highest possible speed in a drag race. In a drag race, the winner is the one who crosses the finish line first so speed isn't very important unless you are able to set a record or want maximum bragging rights. "

 

 

I checked the graph and my speed 66ft before the end of the quarter was 127.36 and the speed 66 feet after the end of the quarter was 130.55, although I let off 14 feet before I should have at 130.72 mph. If I calculate the trapspeed the way that the drag stip does it, I come up with 128.6mph.

 

Aaron

Couple of questions for you Aaron. Have you tried launhing the car and doing a run starting in 2nd gear? In my car I would consistently get better 0-60's in 2nd because of less interference from the traction control and loss of one shift. I believe Id normally run 3.7 0-60's in Sport, while I got as low as a 3.5 starting in 2nd.

 

2nd. How about trying a 60-130 run starting in 3rd in manual mode? I wonder if it would go quicker since you need to shift to 3rd at 80mph, and since in 3rd full power is available from the TCU.

 

3rd. As for your 60ft times. You will be very suprised that with a good set of tires Im certain the car will get better than a 1.9 60ft. Looking at my info I got a 1.71 60ft on those drag radials. Believe me when I tell you that those tires were shot, I didnt heat them, the track prepped sucked and it was pretty cold.

 

Here is my info:

1/4 Mile ET: 11.026

1/4 Mile MPH: 128.859

1/8 Mile ET: 7.202

1/8 Mile MPH: 100.735

0-60 Foot ET: 1.718

Temperature F: 65.0

 

I think on stock tires you will get better times starting in 2nd.

Couple of questions for you Aaron. Have you tried launhing the car and doing a run starting in 2nd gear? In my car I would consistently get better 0-60's in 2nd because of less interference from the traction control and loss of one shift. I believe Id normally run 3.7 0-60's in Sport, while I got as low as a 3.5 starting in 2nd.

 

2nd. How about trying a 60-130 run starting in 3rd in manual mode? I wonder if it would go quicker since you need to shift to 3rd at 80mph, and since in 3rd full power is available from the TCU.

 

3rd. As for your 60ft times. You will be very suprised that with a good set of tires Im certain the car will get better than a 1.9 60ft. Looking at my info I got a 1.71 60ft on those drag radials. Believe me when I tell you that those tires were shot, I didnt heat them, the track prepped sucked and it was pretty cold.

 

Here is my info:

1/4 Mile ET: 11.026

1/4 Mile MPH: 128.859

1/8 Mile ET: 7.202

1/8 Mile MPH: 100.735

0-60 Foot ET: 1.718

Temperature F: 65.0

 

I think on stock tires you will get better times starting in 2nd.

 

I meant 1.9 with the stock tires I am running now. I think I can get even lower with stickier tires as you said. I have been doing my runs in comfort and sport mode. So far my fastest 0-60, and 0-100mph is in comfort, but the highest trap speed quarter was run in sport mode. I will continue to experiment with different combinations. I highly doubt that the 60-130mph would do better starting in 3rd, but I can give it a shot sometime.

 

Aaron

I meant 1.9 with the stock tires I am running now. I think I can get even lower with stickier tires as you said. I have been doing my runs in comfort and sport mode. So far my fastest 0-60, and 0-100mph is in comfort, but the highest trap speed quarter was run in sport mode. I will continue to experiment with different combinations. I highly doubt that the 60-130mph would do better starting in 3rd, but I can give it a shot sometime.

 

Aaron

Starting in 3rd for the 60-130 run might suprise you.

How about a run down as to your thoughts of the SLR after a week, compared to what you used to think before getting aquainted with it.

Well I used to think the SLR had very little room in it. But the one I briefly sat in must have not had the seat all the way back because I fit in it fine at 6'5". In fact I fit in it better than my Gallardo. I really like everything about the car so far. The brakes took some getting used to, but I am used to them now and I think they are great. Believe it or not, this is the first supercharged car that I have owned, and it's a nice change over the twin turbos. Its a great handling car that inspires confidence flying around curves. That is partly due to no body roll and the great Mercedes nannys. The Lambos might handle a bit better, but by the time you find that limit you are already out of control. I really like this cars highspeed stability as well. I have only had it up to about 150mph, but compared to my SL65 at the same speed its very well planted. It will be interesting to drive my TTG when I get it back from Jason Heffner to see how it compares. I have read that the SLR wasnt very successful due to its automatic transmission. For me thats a huge plus and is a big part of what makes this a great supercar daily driver. The ride is stiff, but extremely compliant. Laura and I forget we are even driving a supercar sometimes when we are just out cruising. Sometimes we ask ourselves why people are staring at us everywhere we go. But when you get on the throttle, the engine wakes up, you hear the supercharger whine and that special vibration throughout the car, and the car just flat out hauls.

 

Aaron

 

Posted this question in general chat. Does the SLR have superior aerodynamics to the LP640? Not just in drag coefficient, but in total frontal area (which is not measured by drag coefficient)

 

 

Seems the Murcie has a much wider total area which obviously has a negative effect on drag.

SLR has a coefficient of drag of 0.37 according to R and T.

 

LP640 has a coefficient of drag of 0.33 according to motortend.

 

Aaron

Good data, but as I said, c/d doesn't factor in frontal area.

 

 

For example, a Lotus Elise has a c/d of ~.36, compared to a C6 POS which has a c/d of .28, but due to the Elise being much smaller, they are almost equally aerodynamically efficient. If the SLR was a 1/18 scale model, the c/d would still be .37.

 

 

Cd*a is what we're looking for....

 

 

 

Eh, I guess it doesn't matter. It probably has more to do with the SLR's powerband than anything.

 

 

 

Murcie is 6 inches wider than the SLR but 5 inches shorter in height, and surprisingly, 2 inches shorter in over-all length.

 

 

 

 

ya for some reason the SLR just seems to get squished and distorted in pictures. its a pretty big car.

 

Allan, didnt you say you spun the tires in 3rd at 80 mph when you had your SLR? or is the mode you did it in gonna be different than what Aaron will do in the 60-130 run?

ya for some reason the SLR just seems to get squished and distorted in pictures. its a pretty big car.

 

Allan, didnt you say you spun the tires in 3rd at 80 mph when you had your SLR? or is the mode you did it in gonna be different than what Aaron will do in the 60-130 run?

 

For my 60-130mph runs I started in 2nd at about 53 mph with traction control off, the temps were cold, in the 50s, and the car did not lose traction.

 

Aaron

 

ya for some reason the SLR just seems to get squished and distorted in pictures. its a pretty big car.

 

Allan, didnt you say you spun the tires in 3rd at 80 mph when you had your SLR? or is the mode you did it in gonna be different than what Aaron will do in the 60-130 run?

That was at the dragstrip. poor dragstrip prep.

 

You can hear it:

 

 

The T/C was coming on at 80.