Santa Pod RWYB

[Dieselman]

Re-read my post... It clearly says hand timed stop watch.


As to dieselman... Where are you getting your facts from that a hand operated stopwatch is accurate to 1/10th of a second. There is no consistency to your method. Fair enough if you were doing it on a completely straight road with an automated timing system (santapod). But using a hand operated stop watch... What rubbish!

Did you bother reading the article from Autospeed, they are easily able to make a hand operated stopwatch within 1/10th of a second and having just tried it myself find it works fine.

I just timed 15, 5-second intervals, without really concentrating. The worst error was the first go and that was 0.17 of a second out of the average. Three others were 0.11 seconds out and all the rest were well within 1/10th of the avearge.

0.17
0.01
-0.01
-0.08
-0.08
-0.07
0.11
-0.02
0.11
0.08
-0.07
-0.05
-0.11
0.05
-0.02

You don't need to know an exact time, you need a repeatable average.

While searching the other night I found a thread where some guys are tuning their cars and testing on the road over a measured 1/4 mile. they then went to the Pod and were within 1/10th sec of their times.

Thread..
http://www.fiatforum.com/marea/124445-jtd105-performance-testing-0-60-0-100-a.html

Post..
http://www.fiatforum.com/marea/124445-jtd105-performance-testing-0-60-0-100-a-2.html

Also, you seem to have little faith in your abilities to time your car with a reasonable (to less than half a second) degree of accuracy. We timed my friend's car several times with a stopwatch on our accurately measured quarter mile, and found it to be right within a tenth of a second when he did an rwyb at santa pod.

I can't understand why you have a problem with that, a stopwatch is an exact timing device, sure it's not as sexy as a dyno chart, but it tells you a lot about on the road performance.

Remember, you don't need an exact figure..just repeatability... An inertia wheel dyno won't give you an exact figure either, just a calculated assessed figure.
Take you car to two dynos and it will read differently, take it to the same dyno two days running and it will read differently.

Seriously.
For the Guys getting your cars chipped/tuned do some stopwatch runs before and after and post the results.
It will cost the cost of a few runs up and down a straight road and a bit of time...i.e. nothing.

I just tried the stopwatch again but using my thumb instead of fore-finger. I got all bar 2 of the times within 1/10th second of each other, so the spread against average is now much tighter.

 

[wemorgan]

As above. I've used a stop watch on several occasions at motor races. I then compared to the onboard timer as was accurate to ~0.1s.

Think of it this way. Time a lap of a circuit where the average speed is 60mph. 60mph=27m/s. If you stand by a repeatable marker point and press the lap button each time the car passes. A car is about 4m long. I'm confident that I'm accurate to 1 car length and possibly nearer to 1/2. So therefore 1 car length is 0.15s, so 1/2 a car is 0.075s.

 

[m2287]

right. I have just gone to tescos and bought a stopwatch beacuse the touch screen one on my iphone was pissing me off. The average for my car going from 0-60mph (did 10 runs) is 4.5 seconds (My range was from 4.2 to 5.1).... i think the book says 5.6, all i have done to it is taken the secondary cats and a custom exhaust to the original AMG back boxes. Im not going to complain about this

Surely you would agree that if you have a power curve which has a bigger area underneath it and your car is the same weight as before, that it will be faster?!

 

[Dieselman]

Surely you would agree that if you have a power curve which has a bigger area underneath it and your car is the same weight as before, that it will be faster?!

If it is greater under the whole of the curve. The problem with dyno curves is that;
A: they aren't reliably accurate,
B: they get manipulated....especially when someone spends money on a remap,
C: How do you know what actual on the road difference it has made?

Your figures look good if you were timing yourself. Is the speedo calibrated and did you run to 60 or 62 mph?

A better guide for engine power is to perform rolling runs as that removes the issue of traction off the line. Try 20-80mph..on a private road of course..

It's a shame you don't have readings from before any mods were carried out as a comparison.

If you want a measured 1/4 mile run, mark a start point then drive for 1 minute at 15mph. Voilla..measured 1/4 mile.

 

[m2287]

but if they are inaccurate, they would be inaccurate both before and after by the same degree would they not?

Possibly manipulated but personally, if it were my business I wouldnt tell a customer they had 20bhp more than they had, just in case they go to the RR down the road which sets them straight.

You can feel the difference !

Speedo is just the normal one, I dont think it would work with my satnav - it cant keep up! And i just pressed stop as soon as it hit the 60mark.

hummm, I will try 20-80 tomorrow. Should be getting a set of filters next week so I shall see if that makes any difference too.

 

[Dieselman]

but if they are inaccurate, they would be inaccurate both before and after by the same degree would they not?

Possibly manipulated but personally, if it were my business I wouldnt tell a customer they had 20bhp more than they had, just in case they go to the RR down the road which sets them straight.

I have never doubted that remaps can make a difference, but that can be psychology as well. the car might sound different or have different throttle response, so will feel different, or maybe just the owner expects a difference so it feels different.

A RR only calculates the output figures it doesn't measure them. It works on various assumptions, so the figure given isn't necessarily accurate.
It's easy to make a RR output figure appear better or worse than the actual figure and when someone spends money there is that temptation because most owners will never check, they just say...Wow it feels different.

A stopwatch can be used to check every mod you do, so no kid-ology can happen. If the car isn't quicker the mod hasn't worked.

One of the members on here had a C230k remapped by DMS. I can't remember the exact figures but their claims were something like 15% uplift. He took the car back to a RR he had used previously and found it was something like 1Bhp different (within a normal error rating).

He got a refund from DMS...
...So given that they develop these remaps using RR testing how could that be...??
Nobody ever checks..

Here's a question.

How can a N/a petrol engine remap make more power? I don't see how it can as the Lambda and ECU will keep the mixture within it's normal operating range, close to stoichiometric, so without more air how can more power be generated?

 

[Dieselman]

A great example of timing how mods affect a car.

YouTube - Top Gear's "Faster Than an Evo Challenge" Part 1

http://www.youtube.com/watch?v=IiXfuvy3zH8&feature=related

http://www.youtube.com/watch?v=mUjFVkUEMOM&feature=related

 

[m2287]

I always thought that the remap tricked the ECU into getting different readings from various sensors? Which would in turn change the amount of fuel used?

Alot of my friends seem to comment on how much more fuel efficient their engines are after a remap. I have never had one done on a car personally.....

 

[Dieselman]

I always thought that the remap tricked the ECU into getting different readings from various sensors? Which would in turn change the amount of fuel used?

Alot of my friends seem to comment on how much more fuel efficient their engines are after a remap. I have never had one done on a car personally.....

Maybe it is, or maybe their driving style alters a bit as well.

A remap loads a new lookup table so the ECU references different values afterwards.

Years ago My Boss was unhappy with his BMW 525 performance so we took it to BBR racing, for a new chip.
They admitted that they didn't alter the fuelling at all, just advanced the ignition timing a bit. I think £300 for that is a bit steep.

 

[wemorgan]

A great example of timing how mods affect a car.

I'm sure you can well imagine the kind of tuning threads I've read on the Lotus and MX5 forums I read.

However for a novice track driver like myself driver confidence does play a part. So if I make a change like suspension rebound I'll convince myself the car feels more balanced though the corners, so I'll drive a bit faster through them. But the reality is I possibly could have driven that fast even on the previous settings.

 

[marty359]

Oh dear whats been going on here......I hope the stopwatch operator has had there thumb calibrated

Post your times up after you have been Jon, id pop down but im off to the zoo.

 

[JonMad]

Will do. 13.37s at 111mph sounds hard to beat though

 

[JonMad]

What a great day. I can see how it gets addictive. Shame the fuel cost twice as much as the rest of the day though.

Runs were as follows:
14.6431s at 104.08mph
13.7999 at 106.67
13.6910 at 106.66
13.3948 at 105.94
13.5905 at 105.68
13.5364 at 103.85
13.7354 at 105.67
14.5074 at 103.13
14.7514 at 103.34
13.7408 at 104.08
13.7305 at 104.09
13.6370 at 103.84
13.9520 at 103.85
13.7512 at 104.08
13.7534 at 106.20
14.1389 at 106.17
13.5977 at 106.91
13.5102 at 106.04
13.7183 at 105.29
13.3046 at 105.54
13.4149 at 106.00
13.3798 at 106.30
13.4000 at 106.77

For all but the last four runs I was in auto/sport mode. For the last four I switched it to manual and did the gears myself. Seems to be consistently faster (as well as the four runs being within 12/100s of each other). All runs were with ESP off.

The ones over 14 were with too much wheelspin off the line. I have a video of one of those runs. Will post up shortly. Had a great run against a Noble M12 GTO, neck and neck.

Makes my GPS-recorded 0-100 in 12.7s seem spot on.

Jon

 

[JonMad]

Car #322 was a particularly fast Scooby iirc

More pics:
2011 03 Santa Pod pictures by JonMad_photos - Photobucket

 

[JonMad]

And the video (spin those wheels!)
YouTube - Santa Pod

 

[Adam230K]

I have never doubted that remaps can make a difference, but that can be psychology as well. the car might sound different or have different throttle response, so will feel different, or maybe just the owner expects a difference so it feels different.

A RR only calculates the output figures it doesn't measure them. It works on various assumptions, so the figure given isn't necessarily accurate.
It's easy to make a RR output figure appear better or worse than the actual figure and when someone spends money there is that temptation because most owners will never check, they just say...Wow it feels different.

A stopwatch can be used to check every mod you do, so no kid-ology can happen. If the car isn't quicker the mod hasn't worked.

One of the members on here had a C230k remapped by DMS. I can't remember the exact figures but their claims were something like 15% uplift. He took the car back to a RR he had used previously and found it was something like 1Bhp different (within a normal error rating).

He got a refund from DMS...
...So given that they develop these remaps using RR testing how could that be...??
Nobody ever checks..

Here's a question.

How can a N/a petrol engine remap make more power? I don't see how it can as the Lambda and ECU will keep the mixture within it's normal operating range, close to stoichiometric, so without more air how can more power be generated?

I don't know a great deal about mapping, but what if the map was tailored in a way to make the car hold its torque curve for a further 500 rpm?

When I got my remap my car felt like it held itself alot better than it previously did upto the new 6500rpm redline. Before it felt like it was dying and revving unneccessarily at just 5800rpm.

How do you explain that? I personally think they could've moved my curve forward which would explain the higher BHP figure. After timing it i am so sure it made a difference.

Also I only got the remap done after I finished all my 'mods', the 0-60 was not improved that much but it was the mid range (20-90's especially) that improved by an average of .5 - .6 seconds (did it on a hot day, then on a nice dry but relatively cold day, cold day was where i achieved better results)

P.S. Marty's C32 seems very healthy

 

[Dieselman]

When I got my remap my car felt like it held itself alot better than it previously did upto the new 6500rpm redline. Before it felt like it was dying and revving unneccessarily at just 5800rpm.

How do you explain that? I personally think they could've moved my curve forward which would explain the higher BHP figure. After timing it i am so sure it made a difference.

Also I only got the remap done after I finished all my 'mods',

P.S. Marty's C32 seems very healthy

I didn't say Marty's car wasn't healthy, just that a remap with no other work is not going to make a difference, unlike yours which was done after other airflow mods were made.
You were getting greater airflow so needed a remap to increase fuelling to suit.
Presumably your car was running lean at the top end, hence feeling constrained. It's also possible that Mercedes deliberately restrict the top end output for various reasons.

An air-fuel gauge would have told you the full story.

 

[marty359]

23 runs !! You was having fun

Interesting with using it manual, i'll try it next time. I normally only do 3 or 4 runs im too scared something will break those starts can be hard.

 

[JonMad]

23 runs !! You was having fun

... I normally only do 3 or 4 runs im too scared something will break those starts can be hard.

I thought, well, it's an auto, how much stress can it be under.
Anyway, I had to beat your time!

 

[marty359]

Yeah I noticed that


Next time Jon