alanjack

??

Be interested to know.

pslewis

HA HA HA HA ........................

These Rolling Road 'Shootouts' make me laugh ......

Must be hilarious watching a bunch of geeks creaming themselves over Dyno Graphs!!

This was the last 'Impreza Rolling Road Shootout' cost £100 each too!!

http://img.photobucket.com/albums/08...SNAnalClub.jpg

Discussing their Dynos ......................... over a cuppa at Aunty Bettys Cafe ...

It's ALL MADE UP, you know???

Pete

Brun

MaDaSS

SteveColvin

Might as well lay myself bare to pslewis's taunts with a modest defence of those (myself included) who have had their car RR'd.

To me, there are three (I accept there are many more..) reasons why you should pay your hard earned cash (as opposed to dwindelling retirement fund...) to have your engine's output verified:

1. To ensure that it is actually producing what the manufacturer says it can. Although RR's can only measure power at the wheels - engine power (Pnorm) being a calculation based on estimated losses, I accept this is sometimes 'estimated' more accurately through engine braking measurements... need to know more...
However, insecurities aside, and without 'life's-end perspective' I view RR's as a bit of harmless fun - never paid £100 for it though?

2. To establish baseline measurements prior to modification. People who buy/own Imprezas and similar such cars amazingly have this tendency to want to improve their cars for the sheer fun of it - imagine that? I don't think it did me any harm, then again my bank manager has differing opinions...

3. Obviously, affirmation/confirmation that said hard earned cash and empowered decision making has resulted in improved performance.

Anyway, RR meets are usualy good fun, whether attended by bespecticalled geeks or not, at least these guys have friends/kindred spirits and are not decaying away, venting their spleens in the splendid anonymity of the interweb.

Steve.

P1 SUB

£25 to £35 is the normal price to pay for a power run, dont know where your getting the price of a £100 from

davedipster

Probably the ones that bolt onto the hubs, not many around though.

dipster

davedipster

An engine dyno would be ideal of course. But that is too much bother for a saturday morning shoot out, so people use rolling random number generators.

dipster

cookstar

iTrader: (6)

ASAIK the ONLY really accurate way of measuring the output from an engine invloves removing it.

alanjack

Don't you get bored of posting that picture? Which one is you Pete?

Trout

iTrader: (1)

This form of measuring is also prone to artefacts as the most relevant measure is a dynamic reading which most bench dynos do not utilise - they tend to measure output at a fixed rpm.

In my own limited experience, rolling roads indicated a higher output than the bench of 8-10%

Whether this was an artefact, rolling road optimism, or environmental - who knows.

The most relevant measure of your cars performance is literally that - how it performs.

GrahamG

i was thinking that the other day... get on google images and find us a fresh on please!

silent running

The only use of a rolling road - ANY rolling road - is to establish a rough baseline for further modifications and to give you an idea of the response across the rev range. And even doing that, the only readouts that matter are torque and power at the wheels.

But to be fair, rr 'shootouts' can be a good day out and a bit of a laugh as long as you don't take them too seriously. Always cracks me up when you see write-ups on them in mags with the 'operator's opinion' and the things they come up with..."slight misfire beyond 6000 rpm", "down on power in the midrange, could be a dying fuel pump" etc etc. Brings to mind the scene where Michael Caine picks up his Aston in the Italian Job.

If you really want to see how fast your car is compared to others, go quarter miling instead. Much more accurate IMHO, because no amount of bull****, pub talk or transmission loss will make up for a slow-car. With a decent bit of practice, anyone can run the quarter 90% as well as a pro.

justanotherperson

Rolling Road days are a bit of fun,i've been on a few nyself as well as organised a couple also.
To find an acurate one is not so easy,the problem being most RR have different size/power cooling fans and how they get the cold air to your engine is questionable also sometimes.

The ambient temperature also has an effect aswell,for example if its a red hot day on the first run and a cold frosty morning on the second, well you should have more power on the cold day,for obviouse reasons.

Theres also the time between each run,you could have have heat soak by the second run,so the power will not be the same.

The best thing i would say is go to a well know company and stick with the same rolling road throughout the tuning,you limit the variables that way.

But i do agree the best way is an engine out jobbie.

pslewis

It's the one I have permission to use .... I am the one in the centre of the picture

Pete

Trout

iTrader: (1)

Clearly not someone with ANY experience of serious quarter miling.

If anyone can get in a ten second car and start pulling ten second quarters they are doing extremely well. Even with lower order cars the driver can easily make a 1 second difference or even more - and for a 300bhp that can be the equivalent of 50bhp or more.

This will differ depending on what type of rolling road you are using, tyre pressure, which gear and rolling diameter. Rolling Roads are 'mostly' designed and set up to estimate a PAF rather than PAW. The same car can produce very different PAW figures whilst producing similar PAF figures on different types of RR. As Power Engineering demonstrated a few years ago - the same car on the same day produced three very different PAW figures but the same PAF figures using three very different tyre pressures.

pslewis

Very well written response and I will go easy on you .......

1. Who actually cares if it is producing 214 or 216 BHP? The error in the equipment probably wipes out 20 BHP in any case? Does anyone ever ask for calibration certificates? I doubt it.

2. This assumes that you use the same RR under the same conditions (temp. humidity, etc.) because if you visit a different RR or the conditions are not exactly the same then the results are completely pointless if used as comparisons.

3. Like in 2. above ....... too many variables to give a suitable judgement - yes, you 'may' see an increase - but don't kid yourself that you can measure it with any accuracy to judge the worth of Mods. done.

Yes, I can imagine they are very good fun for those of likemind ........ and fair enough - but, you cannot expect us 'normal' folk NOT to laugh at you, surely to god??

You do know that, hidden inside every rolling road machine, there is a 2 year old child doodling away .............. don't you??

Here is one such doodling:-

http://russ.isitaboat.co.uk/media/ru...1099498192.gif

Quite why that is more appealing that the centrefold of Playboy puzzles me, but to RR fans this is what they 'get off on' with their new found friends

Pete

A5HYV

Just get yourself on a drag strip and test how fast you and your car is. a car is only as quick as the driver in it.

It will only cost you £30-£40 and you will have the best time and also learn and perfect how to drive and launch your car from the lights.

Forget about R/R BHP figures as everones right about the misleading figures you can get from different R/R and from variables. ive seen cars that have been mapped on R/R which produced upto 30 BHP gains but then on the 1/4 miles cars were down on their best ET. So really not always is more BHP the answer to a faster car.

ashyv

JTaylor

This may be of interest to some of you...

http://www.lancerregister.com/showth...t=Rolling+Road

Aztec Performance Ltd

iTrader: (234)

David_Wallis

The only accurate rolling road is the one your car is on at the time, take it off and put it back on and you cant compare imho..

Choose one and stick to it.. Some like the high reading establishments.

I prefer one that can hold my cars power and has a workshop I can use

For me my rolling road of choice is Scoobyclinics (DynoDynamics), and after that any other dyno dynamics roller.

1/4 mile doesnt prove the cars power, mine has potentially around 600bhp, certainly well over 550bhp, yet doesnt yet do the quarter mile quicker than 11secs.. Changing the gearbox seriously improved the cars on the road performance, yet the power didnt change.. So Power isnt the be all and end all..

Utilising what you have, with correct ratios and parts that can actually cope with the abuse and power you have are far more important than a piece of paper.

David

alanjack

Spot on Dave

A faster road car will do me.

Brun

While we're on the subject - what does anybody think that a Scoobyclinic 313 bhp will translate to in Pub talk Well Lane figures?

Aztec Performance Ltd

iTrader: (234)

What do you want the figures to be?

Stab in the dark 340+

davedipster

Better off using a stopwatch and timing a 30-70mph time in 3rd on the same road, than using any rolling road.

dipster

Trout

iTrader: (1)

Depends on how many blue beer tokens are put in the slot

Oooer missus