Toby Posted February 19, 2008 Report Posted February 19, 2008 Right....There seems to be a fair ammount of confusion with regards to Peters rolling road readouts. As I understand it..... You read the middle figure off the left hand column going up in 30,60,90, etc steps. Each big square, made up of 10 little squares is 10 KW 1 KW is 1.36(ish) Horse Power. So if you follow the graph across and you have, for example 90 kw on the graph this is a rear wheel figure and is equal to 90 x 1.36=122.4 hp If you want to try and estimate a fly-wheel figure Peter uses the transmision losses shown on the graph as the bit under the line on "let off". So say the line drops to 20 (2 big squares) under the line Peter tells you you have 20 x 1.36=27.2hp being absorbed by your transmission. There by deducing you have 122.4 + 27.2 = 149.6 flywheel horse power. Some things to bear in mind. The BIG horse power figure doesn't mean as much as the under the graph area. The Diff ratio will change the SHAPE (not height) of Peters graphs as it's power related to speed not rev's - always go with the same diff installed if you want to overlay your previous graphs - important if looking for area under the graph not the sales figure!! Higher reving engines TEND to have higher transmission losses, as should higher powered engines. I have been a few times and have seen various losses - higher number diffs have shown higher losses for me in the past. All rolling roads vary with regard to actual readings compared to one another. The most accurate roads will take into account atmospheric pressure, temperature and humidity. This is usfull to know if you want to make changes and go back to compare results - they could be meaningless if the weather has changed - which it will have. Peter graphs show how to account for this on the back. Always look to see that the graph starts at 0 on the left, I have seen graphs from Sanspeed where the cars start with 10 hp or minus 10hp at standstill. You have to consider this when you work out your figures and add it on or take it off..... I hope this clears up some apparent confusions.
Burns Posted February 19, 2008 Report Posted February 19, 2008 toby, it's 2am, what are you doing subjecting us to serious brain strain like that? makes sense oh, and another question, how do they work out what 1 "horse power" is? what's the way they work it out?
Toby Posted February 19, 2008 Author Report Posted February 19, 2008 Mmmm sorry, Borrowed from the web...... Horsepower is defined as work done over time. The exact definition of one horsepower is 33,000 lb.ft./minute. Put another way, if you were to lift 33,000 pounds one foot over a period of one minute, you would have been working at the rate of one horsepower. In this case, you'd have expended one horsepower-minute of energy. Now!! that's enough to make anyone go to bed!!
Burns Posted February 19, 2008 Report Posted February 19, 2008 Mmmm sorry, Borrowed from the web...... Horsepower is defined as work done over time. The exact definition of one horsepower is 33,000 lb.ft./minute. Put another way, if you were to lift 33,000 pounds one foot over a period of one minute, you would have been working at the rate of one horsepower. In this case, you'd have expended one horsepower-minute of energy. Now!! that's enough to make anyone go to bed!! thanks for that and nighty night
ratman Posted February 19, 2008 Report Posted February 19, 2008 Mmmm 174bhp sandspeed 3.7 diff hot sunny day 151bhp t,o,t,d 4.1 diff freezing cold winter day would that explain the missing 23 bhp
Toby Posted February 19, 2008 Author Report Posted February 19, 2008 Mmmm 174bhp sandspeed 3.7 diff hot sunny day 151bhp t,o,t,d 4.1 diff freezing cold winter day would that explain the missing 23 bhp 190 + at Sanspeeds on a "day" 163 at T.O.T.D on a different day!! The horses at Sanspeed are little ones though, they're fed badly and need shoeing!! T.O.T.D Horses are huge thorough bred race stallions Seriously though you would expect the rear wheel figures to be comparable as that is all both roads can really measure. The software has experience programed into it for the various car set ups and it uses this figure to compute the flywheel figure. There is a difference in the two proceedures though. Sanspeed tends to do his power runs in 4th - which is straight through the box and therefore should have lower losses than at T.O.T.D which was done in 3rd - which is how that machine was calibrated to work out its flywheel horse power. Because of this you would see a slightly lower RW figure at TOTD but not "20 odd" nags IMHO, so one or both of them is wrong!! The whole situation at Sanspeed makes comparing engines very difficult though, but it is very interesting to see different power losses on similar cars. Obviously tyre width and tyre pressure comes into it all too which is why TOTD did all of our tyre pressures to the same on the day. I always do this when I go to Sanspeed too. - A good tip!!
MK2Ed Posted February 19, 2008 Report Posted February 19, 2008 I see what Jo means now... You are seriously nocturnal mate - unless of course you're night shift I'm gonna have to re-visit what u written above and it's lunchtime...
Toby Posted February 19, 2008 Author Report Posted February 19, 2008 I see what Jo means now... You are seriously nocturnal mate - unless of course you're night shift I'm gonna have to re-visit what u written above and it's lunchtime... I'm just hopeless at going to bed - even worse at getting up!!
boXXer Posted February 19, 2008 Report Posted February 19, 2008 i aint even getting involved in this after my last efforts, lol!
Toby Posted February 19, 2008 Author Report Posted February 19, 2008 i aint even getting involved in this after my last efforts, lol! Yes mate, you 'd' man!!
styut Posted February 19, 2008 Report Posted February 19, 2008 This is the graph I got - its 145bhp (presumably at the wheels?) - can you tell what the flywheel figure is from this?
boXXer Posted February 19, 2008 Report Posted February 19, 2008 i aint even getting involved in this after my last efforts, lol! Yes mate, you 'd' man!! Love you too man!
Guest MK1gaz Posted February 19, 2008 Report Posted February 19, 2008 Peter at Sanspeed usually works out the BHP and writes it on the graph and tells you what it is anyway . Rolling road figuires are as reliable as a drunken women with your best mate so don't take too much notice of them !!!!!!!! Torque of The Devil Horses are much bigger than everyone elses though and that's for sure . Mines got 180 T.O.T.D. horses at the wheels (212 at the flywheel) so i can't wait to see what it can do on the other ones
Toby Posted February 19, 2008 Author Report Posted February 19, 2008 This is the graph I got - its 145bhp (presumably at the wheels?) - can you tell what the flywheel figure is from this? Looks like 87kw (87x1.36= 118.3 RWHP) above the line (Wheels) and about 15 KW below - (15x1.36=20) So 118+20 = 138 Flywheel If you go on the internet and search kw to hp converters they list 1kw as 1.341 hp so that makes Peters figure of 1.36 a bit high too. Truth is mate - does it go well? Does it put a smile on your face? Then who cares!!??!!
ratman Posted February 19, 2008 Report Posted February 19, 2008 Mmmm 174bhp sandspeed 3.7 diff hot sunny day 151bhp t,o,t,d 4.1 diff freezing cold winter day would that explain the missing 23 bhp The whole situation at Sanspeed makes comparing engines very difficult though, but it is very interesting to see different power losses on similar cars. Obviously tyre width and tyre pressure comes into it all too which is why TOTD did all of our tyre pressures to the same on the day. I always do this when I go to Sanspeed too. - A good tip!! also forgot to mension 17" rims 205/45 tyre 3.7 diff hot sunny day at sandspeed 13" rims 185/60 tyre 4.1 diff freezing cold winter day at t,o,t,d
Toby Posted February 19, 2008 Author Report Posted February 19, 2008 Mines got 180 T.O.T.D. horses at the wheels (212 at the flywheel) so i can't wait to see what it can do on the other ones Would it be wrong to mention starter motors or any jokes about them now?
Guest MK1gaz Posted February 19, 2008 Report Posted February 19, 2008 Starter motor no4 is holding up well so far (apart from falling out once ) so i'm hoping it's now fixed for good . On second thoughts a few months would be nice !!!!!!!!
Toby Posted February 19, 2008 Author Report Posted February 19, 2008 Starter motor no4 is holding up well so far (apart from falling out once ) so i'm hoping it's now fixed for good . On second thoughts a few months would be nice !!!!!!!! That reminds me! must get shares in Lucus tomorrow!! Modern engines - so reliable! I got like that with mine - gratefull if it started!! In a crowd you're thinking, come on, come on, pleeeaase start!!
Guest MK1gaz Posted February 19, 2008 Report Posted February 19, 2008 No mate , crowds are good , they can always help push when it breaks !!!!!!!
dommo1 Posted February 19, 2008 Report Posted February 19, 2008 How do you work this graph out toby for this one was 270 bhp http://www.oldskoolford.co.uk/phpBB2/vi ... c&start=60 And this one is 230 bhp http://www.oldskoolford.co.uk/phpBB2/vi ... 5&start=75
Guest MK1gaz Posted February 19, 2008 Report Posted February 19, 2008 Sanspeeds graphs are fooooooooking headache material . You can only tell the power by reading the "biro" numbers Peter writes on them , not very scientific but easier . Here's a 185bhp one from my old Harris pinto at sanspeed . Rough spec was a Group 1 head with WR40 cam , 45's , points and a pea shooter ashley twin box exhaust . It also made 175bhp at power engineering and 187bhp at southern carbs + injection so all pretty close to each other
dommo1 Posted February 19, 2008 Report Posted February 19, 2008 I was looking through Little Andys graphs collection and he had a 185 bhp graph that goes another big square and a half higher than the graph your showing here gaz
Guest MK1gaz Posted February 19, 2008 Report Posted February 19, 2008 Yes i've seen lots of them with the same sort power but at different heights on the graph . Peter used a scale rule when he worked it out so there's probably some "Jedi" code he uses !!!!!!!
Mk 1 Mark Posted February 19, 2008 Report Posted February 19, 2008 So what did Mick Mk1 Make then Toby? Go on the Big fella in the boot lol
Guest MK1gaz Posted February 19, 2008 Report Posted February 19, 2008 Nice videos mate , heres my one . 212 Torque of the Devil horses galloping
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