Car performance is WRONG...

[tommy10101]

basicaly, the turbo demo car (cant remember whats its called) has 220bhp per tonne or somthing like that yet it can run 13.6 at 108 mph 1/4 mile times. My dad has a kit car with 260bhp and it weighs less than a tonne (876kg) and that runs 13.8 at 101mph. Therefore, they have got it wrong. I just thought i would let everyone know :)

[keithano]

basicaly, the turbo demo car (cant remember whats its called) has 220bhp per tonne or somthing like that yet it can run 13.6 at 108 mph 1/4 mile times. My dad has a kit car with 260bhp and it weighs less than a tonne (876kg) and that runs 13.8 at 101mph. Therefore, they have got it wrong. I just thought i would let everyone know :)

What mods do your dad's car have? Is it turbo-charged? Anyway, there are too many factors to affect the quarter mile time.

[axus]

Yeah, I must agree. Because bph/tonne is the ultimate measure of performance, right? I mean, I know power has more of an effect on your top speed and mass mostly affects acceleration, but still. I really don't know why they don't make car models equivalent to the car's bhp/tonne... that way you could just see that the BMW 230 is faster than the Mercedes 203.

[tommy10101]

yeh there may be other factors....but 80bhp more per tonne does not equal half a second slower on the strip in any case....they are wrong :(

[hrtburnout]

Mind you, the XFG you're talking about is tuned for racing. :shrug:

[FlintFredstone]

Quarter miles depend a LOT on the ability to launch, thats why subaru's can get under 13.5's even though they are a 1500kg car with 300 bhp and transmission drag like treacle and aero efficiency of a brick.

PS older style subs are 1300 kg's (thats why they can do quarters in under 13 if up to 300 bhp)

So summary of this chaotic post is if you can get a car to launch superfast and have low trasmission losses and good aero then i cant see anything wrong in a 13.6 for a 2 wheel drive heavish car with 220bhp (although it is very optimistic :) )

Simon

[tristancliffe]

Gearing? Might be really slow of the line, but get an extra 7mph by the end. Or your Dad might be good off the line, but have a car geared for 200mph (yet only have power for 150).

Therefore, we pronounce you WRONG!

[pb32000]

Then he's doing something wrong. No doubt about it. I know many people who can run sub 13.8s in FWD cars with less than 200bhp weighing around a tonne.

Out of interest, what kit is it? That's too heavy for a 7esque kit, but too light for a lot of other kits I can think of,

[FlintFredstone]

http://www.letstorquebhp.com/calculator.asp

heres mine:

Power at Flywheel (BHP) : 300
Weight without Driver (KG) : 1500
Power to Weight Ratio (BHP Per Ton) : 203.21
0 - 60 (Secs) : 4.93
0 - 100 (Secs) : 12.98
60 - 100 (Secs) : 8.05
Quarter Mile (Secs) : 13.63
Terminal Speed (MPH) : 102.48
Drag Strip Quarter Mile (Secs) : 13.23
Drag Strip Terminal Speed (MPH) : 105.73

thats only a touch of the prodrive official figures (prodrive have a faster 0 - 60 of 4.6) of 13.44

edit:

i put your dads figures in (presuming that its rwd and he is not homer simpson size)

Power at Flywheel (BHP) : 260
Weight without Driver (KG) : 876
Power to Weight Ratio (BHP Per Ton) : 301.57
0 - 60 (Secs) : 4.07
0 - 100 (Secs) : 10.03
60 - 100 (Secs) : 5.96
Quarter Mile (Secs) : 12.41
Terminal Speed (MPH) : 111.22
Drag Strip Quarter Mile (Secs) : 12.31
Drag Strip Terminal Speed (MPH) : 112.53

edit2:

i cant find a 220 bhp car in lfs (looking at official site)

are you talking of the xr gt turbo at 245, anyway heres the figures for it :)

Power at Flywheel (BHP) : 245
Weight without Driver (KG) : 1224
Power to Weight Ratio (BHP Per Ton) : 203.38
0 - 60 (Secs) : 5.43
0 - 100 (Secs) : 13.55
60 - 100 (Secs) : 8.13
Quarter Mile (Secs) : 13.78
Terminal Speed (MPH) : 100.83
Drag Strip Quarter Mile (Secs) : 13.68
Drag Strip Terminal Speed (MPH) : 101.99

[danowat]

basicaly, the turbo demo car (cant remember whats its called) has 220bhp per tonne or somthing like that yet it can run 13.6 at 108 mph 1/4 mile times. My dad has a kit car with 260bhp and it weighs less than a tonne (876kg) and that runs 13.8 at 101mph. Therefore, they have got it wrong. I just thought i would let everyone know :)

Man, you are SOOOOOO mis-informed it's untrue, there are a hundred and one more factors that go into 1/4 mile times than bhp/tonne.

Besides, 1/4 mile times aren't really a true representation of performance anyway.

[andybarsblade]

http://www.letstorquebhp.com/calculator.asp

fill in the blanks, get the results. anyone know the specs for xrt?

[andybarsblade]

Power at Flywheel (BHP) : 245
Weight without Driver (KG) : 1224
Power to Weight Ratio (BHP Per Ton) : 203.38
0 - 60 (Secs) : 5.43
0 - 100 (Secs) : 13.55
60 - 100 (Secs) : 8.13
Quarter Mile (Secs) : 13.78
Terminal Speed (MPH) : 100.83
Drag Strip Quarter Mile (Secs) : 13.68
Drag Strip Terminal Speed (MPH) : 101.99
:)

[88Nightrider]

Tourq (is that spell'd right) have something to say. Not just hp!

[andybarsblade]

basicaly, the turbo demo car (cant remember whats its called) has 220bhp per tonne or somthing like that yet it can run 13.6 at 108 mph 1/4 mile times. My dad has a kit car with 260bhp and it weighs less than a tonne (876kg) and that runs 13.8 at 101mph. Therefore, they have got it wrong. I just thought i would let everyone know :)

sounds like your dads the factor tbh. so how do you know how much power your dads car has?

[Lible]

Ever heard of setups?

[danowat]

:feedtroll

:thumb:

[ajp71]

basicaly, the turbo demo car (cant remember whats its called) has 220bhp per tonne or somthing like that yet it can run 13.6 at 108 mph 1/4 mile times. My dad has a kit car with 260bhp and it weighs less than a tonne (876kg) and that runs 13.8 at 101mph. Therefore, they have got it wrong. I just thought i would let everyone know :)

Did your Dad have perfect gearing for a 1/4 mile dash? Does he have the reaction times of a god? Did he have a locked diff and appropriate suspension? What tires was he using and were the pressures set for drag racing? Did he change toe/camber for drag racing? How light is the engine, a light flywheel makes a huge difference? How much lag does the engine have if its turboed? How peaky is the engine, is the 260bhp just on one tiny bit of the torque curve? Was the car traction limited? Were the shifts too slow? Do you want me to keep going?

[tristancliffe]

sounds like your dads the factor tbh. so how do you know how much power your dads car has?

Probably either guesswork, believing the manufacturer figures, or actually think a dyno/rolling road is accurate.

He's probably got ~10% less than he thinks he has, as all rolling roads over-read (it keeps the customers happy).

[danowat]

Tommy10101 has been officially

http://natsarmy.altervista.org/pwned.jpg

[andybarsblade]

Probably either guesswork, believing the manufacturer figures, or actually think a dyno/rolling road is accurate.

He's probably got ~10% less than he thinks he has, as all rolling roads over-read (it keeps the customers happy).

this is not directly aimed at him but when most ppl say there car has XXX amount of bhp its normaly guess work, like ive got this car which the manufacturer said had xxx hp when it was built in 1987 but after 200,000 miles ive changed the spark plugs and fitted an induction kit which will suck in nothing but hot air and a big exhaust system so now i have no back pressure, so now its running xxxx hp :x :D:razz:

[PLAYLIFE]

http://www.letstorquebhp.com/calculator.asp

heres mine:

Power at Flywheel (BHP) : 300
Weight without Driver (KG) : 1500
Power to Weight Ratio (BHP Per Ton) : 203.21
0 - 60 (Secs) : 4.93
0 - 100 (Secs) : 12.98
60 - 100 (Secs) : 8.05
Quarter Mile (Secs) : 13.63
Terminal Speed (MPH) : 102.48
Drag Strip Quarter Mile (Secs) : 13.23
Drag Strip Terminal Speed (MPH) : 105.73

thats only a touch of the prodrive official figures (prodrive have a faster 0 - 60 of 4.6) of 13.44

edit:

i put your dads figures in (presuming that its rwd and he is not homer simpson size)

Power at Flywheel (BHP) : 260
Weight without Driver (KG) : 876
Power to Weight Ratio (BHP Per Ton) : 301.57
0 - 60 (Secs) : 4.07
0 - 100 (Secs) : 10.03
60 - 100 (Secs) : 5.96
Quarter Mile (Secs) : 12.41
Terminal Speed (MPH) : 111.22
Drag Strip Quarter Mile (Secs) : 12.31
Drag Strip Terminal Speed (MPH) : 112.53

edit2:

i cant find a 220 bhp car in lfs (looking at official site)

are you talking of the xr gt turbo at 245, anyway heres the figures for it :)

Power at Flywheel (BHP) : 245
Weight without Driver (KG) : 1224
Power to Weight Ratio (BHP Per Ton) : 203.38
0 - 60 (Secs) : 5.43
0 - 100 (Secs) : 13.55
60 - 100 (Secs) : 8.13
Quarter Mile (Secs) : 13.78
Terminal Speed (MPH) : 100.83
Drag Strip Quarter Mile (Secs) : 13.68
Drag Strip Terminal Speed (MPH) : 101.99


What are you trying to say? Your message is unclear.

[pb32000]

Tommy10101 has been officially

http://natsarmy.altervista.org/pwned.jpg

Self pwnage?

:razz: :razz:

Doesnt load for me

[danowat]

Pffff........(wasn't that funny anyway :shrug: )

[word.]

try using "road normal" tyres in LFS

[delray25]

@tommy10101

What did you expect?!? Everyone going "... gee, thanks Tom, I'll shift delete the whole LFS directory right away..." ???

I say you have been comprehensively out-researched. Most Forum regulars know their 5h!t


Squashed!

[stevewhite]

Dont be so hard on the poor guy, he has done nothing wrong. I am sure you guys have already intimidated him enough. He just said things the way he seen them, but didnt know about all the other factors. Maybe if he devoted his life to trolling the lfs forum, he would have known, oh well...

[FlintFredstone]

What are you trying to say? Your message is unclear.


That the calculator is not far off (my car 13.23 in calc and prodrive proven figures of 13.44)

the the xr gt turbo is bang on the money (13.6 calc 13.6 in origonal post)

And his dads car is pants (or he is homer simpson size with the reactions of nelson mandela) for drag strip racing.

Simon :)

[tristancliffe]

this is not directly aimed at him but when most ppl say there car has XXX amount of bhp its normaly guess work, like ive got this car which the manufacturer said had xxx hp when it was built in 1987 but after 200,000 miles ive changed the spark plugs and fitted an induction kit which will suck in nothing but hot air and a big exhaust system so now i have no back pressure, so now its running xxxx hp :x :D:razz:

Yup, agreed. Though the sticker that comes with most induction kits is itself worth 10hp (more if on the side of the wheel arch, just in front of the door).

[danowat]

You must also remember that horsepower is directly proportional to the diameter and number of exhausts

[Bob Smith]

http://www.letstorquebhp.com/calculator.asp
Just to add, that calculator is MASSIVELY simplified. If you want something a bit more detailed and accurate, try my setup analyser preview (http://www.lfsforum.net/showthread.php?t=16961), although you'll have to research/guess a lot if you want to re-create any real cars.

/plug

You must also remember that horsepower is directly proportional to the diameter and number of exhausts
Exactly. You can't even enter that into that calculator.

[andybarsblade]

http://tanetane92.web.infoseek.co.jp/053051.jpg

the fastest car in the world! :scratchch

[ajp71]

http://www.letstorquebhp.com/calculator.asp

fill in the blanks, get the results. anyone know the specs for xrt?

Erm... that looks no more accurate than the original posters logic, doesn't take into account tires, aerodynamic grip or drag gearing, torque curve/powerband, differentials or drivetrain efficiency (a low power 4WD car is quicker than the same RWD car apparently :scratchch ).

[andybarsblade]

Erm... that looks no more accurate than the original posters logic, doesn't take into account tires, aerodynamic grip or drag gearing, torque curve/powerband, differentials or drivetrain efficiency (a low power 4WD car is quicker than the same RWD car apparently :scratchch ).

isnt that true in 1/4 racing? 4wd better grip off the line but will suffer top end aceleration (but that wont matter when terminals are only around 100mph), i can tell you that the evo numbers are very accurate for one

[atledreier]

Also, the BHP/tonne is PEAK values. One car might have a very wide powerband and be able to accelerate much more evenly than a car with the same peak power, but a narrower band, where acceleration would come in burst. Power is area under the torquecurve, not peak horsepower, in my book.

[theirishnoob]

basically, the turbo demo car (cant remember whats its called) has 220bhp per tonne or something like that yet it can run 13.6 at 108 mph 1/4 mile times. My dad has a kit car with 260bhp and it weighs less than a tonne (876kg) and that runs 13.8 at 101mph. Therefore, they have got it wrong. I just thought i would let everyone know :)




ha ha hp is nothing everyone forgets that hp isn't worth **** if you can turn it into traction then driving power

hence when cars like the Ferrari don't do good speed unless there wherein good radials and are rolling along for you drive them hard :D

the point im making is every cars is differant by it down force , drive train etc plus you never said what aftermakert gear he has installed....

[_TdNoZ_]

ha ha hp is nothing everyone forgets that hp isn't worth **** if you can turn it into traction then driving power

hence when cars like the Ferrari don't do good speed unless there wherein good radials and are rolling along for you drive them hard :D

the point im making is every cars is differant by it down force , drive train etc plus you never said what aftermakert gear he has installed....

agree, if u have 1000hk at the enigene u dont have 1000hk at the tyres and the gearing has much to say and how u use it... but still u cant realy compare a game to the real world(unless its lfs :D ).....

[tristancliffe]

ha ha hp is nothing everyone forgets that hp isn't worth **** if you can turn it into traction then driving powerSome clever words, spoilt by a lack of writing ability and no understanding of the underlying concept.

hence when cars like the Ferrari don't do good speed unless there wherein good radials and are rolling along for you drive them hard :DWhat? Sorry, but that's rubbish. I've been driving a 308GTS today, and I can assure you it's fine. Crossplies or 'rolling along' make no difference. You are referring to cars aren't you, and not models?
the point im making is every cars is differant by it down force , drive train etc plus you never said what aftermakert gear he has installed....Somehow you've managed to not make a point at all, until you summed up the point you were trying to make previously.

We speak English on this forum. Perhaps you'd like to join us?

[Smurfen]

make it easy, more HP the faster u go! :D

[ajp71]

isnt that true in 1/4 racing? 4wd better grip off the line but will suffer top end aceleration (but that wont matter when terminals are only around 100mph), i can tell you that the evo numbers are very accurate for one

Take something that isn't really going to be traction limited off the line (100bhp, 1000kg) the drivetrain inefficiency should more than make up for the fractionally quicker start.

[andybarsblade]

Take something that isn't really going to be traction limited off the line (100bhp, 1000kg) the drivetrain inefficiency should more than make up for the fractionally quicker start.

yes but we are talking about somthing that is tration limited arent we.

a stock 4wd road car at 250bhp + and a equally powered rwd/fwd road car over the qtr mile on road tires the 4wd car will win all day long. on its traction off the line the others will be spinning the tyres going nowhere, go to that site and look at the fastest fwd car its pretty lame tbh.

just look at an rb4 vs fxo vs xrt off the line

[Meanie]

I've been driving a 308GTS today, and I can assure you it's fine.

Well...

GODDAMN YOU man. :tilt:
Now i'm jealous. :(

[ajp71]

yes but we are talking about somthing that is tration limited arent we.


No I'm talking about why the calculator thing is inaccurate.

[andybarsblade]

No I'm talking about why the calculator thing is inaccurate.

well you think it is, i think its does a very good job with limited data

[Becky Rose]

EDIT: Oh smeg there was a second page.... Ignore me :)

Tyre size & presures, gear ratio (which on your dads road car will almost certainly be geared for cruising & fuel economy), aerodynamics - all of these things are a factor in quarter mile times ... plus the age of the driver of course, you young sprogs have reactions like gnats compared to us old sloaths... There's more to Drag racing than taking the windscreen wipers off your car to get your bgp/tonne up. How well does your running gear roll, is there a warp in the chassis, how much rubber is making contact with the ground... etc etc. Oh, compound of the tyre, tyre temperature... Gear shift latency, tracking & suspension geometry...

(I'm stopping here because i'm bored of thinking up the many factors involved)

Come back with a mathematical model explaining why the XRT is wrong, and we'll show you the parts that aren't in LFS... which is basically just the aerodynamics and a few very minor things (has Scawen put drive shaft flex in yet?)

It may not be perfect to the tenth decimal place, but i'll say this much for LFS: It aint bad you know :).

[keithano]

make it easy, more HP the faster u go! :D

Not until you get the grip :D

[Thomas H]

Traction and torque is mainly what gives you an ET. Hi-rpm horsepowers will give you top end speed while not affecting your ET all that much, really. Same goes pretty much for aerodynamics Becky (unless your driving a wall, that is)

Thomas

[tinvek]

yes but we are talking about somthing that is tration limited arent we.

a stock 4wd road car at 250bhp + and a equally powered rwd/fwd road car over the qtr mile on road tires the 4wd car will win all day long. on its traction off the line the others will be spinning the tyres going nowhere, go to that site and look at the fastest fwd car its pretty lame tbh.

just look at an rb4 vs fxo vs xrt off the line


thats assuming the 2wd car is traction limited, a 911 with wide tyres and wheels on a good dry surface isn't going to have many traction problems (if you can still find it the original autocar test of the 3lt turbo, with 260 bhp had a picture showing how it left rubber for about 4 ft before gripping) 4wd in this case may loose more through driveline losses than it gains.

Even when you have traction, your 250 hp may not be the same as my 250 bhp as it all comes down to the total amount of power available (at the driven wheels) over the entire speed range, finally to be completly accurate you should really be comparing cars with the same power to weight ratio, 250 hp in a seven or similar will accelerate you a lot faster than 250 hp in a routemaster bus :)

[andybarsblade]

yes porsches have very good grip off the line.

and what you stated about power to weight ratios is just stating the obvious. but i was comparing road based cars. and then said fxo vs rb4 vs xrt

[BlakjeKaas]

Wait.

Isn't it just the setup? =P

[evans]

basicaly, the turbo demo car (cant remember whats its called) has 220bhp per tonne or somthing like that yet it can run 13.6 at 108 mph 1/4 mile times. My dad has a kit car with 260bhp and it weighs less than a tonne (876kg) and that runs 13.8 at 101mph. Therefore, they have got it wrong. I just thought i would let everyone know :)
This kind of argument has a name that I can't recall, but it's the same as saying this to your mother:

"A bird has wings. A bird is alive. You don't have wings, therefore you are not alive."

And come on Tommy, could you please just consider, next time you want to post, that there are a million + 1 variables in physics, and so building your argument on only two of those will not always be true?

[ev0]

I think everybody missed the true intention of this post - In my opinion it was just posted to say: "my dad has a l337 carzor thats wickeder than an XRT :P"

Edit: note to Tommy - It is an interesting topic that you have brought forward, but you would have got a much better response if you had posted posted your statement as a question for debate, rather than using such a strong "THIS IS WRONG" tone. But anyway, my input into the discussion:

My bike weighs 180kg, and pushes approx 130bhp and 110nm at the wheel. I would not be able to get below 10 seconds on it, despite the high torque and power to weight ratio, unless I had a specific drag setup. The best I have ever managed over a quarter mile was 10.5x, I hit the sweet spot on that run - fast pull-away, smooth gearchanges and the front wheel was hovering about 2 inches of the ground for the first 200m. If I had tried to go any faster, I would have flipped the bike. Power is not everything, setup has a lot to do with it, as well as the vehicle's ability to use the power that it has effectively.

[andybarsblade]

130bhp atw on a tl1000s? must be tuned to fook

[danowat]

Aye, TL standard is 113bhp and 108nm of torque (probably flywheel quoted figs too)

[andybarsblade]

new gixer 1000, r1's and fireblades are around 135bhp atw and there quoted from the factory as having over 160bhp

[alland44]

This kind of argument has a name that I can't recall, but it's the same as saying this to your mother:

"A bird has wings. A bird is alive. You don't have wings, therefore you are not alive."

And come on Tommy, could you please just consider, next time you want to post, that there are a million + 1 variables in physics, and so building your argument on only two of those will not always be true?

You mean "Erasmus Montanus"

"A stone cannot fly - You cannot fly - Therefore YOU are a stone, dear mother"

[Rooble]

Some of you people are proper harsh bastards...

And for 'theirishnoob'

Stop doing what any child does and try and reword what everyone else has written, to just look as if you're really intelligent and know what's cooking.

You're only adding insult to the whole thing and its taking the piss, everyone's moaning on these boards how its going down the drain but feel all chummy when you gun down someone in some sort of geek posse.


Edit: Danowat your comment has only confirmed what I thought to begin with so thanks, I mean what good is life if we're not being crapped on, right?

[danowat]

Some of you people are proper harsh bastards...

That's life baby, it's a harsh world :nod:

[amp88]

This kind of argument has a name that I can't recall, but it's the same as saying this to your mother:

"A bird has wings. A bird is alive. You don't have wings, therefore you are not alive."

And come on Tommy, could you please just consider, next time you want to post, that there are a million + 1 variables in physics, and so building your argument on only two of those will not always be true?

A false syllogism (thanks to QI :) ).

[andybarsblade]

ahhhhh amps reach the point of drunkeness that he now sounds inteligent :D

[amp88]

ahhhhh amps reach the point of drunkeness that he now sounds inteligent :D

Oi! I resemble that remark, I'll have you know :p

[evans]

You mean "Erasmus Montanus"

"A stone cannot fly - You cannot fly - Therefore YOU are a stone, dear mother"
Præcis! - Exactly the one I had in mind when I wrote my post, I just couldn't remember the exact words of Erasmus.

And amp, it is indeed a false syllogism :)

[jtw62074]

basicaly, the turbo demo car (cant remember whats its called) has 220bhp per tonne or somthing like that yet it can run 13.6 at 108 mph 1/4 mile times. My dad has a kit car with 260bhp and it weighs less than a tonne (876kg) and that runs 13.8 at 101mph. Therefore, they have got it wrong. I just thought i would let everyone know :)

That's dreadfully slow for that power to weight ratio. Running 260hp with an 876kg car through my drag racing simulation, Straightline Acceleration Simulator, reveals wildly varying times depending on tire traction, wheelbase, and center of gravity height.

With driven tires having a constant friction coefficient of 1, cg height of 22 inches, 106 inch wheelbase, 260hp @ 5000rpm and 340ft-lb @ 2940 rpm, Mucie M21 4 speed manual, gets this 12.84 sec @ 112.0mph (assuming 82% drivetrain efficiency and a 0.4 second gear change time).

That's with a drag coefficient of 0.42 and frontal area of 24 ft^2, which is more along the lines of a big, boxy, American sedan from days of old than what your Dad probably is running. Just to give an idea of how much the aerodynamics alone effect the picture, if the drag coefficient is changed to 0.36 it gets 12.78 @ 113.6mph (much less of a difference than I expected, actually).

It's traction limited all the way up to 60 mph, btw.. Drop the tire friction coefficient to 0.9 and we get 13.33 @ 111.1 mph. Reduce it to 0.85 and we get 13.63 @ 110.5 mph. The point is, just a tiny change in grip here produces a massive change in time.

If we give it as much traction as it wants (1.19 friction coefficient), the time plummets to only 12.29 @ 112.7mph. With better gearing and more grip, it'd go even quicker.

You sure your dad's car is really making 260bhp? :) I'm only using a 2.73:1 differential here and the Muncie's first gear ratio is only 2.2:1, so rather tall gears. He ought to be spinning the tires like crazy up to 60+mph if he wants too. Am I right? If not, the 260bhp number is probably just some bench racing fantasy. :p

I wouldn't say anything is wrong with LFS on this one. The LFS car, especially the particular tires it uses, are different enough from your dad's to account for the time and speed difference quite easily. Power to weight ratio is, as others pointed out, only part of the picture. Most important is traction in this case, it appears.

[JTbo]

Yes, from 1/4 mile speed and vehicle mass you can calculate bhp, even bad launch does not make it too different, naturally it is not whole truth, but mostly close at enough.

If your gear ratios are not matching to engine's powerband, even that can make such difference which topic starter represented.

Surely there can still be imperfections in model too, engine powercurve for example is not like it is in real car and many other stuff is not simulated yet, surely there can be some issues.

[ev0]

130bhp atw on a tl1000s? must be tuned to fook
It is quite far from standard, - every time I crash it I improve something on it :)

next step is to replace the horrible rotary damper...but the ohlins aftermarket replacement shock is ridiculously overpriced.

when I first got it (second hand) it was pushing 124bhp, and 106nm (on the same dino as the latest figures). The major performance increase since then is due to the having the heads gas flowed and the valve seats cut.

[JTbo]

No I'm talking about why the calculator thing is inaccurate.

Calculator is perhaps inaccurate, but you should be able to calculate good estimates from Bhp. http://www.streetrodstuff.com/Tech_Stuff/Horsepower_Calculator.php

There you can see formulas used too.

Rolling road is inaccurate too, still some people think it reveals how much bhp car has :D

If you really like to find out how much bhp engine has, you need to take out it from car and put into proper engine dynamo meter, expensive, takes lot of time, etc.

That earlier calculator was quite bit off for my car, over 19secs 1/4 even it runs around 17,4 secs when stock, now bit faster, so at least for me that first linked calculator did not worked at all.

1/4 speed is good indication of what kind of power level car might have as launch does not affect it a lot.

Car has 130bhp (well, that is again estimate, but 109whp is measured from rear wheels, again rolling road value, just one estimate less here), 1075kg weight and it has run:
0-100kph 9,2secs
0-400m 16,6secs and 140kph
0-1000m 30,3secs and 171kph

Not a rocket at all, but it is not meant to be, yet :D Maybe you can test and find working calculator for those numbers :D

[tristancliffe]

It is quite far from standard, - every time I crash it I improve something on it :)

next step is to replace the horrible rotary damper...but the ohlins aftermarket replacement shock is ridiculously overpriced.

when I first got it (second hand) it was pushing 124bhp, and 106nm (on the same dino as the latest figures). The major performance increase since then is due to the having the heads gas flowed and the valve seats cut.

Wheel or flywheel figures?

If the dyno says 124, then it's probably more like 116. If it's wheel horsepower, then you have around 105hp at the flywheel.

All commerical dynos over-read.

[JTbo]

Wheel or flywheel figures?

If the dyno says 124, then it's probably more like 116. If it's wheel horsepower, then you have around 105hp at the flywheel.

All commerical dynos over-read.

Tristan, what is wildest misleading dyno reading you have seen?

I have seen how some chip seller took classic before and after graphs, gain was something like 150hp with chip and in other dyno it was more like 10hp and we are talking less than 300hp level here. It is dead easy to fool someone with dyno curves, you can get almost that power to paper what you like, no matter what car has.

One thing we laugh here is how at Sweden their dynos seem to show at least 100hp more as when same car is tested here after it is bough, it gets that much less in dyno :D

But Tristan, if dyno shows 124hp from wheels, how you end up to 105hp at flywheel. Lot bigger change than 124 -> 116 and there should be bigger margin of error because of faulty drivetrain loss estimates dyno/operator uses?

[Bob Smith]

All commerical dynos over-read.
Why is that?

[Thomas H]

Must have been quite busy there JTbo, checking all those Swedish dyno's out...

Thomas

[andybarsblade]

its very easy to fool dyno readouts by changing the abient temp settings, putting the temp sensor in a cup of tea while doing the power runs ive heard of before lol.

24% losses through the drive train is what is normally quoted for lancer evos 4wd, dunno about bikes but i would guess its alot less around 10-13%

[JTbo]

Must have been quite busy there JTbo, checking all those Swedish dyno's out...

Thomas

You probably misread, I was talking about cars that are on sale in Sweden and then shipped to here, mostly rally cars etc. I'm sure same thing happens everywhere, seller gets big figures in dyno by fooling it to help selling car ;)

[tristancliffe]

Tristan, what is wildest misleading dyno reading you have seen?Hard to say, because we don't really know what the accurate power figure is. But we had a car measured that we reckoned was probably about 350hp, but the dyno said 415!!!! No way on earth was it 415!But Tristan, if dyno shows 124hp from wheels, how you end up to 105hp at flywheel. Lot bigger change than 124 -> 116 and there should be bigger margin of error because of faulty drivetrain loss estimates dyno/operator uses?Well, I worked on the basis that a dyno reading of 124 really means 116ish. And then there are efficiencies, which mean that (assuming the 124 was a wheel power figure) you're looking at arounf 105 - 109hp at the flywheel (again, ish).

Why is that?

Because people go home thinking "wow, it's way better than I thought. I'll use that Rolling Road again". If they under-read people wouldn't use their service. So everyone's over-reads by quite a margin to keep the customers happy, and generate return custom. When telling a customer figures, never tell him a figure below what is real, always over-quote. This applies to work cost estimates as well...

[Thomas H]

You were generalizing a bit there JTbo, that's all. Had to make a comment... :)

Thomas

[JTbo]

I worked on the basis that a dyno reading of 124 really means 116ish. And then there are efficiencies, which mean that (assuming the 124 was a wheel power figure) you're looking at arounf 105 - 109hp at the flywheel (again, ish).


But wouldn't wheel power be less than flywheel, I think you got it wrong way there? ;)
Flywheel 116ish and wheels 105-109ish, right? ;)

[Thomas H]

Was just about to write the very same thing :)

[JTbo]

You were generalizing a bit there JTbo, that's all. Had to make a comment... :)

Thomas

Ah surely, but that is probably same that side of sea, because at least those rally cars that are sold here do lose quite lot of power again when brought to your place at least according to dyno tests :D

Similar to freeflow airfilters, how they make big power increase in NA engines and in fact they loose some power because intake temps rise. Marketing, making stuff sell. Again same with dyno business, they show too much bhp just like Tristan says, sales, profit, that is called business and sometimes it comes to bit ridiculous as these rally cars they try to sell _specially_ from Finland to Sweden or opposite direction, we have this little competitive history, which at least I find very amusing and worth joking ;)

[tristancliffe]

Duh, brain fade moment... obviously, you are correct.

/beats head with frying pan for being a complete dunce

[andybarsblade]

even then i think your being generous, like i said honda/suzuki ect quote 170bhp at the crank for their 1000cc sports bikes but dyno's show alot less

[Poffter]

Reading this thread almost made me vomit, and my stomake is quite gutsie...

The pure amount of generalisation, pessimism and cynnicim is alone a big reason to kill this thread but on the other hand the amount of knowledge some people showed in a fashionable and polite way almost slid the scale to 0.

Don't you think it's wrong to go the same way every time someone is trying to make a point but makes the big mistake of taking "his" knowledge and putting it up against figures?
About free-flow air filters never giving more power, rolling roads are crap, dynos don't work, this and that and so on. I don't now what the word is for this type of communicating so unnecessary repeating will do for now.

A properly cordoned off free-flow air filter will give extra power to some cars.
A, according to engine displacement and configuration correct, free-flow exhaust will give extra power to many but not all cars.

Rolling road shows what power you have at the wheels and that is the only, to me, figure that matters, why quote the engine power if the WBHP is 50 BHP lower?

A dyno is to me the type of device you bolt to the wheel hubs whereas a rolling road is no more than 2/4 rolling tubes, correct? And this gives a more correct reading bla bla bla.

And saying that all commercial dynos are over-reading, isn't that a bit of generalization? Since you(tristancliffe) haven't tested all the cars in the world with all the different dynos available(no time in hell), probably not even the most popular in the UK with the standard dynos(possible but come on?) you can't say for sure that it's always in their interest to make them over-read.

Atleast here in Sweden we want the real power, to a point, getting extra big figures at one dyno when the manufacturer of the after-market parts quoted a 5% (example) lower BHP upgrade you know somethings wrong, you don't get positively surprised.

I'm just mad at everyone always giving these statements, hardly arguments, and getting away with it.

Don't bother to correct any misspells unless they alter the meaning of the sentence, it's 4:40 am and I still spell okay compared to some others whom have english as their native language.

[JTbo]

Generalisations comes because kids believing F&F crap are generalizing just opposite stuff, so it is constant rope pulling...

Yes, freeflow filters can help in some cases to get bit more power, mostly those are to be avoided because weaker filtering and unless installed so that cooler air is available than most common next to exhaust manifold install offers. Some cars stock filter is just too small to provide enough air to engine, in these cases freeflow filter can help, but better option is to find bigger stock type filter if possible to fit to engine room.
Mostly freeflow filters are something that makes seller happy and kid buying one thinks engine is more powerful because of increased intake noise.

Simple way to test if air filter is resisting element is to measure vacuum between throttle plate and air filter or if you have turbo, then between air filter and turbo intake.

At least here we don't separate dyno or rolling road, everything is talked as dyno, that is because car people is often bit simple (sorry, don't hit too hard ;) ) guys that do stuff quite conservative way so to say. So many don't even know difference, that is then why there is only one word used. But yes, dyno which you bolt to wheel hub is giving more reliable reading of wheel power, as I understand Rototest should be quite reliable also, almost only one we can say it measures power without removing engine from car and not questimates it.

Why to repeate these things then? Well, because there are more of those who don't know than those that do know and hopefully people can gasp little idea of questioning what marketing tells them from these things.

[andybarsblade]

the only things i said is that dyno's can be made to over read by putting the temp sensor in a hot cup of tea, and that manufactuers over quote their own power figures, both of those's statments are true, ive never seen a bike make whats been quoted from the manufacturer standard

[Poffter]

the only things i said is that dyno's can be made to over read by putting the temp sensor in a hot cup of tea, and that manufactuers over quote their own power figures, both of those's statments are true, ive never seen a bike make whats been quoted from the manufacturer standard

You do know that as of 2003/2004 alot fewer car companies stopped over-quoting their power figures because of massive lawsuits in the US? Mazda had to pay an enormous sum of money because the RX8 lacked 7-8 bhp.

[Jamexing]

Practically, there is no way a dyno could tell you what the engine actually makes IRL operation, even when the dyno is fundamentally very accurate and precise. The difference in actual power difference between a car with an open/closed hood running on a dyno and a car running full speed at the track with plenty of cool airflow into the air intake and excellent cooling (aka so good that the fan is actually switched OFF to reduce fan parasitic drag) can be quite surprising, especially in these days of electronically managed engines.

Let's look at this simple scenario. A car is on a high speed track and it's cooling system is more than adequate for keeping temperatures in the optimal ranges. With a well designed and implemented carbon fiber hood that's well vented as well, underhood temps are actually quite low as the high speed intake air easily removes all excess heat. With a cold air intake right at the grille opening, the engine enjoys an excellent supply of cool and clean air. The ECU senses this extra air inflow and deems it safe to advance ignition to maximize power and efficiency. Under these condtitions, the actual power produced in operation is significantly higher than dyno tests could measure (assuming an accurate dyno). If there's a well designed and installed ram air intake, the power output actually increases with speed by as much as 5% or more as speed climbs.

Then there's the situation where a poor car is on a dyno revving its guts out in an attempt to generate a good power curve with stale, non-moving air. Poor thing asphyxiates and burns up and the ECU retards ignition to protect the engine. Result? Lousy power curve.

[andybarsblade]

unless you use an engine dyno

[jtw62074]

Manufacturers have the option of quoting power figures as SAE standard. When they do this, a neutral SAE official attends and oversees the test to make sure there's no monkey business going on. As a result, the figures manufacturers are quoting ought to be quite accurate, at least as far as what the engine is doing on a test stand.

I've had a lot of people use rolling road dyno data in my drag racing simulation and report back very accurate results, so I'm a little surprised to see that these dyno shops overquote the power so frequently. They'd need to alter the software that comes with the dyno in order to do it, I'd think (maybe there's an ini file or something that allows it).

Still, the reasoning makes sense for overquoting, so perhaps it's not all that surprising or infrequent.

[MAD3.0LT]

lol tyres arnt everything allso my car with 235's cam get off the line as good as a car with 265's suspension weight distrobutions tq curv's all these things come into factor and i have seen 500 HP cars run 14.5's with 117 mph u can run 13's at 98 mph if u get a good launch :D