The online racing simulator
Car performance is WRONG...
(86 posts, started )
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...
Quote from PLAYLIFE :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
Quote from andybarsblade :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

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).
You must also remember that horsepower is directly proportional to the diameter and number of exhausts
Quote from andybarsblade :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 ).
Quote from ajp71 :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 ).

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
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.
Quote from tommy10101 :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

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....
Quote from theirishnoob :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

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 ).....
Quote from theirishnoob :ha ha hp is nothing everyone forgets that hp isn't worth **** if you can turn it into traction then driving power

Some clever words, spoilt by a lack of writing ability and no understanding of the underlying concept.

Quote :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

What? 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?
Quote :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?
make it easy, more HP the faster u go!
Quote from andybarsblade :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.
Quote from ajp71 :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
Quote from tristancliffe :I've been driving a 308GTS today, and I can assure you it's fine.

Well...

GODDAMN YOU man.
Now i'm jealous.
Quote from andybarsblade :yes but we are talking about somthing that is tration limited arent we.

No I'm talking about why the calculator thing is inaccurate.
Quote from ajp71 :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
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 .
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
Quote from andybarsblade :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
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
Wait.

Isn't it just the setup? =P
Quote from 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

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?

Car performance is WRONG...
(86 posts, started )
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