BHP gains and speed gains.... - This is for the pro's

[Ste]

When i get a BHP gain of say a nice round number of 10. How much of an increase am i getting in terms of speed.

IE: 0-60

Now i know weight etc comes into it but say on a car at 1000kg's with 100bhp does 0-60 in 10 seconds what would an extra 10bhp do to the 0-60 time on a rolling road so no crap about weather and shit.....

[Tobs]

probs not alot mate

[MaRiO89]

Drop it half a second at a push.. Slag it and you'll see quite a noticeable gain.. :)

[Ste]

I dont wanna know how to go faster i just wanna know what almost exactly the gain would be.... there has to be a calculation out there for it.

[Ryan]

you wont gain alot. it will just slightly increase the power to weight ratio.

once your in real power territory though its not just the ammount of power you put out but also the traction. 180bhp could be 10x faster than 300 if a 300 brake car just spins and melts the tarmac.

not 100% accurate but play with this
http://www.letstorquebhp.com/calculator.asp

[KamRacing]

You're bhp at the flywheel is largely irrelivant. What really matters is the bhp at the wheels. This differs depending on what your gearing is (and what gear you are in), weights of your flywheel, wheel size,weight and parasitic losses amongst other things. Then you have the weight of your car to add to the pot.

[VTS_16v_Boy]

Like my thread in General Chat this morning, a friends 1300 Micra kept up with and and was all over the back of a Chav in a C2 VTR that flashed him and thought he could show off infront of his girlfriend. Instead he must have looked as sick as a dog when a L reg 1.3 Micra could keep up with his VTR.

Going to show that a lighter car will always out performe a heavier car with more bhp :y:


As for working out bhp gains to 0-60mph times there are just far too many variables to caculate.

With transmission loses, driver ablity, tyres etc.

Plus BHP wont make the car any faster just slight quicker and 10bhp isnt much, expect a induction kit, manifold and sports exhaust to gain you around 10bhp.

As for the difference in real world performance . . . like mentioned really second maybe two with really good tyres and the correct tyre pressure.

Breathing mods will improve the way the engine revs and pulls but wont transform the car into a fire spitting beast

[Ste]

Im not interested in how weight, different air filters etc will effect power and performance. I just want to know what power increases gives what speed increases....

I understand what everyones getting at, but i was assuming ther'd be some calculation that would give a figure, then allow myself to make an educated guess on what the other elements will do to the power.

Im assuming the only way to get an idea is to rolling road before and after mods!

[Ryan]

i posted a link dude. read my post.

[Ste]

Aaah thnks mate. Thought it was part of your sig ;)

According to that 10 bhp gain on a car that weighs 1000kg is roughly 0.8

Not bad tbh imo

[Ryan]

its not going to be accurate but you get the idea.

if it was 100% accurate i want this!

Power at Flywheel (BHP) : 185
Weight without Driver (KG) : 750
Power to Weight Ratio (BHP Per Ton) : 250.63

[KamRacing]

Quite a useful site as a very rough guide.
Makes out that the 309 we're building will be a flyer.
850kgs max weight + 260bhp + RWD

It does explain the limitations on there
http://www.letstorquebhp.com/%5Cexplained.asp

[Ste]

Quite a useful site as a very rough guide.
Makes out that the 309 we're building will be a flyer.
850kgs max weight + 260bhp + RWD

=


http://www.lightandmatter.com/html_books/0sn/ch01/figs/sled200dpi.jpg

[VTS_16v_Boy]

hehehehe

You could spend ages playing with that thing, but like already mentioned best taken with a pinch of salt and the only real way of telling what your running is Rolling Road and a Drag Strip.

[Ryan]

Quite a useful site as a very rough guide.
Makes out that the 309 we're building will be a flyer.
850kgs max weight + 260bhp + RWD

as long as you dont drive it like a girl ;)

argh you dont happen to know anywhere other than special tuning for groupN topmounts, reinforcing plates for topmounts and the plates for wishbone floor mounting strength do you dude?

i would like to order from the french but i cant read frnech and the boutique site is poo to use.

[Ryan]

hehehehe

You could spend ages playing with that thing, but like already mentioned best taken with a pinch of salt and the only real way of telling what your running is Rolling Road and a Drag Strip.

which even then usually is highly innacurate

[Toad]

Yeah, according to that, I should be able to do a 1/4 mile in just under 14 seconds! I have never been on the strip, but I know I would be at least have a second off flat 14.

165 BHP, 840kg = 199.58 BHP/Tonne

[VTS_16v_Boy]

which even then usually is highly innacurate

Yes but its the closest thing to accualty knowing what your pushing bhp wise.

Plus at least you can walk into the pub and have proof of what your pushing even if it is slightly off :oops:

[Ryan]

Yes but its the closest thing to accualty knowing what your pushing bhp wise.


no its not an engine dyno is ;)

[VTS_16v_Boy]

no its not an engine dyno is ;)

Yer but how many people are gona do that :oops:

[Ryan]

Yer but how many people are gona do that :oops:

its more accurate though lol ;)

[williamsvts]

do you want to know what difference it will make on a rolling road 0 -60 time??? that will be totally pointless as it wont perform like that on the road.