Pushing the limits of 4 cylinders?

[[GSV]Trig]

Look at where his power is richie, he dont know what torque is

[hotpurple]

Depends if you can keep your engine in the power band. Torque is only really important on a very twisty track where you will dip out of the power band of your engine.

As we all know, power is torque * rotational speed. A high power output will lead to better accelleration as the engine is doing more work, and hence giving the car more kinetic energy. So torque is really only important for giving you a good power output.

Chris

[Richie]

Originally posted by hotpurple
Depends if you can keep your engine in the power band. Torque is only really important on a very twisty track where you will dip out of the power band of your engine.

So are you saying it IS important (like here) or its NOT important (like earlier) ??


What you want is a maximum but flat torque output spread as much as possible over the rev range.... Say (for examples sake) 325lb.ft from 2500rpm - 6000rpm (red lines at 6500 or so)

[hotpurple]

That would give you a nice responsive engine yes. Sorry, I did confuse matters a bit there. I meant torque is not important on it's own, it has to be combined with rotational speed to create power.

Race engines take the approach of lots of revs, not much torque and still produce a lot of power. A city car on the other hand would require lots of torque low down in the rev range to enable quick getaways and easy round town driving.

With the correct gear ratios it is possible to keep the engine on cam and in the required rev range to produce meaningful power output, whilst also navigating a twisty track, however it would probably be a lot easier for a novice driver to have a slightly detuned engine that had a wider power band with a lower ultimate power output.

Dealing with gear ratios is very important as it is quite possible to tune an engine so much that changing gear drops it out of the power band, which is quite funny to watch.

Chris

[Zak33]

5labby mate....while you (rightly) defend your much loved Volvo.....it sadly has NO COMPARISON to the Honda unit that Hotpurple is on about....

they have to be driven to be believed. Honda know engines in a way Volvo DREAM ABOUT

However.....they dont suit lots of drivers...lots of revs on those 16valvers.....the torque is HIGH UP....hence a shorter gearbox etc.


And you have one vital over it....

YOUR OLD SWEDISH BEAST IS REAR WHEEL DRIVE (just don't mention the leaf-spring rear suspension, from just before horse and carts were a new thing )

[Moby-Dick]

Dealing with gear ratios is very important as it is quite possible to tune an engine so much that changing gear drops it out of the power band, which is quite funny to watch.

that can happen in my 200sx if you dont change gear quick enough when booting it

[Maffu]

Originally posted by [GSV]Trig
Any car in my eyes should have at least 100Bhp/litre to be worth its salt,

If it's not making 1bhp per 1kg, I'm not interested. The 'toy' I'll be getting soon will have 150bhp/ltr. w00tage.

[[GSV]Trig]

[Tumble]

hehe mine's got loadsa torque.... lovely stuff for getting out of mudholes.... dunno bout the redline tho - I *think* its at about 2500-3.. but it sounds waaay too scary up there to try, although the turbo does sound sweet

[TiG]

I'm dead on the 100bhp per little, 180bhp for 1.8ltrs. Tho its not all about figures guys, its about how you feel in your car when you drive it.

If thats anything that i've learnt here its that figures means for squat, What you need to do is experience the feel of car/engine/breaks or whatever so you've got a true appreciation of them.

As explaination and words are NO comparision to trying to BOOT a car round the track etc.

Although it was nice to see a bit of a lively discussion on here, first one in a while

TiG

[Richie]

I feel positively underpowered around here with my lowly 65BHP/litre

[spazman]

ive seen the Top Secret Honda Civic Type-R on men and motors and that was pushing 510bhp from a 1.8 turbo vtec lump. Running like 23psi or something mad like that, i dont think it was road legal though for some reason. Also the most powerfull evo in the world is like 774bhp, that 2.2 4 cylinder. Tuned by some UK company. Thats crazy .

[Maffu]

Norris Designs. And the Top Fuel Civic Type RR has well over 500bhp, too.

The 'drag' Civics in the use run 900+bhp from 4pot vtecs.

[Lowe]

112.2 bhp per litre here.

I'm turbo'd though so I guess I don't count.

[hotpurple]

Getting high volumetric efficiency with a turbo is the easy way out. When combined with a good engine in the first place though they can be very good.

Chris

[Richie]

Supercharging mine comes up with 417BHP and 380-ish lb.ft all at 6psi