Tyres jitter about with a squittering sound, engine revs drop in sympathy with the increasing tyre pressure, clutch slips a bit as you balance these forces.
In any case, my 3500 rpm with clutch probably involves more airflow and fuel flow than if I red lined it and surprised the clutch. Revs are not in that way connected to the power output. Power output is, of course, measured under load, not by rpm.
Wheelspin
engine revs drop in sympathy with
Why has tyre pressure gone up, and what could that possibly have to do with engine revs dropping???
It has to, or the wheels, but we were "dumping" the clutch were we not?
Well it is connected since at 1000 rpm bugger all power. At say 6 thousand, maximum power, but we are talking about stored inertial energy are we not?
But side stepping the clutch has nothing to do with power, only rotational inertia in engine components.
Its obviously a bad way to start off for max acceleration.
Maximum car acceleration occurs when tyre slips (5 percent ish for hot sticky slick) about 12 percent on road rubber with little gain by heating it up, as road compounds are not normally very sensitive to heat. Although some expensive racy track ones are slightly improved in grip..
I do it many times a day and I say it is "squittering". Look it up... ;)
I didn't mean tyre pressure, but the pressure on the tyres, which increases as you feed in the power.
Nah, we're talking about traffic light squirts. Got to ride the clutch.
Not so much, AFAIK. More what the engine produces when you're engaging the clutch. I've tried revving the engine up and have come to the opinion that the best way to engage is to come in around 3500 rpm with the throttle down and ease the clutch up to keep the power going through to the back.
Generally it involves squittering. Which the OED will define as the feel of the rear tyres when you are winding them up... ;)
Buggy was 2.5bhp, 3.5kg, truck 3.5bhp, probly 6kg.
I dunno :) ?
I tried! Its too new!
Mmmm But you are not then taking advantage of the stored energy you could have begun with by starting at high revs!
buggy=714hp/tonne, truck 583bhp/tonne
Thats really high!
And a 4500 bhp drag top fueller with / without driver? What would it weigh?
300bhp bike is about 450 lb without fat rider so what might that be? And with average biker on board?And a F1 car with and without driver?
And a 200 hp turbo car like a cossie with/out driver?
And a Ka with driver?
A moped?
If you are busy I will work it out in the morning! Interesting to compare.
ROFL
Where's your Nurse?
Mandy, Kristen, Emma, etc all eventually left, now I have a Jenny (19 and lovely) and my bird 32 and lovely! None of them will wear the uniform...
He he he, Burgerman will be really dischuffed when he finds out you've been using his 'puter...
I expect they'll all catch up in due course. ;)
This is absolutely true, yes. The rotational inertia will be stored energy that can be used directly but there's also the question of whether the engine is accelerating and therefore has higher gas flow and fuel speed.
If you have an engine revving at a constant 6000 rpm, *without load* it is using comparatively little fuel, you see. Whereas, when accelerating hard from idle it is using more fuel, and if you really want to get the best bang for your buck, you are holding it on the handbrake at 6000 rpm with the clutch spreading the heat out at the point where you release the handbrake and let the "loaded" power at 6000 rpm start working from the 0.04th second.
But doing that overheats the clutch so, afterwards, you probably can't make it go forward properly with full throttle - already using the T shirt to clean oil galleries, squire. Once the slipping clutch starts, it gets worse until you can cool it off.
On the whole I have found that dumping the clutch at 6000 is a poor strategy, whereas guessing the point at which the lights will change and accelerating rapidly against the clutch on the handbrake to about 3500 and then just squittering away with clutch control hoping it won't get too hot before I am disengaged (or is it engaged? I keep forgetting).
I've always understood that racing clutches did this quite well at the expense of a short life and you don't generally want to remove the engine from the car every few fast starts on a road car - hence my recommendation to use a stock clutch which will last longer and you'll have to accept that making it work too hard means it overheats and you have to slow down for a minute or two. Which will basically happen on uprated ones too, they get hot just the same. They merely are able to conduct more power without slipping and it is the slipping that generates that heat.
mmm....
Gas flow depends on two things. Revs Throttle plate position.
So... If it already HAS revs, (and all that free strored energy) it is ready to flow more gas faster when you stamp on the go pedal on the green light?
Its using a little more than one at idle, but this is BEFORE the lights change!
But thats after you already wanted to leave on the green. Now you have to build revs (and with it airflow at WOT) which takes time!
and if you really want to get the best bang for
Yep, and it takes the slack out of the transmission etc too.
On a serious bike or car it just destroys itself in about 1 second...
Obviously! It was never suggested as a fast way to get away! I think everyone knows that!
Squittering. (Wheelspin!!!!) Some (few percent) is desirable for max traction.
No race clutches and paddle clutches are usually made of harder stuff. They dont wear out faster, just the oposite, but they are a bit on / off and a little less cuddly to use on a road car with a heavy pedal to boot..
Which
The paddle one in my V8 sierra was actually a sintered metal affair, it does not really over heat, but it wears the flywheel and clutch cover faster than a normal soft clutch.
>Some of us don't have huge engines and nitrous. We have to put up with turbos instead...
[snip]Don't forget boost.
You get the momentum, but once that's gone, and with the wastegate wide-open, you'll need to wait for the boost to build up after you snap the throttle open
There might be a bit of milage in loading up the engine with the clutch and the brakes before the lights change if you have a turbo... and a clutch-changing business.
It actually works quite well when you're already rolling so you don't need to knacker the clutch. When watching a small overtaking gap approach, I've been known to open up the throttle a bit early and hold the speed down with my left foot on the brake. When the gap arrives, release the brake for instant catapulting :o)
It's bloody tricky though. The old left foot always wants to press the brake really hard...
Cheers,
Colin.
Ohhh turbo motors! OK I ran some silly turbo engines!
The wastegate only opens at full boost! Its closed otherwise...
Loading the motor (via brakes and clutch) helps develop a bit on boost on sad street engines with tiny turbos.
You get more boost by reving the crap out of it. And blipping the throttle. At least you do if changing clutches isnt a hobby.
Why not fit nitrous. INSTANT power and full boost at silly low rpm.
Yep. Been there, you try to go through the screen...
It's not really all that interesting unless they're all designed with the one thing in mind...?
Easiest way to emergency brake without necessarily wanting to. Until you get used to it, of course.
Ahh, but what you need is nitrous, huge engine AND turbo.
I like the cut of your jib.
Fraser
AIR, I copied the word from Leonardo da Vinci... ;)
Working fitfully rather than solidly, either by design or circumstances. Although, not usually used in the context of tyres... ;)
The difference is that in one circumstance the throttle pedal is barely down while in the other, you can have it to the floor, before the lights change.
Yeah, the thing is, you judge when you want to be revving up so that you are accelerating the engine and gradually also slipping the clutch so that when you get the green, you release the brakes and shoot off really quickly. It can all go horribly wrong, naturally.
I'd not thought of that, but you're right.
Well certainly this can be true. But I'm not trying to do that, anyway, it doesn't work for all sorts of reasons. But something similar that is less demanding on the hardware but still has similar advantages.
Well try it the way I'm suggesting, it can either work or not, and I'll bet this depends on cars anyway.
I must admit I've never had one, but from descriptions, they're only necessary if the stock clutch can't handle the power. Looks like there are even more exotic options available, which comes as no surprise.
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