CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Cause of Manual Stalling

I’d like to know what causes a difference in stalling in different cars.
For example I have 2 different cars of the same capacity engine but they behave differently.
One can easily drive start car A on gear 2 easily without even reving hard. But car B might easily stall after going over a bump if you are in gear 2, this means i have to down shift to gear 1 and rev hard. What causes the difference?

Differences between the car A and B… Gear ratios, final drive ratio, weight, wheels, tires, clutch diameter, clutch take-up travel, clutch pedal design, clutch material, clutch design, pressure plate spring rate, diameter, design, suspension design, wear and tear on the car, computer controls for ignition, throttle-by-wire and finally the different engineer’s preferences that decided on all these things when the car was being tested before being released for sale.

By this explanation, you should understand that there is no simple answer to that question.

3 Likes

I guess it never occurred to the poster to say what these vehicles were .

2 Likes

I’m a little confused about one car stalling after simply going over a bump. Unless you were really lugging the engine and already at the edge of stalling, which is a bad thing to do, that shouldn’t happen. Is that what you’re doing here?

My guess (since you don’t mention anything at all about the cars), would be really bad maintaince on 1 and probably sub-standard on the other. Just the one is handling it better.

Well, it’s not simple matter. First and foremost - technology. 10 years old engine will behave differently from new engine. Pressures in the pistons are completely different nowadays. Same goes for injectors, pumps, turbos, gearboxes. F1 has 1.6L engine, and it will tear your butt to pieces in a race, even if you bring a 12LV12. But it will do it at 12000 rpm while your V12 can casually coast in idle up a ski ramp. Fuel is another thing - diesels are torque oriented cars that like to keep going, petrol engines tend to be more power and speed oriented because petrol won’t take as much compression. Then it also depends on what lift your engine has, what gear ratios your gearbox provides and what wheels your car is wearing. Long story short, it all boils down to how much torque your car can put on the ground.

Also your driving style may be poor, and one of the cars just has much much more torque to handle that.

Or one of the cars is broken.

1 Like

Current F1 rev limit is… wait for it… 15,000 rpm, increasing to 18,000 rpm in 2021 (or 2022, not decided yet).

Back a few years (early 2000’s) , 3.0L V10’s used to spin 19,200 and made 900 HP! Back when pneumatic valve springs took over from steel springs.

1 Like

“Oh no not the bees!” :smiley:

But… yea… actually if I’m not mistaken, 18000 rpm on four pistons is 72000 beats per minute, that should be 1200 beats per second. Those things should sound like a TV after broadcasting hours. :smiley:

You math is a little bit off… F1’s use 1.6L V6 engines… spinning 18,000 rpm is 300 revs per second times 3 = 900 beats per second (a 4 stroke engine only fire every other rev so in a V6, only 3 fires per rev)

I think that may help the 750 beats/sec sound from this year just a bit. The changes to the exhaust a couple of years ago helped sweeten up the “blaaaatt” noise the cars started making in 2014. Sort of like a bad fart pipe on a Honda Fit.

1 Like

Oh in that case I was mistaken, yes, they hit every other beat, forgot about that.