Can you get faster acceleration by using less throttle?

Jotun

Jotun

Jotun

Soldato
Joined
11 Jun 2005
Posts
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Location
Liverpool
A friend of mine was telling me using less than full throttle can give better acceleration, because using full throttle can mean that there's too much fuel in the engine and so not the best air to fuel ratio and so produces less power. I was wondering if anyone knew if this was true or not? (assuming that there's no wheel spin).

I was under the impression that the throttle only controlled the valve letting the air into the engine, and then depending on the RPM of the engine, the ecu then decided how much fuel to add in, and the lambda sensor gives some feedback to let the ecu know if it's added too much or not.

I drive a 1.6 Astra with a whopping 98bhp, so it's not going to make much difference to me anyway, but my google-fu is weak and I can't find an answer on the internet
 
In modern engines isn't the amount of fuel in fact determined by looking up the volume of air passing the MAF(s) sensors on a fuel map and then injecting the required amount of fuel?

The ECU shouldn't allow the engine to run rich (unless it's warming up etc). So... foot to the floor!
 
Thanks for the replies guys, it didn't sound right to me but I didn't know enough to tell him it was wrong.
 
Id say my VRS 1.8 turbo tends to pull much stronger on gently squeezing the throttle rather than flooring it, not sure if its due to the turbo. And yes a throttle body alignment has been ran.
 
IIRC, the throttle pedal simply opens the throttle body, allowing air in, the car then works out how much air there is and puts an appropriate amount of fuel in.
 
As said if it's over fueling it's deffinatly better and noticeable. My car massively over fuels and it just makes induction noise and doesnt really respond compared to slowly putting my foot down.
 
Only way that less throttle can improve acceleration is in terms of traction.

All this talk about fuel mixing and air is just nonsense IMO.
 
I think his just been in the gears at the wrong revs.

My gf said her car wasn't pulling and could not reach 70 even she put her foot right down.

So i just changed gears at high revs, and got to 70 in no time. She was like wtf.

It was a clio and you do have to go at high revs to get any power out of it.
 
NathanE said:
Only way that less throttle can improve acceleration is in terms of traction.

All this talk about fuel mixing and air is just nonsense IMO.
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Bullstein, Ive drove cars where part throttle is sharper with a cleaner response from the 12.5 AFR or so, when OEM's might go for a safe 10:1 at WOT the car is very wooly and overfuels and makes less power. At low rpm both engines are getting sufficient air for a high VE but the fuel ratio and spark makes much better time cylinder peak pressures after the combustion event.

Its a sympton of lazy/safe mapping typically when the cars are running good quality fuel and well maintained as the factory calibrations are ready for neglected cars.
 
What has happened to the word 'driven'? It's as if it has been removed from the dictionary.
 
NathanE said:
Fixed
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Lol.

Remind me how many car's you have mapped. A lot of turbo cars will pull better on less than full throttle. This is because they run hot plugs for avoiding plug fouling, however this means they need loads of fuel at full throttle to stop the plugs overheating and causing detonation.
 
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