HI THERE
sorry to sound silly but what is the ideal rpm to change gear loosing the least power?

sam MY99

 

1 rpm less than the redline

Seriously though, it is down to how hard you drive. If I was you, I would be taking it to the redline. You will get others who advocate changing early because it is pointless going so high.

Personally I think it pointless having a Scooby unless you redline it but then I enjoy fast cars because they are fast.

There is a good argument for driving less hard and using the motor's flexibilty. Depends what flicks your switch.

On the track you redline it.

Kind regards

Ben

 

Howdy

Benny Boy is right..But I wouldnt quite go that high as to the redline..... maybe a little less ...lol....

It all comes down to what you want..and how hard you want to push your car to get it...

Scoob power does drop after a certain point (unless you have modified the car)... the trick is not to exceed that point.... Its hard to explain in words.. the trick is that once you have changed gear and your revs have dropped, its to get the dropped revs to be near as damn it to the max power.... its all down to the "power band".. there will be a specific rev range where you can get the most from your car... so the trick is to rev the car to the top point.. and in theory when you change, the revs should drop to the lower point of the power band.... Hence the engine is always "on power"...Am I making sense ? I dont normally...

Anyways... I want an orange...

tara

J.

 

firefox,Benny/b
may i should have phrased my question better where along the RMP to you get the optimum poewr band on MY99

 

Hmmmmm ..... 1000rpm before the Redline .

Redline change ... errr the engine will be running hot and the ECU will dump more fuel and that will slow down the car.

I personally think ..... just after the turbocharger max spooling. So that depends on the turbocharger ..... then again ... ??

Good question ..... anyone?????

Cheers.

 

Hi,

The fastest change up point is where the the torque at the wheels in the current gear just falls below the torque at the wheels in the next gear up. On most cars the gap between the gears is such that the car will run out of revs before the torque advantage provided by the lower gearing is outweighed by being nearer to the peak torque point in a higher gear.

In other words, if the ratio difference betweem gears is say 10%, then the engine would need to make at least 10% more torque at the revs required for the same speed in a higher gear to accelerate as fast as it would in the lower gear.

On my MY98 UK, torque (boost?) starts to drop off quite rapidly at about 6500 rpm, so I usually change up at that point. If I had a stonking turbo and other bits like Firefox, it would probably be worth hanging on until the redline (not least because his is 1000rpm higher).

To sum up, the answer depends on on the shape of your torque curve, gearing, and engine rev limit. If you have a power plot, and know your gear ratios it should be relatively easy to work it out precisely for your own car.

Cheers,

Alex

P.S. Disclaimer - I am prepared to be wrong about this.

 

On the [rare] occasions I put my foot down in my MY98

1st 6500
2nd 6500
3rd 5500

Then I take it off again.
But I am mild with the clutch so lose a lot during the changes. I guess.
If you start making upgrades to the car, tell the guys where you want the power to be.
Are we allowed to do that?

 

Hi..

Its very rare for me to take the car to redline.... even though I can maintain maximum boost right up there...

I always like to change at 7000 revs.... that way the car is still on the power..and when I have changed gear and the revs have dropped, the car is also still on the power...

DYNT (as always) is right.. it will depend on your car......and what mods you have done.. standard cars will lose power after a certain rev (probably around 6500 on a 99?)...so whats the point in going above it ?

J.

 

I personally feel the most urge when I change up at around 6000 to 6300rpm. Peak HP is developed at 6150rpm on my MY99 and at that point torque is on its way down so there's no point in pushing further.

 

After a rolling road session at Power Engineering, I saw that the torque on my car was more or less a flat line until 5,500rpm, when it gradually dropped off.

I find that on a fast run I'll normally take 1st and 2nd gear just bit past that (6,000-ish rpm), then normally 5,500rpm for a higher gear (when roads allow officer!!)

Andy

 

Alex M is quite right - the torque at the wheels is the crucial point.
Orville may have a flat torque curve from the engine but he certainly will have differernt torque at the wheels in different gears.
I would recommend changing gear just before the rev limiter spoils the party.
(Turbochargers can become unstable when the flow is interrupted by action of wastgate or fuel surge due to unspecified or uncontrolled fuelling when the ignition is cut by a limiter and reinstated sometime later after a large quantity of fuel has been dumped into the system.)
_ I am ignorant of the specific rev limiting strategy but consider it much better to be in control than risk surging.