Old race cars rev counters-help the ignorant
Discussion
Keep seeing red needles on rev counters in older racers, ones the 'red line' at 7200 rpm but often see a 2nd on there is well.
Im pretty new to racers of the 60s-70s so sorry if its an obvious question. Im young so have pity, still so much to learn...
Here is an example from a 250 TR, My guess is the larger needle is for rev matching
Thanks for the help in advance!
Im pretty new to racers of the 60s-70s so sorry if its an obvious question. Im young so have pity, still so much to learn...
Here is an example from a 250 TR, My guess is the larger needle is for rev matching
Thanks for the help in advance!
Edited by Fantuzzi on Monday 30th April 21:00
I don't know either, but my best guess is the one up at 7k is the optimum shift point and the lower mark is the speed the revs drop to after the upshift, which should co-incide nicely with the start of the 'power band'. The driver knows that if he or she is below the lower marking, the engine is operating out of it's optimum range and a lower gear should be selected.
zac510 said:
It's the telltale. It moves to show the highest point the engine has been revved to.
A primitive form of datalogging
The mechanics used it to know when the engine has been overrevved.
Ah thought it would be something along those lines. Thanks for the help. Its hard work trying to be a car anarak!A primitive form of datalogging
The mechanics used it to know when the engine has been overrevved.
williamp said:
could also be from the owner: a sort of "dont rev past here..." I have seen a D-type with a £ sign after 6.5k revs for the same reason!
Thats brilliant the car in the pic was sold for 16 million dollars at auction, thats not a repair bill I'd like to recieve for a engine rebuild!
Eric Mc said:
Damon Hill drove a 250GTO into the gravel at Goodwood as he tried to wind back the red needle on the dial.
He'd have a job, the reset button is on the back of the tacho behind the dash.If in doubt, tape a pin to the reset button, if the driver comes into the pits sucking his finger you know the score.
zac510 said:
It's the telltale. It moves to show the highest point the engine has been revved to.
A primitive form of datalogging
The mechanics used it to know when the engine has been overrevved.
A rough equivalent can be seen on Days of Thunder when Cole deliberately blows the engine and Harry checks the tacho when the car is back in the pits A primitive form of datalogging
The mechanics used it to know when the engine has been overrevved.
I have something similar on the Stack electronic (now archaic!) revcounter on my beasty. A button on the dash re-calls the highest revs.
It goes up to 8K.
Thankfully the little V8 in the Belmont is good to about 8200 when it starts to go off peak, but will turn to nearly 9000...... (singing!)
It goes up to 8K.
Thankfully the little V8 in the Belmont is good to about 8200 when it starts to go off peak, but will turn to nearly 9000...... (singing!)
Fantuzzi said:
Mason is a good sport, hes nicer than me, dont think I'd let Brundle nail it at the revival like that! My goodness that was expensive grid!
Watched this on the TV, worlds most expensive racing grid. Throughout the race I was wincing at the millimeter close racing, almost couldn't watch. Awesome spectacle though!
johnfelstead said:
He'd have a job, the reset button is on the back of the tacho behind the dash.
If in doubt, tape a pin to the reset button, if the driver comes into the pits sucking his finger you know the score.
There speaks the voice of experience... If in doubt, tape a pin to the reset button, if the driver comes into the pits sucking his finger you know the score.
OP I can’t remember if it is Grand Prix or Le Mans but there is a shot in one of those films where a driver is telling his team manager/mechanic that the engine “Just lost all power” and died on him for no reason. Cue camera following the team manager/mechanic to the taco and noting that the telltale is sitting about 2-3k higher than the rev limit...
ETA - Doh!just seen someone else had posted about a similar scene in DoT - Note to self, read whole thread first...
I recall driving a Cosworth DFV engined Lotus F1 car at SIverstone many years ago where the rev counter had a tell tale. I was instructed not, under any circumstances, to red-line the engine.
I did because I missed a gear & the tell tale shot round almost to the limit. On my return to the pits i was frantically trying to work it how to reset the rev limiter so that no one would know that I had buzzed the engine.
I couldn't do it so when I exited the car the mechanic looked into the cockpit, saw the tell-tale & gave me a huge b
king for red-lining the engine.
Thankfully I didn't damage it however had I done so my boss would not have been happy with the repair bill he would have received.
I did because I missed a gear & the tell tale shot round almost to the limit. On my return to the pits i was frantically trying to work it how to reset the rev limiter so that no one would know that I had buzzed the engine.
I couldn't do it so when I exited the car the mechanic looked into the cockpit, saw the tell-tale & gave me a huge b
king for red-lining the engine.Thankfully I didn't damage it however had I done so my boss would not have been happy with the repair bill he would have received.
johnfelstead said:
Eric Mc said:
Damon Hill drove a 250GTO into the gravel at Goodwood as he tried to wind back the red needle on the dial.
He'd have a job, the reset button is on the back of the tacho behind the dash.If in doubt, tape a pin to the reset button, if the driver comes into the pits sucking his finger you know the score.
disco1 said:
Fantuzzi said:
Mason is a good sport, hes nicer than me, dont think I'd let Brundle nail it at the revival like that! My goodness that was expensive grid!
Watched this on the TV, worlds most expensive racing grid. Throughout the race I was wincing at the millimeter close racing, almost couldn't watch. Awesome spectacle though!
Now the weekend the Goldsmiths stacked their 2 Aston DP cars, *that* was an expensive weekend out for the family!
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