[Closed] Why is there a REV Counter in most cars?

Sui - I think you are a tad confused. I don't think you can make biodiesel from cellulose very easily...

Rev counter: in my Lotus it can be more useful than the speedo and I find myself watching that than the speedo in some situations. 4k revs in 5th = 80mph, each 500rpm is +/- 10mph. Very useful on track days to hit the sweet spot for gear changes. And isn't that what the red limiter light is for 🙂

In wifey's Audi V6 TDI 3.0 then rpm is pretty pointless. It just goes. And anything above 2,500rpm is a bonus.

I'd expect that most people would *know* when to change gear though, by engine tone or the fact that the car is labouring or not making progress at full throttle. You can just feel these things, even in lovely comfortable luxury cars. Or maybe not.

There is a whole lot of mis-information on the use of revs though. I've seen drivers who religiously change up or down at 2,000 2,500 or 3,500rpm. Why? I ask them... Because my driving instructor told me to. D'oh! No consideration for the road, the load, the speed just robotic change up / change down when at that point 😮

As for temp and pressure gauges, I've got a water temp retro-fitted and oil pressure too. Wait until the oil temp and water temp are pretty much aligned before giving it some beans otherwise a risk of engine stress due to a huge temperature gradient. Oil pressure is there to monitor the oil condition - too low at a certain RPM and the oil is past its best, zero - and I have a major oil leak :o.

TBH I wasn't really too fussed about all this stuff until I trained to be a pilot. In the most basic aircraft you learn to control the flight using engine rpm and you have to get attuned to hearing the engine and what it is doing. From engine note you can judge airspeed and from that make a good safe landing. You also learn the importance of engine Ts & Ps.

As for most modern cars having a rev counter? I dunno. A pointless exercise really.

Epic willy wave ----------^

I drive a Lotus on a track
I can drive better than the guy who taught you
I can fly a plane

molgrips - Member
Sui - I think you are a tad confused. I don't think you can make biodiesel from cellulose very easily...

your correct and i've alluded to the wrong point -my bad - The biomass (of which cellulosic ethanol is produced through a catalytic process) can be changed into an 'oil' type through a pyrolysis or de-oxygenation process, then through selective cracking / catalytic stabilisation process. the end result is a synthetic parrafine. removing oxyegen from the double bonds allows you to manipulate the remaining hydrogen atoms and putting it back through a catalyist bit of propane to produce straight chain parrafines........ and this is where my chemical engineering knowledge slowly grinds to a halt... either way there are some very clever processes coming on line making the use of "waste", or true renewable (2nd Gen) feedstocks..

can be changed into an 'oil' type through a pyrolysis or de-oxygenation process

So different again from FAME/RME?

Sounds very energy intensive tho.. 😕

Given the availability and difference of various biofuels though it would seem we still need a distribution of different engine types. However, market forces would determine that over time. IE if E85 was only 60p/l then a lot of people would buy E85 cars 🙂

That was an epic willy wave indeed 🙂

So some folk in the Volvo 'community' get 300bhp from their 2.0l petrol

Well Mitsubishi get a reliable(ish) 400bhp from a 2.0 litre unit! Only driven the FQ360 (366bhp) but even that is an EPIC engine.

LOL at willy wave. Off to pose in our 1.3litre Jimny. Might even put the roof down 😉

My point is it's a big percentage increase from using ethanol and tweaking a screw on a crappy old engine.

Ultimately your car would be throttled by the valves and have completely variable intake runnner and plenum sizes across the rev ranges.

already available in production cars...

To be fair, orange lights are warnings, reds mean stop. If they've used an orange light for a fault that's immediately terminal if ignored it's a design fault IMHO. Many sensible cars have an orange warning lamp for mild faults and a big red STOP if it's a fatal fault like oil pressure.

yes my bad, driven too many old cars - i always associate oil pressure funked with orange... moderns have red... though most clubman comp cars still have a nice big orange light..

in my last comp car i had combined big LED shift light (green for shift, red for def shift and orange for knackered... no need to look at gauges and dials them - oh apart from high water temp buzzer and light 😉