Sorry should have clarified - on a standard car, available refers to those revs below the redline on a rev counter, rather than to the rev-limiter.

I believe the 110TDI has it's red line starting around 4k rpm so 90% of that would be 3600rpm which is about where peak power is developed....

Chris

Sorry should have clarified - on a standard car, available refers to those revs below the redline on a rev counter, rather than to the rev-limiter.

I believe the 110TDI has it's red line starting around 4k rpm so 90% of that would be 3600rpm which is about where peak power is developed....

Chris

I couldn't say where the red line is off-hand, largely because if I'm using those sorts of revs I'm working by feel and ear, not looking at the instruments (unless pre-MOTing), but I'm fairly sure peak power on the 110 is about 4_000RPM.

Only using half the revs is fine, if that's how you like to drive. If you're a cop, you're going to need a bit more than that. The red lines are set conservatively (we know that because many people have them raised along with a remap), and usually precede the rev limiter by 500-1000 rpm. Small engines do tend to need to be revved harder to give of their best, and the best person to judge whether the engine is straining or not, is the driver. At the point where it's pointless applying any more gas, engines usually signal the driver by becoming less responsive, and just making more noise, rather than producing more go.

I remember Jason telling me off for redlining his Fabia. I should have been paying more attention to the rev counter, perhaps, but my right foot and my backside told me the car was happy producing those revs, and indeed still felt as if there was more to give.

A lot of French and Italian engines love to rev, but sound harsh doing it. I think it's partly the lightweight materials they use when building both engines and bodywork.

Don't get me wrong; I'm happy to rev an engine hard when it's worthwhile.

It's not worthwhile to rev hard when you can't accelerate faster because that just accelerates you into the back of the car in front, or when you can feel the power tailing off.

Anyone who is looking at improving their driving is on a great line of thought. The ROSPA course is excellent.

Anyone who is looking at improving their driving is on a great line of thought. The ROSPA course is excellent.

Certainly is

Chris

I have driven in many different countries and although I'm known for a fair bit of bitching about driving in the UK I guess, including my own every once in a while, it is not all that bad really.

Standards in some countries are higher, or more enforced, and as such, generally drivers behave better as they know they are being watched not just for speed, but for lane discipline, and paying attention.

I was dodging buses in Quito that went through red lights, cut across 3 lanes of traffic, generally trying to get through the car I was driving 'sideways/through it' instead of going in front or behind. I must admit I used a few blocking techniques that ensured aforementioned bus driver was faced with a red light AND blocked in by several vehicles so I could make my way safely after that.

Driving differs all the time, I drive a powerful car very much different from a less powerful one, in particular when overtaking. By powerful I mean power/weight mainly. Also apparent ability of other drivers, road conditions, visibility etc etc. A few years ago I got very wound up in traffic a lot. I am not a brilliant driver, but I tried to learn a bit from the refresher course I had post-crash. It has convinced me that a refresher course, or independent review of my driving ability is a good thing.

Without it, I reckon everyone eventually slips into automated driving, and gets more sloppy over time with awareness and/or safety etc.

I still have not had time do do Rospa or IAM, but perhaps one day

Police guidelines IIRC are to use no more than 90% of available revs which is typically where peak power is made, and hence mechanically sympathetic.

Chris

on a rolling road my car torque peaks at about 3-4k revs and the fsi part kicks in at 3k revs and 4.5k revs going by the rolling road graph onwards dont seem to be any benefit.

on a rolling road my car torque peaks at about 3-4k revs and the fsi part kicks in at 3k revs and 4.5k revs going by the rolling road graph onwards dont seem to be any benefit.

Not being able to accelerate beyond 4.5k sounds pretty lame for a modern petrol - are you sure they didn't sell you a diesel by mistake :P Btw, Superchips measured peak power at 6.5k rpm so it should pull nicely up until then. If you chuck me the keys I'll happily give you a second opinion

Chris

I'll echo Chris's offer for giving you a second opinion

I would be amazed if the power peaked at 4.5k rpm on a 2 liter engine, and the torque at the wheels will be way higher in the lower gear when revved up to 6k rpm on a 2 liter petrol I would have thought.

Was driving a 1.4 petrol Kia in a mountain area which deffo needed a damn good revving to get up to speed hehe

Not being able to accelerate beyond 4.5k sounds pretty lame for a modern petrol - are you sure they didn't sell you a diesel by mistake :P Btw, Superchips measured peak power at 6.5k rpm so it should pull nicely up until then. If you chuck me the keys I'll happily give you a second opinion

Chris

i never said it didnt accelerate beyond 4.5k chris, i said "on a rolling road my car torque peaks at about 3-4k revs and the fsi part kicks in at 3k revs and 4.5k revs going by the rolling road graph onwards dont seem to be any benefit." the bhp carries on going up (25bhp) but the torque starts dropping. Seeing the torque is the more important in gaining a more powerful car and my revs can keep reving up to 6k there isnt any benefit to me to take my car up that high on the rev range.

Here is my graph from the jkm rolling road for you to study.

Seeing the torque is the more important in gaining a more powerful car and my revs can keep reving up to 6k there isnt any benefit to me to take my car up that high on the rev range.

I'm not sure why torque is more important in gaining a more "power"ful car, but torque and bhp are intrinsically related. In essence, torque gets you moving and horsepower keeps you moving, which is why your car will accelerate (ie continue to gain speed) up to its peak power. Changing at 4.5k is throwing away 25bhp of usable power and I'll wager that the car will accelerate quicker changing at 6.5k than at 4.5k.

As a comparison, a powerful car like a Civic Type R develops peak torque at 5,600rpm which is outside the VTEC zone

Chris

No, a Honda VTEC is not powerful! It is just very high revving in an attempt to compensate for its lack of power.

Something like a Ferrari Daytona, where the torque "curve" is approximately parallel to the X (revs) axis of the chart, and the power curve close to "power = mX + c" where m and c have the usual meanings of gradient and a constant repectively is powerful!

Quite, AIUI a VTEC is little more a boggo 130bhp 2.0l motor that can rev past 6000rpm and find its extra 70bhp that way, whereas your properly powerful V8s / V10s are subject to no such compromises. And ISTR that BHP cannot directly be measured as such, and is simply the (measurable) torque multiplied by some factor or other, divided by the revs. So unless you drive your CTR at 6000rpm+ all the time, it's no more 'powerful' than your average rep-mobile...

Although, quite what this has to do with positioning for making good progress when driving is beyond me! :P

Power and Torque are directly related, via rpm. One is derived from the other:

                                Torque * RPM

       Horsepower      =       ------------

                                   5252

The fact that your torque tails off at higher revs but power is still climbing is because of this. Your car should still feel responsive and be accelerating up to at least 5800 rpm, according to that graph. Where to change gear will depend on your gear ratios, but since you have quite a nice flat torque curve up to 4600 rpm, you should be able to take the car well past that and still drop into a nice spot on the curve in the next gear up.

As for VTECs aren't we forgetting perhaps the most important feature of those engines which is the variable cam profile which comes in above about 6000 rpm, changing the engine characteristics.

Edited 8 January, 200917 yr by ncarring

Perhaps a poor example but I was thinking of a relatively more powerful (ie with a higher peak BHP figure) than the Octavia. To revise my example then, how about an F1 car? 2004 Ferrari F1 figures are around 1000bhp (so quite powerful ) and 200lb ft of torque...

Maybe a kind mod could split this discussion out from positioning?

Chris

Changing at 4.5k is throwing away 25bhp of usable power and I'll wager that the car will accelerate quicker changing at 6.5k than at 4.5k.

i wager it wont as the cut out happens as soon as you hit the red line and inside the red is where the 6.5k bit is

i wager it wont as the cut out happens as soon as you hit the red line and inside the red is where the 6.5k bit is

You're on - when would you like to do it?

Chris

but the engine rev limiter cuts out at 6k revs and wont let you rev till its dropped back to i beleive 5.5k revs :p

but the engine rev limiter cuts out at 6k revs and wont let you rev till its dropped back to i beleive 5.5k revs :p

But looking at your rolling road graph, there's no evidence of power being reduced dramatically until 6700rpm?

Just checked Superchips too and they show a similar peak to your JKM graph...

http://www.superchips.co.uk/curves/vag20fsi.pdf

If you want we can meet up for a play

Chris

????? well i dont understand how theres does it, i KNOW the rev counter limiter cuts in on 6000 as twice i have pushed it and both times its cut in and its not an area of the rev counter i want the needle to regularly visit thus a reason for a rev limiter.

Specialist subject the b100dy obvious - Since you have a dyno report of peak power at 6_500, your rev counter doesn't read right!

Specialist subject the b100dy obvious - Since you have a dyno report of peak power at 6_500, your rev counter doesn't read right!

...or the dyno report's for the wrong car and/or a work of fiction!

...or the dyno report's for the wrong car and/or a work of fiction!

Well, in theory yes, but the dyno data backs up the manufacturer's figures for the rev limit, and peaks on the FSI. :P