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Discussion Starter · #1 ·
You seem pretty clued up on the E and you seem to know a fair bit in general, so earlier today somehow or another I ended up in a position where I was trying to get past a car and then move back into that lane on a dual carriageway with traffic lights, car in question was a 58 plate totally rough and ropey looking Skoda Octavia (original mk1 shape) base model 1.9 TDi 90bhp ex taxi (the number plate said The Taxi Centre on the bottom) anyway he was about 2 car lengths ahead at 20mph when I pulled out and tried to pass him so I could overtake and pull back in, he saa i waa going to overtake and started acxelerating too, however I absolutely hammered my car upto 57mph and he was pulling further and further ahead, only when my digital speedo was ahjowng 57 did I start to get closer again, but I think he had stopped accelerating at that point, now obviously I'm not daft, I know just because both cars have the same bhp means bugger all, plus he has a larger capacity engine and with it being a TDI he will have a Turbo and boost and much better torque but I thought with a Corsa being a lighter, smaller car with a more up to date engine there wouldn't have been as much of a gap in it, can you explain the theory of how I ended up so far behind?

Also what's the optimum gear change speeds, not rpms, on the 1.4 n/a? The other day me and an older woman (looked late 50s) in a 1.2 newest shape Polo both sitting at a red light in the lanes next to each other, I didn't race off or even mildly thrash it, I pulled away quick as I always do, but despite the fact this woman was in no way caning it she pulled off quicker than me, got up to speed quicker and was again about 2 car lengths in front, I then put my foot down and had to thrash it and was doing nearly 40 (in a 40 limit) before I caught up and passed her, not sure how she managed without thrashing it, to get up to speed quicker than me in a car with a smaller less powerful, less torquey engine, in a similar car of similar size and weight, as I wasn't hanging around I can only assume I'm not being in the optimum gear at a particular speed and rpm to make the quickest progress, I know the optimum for normal, economy driving is before 2500rpm but let's say I want to get my car up to its theoretical Max speed in the shortest/quickest time possible at what rpm do I change up, how do I know when to change up? Because sometimes the revs just keep getting higher as i floor it but my speed is only slowly creeping up hence I'm in the wrong gear and not changed up at the right time, other times I change up too early and the revs drop too low/I labour the engine, I'm not used to having to know how to get the best performance from a lower powered car, most cars I drive at work have more than enough power that the crappest driver on the planet can beat mostly everyone off the line.
 

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The 1.9TDi was the best engine VW ever made, far superior to the naff 2.0 that replaced it. The old Skoda Octavia doesn't weigh any more than your Corsa but that 1.9TDi has nearly twice the torque of your 1.4na at low rpm and that is in stock form. The 1.9TDi is easily mapped to 150-200hp too and then has even more torque. It is torque that you need for launching a heavy car away from the lights.

The Corsa in 5 door form weighs the same as my SWB Land Rovers! At least Dafny is a 3 door which weighs less and the 6 speed box weighs less to so in total Dafny is 100Kg lighter than a 5 door 5 speed model so has an immediate advantage at the lights. The 1.4T also produces a fair amount of torque too, 60% more than the 1.4na from memory and most noticeable when launching away from the lights.

Most of my big 4x4 2.5TDi pickup trucks would beat a 1.4T Corsa away from the lights let alone a 1.4na. They have masses of torque, rear wheel drive and very low gearing which is what you need for rapid acceleration.

Also from my experience with Dafny the Corsa has quite tall gearing for a little car, probably to give it better mpg which obviously works as I know. However taller gearing means slower acceleration. Dafny only does 2800'ish rpm in 5th at 70mph, my diesel pickup trucks and Land Rovers would be doing 3500-4000rpm at the same speed which shows how tall the Corsa gearing is.

I have had a few 'races' with far more powerful cars than Dafny and I've beaten them due to simply timing the gear changes so that I keep her near her peak power/torque which is 3500-3750rpm, so I change at 4K rpm or earlier when 'racing' but I would normally change up at 2000-2500rpm when driving for economy. I also get into 2nd gear very quickly, probably within 20 feet of the lights. I sit with my handbrake on, foot down on accelerator so that engine is spinning at 3K'ish and as lights go green I lift clutch and floor accelerator at same time. Result is very rapid launch. Get into 2nd fast and move up gear fast because sitting in lower revving over 4K rpm gains you nothing in the 1.4T. I haven't driven a 1.4na (other than a test drive) so don't know if the same applies.

To be honest though none of the very latest generation hatchbacks are that quick. Even the VXR is dreadfully slow considering it has 200hp. Back in the 80's my Parents had family saloons and large sports tourers with less hp than that and yet were quicker to 60. My old MG Montego turbo was slightly modified but even so it only had 150bhp and yet still managed 0-60 in under 7 seconds for a large family saloon car. My V8 Land Rover did it in less than 6 seconds despite only having 240hp'ish (although it had double the torque of the VXR) The difference I think is gearing. The MG topped out at about 115mph, the Land Rover at just 90mph due to very low gearing.

Anyway, you may be slower than the VAG group cars but you probably get better mpg :)
 

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Also you must not compare peak torque or power figures without checking at what rpm they were measured at. A car that produces 150Nm of torque at 1500 will be quicker and more usable than one that produces 150Nm at 5000rpm.

Diesel cars can be very quick because they produce their torque from very low rpm and normally bags more of it than petrol cars.

Your 1.4na sounds like it is similar to my 1.4T in not liking being revved high. The 1.4T has a very narrow power band and that means they don't tolerate bad gear changing. All too easily to bog down if you change up too early which kills your acceleration as they are gutless below 1500rpm. A big capacity torquier engine would be more forgiving. If you want to make rapid progress in a 1.4T you need to be pretty hot on your gear changes. The 1.0T is better in that respect because it has a much broader power band. However the 1.4T suits my driving, not really a sporty engine more of a long distance cruiser :) It sounds like your 1.4na exhibits very similar tendencies!
 

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Discussion Starter · #5 ·
Yeah I was really annoys that morning that the old dear in her 1.2 3cyl Polo managed to get up to 40 from standstill quicker than me (neither of us were ragging it obviously) but the Polo just seemed to get up to speed much quicker despite me trying to get up to speed as quick as I could without "racing" because I wanted into that lane and wrongly assumed that if I say behind her in that lane it would leave the other lane free for someone else to be first off the lights and I'd be stuck behind not only her but all the other cars whod have passed her and moved it, it was so weird because I then got frustrated and began booting it and even thrashing it whilt she maintained steady acceleration I only just got past her until I hit 50 and "took off" there just felt like a huge flat spot.

That was a large part of why I wanted a diesel, so I could out accelerate people at normal speeds on ordinary roads without having to race.
 

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Yes agreed, if there was a bigger diesel on offer I'd have gone with it but the 1.3 diesel is too small. Also small diesels don't last very long and are more problematic than larger unstressed diesels once they get to higher mileages.

You also need to factor in other things too Hendry. The smaller engined Polo may have lower gearing than the Corsa or it certainly felt like it when I test drove one.

Wider tyres, while great for putting power down if you have it, tend to increase rolling resistance and slow you down. The 215 wide tyres on Dafny are way too wide really and even your 195's are still way too wide for the power of the engine, size of car and relatively short wheelbase. However I'm a sucker for big tyres! Ideally you would have 155 - 165 tyres on a 1.4na Corsa and that would improve your acceleration and fuel economy.

You shouldn't have a flat spot on a normally aspirated engine. It should rev freely from idle right up to the redline. However in order to give it better economy VX may have put an odd ECU map on it that concentrates on torque at say 1800rpm which is where you would tend to need it for normal driving, I guess this would have the effect of stifling performance at higher rpm.

You could always get it put on a dyno to see how much power it actually has and at what rpm. I have a dyno just 2 miles from my house and they only charge £35'ish for a run. Last time I had one of my Land Rovers up there I got 2 hours testing for £40 :) (partly because the tester couldn't believe it only had 26hp at the wheels so thought something was wrong with the dyno! :lol: )
 

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The 1.2 Polo probably had the TSi engine in that's 90ps. My Ibiza (also built by VAG) has 105ps. I see on their website that VW now have a 1.0l 110ps engine in the lineup!
 

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Are they not badged as turbos Leachie or do VW just put 1.2 on there even on the TSi's?
 

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Not sure about the VWs althought I think they may have TSi or TFSi on the back. My Ibiza just has Ibiza on the boot lid and the TSi badge is under the indicator on the wings.
 

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The funny thing is that Hendry assumes the old dear was not putting her foot down but my Mother, even when she was in her 50's was still driving around in high performance cars (Capris, MG turbos etc) and my Dad was driving V6 or V8 sports cars. Neither of them used to hang around. The earliest memories I have of travelling in the car with my Dad was sitting in the back of his Jag XJ6 doing 100mph on some A road heading towards Bala in North Wales. Even in her 70's my Mother would still make 'rapid' progress.....(albeit in a Corsa at that stage)

Bearing in mind I'm no spring chicken (nearly 50) yet I'll often leave youngesters trailing miles behind in whatever I drive, even the 26hp Land Rover out accelerates many modern cars from the lights, Dafny is far quicker still and I'm potentially about to buy a VXR.

You wouldn't necessarily know I was flooring it (other than leaving people behind) as I change up early and quickly meaning you won't hear my engine revving or screaming like many youngsters do. In my 0-60 tests in Dafny I was in 4th after just 6 seconds which means under hard acceleration I'm changing gear every 1-2 seconds upto 4th which is good for 60mph although I think I needed 5th for my quickest run which was done in 9.4 seconds. The revs never exceed 4K rpm in my quickest 0-60 run which proves that revving high is a waste of time in the 1.4T. (and potentially the 1.4na too going on what Hendry is saying)
 

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For all we know she could be feeling rather pleased with herself for beating a 'boy racer'! :lol: (I am nearing 'old dear' territory myself, and I don't always drive like a granny either! ) Being old has it's advantages though - cheaper insurance for a start! :D
 

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Mum has the 1.2 tsi engine in her 15 plate polo, so its a turbo, only badges on the back are tsi and blue motion, on a slightly different note, she just returned from a week away covering 250 miles at approx 54-55 mpg mostly A roads.
 

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Hendry, you don't have to hang your head in shame. I was beaten away from the lights this morning by a Transit van! :oops:

Curiously I could hear his gear changes and it sounded to me like he could hold his lower gears for far longer than my 1.4T.

This confirms what I've said before, that the gear spacing in the Corsa gearboxes is odd and not really best matched to the engine characteristics. With the 1.4T having no power above 4K rpm means you have to change up early which kills speed, the first few gears being too low to allow quick 0-60 times with an engine that has such a narrow power band.

The small Corsa petrol engines are largely gutless at lower revs roo so you have to wait for them to spin upto their power band when pulling away and after each gear change which also loses time.

However I never bought the 1.4T for doing 0-60, it was bought for cheap running costs and good economy at motorway speeds where its power band does work well with the taller 5th and 6th gears. eg. Yesterday I was getting 70+ mpg at 70mph with four people on board. A figure the polo or transit could not hope to match.

I found the 1.0T was better suited to the gearbox because it could continue to deliver power upto high rpm so it allowed for one less gear change on a 0-60 sprint. Each gear change costs you about a second in lost time and the fact you aren't putting power to the wheels while changing gear however the 1.0T was not as effortless to drive at high speeds with a family on board. Fords often have taller gearing which allow them to hold 3rd to 60 which I can't do in my 1.4T. If I had a taller 3rd gear I could probably knock a second off my 0-60.

There also seems to be a big gap in gearing between 3rd and 4th. 3rd often being to low for driving in 30 limits while 4th is too high. This also causes problems under fast acceleration where you change up to 4th and momentarily lose momentum while you are waiting for the 1.4T to spin back up into its power band.

Considering my 1.4T has 100PS it is still relatively slow compared to other cars I've owned with similar power and weight. In fact my best 0-60 time of 9.4 seconds is still pathetic for a small car with 100PS. It is difficult to explain how a car with so much power is so slow? It is heavy even in 3 door form which won't help, it is also tall and not that aerodynamic (head winds cause it to really drop mpg compared to other cars I've owned), the odd gear ratios also don't help and the narrow power band partly explains some of it but I still can't fully work out why it can't deliver better performance.

Having said that the VXR suffers the same problems. Despite 200PS it still takes 7 seconds to 60! Dire for a small car with so much power. I would expect sub 5 second 0-60 times for such a small car with so much power. I guess if it was rear wheel drive it would help as I suspect the traction control effectively wipes out half the power as it struggles to put that much power down?

To put it in perspective my wife's 1.7 ton Land Rover with just 26hp does 0-60 in 16 seconds, sounds slow but considering its tiny amount of power it is making far better use of it than the Corsas.
 
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