GolfGTIforum.co.uk
Model specific boards => Golf mk7 => Golf mk7 GTD/TDI => Topic started by: Exonian on 22 May 2015, 09:26
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Silly question but (for once) I'm being serious.
If you live in Norfolk then you can ignore this topic.
Living in the south west however means lots of big hills, and therefore the ability to go up them is quite handy.
I was being passenger driven in a (I think) 150 TDI which a friend had on loan for a couple days and it really struggled with a couple of biggish hills in top gear (dual carriageway, A380 split at Telegraph Hill which anyone who's been to Torbay will have had to conquer).
Now I'm sure the mk6 GTD's I drove went up it pretty smartly and I know a couple of remapped Diesels I had years ago struggled a little on that hill and fared badly pre-remap.
With the prodigious torque of modern diesels I was a bit surprised the more modern car didn't like the hill, and it reminded me of the 140 TDI Cabrio I had for a week in October/November while mine was in for service, which really didn't like big fast hills in top gear. Obviously higher gearing offsets the torque figure a little but GTD's always feel very punchy through the gears and even the Cabrio went well on flat roads.
So, with 280 lb ft of grunt, how do GTD's cope with steep high speed hills?
Funnily enough a GTD passed us a bit later at break neck speed but that was on a better bit of road.
Obviously with a tuning box or map the GTD should eat hills like they're not there but I'm curious as to how the standard car copes.
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Never had any issues with any hills of any sort.
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Theres a huge incliine up from Scotswood Road to the A1 above it on a sliproad (mcmaddy might know it well) and there's not a lot that can keep up with my GTD getting up that - it is easily a 15% gradient over about 1/2 a mile.
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I can't report any issues climbing hills in my 150hp estate (e.g. fish hill near Worcester - iirc 12 or 13% gradient) - but then I wouldn't try to do that in any car in top gear. Much like I wouldn't go it down in a high gear having to brake all the time but in 2nd and 3rd (at 3000 rpm engine braking is pretty good).
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Yeah the GTD does pull like a train - especially impressive considering top gear is well over 30mph / 1000 revs !
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It flies up Sutton bank too so no issues.
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A high torque output is what you need but absolute torque is only half the story.
Imagine the same car with different engines one with 300 lb/ft torque but gearing of 30mph/1000 rpm and the other with 150lb/ft with gearing of 15mph/1000 rpm and a proportional torque spread. Which one will accelerate faster (it doesn't matter whether its on the flat or uphill)? They should, in theory, offer the same acceleration...
This explains how, for example, a Honda S2000 can accelerate as fast (or faster) than a GTD in spite of a massive torque deficit, it has shorter gearing (and a wider rev range).
So, the perceived lack of performance up hill is likely to be due to the longer gearing many (diesel) cars run these days to allow for better fuel consumption... change down a gear (or two) and you will discover improved acceleration...
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Seems a bit of a pointless question - I mean 6th gear is basically an "over-drive" cruising gear on any car. If you find that whatever you are doing doesn't pull well in 6th gear, choose one of the other gears? You've got 5, one of them will work unless you are on a 70 degree incline.
On a normal flat (ish) road you can happily plod around in 6th gear in the GTD from about 30mph upwards, but maybe not a hill - but why would you?
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Seems a bit of a pointless question - I mean 6th gear is basically an "over-drive" cruising gear on any car. If you find that whatever you are doing doesn't pull well in 6th gear, choose one of the other gears? You've got 5, one of them will work unless you are on a 70 degree incline.
On a normal flat (ish) road you can happily plod around in 6th gear in the GTD from about 30mph upwards, but maybe not a hill - but why would you?
Exactly. Are there people out there that would push on in 6th up a steep hill at 40mph rather than drop it down to 4th or 3rd gear and wonder why they have almost no acceleration?
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Not read the thread but this is all about power/torque to weight ratio and gear ratios.
6th is a tall gear to give good mpg at cruise speed. If you want to climb a hill quickly you need a lower gear, simple.
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Seems a bit of a pointless question - I mean 6th gear is basically an "over-drive" cruising gear on any car. If you find that whatever you are doing doesn't pull well in 6th gear, choose one of the other gears? You've got 5, one of them will work unless you are on a 70 degree incline.
On a normal flat (ish) road you can happily plod around in 6th gear in the GTD from about 30mph upwards, but maybe not a hill - but why would you?
No, not a pointless question.
I have some steep hills nearby which are NSL dual carriageway. so therefore I find it quite normal to stay in a high gear and blast up the hills at NSL. The TDI I was a passenger in struggled a bit which surprised me as it has nearly as much torque as my GTI and the gearing doesn't seem massively higher. Therefore I wondered if a GTD would need to change down as I used to drive mk6 GTD's quite a bit and they used to fly up the hills in top gear and could even accelerate in top gear.
Anyway I've arranged to borrow a local forum members GTD and put it to the test...
It's nothing scientific, just a plain old question about real world performance because I'm curious about such things.
And certainly nothing to do with labouring an engine off boost which would be plain daft.
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Exonian Il race you up Haldon Hill!!! ha
Pick my GTI up tomorrow afternoon!!!
:wink: :wink:
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Congrats! At last! You'll love it. :cool:
Get some miles on it, they really loosen up after a while.