BlueMotion Gearbox (JDD) fitted into 1.4 TDI AMF engine

DJ 190 said:
Well, is there anything more to say? He gave such a comprehensive report .... nothing missed, really. EXCEPT fuel consumption figures? I've gone the "JDD" route, myself ....

David
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Great news David, I think you will be very happy with the JDD gearbox. I like mine more now than I did at first and couldn’t be happier with the change, the only downside at first was the driving at 30mph in 3rd but that is not the case now after getting used to the lower revs…..maybe why my MPG has gone up?

Looks like a good deal on the gearbox you bought with very low miles...well done finding that!

When you getting the work done?
 
timmus said:
You will, of course, also have a really long 5th that's not too far off the length of my 6th, meaning your motorway economy should be excellent. Personally, though, I couldn't live with the large gaps between 2->3 and 3->4 in particular. For all that Simon's videos show the car reaching cruising speed quite comfortably, that's not representative of a lot of driving. For all that you said "Well, is there anything more to say? He gave such a comprehensive report ...nothing missed, really.", I feel there's still a lot not known to most of us about this mod. For instance, I'm not convinced this setup will perform nicely when down-changing. Imagine approaching a corner in 4th and knowing you'll not have control of the vehicle unless you change down. It'll be a bit like dropping from your 0.681 gear down to 4th, with every gear change. I've not driven Simon's car and so can only comment based on my understanding of the ratios, but I reckon that'd annoy me intensely.

Cheers,

Tom
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There is no ‘large gaps’ in any of the gears and the change down is fine, you seem slightly dogmatic about the JDD gearbox ratios in the A2.

These ratios are the same ratios as the Audi A2 1.2 TDI so I cannot understand the continued skepticism about these ratios?

I have not seen any 1.2 TDI owners complaining about the down changes or any ‘large gaps’ in the gears?

It would be interesting what other A2 1.2 TDI owners think about my report, does my write-up of the ratios tally up with your car?
 
Zoltar said:
...you seem slightly dogmatic about the JDD gearbox ratios in the A2.
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Apologies, Simon. My post does cite you as the authority on the matter, and it was merely intended to urge caution, especially as David seemed to be asking quite fundamental questions after buying the 'box.

Your latest report convinces me more of its suitability, especially within the context of your driving style and circumstances. Whilst I'm rarely a cynic, I'm a sceptic where most things in life are concerned until I've been presented with compelling evidence. It must be the physicist in me.

When I spotted David's JDD 'box at Stealth, I had a brief conversation with Vince about it and he voiced the same scepticism. Both of us are in no doubt that it works, but engineering is invariably a balance of trade-offs, and I simply don't yet know what those trade-offs are.

I greatly admire your pioneering attitude and welcome your real-world reports. As I implied previously, I've only got numbers to work with, and - where cars are concerned - numbers don't always paint the full picture.

Cheers,

Tom
 
Well, I believed in you, Simon .... enough to go down this same route myself .... I suppose that must be the optimist in me!

David
 
If you keep the revs under 2,000 rpm I can get anything from 74-88 mpg :-D

Forgot to say,car gets filled up every ten weeks :cool:

Better add this is a Blue motion jdd fitted to a polo. 3rd,4th&5th are longer than normal sorry for confusion but basically a 80bhp tdi version of the 90 I got in the A2
 
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Having just had a re-read of hotstuff's Silenced! thread http://www.a2oc.net/forum/showthread.php?21760-Silenced!/page2, I think that would work well with a JDD because it helps it pick up better from lower revs.
I recall the Polo Bluemotions being fitted with different engine mounts to take into account the lower idle speed and generally lower revs, I don't know if they'd be of any benefit/fittable to a JDD A2.
 
chubbybrown said:
If you keep the revs under 2,000 rpm I can get anything from 74-88 mpg :-D

Forgot to say,car gets filled up every ten weeks :cool:
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I'm sorry ..... I can't seem to find what your comments are referring too? .... I am interested to know? You have just made the statement "out of the blue"! What is your gearbox? What car is it? What were your driving conditions? I have only ever achieved ~60 mpg .... and I drive very steadily. I usually drive 65-75 mph and I have a 0.681 ratio final gear. Please elaborate on what you have said .... 74-88 mpg? WOW!

David
 
Zoltar said:
... The tanks I have done though, have given me about a 10-15% increase in MPG doing mainly stop start city traffic conditions, so can't complain with the extra 40 miles per tank so far. ...
...I wasn’t used to driving around under 2,000rpm at first but the engine has no problem with that and I find it will pull easily from 1,400rpm on. ...
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When you are doing city driving, the change in MPG is probably mainly due to your change in driving style (lower RPMs) than the gearbox itself. The MPG benefits of the JDD's higher gearing will only really come into play beyond 50/60mph or so, when the old EWQ would have been spinning like crazy compared to the JDD's 5th. Prior to that point, both the EWQ and the JDD would have suitable gears available.
 
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This sounds like a really good mod if you are looking for that better mpg especially on the motorways.

Just out of interest for those of you who have done this modification/longer 5th gear/addition 6th gear coupled with the remapping - how much does these modifications add your insurance premiums?

Trying to decide whether to go for a gearbox mod or not!

Cheers

Leon
 
Foster said:
... - how much does these modifications add your insurance premiums? ...
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I have the 6-speed. £26 cheaper for a modified-car policy, compared to my 'normal-car' renewal quote from my existing insurer. But note that I did not attempt to get competing quotes for my renewal of course, since I needed to change the type of insurance anyway.
 
Well, it certainly isn't a "performance" mod, is it? If anything, you are going to be driving even more sedately, at lower revs? BUT, you know what Insurance Companies are like? Always suspicious and ready for a hike in your premium? There are always the worriers in life, though ....

David
 
I gather we won't see it as a "performance mod" but telling your insurance company, I have increased the power of my car by 33% and have given it a longer 5th gear(or even 6th gear), I am pretty sure that will come across as a "performance mod"....


DJ 190 said:
Well, it certainly isn't a "performance" mod, is it? If anything, you are going to be driving even more sedately, at lower revs? BUT, you know what Insurance Companies are like? Always suspicious and ready for a hike in your premium? There are always the worriers in life, though ....

David
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Foster said:
I gather we won't see it as a "performance mod" but telling your insurance company, I have increased the power of my car by 33% and have given it a longer 5th gear(or even 6th gear), I am pretty sure that will come across as a "performance mod"....
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I'm sorry .... I had not realised that you had linked the gearbox swap/ 5th gear mod to tuning by "Stealth" . Power is increased, of course ....

David
 
A few of questions if I may? ...

1. Is the car now more sprightly to 62mph?

2. Have in-gear acceleration times improved? i.e. real world driving, 50-70 in 5th etc.

3. Does this gearbox swap negotiate the need for a 6th gear modification to achieve +70mpg with motorway cruising?
 
IT is good to know who you are addressing, here? There is a wealth of knowledge and the answers to all you questions by using the excellent search facility of this forum ..... e.g. jdd gearbox, 6 speed mod gearbox, gearbox ... just have a look!

David
 
pietch said:
A few of questions if I may? ...

1. Is the car now more sprightly to 62mph?

2. Have in-gear acceleration times improved? i.e. real world driving, 50-70 in 5th etc.

3. Does this gearbox swap negotiate the need for a 6th gear modification to achieve +70mpg with motorway cruising?
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Hi Pietch,

It may help to be a little more specific about what you're looking to achieve and what your priorities are. Your post suggests that you're looking for better acceleration, but also suggested you're after increased economy. Generally speaking, longer gears result in reduced acceleration but a higher top speed. Is your car remapped?
I have achieved 70mpg from a standard, unmodified TDI SE, so changing the gearbox isn't strictly necessary...

Cheers,

Tom
 
timmus said:
...I have achieved 70mpg from a standard, unmodified TDI SE, so changing the gearbox isn't strictly necessary...
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Ditto, as Tom says, no mods necessary for 70mpg (just a suitable journey & sensible top cruising speed). Lots of mods necessary for 80+mpg though LOL. However it varies significantly according to the type of driving you do, if you do short distance city driving you will never see 70, but if you mainly do long motorway miles you should see it regularly.

Yeah ... longer gears = slower acceleration & higher mpg due to lower RPMs. The 6 speed box has the same gearing in the first 4 or 5 as the standard box, so the acceleration is the same. The JDD raises gears 3-5, so they are slightly wider apart, hence acceleration will be slightly less. But probably not enough to notice.
 
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timmus said:
My insurance also dropped in price as a result of moving to a modified policy.

Tom
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Sounds like if anything insurance will go down on a modified policy with the gearbox alone any how. So not another expense to worry about. Really keen to get a longer 5the gear now, given the possibility that 80mph speed limits might be introduced and I do a fair bit of driving in France.
 
I'm going to have a spare gearbox with a modified 5th gear, soon. The final ratio is 0.681, however.... Bear that in mind when you make a decision, regarding your requirements .... I am going to enjoy being able to list, under the specifications of my A2, "blue-motion gearbox fitted!" Yes, that sounds good!

David
 
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