Longer Gearing In 5th?

[pugdamo 111 2 Cars]

Hi all,iv got a 1.6 GTI and i often drive on duel carraigeways/motorways and fancy a bit longer gearing in 5th,but i like the closeness of 1st to 4th. I was thinking about putting 5th gear in from a diesel but wanted to know how the longer ratios are achieved?is it done by the final drive or by induvidual gears? I didnt want to put the gear in and it be the same,lol.

Any advice greatly appreciated

[DamirGTI 342]

How about 405 SRi gearbox i have one on my car and it's nice/quiet for motorway driving with long 5-th gear and short 1-st 2-nd , and maybe 3-rd as well kinda like 1.6 box in the first three gears .

 

Damir

 

EDIT : oops , just spotted , you have a 1.6 engine ! sorry in this case i dunno how will an 405 SRi box perform with 1.6 engine .

Edited February 10, 2009 by DamirGTI

[Goliath 94]

I believe it is done by the gears rather then the final drive. I know people have done what you are suggesting before and had the desired results of a loger fifth.

I personally think it is a good idea and will be doing this, or something similar myself but a lot of people think that the whole point of a 1.6 is for the low ratio gears.

[GLPoomobile 958]

I had some wierd gearbox like this on my old 1.9 (one of the ex owners was a squaddie who used to drive it between the UK and Germany a lot), and to be honest, it was horrible. Even with the torquier 1.9 engine, the drop off from 4th to 5th was just annoying, so it'd be even worse in a 1.6.

 

I think you'd have to be really convinced that you can't live with the current gearing to consider a longer 5th.

[philfingers 5]

Hi all,iv got a 1.6 GTI and i often drive on duel carraigeways/motorways and fancy a bit longer gearing in 5th,but i like the closeness of 1st to 4th. I was thinking about putting 5th gear in from a diesel but wanted to know how the longer ratios are achieved?is it done by the final drive or by induvidual gears? I didnt want to put the gear in and it be the same,lol.

Any advice greatly appreciated

drop me a Pm with your email address and I'll send you a gearing calculator to figure it all out. Runs in excel, easy to use

[skeggyrik 3]

My old 205 Mi16 that I bought from Wurzel and then sold onto Alastairh had a 1.6 box with a different 5th, it was an Mi 5th I think, Wurzel fitted it. Easy job to just pop the fifth off apparently.

1st-4th super 1.6 gearbox fun upto 110mph ish then a big drop changing into 5th for cruising. At Cadwell I only ran out of 4th just as I go to the end of park straight, wasn't worth changing up to 5th as it wouldn't pull it up the hill.

 

It was a bit of pain on the road if not on duel carriageway as you had to change down to make any real headway and you'd be up at 5k rpm in 4th.

Admittedly it did what it was supposed to do and at 80-85 it sat nicely cruising. It would pull to 140 odd (indicated) given the space and a stupid risk to my licence.

 

Can only imagine it would be a whole lot worse to drive fitted to a 1.6 though, I recon you'd be stuck for acceleration in 5th having to change down anytime you wanted to speed things up. It was slightly too tall on the Mi engine so on the 1.6 would be bad news. Maybe there is better option such a diesel 5th. Note that you will have to factor in the 1.6 final drive in any calcs you do.

 

Rich

Edited February 11, 2009 by skeggyrik

[mattbenselin 0]

I have thought about this before also...

 

I have a 1.9 engine on a 1.6 'box and absolutely love the acceleration and effortless performance of all the gears. You can drive in 5th comfortably from 30-120+!

But for longer periods on a fast road such as motorway the higher rpm is noisy and causes the petrol needle to head the wrong way fast!

 

I was sure I would put a 5th gear from another 'box into mine (1.6 5th: 0.87) to solve this and thought about ones from a 205 D (0.76 5th) or 405 D (0.66 5th) or similar.

In theory using a 205 diesel 5th gear would drop the rpm at 70mph by 450rpm (approx. 3202rpm), a 405 diesel 5th gear would drop it by 870rpm (approx. 2780rpm).

 

I spoke with a few people who said it would work but the drop between 4th and 5th would be severe and not nice to drive with. In the case of the 405 5th gear there is a 62% difference in ratios compared with the standard 23% difference.

 

 

Alternatives are using a Mi16 box which has good 1st-3rd gears and longer 5th but they are not as common. You could use a 1.6 'box with a 1.9 final drive, here are some numbers:

 

1.6'box:

rpm @ 70mph: 3665

mph @ 6500rpm: 1st-33, 2nd-57, 3rd-79, 4th-101, 5th-124

 

1.6'box with 1.9 FD:

rpm @ 70mph: 3331

mph @ 6500rpm: 1st-36, 2nd-63, 3rd-87, 4th-111, 5th-137

 

1.9'box:

rpm @ 70mph: 3331

mph @ 6500rpm: 1st-41, 2nd-64, 3rd-87, 4th-111, 5th-137

 

Mi16'box:

rpm @ 70mph: 3493

mph @ 6500rpm: 1st-34, 2nd-54, 3rd-77, 4th-102, 5th-130

 

1.6'box with 205D 5th:

rpm @ 70mph: 3202

mph @ 6500rpm: 1st-33, 2nd-57, 3rd-79, 4th-101, 5th-142

 

The option of using a 1.6'box with 1.9 FD looks good but I don't know how the acceleration would be affected in the lower gears due to a lower FD (1.6: 4.06, 1.9: 3.69).

Anyone had experience of these combinations?

Edited February 11, 2009 by mattbenselin

[Atari Boy 11]

I have a 1.9 engine on a 1.6 'box and absolutely love the acceleration and effortless performance .......but for longer periods on a fast road such as motorway the higher rpm is noisy and causes the petrol needle to head the wrong way fast!

 

Sorry, mini hijack. I have the same setup 1.9 with 1.6 box. I am taking the car to Germany in April. Is it going to be super thirsty, what sort of MPG should I expect on a ‘run’?

 

Thanks

 

Jonny

[mattbenselin 0]

I could never tell what mine did with the dodgyness of the fuel needle and the changing weight of my right foot meant I never paid enough attention! But it won't be good! Not that you should mess with your 'box just because but give it some thought.

 

Some more info here or as philfingers said there as excel docs which will do it all for you, I have a few that all work if anyone needs them. Quite interesting, if you have a beard!

[Atari Boy 11]

Thanks for the feedback, interesting. I too have a inaccurate fuel gauge needle and I can’t reset my odometer.

I use the car for fun so I usually I am not bothered about how efficient it is.

The 800 mile round trip to ‘Ring has changed my mind.

Fogive my thickness, I am not great on gearbox ratios, but last time I went over I had a 1.6 engine with 1.6 box, will I have poorer mpg with a 1.9 engine and the same 1.6 box?

[mattbenselin 0]

Using a 1.6 box instead of 1.9 box on a 1.9 will just make it rev quicker in each gear not necessarily use more fuel compared with 1.6 engine/1.6 box combination.

However, the 1.9 uses a different ECU and fuelling/ignition components along with a longer stroke and slightly different cam to produce more power. The injectors are bigger also so I guess all this adds up to more fuel being used so poorer mpg than the 1.6.

 

There are more factors to include such as torques values, weight of the car and occupants, tyres, weather, road surface etc. but a long answer short would be: YES!

Edited February 11, 2009 by mattbenselin

[Atari Boy 11]

The 1.9 uses a different ECU and fuelling/ignition components along with a longer stroke and slightly different cam to produce more power. The injectors are bigger also so I guess all this adds up to more fuel being used so poorer mpg than the 1.6.

Using a 1.6 box on a 1.9 will just make it rev quicker in each gear not necessarily use more fuel, though 1) there is the tendancy to rev higher in each gear cause it's fun! = more fuel used, and 2) the actual speed is lower per rpm than a 1.9 box so the engine has to rotate more to make the car move at the same speed = more fuel used.

eg: 1.9 engine + 1.9 box = rpm @ 70mph 3331

1.9 engine + 1.6 box = rpm @ 70mph 3665

 

There are more factors to include such as torques values, weight of the car and occupants, tyres, weather, road surface etc. but a long answer short would be: YES!

 

Great effort, thank you.

[mattbenselin 0]

Edited what I said cause I read your previous reply wrong, but the answer is still yes!

I nearly went to the ring last spring but could not afford the fuel on top of everything else. I am in about 17 minds whether to mess with the gearbox. For short journeys and quick blasts up the motorway the 1.6 box is great but for longer trips I wish I had a 6th gear! (gti-6 box you say; thing is I like being able to turn!)

 

For the time being I am going to stick with the 1.6 box as is. If it fails or I need a new clutch I may hybrid it.

[pugdamo 111 2 Cars]

Thanks all,i didnt expect so many replies so soon,i think i might go with a 1.9gti 5th gear,i doesnt take long to change it so ill prob do it and let you know how it goes. I do think the drop from 4th to 5th with a diesel 5th might be annoying so thats why im going to try the 1.9gti 5th.

 

Thanks again

[trialster 0]

Thanks all,i didnt expect so many replies so soon,i think i might go with a 1.9gti 5th gear,i doesnt take long to change it so ill prob do it and let you know how it goes. I do think the drop from 4th to 5th with a diesel 5th might be annoying so thats why im going to try the 1.9gti 5th.

 

Thanks again

the 1.9 5th is the same as the 1.6 5th!

 

its the first 2 gears and the FD that differ in the 1.6 and 1.9 boxes.

 

i'm guna crack open the boxes and put mi mi16 5th on the 1.6 box when i get it

[philfingers 5]

the 1.9 5th is the same as the 1.6 5th!

 

its the first 2 gears and the FD that differ in the 1.6 and 1.9 boxes.

 

i'm guna crack open the boxes and put mi mi16 5th on the 1.6 box when i get it

 

It's not even the first two gears between 1.6 and 1,9 boxes it's only first gear which is different. Which is why there's a big drop 1st to 2nd.

 

My old 309 1900 8v ran 1900 gears with 4.44 (Mi16) CWP. On a run to Scotland (I worked in Aberdeen for a while) it would do around 34mpg sticking to 70mph (@~4200rpm I think). Run it much faster and it used a fair buit more. Motor was std but 309 is heavier. Interestingly it was only about 1 mpg worse than when it was std 1900 box. For a car to travel at 70 mph needs a given energy, you don't theretically use any more travelling with a 1900 or a 1600 box. the motor will be rev more but still making the same power to maintain the same speed. Which is why the difference is minimal. Std engine dropped to 12-13 mpg on a road rally

My semi Gp A 8v 1900 would do around 20mpg on the road. Dropping to 8-10 mpg on a road rally

[djinuk 2]

what would you expect from a 1.9 box with a mi16 final drive ? would it suit a gti6 engine quite well?

[Anthony 1,002]

what would you expect from a 1.9 box with a mi16 final drive ? would it suit a gti6 engine quite well?

It gives a very short ratio 'box - good for trackdays, not so good on the road (particularly with motorways involved).

 

To give you a rough idea, it's about the difference between a 1.9 and 1.6 'box again, and the 5th gear on the 1.9 with Mi FD combination is about the same as 4th on a normal 1.9 box.

[unariciflocos 49 1 Cars]

Here you can find quite a complete and comprehensive article on gearboxes. Edited February 12, 2009 by unariciflocos

[Anthony 1,002]

Sorry, mini hijack. I have the same setup 1.9 with 1.6 box. I am taking the car to Germany in April. Is it going to be super thirsty, what sort of MPG should I expect on a ‘run’?

Really depends on so many other factors, like how well setup your engine is and how heavy your right foot is.

 

My own 1.9 8v with a 1.6 'box has given 39mpg (over 400 miles to a tank!) before now, and usually gets around 35-36mpg.

[mattbenselin 0]

trialster; the 5th gear in the Mi16 'box is the same as a 205 D. You will still get the same drop in revs when changing into 5th from 4th. The change is too obvious to be nice to drive with and only works when cruising at a higher speed with no intention of accelerating.

 

I really like the standard 1.6 'box but am thinking about using that with a 1.9 FD so lower the rpms but keep lower gear acceleration.

 

Any thoughts?

[Anthony 1,002]

I really like the standard 1.6 'box but am thinking about using that with a 1.9 FD so lower the rpms but keep lower gear acceleration.

That will basically be the same as a 1.9 box but with a shorter 1st gear....

 

1.9 Mi16 gearbox is a good compromise between having shorter 1st/2nd/3rd for acceleration, and a longer 4th/5th for cruising.

[djinuk 2]

from the sounds of what you are saying then using the mi16 final drive in a 1.9 box dosent really offer any benefits over a standard 1.9 gearbox.

[Anthony 1,002]

from the sounds of what you are saying then using the mi16 final drive in a 1.9 box dosent really offer any benefits over a standard 1.9 gearbox.

Define "benefits" - it gives significantly shorter gearing as the final drive is 4.4 rather than 3.6 of a 1.9, so if you want a short-ratio box then it's great, whereas if you want a box for touring across Europe then it's going to be completely unsuitable.

 

Match the gearbox to your intended use of the car (commuting, trackdays etc) and the engine's characteristics (ie high-rev screamer, or lazy torque)

[djinuk 2]

ah well my car will be track day, aswell as commuting car, however rmy work is only 7 miles away so motorway journeys wont be too common. The engine will be the gti6 so im not really sure what category that sits into. sorry about my lack of knowledge in the arae of gearbox's as ive never really looked into it before.