48 replies to this topic

[flamejob]

It seems to me that the minispares one would be good to go for in terms of a useable road car, the JKD one is a dog box which, whilst fun on a sunday or racetrack, would be hell for an everyday car.

I disagree with Ethel, why not have more gears? If the engine is strong enough to have a longer first then the whole gear range gets longer with a 5 speed, or you just have the 5th as an overdrive on the lovely motorway.

[Guess-Works.com]

Using the 5th as an overdrive is the way to do it, but how many people actually do that... nowadays people are use to using the top gears in a different fasion and just accelerate (or try to) in them.. where as in real 'overdrive' days you knocked it back to 4th to perform any kind of manouver...

The problem is, running that high final drive, puts HUGE stress on the gearbox and diff...

How many MPi's running a 2.7 FD have we heard about which have blown the diffpin out the back of the box or stripped gears...

The mini is not a modern car... stop trying to drive it like one !

[Jammy]

With the 5 speed boxes with the direct (1:1) 5th gear, yes these would theorectically give you quicker acceleration, but the small gain in acceleration from gearing is probably going to be spent shifting through the extra gear!

The 5 speed boxes with overdriven 5th, you won't gain any acceleration, and your top speed probably won't be much different (the mini is still a brick against 100mph airflow), it'll just drop the revs by a few hundred rpm at motorway cruising speeds. You'd have to be doing A LOT of motorway miles to regain the money you spent on the box in petrol you save!

As said above, just make sure you have the correct final drive for the type of driving you'll be doing. The four speed box really is suitable enough for nearly all situations.

[insamoufonyx]

With the 5 speed boxes with the direct (1:1) 5th gear, yes these would theorectically give you quicker acceleration, but the small gain in acceleration from gearing is probably going to be spent shifting through the extra gear!

The 5 speed boxes with overdriven 5th, you won't gain any acceleration, and your top speed probably won't be much different (the mini is still a brick against 100mph airflow), it'll just drop the revs by a few hundred rpm at motorway cruising speeds. You'd have to be doing A LOT of motorway miles to regain the money you spent on the box in petrol you save!

As said above, just make sure you have the correct final drive for the type of driving you'll be doing. The four speed box really is suitable enough for nearly all situations.

with it costing me around £7 a day to do 30 miles motorway i would imagine it would be worth it, when im going down the motorway at 70 im reving at 3,500 and lets me honest who achualy does 70 on the motorway?

[Bungle]

i find my 5 speed box great (great for the kids) living in Cornwall i need a low geared mini for lots country lanes a top speed of 60 would be OK

but living in Cornwall mean's most shows are over 3 hours away so its nice to sit in 5th on the motorway and drop the revs down that little bit lower the noise level and have a bit more MPG

the 5 speed box gives me a low and high gearing in 1 box

[Ethel]

I'm not saying 5 gears are bad, just that neither is having just 4 and there are better ways to spend that kind of money on a Mini.

[Guess-Works.com]

From the age of the vehicle and model...

Your calculations for 3,5k@70 would be about right... 3.1:1 FD

You have one of the best distance ratios already in your car, anything less (2.9 would make sod all difference) would need to be a 2.7, and to be honest, don't even go there...

By you're own admition, you don't stick to 70, which means your poor mini is chucking in fuel by the bucket load... I can drive my 1330 which is not the most economical of engines, along at 60 mph, and return over 30 to the gallon.

On a 30 mile trip, 60 mph on the motorway, vs 70 is only going to take 4 minutes longer...

I don't understand the concept of spending money to save money... say you save a pound for every 30 motorway miles you run, that means you'll have to drive 45000 motorway miles before you've recouped the cost of the gearbox, let alone fitting it...

IMO, money would be better spent finding out why you use £7 fuel on a 30 miles motorway trip.. whether it be a fueling/mechaincal issue with the engine, or just a heavy right foot...

[insamoufonyx]

ok then what other ways would there to up my mpg? i tryed driving fairly economicly for a full tank ( between 2k-3k revs) for the whole tank as much as i could, i work out at the end of the tank i only got about 24mpg, witch is rediculous if i think about it.


cheers

[Jammy]

Take 95p as the going rate for fuel per litre. Thats 7.37 litres you can buy for that £7. 4.55 litres in 1 gallon, so thats 1.62 gallons your using for your 30 mile journey, times 1.62 by 30 miles and that gives you ~48mpg. I doubt you'd see that increase by much with the 5 speed box.

Even if you get 55mpg after you fit a 5 speed box, your talking a hell of a lot of miles before you recoup the £2000+ you'd have to spend on buying one. MUCH easier and quicker to get a different FD fitted and uprated diff pin.

[Ethel]

30 divided by 1.62 = 18.5mpg See me after the lesson young master Jammy

You're still right that a 5 speed box isn't where you want to be looking to sort out mileage like that..

Mind you empty pockets would make you think twice about stamping on the go pedal.

[insamoufonyx]

30 divided by 1.62 = 18.5mpg See me after the lesson young master Jammy

You're still right that a 5 speed box isn't where you want to be looking to sort out mileage like that..

Mind you empty pockets would make you think twice about stamping on the go pedal.

i was quite confused when i looked at jammy's figure lol! this sound more like it, what should i start by doing to sort this out, because at the minute its rediculas!

[Jammy]

Ha ha, knew it didn't seem right, and didn't think I get the calculation correct, my Maths has really gone down hill since leaving school!


My point still stands though!

[Guess-Works.com]

I'd be tempeted to get the car on a co2 meter, and serviced... and also get yourself a vacuum gauge... that'll tell you immediately if you're running around on more than part throttle..

[JetBLICK]

On that basis i'd say you've got a fueling problem, or you're leaking fuel. I'm not one for economical driving, I get about 120 miles out of one full tank, thats about 24mpg, and my car does 5000 rpm at 70mph!

Edited by JetBLICK, 21 September 2007 - 10:02 AM.

[insamoufonyx]

I'd be tempeted to get the car on a co2 meter, and serviced... and also get yourself a vacuum gauge... that'll tell you immediately if you're running around on more than part throttle..

already have a vacume gauge, what should i look for on that? throttle about half way the needle is on drive, foot to the floor it sits back on the needle again?