Which Gearbox Is Best?

[richors 0]

Hi - I am sure there has been previos info on this but my searches are not getting me far for some reason.

 

I have decided to get another gearbox to go with my standard Mi engine - current one keeps jumping out on track.

Car is not used on the road.

Which gearbox do people think works best for Mi and track combination and where is best place to get one from?

 

cheers.

[Ahl 4]

Try searching for 'best gearbox' - it seems to bring up tons of posts that will help you.

 

Searching for 'best mi16 gearbox' didn't work very well though! Strange.

[Sandy 189]

I don't know how many times i've posted this, but searching isn't bringing it up.

 

Mi16 IMO is the best road box, it has a reasonably tall first for easy traction on launch and the smallest rev drop into second, which is a nice shortish gear, thrid is reasonably close after that and fourth is close enough, by which time you're losing your license anyway and fifth is a decent motorway gear. The 1.9 is too tall for all but the torquiest engines in first and second, the 1.6 has too short a first gear for good launching and a uselessly short fifth compared to the Mi16. Here's the comparison of maximum speed in each gear with 195/50/15 tyres and 7000rpm limit:

 

Box-----1st-----2nd-----3rd-----4th-----5th-----RPM@70MPH in 5th

 

Mi16-----36-----56-----82-----109-----139-----3520

 

1.6-------34-----61-----84-----107-----132-----3724

 

1.9-------43-----68-----92-----117-----144-----3402

[richors 0]

Thanks for that - great clear info.

 

I will try some different searches tonight too. Anyones opinions based on track usage would be most helpful too as the car won't used on the road so i guess 1st and 5th don't matter too much most of the time and top speed isn't too big a deal either.

 

cheers

 

Mark.

[boombang 2]

1.9 with an Mi16 final drive IMHO but if you do a search you'll find a few hundred more opinions.

[Rob_the_Sparky 9]

From what I understand it is fairly easy to swap 5th and final drives from box to box so hybrid boxes are not that uncommon...

[Jonmurgie 2]

I think the general consensus is the 1.9 8v box with the Mi16 final drive seems to give the best 'track' box although depending on what power you run you may end up at the redline in 5th as that's about 125ish

 

That's what I run anyhow, here's the spec and some excel sheets for you to download and play with: http://www.mdracing.co.uk/gearbox.asp

[richors 0]

Brilliant - much appreciated.

 

Mark.

[smckeown 1]

the only problem with the 4.43 CWP is that you change gear a lot and your top speed is much reduced. I have now moved to a standard 1.6 box to see if that's better for track work

[Rob_the_Sparky 9]

Or a 1.9 box with a 1.6 Final drive...

 

Surely it is going to depend on the track.

[richors 0]

Well i never get close to 125 on the circuits i do so not too concerned if top speed is around that really.

Will see what box i can pick up locally if possible.

Are all friction plates and release bearings the same etc or does it differ according to box - 1.6/1.9/Mi etc?

 

Not done one before.

 

cheers

[Jonmurgie 2]

All the internals etc. are fully inter-changeable between the BE1/BE3 gearboxes so no problems there...

 

If it's a standard Mi16 motor then the Mi16 box would do fine as 5th is just a little longer... when I fitted my Mi16 I only had a 1.9 8v 'box and it was utter s*ite as everytime you changed gear it would drop out of the power band (4k and above) so fitting either the 1.6 or the Mi16 'box as it comes it great, or dropping the Mi final drive into the 1.9 8v box is ideal IMO

[Kev-G 1]

All the internals etc. are fully inter-changeable between the BE1/BE3 gearboxes so no problems there...

 

Not true....

 

Unless using a track with long straights/speeds then either a 1.6 or 1.9 'box with a Mi F/D will be great (1.9 box will give a slightly longer 1st gear so is theoretically better, but it only affects 1 gear....)

[Sandy 189]

when I fitted my Mi16 I only had a 1.9 8v 'box and it was utter s*ite as everytime you changed gear it would drop out of the power band (4k and above) so fitting either the 1.6 or the Mi16 'box as it comes it great, or dropping the Mi final drive into the 1.9 8v box is ideal IMO

The 1.9 8v has the closest gear ratios of all the above (except 4th to 5th of 1.6), so the revs will drop less. The taller final drive is what takes the edge of it.

[Jonmurgie 2]

Not true....

Eh, what's not true... that all the internals can be swapped about and fit with each other?! Not sure what you mean there at all Kev!

 

Sandy - the 1.6 8v has the closest ratios as standard as 1st gear is much shorter then tne 1.9 8v, and obviously the closer final drive too... check out the excel sheets and see for yourself: http://www.mdracing.co.uk/gearbox.asp

[Kev-G 1]

Eh, what's not true... that all the internals can be swapped about and fit with each other?! Not sure what you mean there at all Kev!

 

Sandy - the 1.6 8v has the closest ratios as standard as 1st gear is much shorter then tne 1.9 8v, and obviously the closer final drive too... check out the excel sheets and see for yourself: http://www.mdracing.co.uk/gearbox.asp

 

It's NOT true to say that ALL BE1 and BE3 internals are interchangeable....The fact that I put the statement directly after your quote should have given it away.. In fact, it's not an entirely true statement even for BE3 'boxes.

 

Other than 1st gear (actually 1st/2nd cluster) and FD, 1.6 + 1.9 'boxes are the same....Early BE1's had what is termed a close ratio 'box and these have different gearing

[Jonmurgie 2]

So can you teach me what parts are not interchangable as I believed they were?!

 

Perhaps if you can explain WHY you are saying that rather than just say it again it would save all this confusion

[Sandy 189]

Sandy - the 1.6 8v has the closest ratios as standard as 1st gear is much shorter then tne 1.9 8v, and obviously the closer final drive too... check out the excel sheets and see for yourself: http://www.mdracing.co.uk/gearbox.asp

I know what's in these boxes, having taken a few apart Close gearing means the revs drop less between gears. The first gear is shorter on the 1.6 box (normal or close ratio type) than the 1.9 or Mi16, but second is the same ratio on all, so the 1st-2nd gear change on the 1.6's loses more revs than the 1.9 or Mi16, therefore the ratio spacing is wider, not closer. Here (again ) is the revs you'll drop to between gears, changing up at 7000rpm on the various boxes:

 

Box-----1st-2nd-----2nd-3rd-----3rd-4th-----4th-5th

 

1.6-----3982-----5058-----5502-----5664

 

1.9-----4435-----5146-----5507-----5692

 

Mi16---4435-----4843-----5250-----5469

 

As you can hopefully see, the 1.6 loses more revs between gears than the 1.9 mostly, therefore it is the 1.9 that has closer gearing, especially the spectacular 450rpm difference on 1st to 2nd changes.

[Jonmurgie 2]

Jeez... who's being patronising now! You have PM to sort this out before it gets out of hand

Edited September 1, 2006 by Jonmurgie

[smckeown 1]

here's my contribution:

 

Here'e a graph showing the percentage differences between the ratios. Wouldnt the best box be the one with less % change ? The final drive can always be used to lower the overall gearing of those rations all in proportion

 

 

 

Therefore the winner is the 1.9 box (final drive irrelevant)

Edited September 1, 2006 by pugtorque

[boombang 2]

I think most of you have totally missed the point.

 

Gearing in an ideal situation should be chosen to match the torque.

 

There is no such thing as a "best box" but a best box for a given specification for a given purpose.

 

Every day driving on an engine with decent torque spread an Mi16 box is great.

 

Track work on a highly tuned engine with very narrow torque band needs a closer box i.e. a 1.9 with Mi FD or if VERY narrow and top speed isn't an issue the 4.8 CWP.

 

A 1900 TT has huge torque spread so generally speaking a longer box would be better - say a 1.9 box.

 

If you had a car for occasional track use but still needed some comfort you may decide on a 1.6 box, or a 1.9 with 1.6 FD.

 

 

In this case I will still stick with my choice of 1.9 with Mi FD as it keeps the Mi on the boil (in my experience on slightly modded engines peak torque is 5k to redline!) and is forgiving if you get the wrong gear on upshifts.

[Kev-G 1]

So can you teach me what parts are not interchangable as I believed they were?!

 

Perhaps if you can explain WHY you are saying that rather than just say it again it would save all this confusion

 

Get a couple of 'boxes and take them apart to compare..

 

BE1's have a different reverse mechanism, and the 1st/2nd cluster is certainly not interchangeable....There are also differing threads/spline sizes on various boxes which mean that you can simply take any mix of gears and put them together.

 

If you didn't post misleading information then there would be no confusion

[philfingers 5]

Sandy, agreed the 1.6 has wider ratios. The closest ratios of any std box (all through the ratios) is the std 1.9 but it has a long final drive. (geared for 137mph at 6000rpm in 5th, altho std 8v would never pull it). My 1.9 ratios with Mi 4.44 CWP gives around 115mph at 6000rpm in 5th. As the car is used for road rallying this suits me fine. Whereas the std box would give me around 60mph in 2nd the hybrid gives me 65mph in 3rd. So I have an extra gear to play with!

[Craigb 2]

Sandy, agreed the 1.6 has wider ratios. The closest ratios of any std box (all through the ratios) is the std 1.9 but it has a long final drive. (geared for 137mph at 6000rpm in 5th, altho std 8v would never pull it). My 1.9 ratios with Mi 4.44 CWP gives around 115mph at 6000rpm in 5th. As the car is used for road rallying this suits me fine. Whereas the std box would give me around 60mph in 2nd the hybrid gives me 65mph in 3rd. So I have an extra gear to play with!

 

Thats exactly what i had on my last road rally , the std 1.9 box just wouldn't pull. I only used 3 gears all night . I have since changed to 4.44 cwp to let me play with all 5

[Sandy 189]

I was going to include the Mi16FDR/1.9gears hybrid in my figures, but as I was only quoting rev drops I didn't bother, because the final drive won't alter that.

 

I agree that the Mi16FDR/1.9gears is a very good track and competition combination, although the driver of one of the cars i'm involved with says he spends too long on the limiter in 5th at some venues (8/29.1/15 slicks). Depends on the engine power and car weight.

 

Given that 2nd gear is the same for all and the 2.92:1 first from Mi16 or 1.9 is closest to that (and they are both cut onto the input shaft), it's logical to take that as you starting point and choose the FDR next to give the first/second overall gearing you require, then select the 3/4 and 5th to suit the type of driving you do. If you can't be bothered with rebuilds, the Mi16 box is the logical choice.