E30 Zone

hi guys i have a getrag 260 box in my track car and would like to get hold of a close tratio box, which I believe maybe called a 262CR is this correct are they hard to come by?

Ultra-cheap option - fit a Getrag 240 from a 320i. It has the same ratios as the Sport box.
The 260/240 designation refers to the maximum input torque in Nm, so the 320i box is a little weaker, but failures are very rare.

ok thanks Handpaper !
are the 240 boxes identical in terms of clutch bell housing?

handpaper wrote:Ultra-cheap option - fit a Getrag 240 from a 320i. It has the same ratios as the Sport box.
The 260/240 designation refers to the maximum input torque in Nm, so the 320i box is a little weaker, but failures are very rare.

Hi,

that´s wrong. Only gears 1-3 are a little bit "longer", 4th is 1:1 and 5th 0.81:1.

What you are looking for ist GETRAG 242 from E21 or very early 323 E30. This gearbox has 5th 1:1 and first gear is left down.

http://www.pro-track.de/bmwe30racing/00 ... ag242.html

Regards

Christoph

dcoeinside wrote:that´s wrong. Only gears 1-3 are a little bit "longer", 4th is 1:1 and 5th 0.81:1.

Its not the absolute ratio of a gear-set that defines a gearbox as either a close or long ratio box. Its the % shift between the gears.

The Getrag 260 has ratios:
1st: 3.83:1
2nd: 2.20:1
3rd: 1.40:1
4th: 1.00:1
5th: 0.81:1

with %ratio shift between:
1st & 2nd: 42.5%
2nd & 3rd: 36.4%
3rd & 4th: 28.6%
4th & 5th: 19.0%

The Getrag 240 has ratios:
1st: 3.72:1
2nd: 2.02:1
3rd: 1.32:1
4th: 1.00:1
5th: 0.81:1

with %ratio shift between:
1st & 2nd: 45.7%
2nd & 3rd: 34.6%
3rd & 4th: 24.2%
4th & 5th: 19.0%

And finally, the Getrag 245CR has ratios:
1st: 3.76:1
2nd: 2.33:1
3rd: 1.61:1
4th: 1.23:1
5th: 1.00:1

with %ratio shift between:
1st & 2nd: 38.0%
2nd & 3rd: 30.9%
3rd & 4th: 23.6%
4th & 5th: 18.7%

Thus, compared to the Getrag 260, the Getrag 240 has a marginally smaller % shift from 2nd to 3rd, and from 3rd to 4th, but has a notably larger shift from 1st to 2nd.

Compared to both the Getrag 260 and Getrag 240, however, the Getrag 245CR has notably shorter shifts between all gears except 4th to 5th (which is roughly the same).

However, while the 245CR has shorter shifts than the 240, which in turn has marginally shorter shifts than the 260 (after 1st), none of these three gear-boxes (SFAIK) actually qualifies for the term "close ratio". To do so, the % shift between all gears (by the standard definition of a close ratio box) must be less than 25%.

Paynts wrote:... and would like to get hold of a close tratio box

I thus know of no OEM specified "close ratio" gearbox from a road going car, although the Getrag 245CR might well qualify for the term "closest available" ratio gearbox.

FYI, Absolute ratios (from engine to wheels) can be adjusted up and down (simultaneously) by changing the ratio of the final drive and/or changing the diameter of the drive-wheels, but the % shift between gears can only be changed by physically changing the ratio's within the gearbox.

EDIT: Comments with regard to Getrag 242 changed to indicate Getrag 245CR.

Hi GeoffBob,

you have done a really good job. All you write is correct. Yes, the 242 is only a "sportbox". A close ratio box is like GETRAG 2.33:1.0 for example M3 DTM.

Regards

Christoph

Notice: GETRAG 242 is about 750 Euro in germany. Used conditions of course.

GeoffBob wrote:

dcoeinside wrote:that´s wrong. Only gears 1-3 are a little bit "longer", 4th is 1:1 and 5th 0.81:1.

Its not the absolute ratio of a gear-set that defines a gearbox as either a close or long ratio box. Its the % shift between the gears.

The Getrag 260 has ratios:
1st: 3.83:1
2nd: 2.20:1
3rd: 1.40:1
4th: 1.00:1
5th: 0.81:1

with %ratio shift between:
1st & 2nd: 42.5%
2nd & 3rd: 36.4%
3rd & 4th: 28.6%
4th & 5th: 19.0%

The Getrag 240 has ratios:
1st: 3.72:1
2nd: 2.02:1
3rd: 1.32:1
4th: 1.00:1
5th: 0.81:1

with %ratio shift between:
1st & 2nd: 45.7%
2nd & 3rd: 34.6%
3rd & 4th: 24.2%
4th & 5th: 19.0%

And finally, the Getrag 242 has ratios:
1st: 3.76:1
2nd: 2.33:1
3rd: 1.61:1
4th: 1.23:1
5th: 1.00:1

with %ratio shift between:
1st & 2nd: 38.0%
2nd & 3rd: 30.9%
3rd & 4th: 23.6%
4th & 5th: 18.7%

Thus, compared to the Getrag 260, the Getrag 240 has a marginally smaller % shift from 2nd to 3rd, and from 3rd to 4th, but has a notably larger shift from 1st to 2nd.

Compared to both the Getrag 260 and Getrag 240, however, the Getrag 242 has notably shorter shifts between all gears except 4th to 5th (which is roughly the same).

However, while the 242 has shorter shifts than the 240, which in turn has marginally shorter shifts than the 260 (after 1st), none of these three gear-boxes (SFAIK) actually qualifies for the term "close ratio". To do so, the % shift between all gears (by the standard definition of a close ratio box) must be less than 25%.

Paynts wrote:... and would like to get hold of a close tratio box

I thus know of no OEM specified "close ratio" gearbox from a road going car, although the Getrag 242 might well qualify for the term "closest available" ratio gearbox.

FYI, Absolute ratios (from engine to wheels) can be adjusted up and down (simultaneously) by changing the ratio of the final drive and/or changing the diameter of the drive-wheels, but the % shift between gears can only be changed by physically changing the ratio's within the gearbox.

dcoeinside wrote:Hi GeoffBob,

you have done a really good job. All you write is correct. Yes, the 242 is only a "sportbox". A close ratio box is like GETRAG 2.33:1.0 for example M3 DTM.

Regards

Christoph

Danke Christoph,

Ah yes, the E30 M3DTM! Magnificent cars!!



But I agree with you that, despite only being a "sportbox", the Getrag 245CR is still a good choice of gearbox for track work.

The big advantage of the Getrag 245CR, however, is not so much in the reduction in % shift between the gears (it's actually not that much) but the fact that all its gears have a much higher (absolute) ratio. This has the same effect as increasing the ratio of the final drive by roughly 18% (compared to the other boxes).

This is truly where the "wow" factor of the Getrag 245CR comes from, and makes this a valuable and useful gearbox to obtain for trackwork. Its direct-drive 1:1 5th gear does of course limit the top speed of the car (especially if a high ratio differential is already fitted) but provides magnificent acceleration, which is often what is so important on the track.

Regards
Geoff

EDIT: Getrag 242 replaced with Getrag 245CR

Paynts, seems I forgot the following in my original post:

A Getrag 262CR box has ratios:

1st: 3.72:1
2nd: 2.40:1
3rd: 1.77:1
4th: 1.26:1
5th: 1.00:1

with % ratio shift between:
1st & 2nd: 35.5%
2nd & 3rd: 26.3%
3rd & 4th: 28.8%
4th & 5th: 28.6%

1st to 2nd is much closer on this box than the getrag 245CR, but 3rd to 4th and 4th to 5th are actually wider. With the exception of 1st to 2nd, the gears on the 262CR are more evenly spaced and for this reason I think you will find this box better suited to your application.

Incidentally, the dog-leg pattern that the shifter on the 245CR and 262CR follows is due to the clustering of the gears. Most boxes find the 1st & 2nd, and 3rd & 4th gear clusters paired next to each other in the box. Hence the reason the shifter slides from 1st back into 2nd (similarly with 3rd and 4th) but must shift side to side to move between the two pairs. A dog-leg box, however, has 2nd & 3rd, and 4th & 5th, paired next to each other. 1st is off by its lonesome.

Now here's the really interesting bit (and not a lot of people know this, so keep this to yourself ), the reason a dog-leg box works this way is because it is made from a 5-speed box (direct 4th with over-drive 5th) with a new high ratio 1st gear located where you would expect to find the usual low ratio 5th gear.

Thus, old 5th becomes new 1st
old 1st becomes new 2nd,
old 2nd becomes new 3rd,
old 3rd becomes new 4th, and
old 4th becomes new 5th.

This is the reason the Getrag 245CR and 262CR have direct drive 5th gears (old 4th), but the basic Getrag 245 and 265 have direct drive 4th gears

Its exactly the same arrangement/layout of the gears inside the box, but with a modified selector to put 1st on the otherside of where 5th was before. And of course the gears are renamed. Not to mention, the 245CR and 262CR also have completely different gear ratios (else the whole exercise would be a bit pointless).

EDIT: Getrag 242 replaced with Getrag 245CR

crikey ! info overload! ok now which of the Getrag numbers you guys are talking about is the standard"sport" box as found in the 325i Sport? also just to be clear the most important ratio change in this box is in my experience 2nd to 3rd theres often a debate amoungst me and my fellow driver as to weather a corner is a second gear or 3rd gear and this is the numb of my interest
Thanks Guys!

325i
1st: 3.83
2nd: 2.20
3rd: 1.40
4th: 1.00
5th: 0.81

325i Sport
1st: 3.35
2nd: 2.03
3rd: 1.36
4th: 1.00
5th: 0.81

Oh Goodness, what am I talking about - Getrag 242, my arse - that was a 4-speed box. I mean Getrag 245. 'Thought I would mention this before someone else points it out.

'Have modifed my first post above accordingly. Like you say Paynts, info overload! Too many useless bits of info floating round my head.

The Getrag 245/4 was a standard long ratio box with 1:1 4th.
The Getrag 245/10 was a close ratio "dog-leg" box.

It's basically one of the dog-leg boxes that you are looking for - not only as a result of its closer ratios but due to its direct drive 5th.

I'd recommend a 262CR from an M3 or M535i.

A 262cr is quite tricky to fit to an M20 engine. You will need the bellhousing from a US Spec 528e and these are rather thin on the ground.

right ive got a 260 box but its the same box as I've seen advertised as being from "sport" cars on ebay etc. This is not a dogleg first box the part number seems to match up to other info on the net as it being from a 325i sport - or have i just got a standard 325i gearbox?

Theo325 wrote:A 262cr is quite tricky to fit to an M20 engine. You will need the bellhousing from a US Spec 528e and these are rather thin on the ground.

Point is thought that it is possible Theo, even if he has to import parts. Personally I think it's worth it to get the ratio's. Not that a Getrag 245CR box would be a bad choice. However, I do honestly believe that the % change in ratio between gears on the 262CR is better suited to track work than on the 245CR box.

The alternative, Paynts, is to modify or have modified a box to suit. This is what I am busy doing on my track car. My chosen ratios are:

1st = 2.00:1
2nd = 1.55:1
3rd = 1.23:1
4th = 1.00:1
5th = 0.85:1

with % shift between gears:
1st to 2nd : 22.2%
2nd to 3rd : 20.7%
3rd to 4th : 18.9%
4th to 5th : 15.4%.

This is a true close ratio box designed for track work. 1st gear ratio is low enough to corner with (will do 60mph at 7000rpm in 1st). I only mention this to illustrate the difference in the ratios compated to a normal box.

Paynts wrote:right ive got a 260 box but its the same box as I've seen advertised as being from "sport" cars on ebay etc. This is not a dogleg first box the part number seems to match up to other info on the net as it being from a 325i sport - or have i just got a standard 325i gearbox?

You have one of the Getrag 260 variants (260/??). Would have the sport ratios, as illustrated by Theo, if from a 325i sport, but by no means a CR box. Certainly closer (sportier) than the standard box, but not a CR box. Has direct drive (1:1) 4th gear.

I agree, the 262cr is a much nicer box to use when you are hammering it.

To determine which variant of the 260 box you have check the front edge of the bellhousing for a stamping. A sport box will be marked TNN or HJ.

Paynt's, to add to the info overload, here's some pics for you from Metric Mechanic.

Here's a standard Getrag 260 with integral bellhousing. Your gearbox will look like this.




Now here's a standard getrag 262 (bellhousing separate). The basic Getrag 262, like the basic Getrag 242, is a 4 speed box.




Now here's a Getrag 262CR sport box. Note how the box is longer (extended) compared to the basic 4-speed getrag 262. The extra bit (bolted between the main and end housings) houses the extra gear that becomes the "new" 1st gear. It's as a result of this modification that the box adopts the dogleg shift pattern.




Now, as I said, the Getrag 262CR box is created by adding a high ratio (new 1st) gear into the basic 262 box. However, if you add a low ratio gear (new 5th) instead of a high ratio gear (without the modified shift linkages) you get a Getrag 265.



See the similarity between the 262CR and the 265? It's basically the same box (different casting in the middle), but with different gears (and different shift pattern). One of the best ways to build a race-spec box is to modify a Getrag 265. The Getrag 265 has a reputation as a strong and reliable gearbox.

Hope this helps (and is of interest to others too).

One last thing. I have a sneaky suspicion that the bellhousing from an S38 motor (B36 or B38 variant, European E34 M5 car) will work to join a Getrag 262CR to an M20 motor. SFAIK, the European E34 M5 uses the same bellhousing as the US E28 528e with a Getrag 265 box. I could be wrong on this, so please don't quote me. I am sure someone will confirm or refute this in good time.

Sadly, that's not true. The E34 M5 (and E28 M5) use the Getrag 280 which has an integral bellhousing. The bolt pattern on these boxes is the same as the M30, S14 and M10 engines and therefore different to the M20.

Theo325 wrote:Sadly, that's not true. The E34 M5 (and E28 M5) use the Getrag 280 which has an integral bellhousing. The bolt pattern on these boxes is the same as the M30, S14 and M10 engines and therefore different to the M20.

Oh crap, sorry Theo. Thanks for putting me straight.

I thought i had replied to this before but the forum seemed to loose my message

I'd like to sort a closer ratio box out and spanner work is easy for me but i need to know where to start and which blind alleys to avoid seems like the 262CR box is not compatable to my M20 in any of the other BMW aplications? is this correct? is a 245 box available that will bolt straight onto the M20 ? (I dont mind shortening props etc as I have access to lathes and engineers)

Paynts wrote:I'd like to sort a closer ratio box out and spanner work is easy for me but i need to know where to start and which blind alleys to avoid seems like the 262CR box is not compatable to my M20 in any of the other BMW aplications? is this correct? is a 245 box available that will bolt straight onto the M20 ? (I dont mind shortening props etc as I have access to lathes and engineers)

First prize is a Getrag 262CR. Bellhousing, as per Theo325, from a US spec 528e. Will require that you put some effort into hunting parts, but well worth the effort IMO due to the best gear ratios for your application.

2nd prize is a Getrag 245CR, which will bolt straight up. But be sure to get the close rato (dogleg) version (Getrag 245/10 or 245/11 I think?). Do a search on the zone for "dogleg" boxes to find out more.


Here is a basic 5-speed (not dogleg) Getrag 245 with integral bell housing (just like the 260)




The basic Getrag 245 was derived from the 4-speed Getrag 242 (in the same way the 5-speed Getrag 265 was derived from the 4-speed Getrag 262).



See how the 245 is just a longer version of the 242?

It therefore makes more sense that the close ratio dogleg version of the 242 would be called the Getrag 242CR (in the same way as the Getrag 262CR was named). SFAIK, with the exception of a few rare "modifed" versions of the 242, the close ratio dog-leg version of the 242 is called the 245CR. This is what you would have to look for. But be warned, they have a reputation for giving problems.

One final (very attractive but expensive) alternative is that you could order a race prepared (modified ratio) Getrag 265 from Metric Mechanic. Expensive, but this would get you a set of proper close ratio gears. They would likely be able to source the required bell housing for you.

Hmm thanks all ! esp Geoffbob

I'm going to ponder options ive looked into the 245/10( E28 323s?) and the 528e option and both will take some sourcing!!!

I got my got my bellhousing from ebay.com andf my boxes from buying and fragging m535i's

The other option to use any of the m5*/s5* boxes as they bolt up but you got to modify the gear linkage to suit the differing angle of the boxes

Jason

Paynts wrote:Hmm thanks all ! esp Geoffbob

I'm going to ponder options ive looked into the 245/10( E28 323s?) and the 528e option and both will take some sourcing!!!

You're welcome.

These are sought after items for exactly the reasons you are after them .

2 PM's for you still sitting in my outbox since the weekend.

Regards
Geoff