Discussion in 'Parts' started by csimyson, Apr 15, 2019 at 11:34 AM.
After a 5 speed box for 73 csi.
which box is best for our cars
Any one got 1 for sale uk
IMO, a close ratio 5 is the perfect combo for the 3.25 diff in a CSi... and overdrive is a waist of two gears.
Getrag 265/5 is a close ratio gearbox and has the same gear ratio in fifth gear as the stock Getrag 262 has in fourth gear.
So if you're looking to get some rpms down for highway cruising, the Getrag 265/6 overdrive is a much better alternative.
Both of these are common for 5-speed swaps in our coupes, you just need to know what you want to achieve with the swap.
Then there are several different diff gear ratios that can mix it up a bit, but your CSi should have 3.25.
Be aware that newer 265/5 and 265/6 gearboxes may not have the mechanical drive for the speedometer, but a handy person can add that to a gearbox that came without speedo drive.
Getrag 262 4-speed (stock)
1st - 3,85:1
2nd - 2,20:1
3rd - 1,40:1
4th - 1,00:1
Gertag 265/5 CR 5-speed
1st - 3.72:1
2nd - 2.40:1
3rd - 1.77:1
4th - 1.26:1
5th - 1.00:1
Gertag 265/6 Overdrive 5-speed
1st - 3.82:1
2nd - 2.2:1
3rd - 1.4:1
4th - 1.00:1
5th - 0.81:1
Curious how many here run a 3.25 diff with an overdrive? I had a 72 CSi the PO set up that way and 5th was unusable for 99% of real world driving in a classic car. Maybe the autobahn or runs across Montana? The overdriven 5 speed rage in the US has a lot to due with all the 3.45 and 3.64 diffs on the US cars.
Agreed in full. I just had this conversation the other day with @sfdon and @Peter Coomaraswamy. I have the same 3.25 and an overdrive 5 speed seems suboptimal IMO. I’m curious to know what your goals are @csimyson.
I haven't tried running an OD box with a 3.25 diff.
What I have tried, is running a 262 with a 1:1 ratio fourth gear and a 3.25 diff.
That's no joy going for longer drives, and I constantly keep trying to grab for the next gear to get the car a little more relaxed.
Getrag 262& Getrag 265/5 in highest gear, 3.25 diff:
Getrag 265/6 in highest gear, 3.25 diff:
Is it optimal? Probably not, but it depends on your needs. Totally unusable? I can't agree.
This is just my opinion
With my 3.45 and 265/6 I run at 77mph at 3000rpm. Perfect for fast highway speeds and ready to drop the hammer if needed at this rpm. Of course, the b35 makes accelerating even easier at most rpms!
Here in the States many coupes with overdrives are running 3.5 and bigger engines as well. I will concede, unusable is an exaggeration, but I stand by preference for a CR box for a stock, 3 liter, injected E9. Actually, there is nothing wrong with the 4spd- there's something special about those long pulls with a well tuned Djet six.
I run a dog leg 5 speed and LSD diff both from a pre 1979 E24 635, I thought the 3.09 would be useless but its absolutely perfect for my cs, pick up, speed both spot on.
FWIW. I had a ljet 3.0si and changed to an 5 speed OD box and a CSi diff. The result was,IMO, perfect. But the bigeest mistake I made was to sell it for peanuts. Hey ho. sadly it has never been heard of since.
I can't wait to be able to join this conversation!
Love my 265/6, has made my CSi so much better than the stock 4-speed. Crossed Nevada 140kph @ 3100 to 150kph @ 3400
Andrew, you must have a 3.25 as yours is a CSi
Gratuitous pic with my 265 OD and 3.64 diff allegedly exceeding the speed limit somewhere in Alabama headed to the Vintage
that's why your coupe was so warm when you got to my house. at least it wasn't breathing hard for being run thru the paces.
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