B&M shift reduction

[Tool Pants]

We put a B&M short shift kit in Pixrken's supercharged 2000 996 today, and the reduction was the highest I have seen. 43%.

[dj996]

I can tell you there is a difference between the B&M and the factory SSK. The Porsche SS has about 10% shorter travel, although that is by feel.

[Tool Pants]

We need to start measuring more cars before and after.

We put the Porsche short shift in a 2003 C4S in November. The reduction was 36.85%. I measure the same way I did with the B&M install on the 2000 996 and it was 43%. This could be due just to the play in the shift cables or my human error, or maybe the transmissions are different.

This is the Porsche version of the B&M shift.

[boxer6]

hmmm, I didn't measure mine... I wonder what mine will come out to.

[Tool Pants]

David in the UK with a Boxster S measured his, before and after, with the B&M unit. I asked him to do it in inches. He came up with a 41.6% reduction.

[boxer6]

Someone told me if the shifter's throw is bigger than 35% it put too much load on syncro and can wear out or damage it. Is it true?

[Tool Pants]

The syncro debate - sure beats the oil debate.

Any syncro on any car can wear out over time. That is just the nature of a syncro since it's job it to get 2 gears spinning at different rpms to the same speed. In my younger student days I use to rebuild transmissions. The 2nd get syncro gets the most wear, and the top gear syncro the less. Give me your stock car for a day and I can speed shift it so that it will need at least 1 syncro. Give me your short shift car and I can drive it for over 100,000 miles with no syncro change.

There is a guy on the message boards who has repeated this 35% thing over and over. Ask him what is the source of this info.

If you give the syncro time to do its job it will last. Your syncro does not know what type of shift lever you are using - the factor is the human hand on the shift knob. But if you try to make it work faster then it knows.

Here is Danny's 2000 Boxster 2.7, a local Boxster owner. He has had a B&M for many years and cut the shift lever down, a lot. I was going to measure the percentage of reduction on his car, but there was not much to measure. The shift throw on his car is like turning a light switch on and off. He has no transmission problems. I have problems finding the correct gear in his car since I am not use to it. Danny does not have this problem.

[boxer6]

I guess it all depends on how the person drives the car.

[Tool Pants]

Exactly. Syncros need time to work - not matter what shift lever you have. If you give them time to work with a short shift then they are not going to wear out any faster then with a normal shift.

Tomorrow we put in a B&M with an EVO shift link. I will measure that combination as well.

[Poursha]

With the B&M under car kit, my 3rd to 4th gear shift throw went from 5" to 3 1/2", or a 30% reduction (the kit has a choice of 10%, 20% or 30% reduction, and I set it to 30%). Neutral moved forward 1/4".

The following shows stock on top and B&M on the bottom. The reduction in 3rd is greater than the pictures show, because neutral with the B&M is moved forward about 1/4".

Edited July 25, 2004 by Poursha

[Tool Pants]

So far the winner is the lowly 2.7 Boxster 5 speed. :P

With the B&M the first to second throw was reduced by 38.3%. Third to fourth by 46.4%. What is unique is that the reduction is not the same for both measure throws, but then as you can see the oem throws did not match either. It is on the 6 speed 996s I have measured.

[threeOh]

Great topic and a great short shift. I can't comment on reduction as I had the B&M installed before I picked up the car but its a lovely product -- after it loosens up a bit.