Problems w/ over 30% reduction short shift ...explanation?
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Joined: May 2001
Posts: 70
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From: San Jose, CA
Where's DJ996? He's the one who raised this whole issue when he posted the following statement in another thread:
"Also keep in mind the B&M reduces shift throw by 30%, about the same as the GT3RS racing shifters at 33%. Porsche feels any more reduction is hard on the transmission."
Hey DJ, can you please clarify? Or Loren, how about you?
Inquiring minds want to know! (Especially since I am also considering a short shift kit.)
I think I'm leaning towards Alon's idea that you need a little 'play' when your syncros and gears are coming together.
"Also keep in mind the B&M reduces shift throw by 30%, about the same as the GT3RS racing shifters at 33%. Porsche feels any more reduction is hard on the transmission."
Hey DJ, can you please clarify? Or Loren, how about you?
Inquiring minds want to know! (Especially since I am also considering a short shift kit.)
I think I'm leaning towards Alon's idea that you need a little 'play' when your syncros and gears are coming together.
Three Wheelin'
Joined: Aug 2002
Posts: 1,962
Likes: 1
From: Toronto, Ontario
I'm sure that you haven't offended any S2000 owners since most of them know that one of the weakest links on that car happens to be the transmission (and that horrible gauge cluster). Anyhow, I agree that the RUF felt much more factory like versus the B&M which required a lot more effort to shift. I guess that most people are quite happy with their B&Ms but i wouldn't trade my RUF for it. That being said, I'm sure that if you went back to stock, you'd feel a bit of a difference in terms of shift effort no matter how small it would be.
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Joined: Jan 2003
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From: Los Altos, CA
Another thread in the past referred to the potential for faster shifts being the cause for a limit on the amount of throw reduction. Going the same linear speed on the short vs the standard shifter (human side) results in the actuator side (bottom part pushing the cable) going faster by the ratio of the lengths. There just seems to be greater potential for "mashing" or missing. I believe the speed argument.
Regarding design, the short shifter does not have a longer throw on the cables. Cables move the same amount. What is different is the pivot point. If you put the normal and short shifter (B&M) side-by-side, you'll notice the pivot point of the B&M is higher relative to the two bearings coming out the fore and aft ends.
Awesome shifter but I suppose you CAN get similar results by chopping the stock shift lever!
Andy
Regarding design, the short shifter does not have a longer throw on the cables. Cables move the same amount. What is different is the pivot point. If you put the normal and short shifter (B&M) side-by-side, you'll notice the pivot point of the B&M is higher relative to the two bearings coming out the fore and aft ends.
Awesome shifter but I suppose you CAN get similar results by chopping the stock shift lever!
Andy
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Joined: Feb 2003
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From: Westhampton Beach, N.Y.
Not yet... <img border="0" title="" alt="[Wink]" src="wink.gif" />
Just spoke with a friend of mine who is very technical.
He is 98% sure that the "beating the synchros theory" is correct.
I really wanted to try out the IMEC shifter to try something different but since it's 40% reduction I think I'll stick with the B&M.
Just spoke with a friend of mine who is very technical.
He is 98% sure that the "beating the synchros theory" is correct.
I really wanted to try out the IMEC shifter to try something different but since it's 40% reduction I think I'll stick with the B&M.
Drifting
Joined: Jun 2001
Posts: 3,199
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From: Houston, Texas
Sorry, I'm not the original source on that info, bobC4S originally posted it back on 5/23/03:
"I went with the B&M short ****er because
B&M shortens 30 % and you do not have to do anything to the cables except reconnect them.
Porsche uses a 33% shorter shifter on GT3Cup cars
Porsche feels anymore then that puts excess load pressures on engagement of internal shifter shaft pins & gear fork pins. I got mine from Bobby at Foreign Affiars if you tell him your from Rennlist he only charges you $ 199.00"
If you talk to drivers of GT3RS / Cup cars at the track they will tell you it has a short shifter similar in throws to the B%M. Actually as a point of fact, the EVO short shift withthe needle bearings is the closest to the RS shifter.
"I went with the B&M short ****er because
B&M shortens 30 % and you do not have to do anything to the cables except reconnect them.
Porsche uses a 33% shorter shifter on GT3Cup cars
Porsche feels anymore then that puts excess load pressures on engagement of internal shifter shaft pins & gear fork pins. I got mine from Bobby at Foreign Affiars if you tell him your from Rennlist he only charges you $ 199.00"
If you talk to drivers of GT3RS / Cup cars at the track they will tell you it has a short shifter similar in throws to the B%M. Actually as a point of fact, the EVO short shift withthe needle bearings is the closest to the RS shifter.
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Joined: Feb 2003
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From: Westhampton Beach, N.Y.
Cool...my friend just bought the EVO shifter but hasn't installed it yet so I don't have any first impressions.
So you can change the bearings on the B&M?
What does it come with stock?
So you can change the bearings on the B&M?
What does it come with stock?
Drifting
Joined: Jun 2001
Posts: 3,199
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From: Houston, Texas
The B&M comes with aluminum/teflon bushings, with an adjustment screw on one bushing, much better than the cheap plastic oem units.
Even better, IMO, are the EVO true needle bearings which are intended for use in the stock shifter. They look exactly like an old universal joint bearing off a driveshaft if you have ever worked on older cars. They require no adjustment screw. I'm going to try them on my B&M shifter to see if they can be used, I'll post results soon. Looking at them, I see no reason they could not be used for this application.
Let us hear how your friend likes the EVO shifter. Maybe the best setup would be a B&M shifter morphed with the EVO bearings.
Even better, IMO, are the EVO true needle bearings which are intended for use in the stock shifter. They look exactly like an old universal joint bearing off a driveshaft if you have ever worked on older cars. They require no adjustment screw. I'm going to try them on my B&M shifter to see if they can be used, I'll post results soon. Looking at them, I see no reason they could not be used for this application.
Let us hear how your friend likes the EVO shifter. Maybe the best setup would be a B&M shifter morphed with the EVO bearings.
RL Technical Advisor
Joined: May 2001
Posts: 11,870
Likes: 75
From: Portland Oregon
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Karl S:
<strong>I guessing on this but could it be that they are concerned that by shortening the shift, you can make the shift more quickly and potentially beat the syncros on a shift, resulting in misaligned gears and damage.
Karl</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Bingo!
Karl hit the issue right on the money. The geometry of these ultra-short shifters moves the transmission internals too quickly. All this does is accelerate wear on the syncro's, operating sleeves, and in some cases, shift forks.
IMHO, this is another case where "Less is More".
<strong>I guessing on this but could it be that they are concerned that by shortening the shift, you can make the shift more quickly and potentially beat the syncros on a shift, resulting in misaligned gears and damage.
Karl</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Bingo!
Karl hit the issue right on the money. The geometry of these ultra-short shifters moves the transmission internals too quickly. All this does is accelerate wear on the syncro's, operating sleeves, and in some cases, shift forks.
IMHO, this is another case where "Less is More".
RL Technical Advisor
Joined: May 2001
Posts: 11,870
Likes: 75
From: Portland Oregon
Hi Doug:
LOL,.....All I am saying is that the short shifters that reduce throw more than Porsche's recommendations will really accelerate wear on the transmission's internals.
Given that Porsche does not sell or offer any pieces for the 996 tranny yet, rebuilding one is not possible and one would simply have to exchange it for a new one. I've not had any opportunity to take one apart yet, but I'd hazard a guess that they are using the same type of soft brass syncros as found in the 993 tranny's and these were not known for longevity.
I think the EVO or B&M ones are OK.
LOL,.....All I am saying is that the short shifters that reduce throw more than Porsche's recommendations will really accelerate wear on the transmission's internals.
Given that Porsche does not sell or offer any pieces for the 996 tranny yet, rebuilding one is not possible and one would simply have to exchange it for a new one. I've not had any opportunity to take one apart yet, but I'd hazard a guess that they are using the same type of soft brass syncros as found in the 993 tranny's and these were not known for longevity.
I think the EVO or B&M ones are OK.
Drifting
Joined: Jun 2001
Posts: 3,199
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From: Houston, Texas
Thanks Steve, your input is always appreciated. What would be a symptom of the synchros/internals not being ready for a shift? For example a couple of times last weekend at TWS coming into turn 2 going from 4th to 3rd,I would rev match and...nothing - like the shifter has hit a wall. Then I try again and it goes right in. Didn't happen every time just a couple of times, I figured my rev matching and shift wasn't just right. Could this be a symptom of the synchros not being "ready"??