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Full Version: Show me your non-stock -6 accelerator linkage please
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sww914
I think that the -6 factory accel linkage is overly complicated. From the pedal, it goes through a rod, and arm, a cable, back to a bellcrank, up another rod, to another bellcrank, another rod, the crossbar, one more rod on either side and THEN to the carb arms. I can't understand why Porsche did it this way unless it was just so that it would resemble the 911 setup. I'm not one who questions everything that Porsche ever created, I'm not a wheel re-inventer, but I'm not a purist either.
It seems to me that every extra link and every extra rod adds a bit of friction and another potential failure point. I remember seeing Drew365 get sent home from Buttonwillow for the weekend on Saturday morning because the bellcrank shaft that screws into the side of the intermediate plate broke off. It seems to me that a cable gracefully arced around the side/back of the engine to a bracket to hold the sheath and a ball socket to clip on to the crossbar ball would be a lot cheaper, simpler, smoother, and more reliable.
In the interest of not re-re-inventing the wheel, I'd love to see what you guys have come up with.
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Porcharu
I don't have a picture to share but I have a thought to share.
German engineers LOVE complex linkages. Want proof? Look at a 1980 VW Rabbit shift linkage, now look at a 1980 Honda Civic shift linkage. The VW has multiple bell cranks, several pivots, lots of adjustments - lousy shifting car (I had one and I loved the car.) The Honda has ONE rod and one simple pivot joint, nothing else - the car shifts like a hot knife in butter (I had one those too - it ended up being the first Integra engine into Civic swap in the US - I think.)
Anything that takes out 'crap' in a linkage is a good thing. I do muscle cars too and any time I have installed a hydro clutch linkage in place of a mess of bellcranks and links everything works much better.
Just my $0.02
Steve
SirAndy
i got my accel cable from Patrick Motor Sports ...

one side fits the 914 pedal cluster, the other end fits the 3.6L throttle body.
no linkage needed, it goes straight to the throttle body.

it's actually a very clean install and so far, it has been working great!
bye1.gif Andy

sww914
Thanks for the arrows Andy. Is that like a Morse cable? They're boat cables that have a strong rod going into the sheath at either end so they can push and pull.
SirAndy
QUOTE(sww914 @ Feb 5 2008, 10:26 PM) *

Thanks for the arrows Andy. Is that like a Morse cable? They're boat cables that have a strong rod going into the sheath at either end so they can push and pull.


nope, real cable all the way. but it has heavy duty double shielding on the motor end to keep the cable insulated ...

shades.gif Andy


PS: i just looked at the PMS website and they don't list the cable anymore ... confused24.gif
they do list a "conversion" cable now, but it has the hookup to the bellcrank ?!?
SirAndy
sorry, i lied ... biggrin.gif


here it is "THROTTLE CABLE KIT - PORSCHE 964 / 993 3.6L DME ENGINE CONVERSION":

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rick 918-S
Not a 6 but heres mine. I tried the cable thing but had too much drag. It caused the throttle to stick and I could only get 3/4 throttle from the cable without a major change to the linkage anyway. I ended up with ball bearing bell crank and rod ends. The advantage is I still have the stock 4 cyl. cable. If it breaks (as they have been know to do on occasion) I can get a cable quickly.

Not the best photo.
davep
I think there may be one advantage of at least one bell-crank and that would be to vary the ratio of the pedal movement to the throttle movement. Pushing on the pedal changes the length of the cable at the throttle end. If the full pedal throw change does not change the throttle from fully closed to fully open, then the ratio has to be changed to accomplish this. This is possibly why Rick could only get 3/4 throttle opening. Other than that, using the KISS principle has great advantages. If you have had a chance to look at original linkage parts you can spot several areas of wear that can cause significant problems over time.
PRS914-6
Mine is like Andy's but done slightly different. I used a 993 outer throttle cable and made my own inner cable. The inner cable can be had at most motorcycle shops. While similar to Patrick's my inner cable is one piece and not spliced together.

The throttle pedal end of inner cable uses a 5mm bolt with a hole drilled in it and silver soldered to the cable to attach the ball joint. The engine side uses the 993 barrel sleeve but is retained with a silver soldered crimp sleeve (used for metal leader line for fishing). I used a little brass tubing to protect the cable but it's really not needed.

The throttle action with the 993 engine is very long so I cut off the ball end at the pedal assembly and re-welded it on a little higher to speed the action up. Still a little long winded but works pretty good.
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brant
I don't have my pictures with me (other computer)
but there are decent pictures of my non stock arraingement in my race car thread
(linked in my posts)

its also a 4 cylinder cable with a home made bell crank
probably 20$ worth of parts if you weld (or braze and MIG and TIG) it together on your own.

brant
John
Carbs or fuel injection?

I have made (2) of these so far (for 3.2 engines) and they both work smoothly and flawlessly. One has been in service for the last 16 years. (Maybe I should change that cable.....) It does use a stock 4-cyl cable.
Mugs914
CIS 3.0... Uses stock four banger cable.

I don't see any reason to use the /6 style bellcrank and pushrod system unless you are doing an original six or a clone (or if you just like that system). Direct cable is much easier and, I think, more reliable.
T H O M A S
overkill?did this on the aubergine car ,uses -4 cable
Ferg
From my old 3.2 conversion

Ferg
and the bracket

MoveQik
My 3.2. It's a Rich Johnson unit.

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SirAndy
QUOTE(PRS914-6 @ Feb 6 2008, 06:58 AM) *

While similar to Patrick's my inner cable is one piece and not spliced together.


just to be clear, only the very first cables from PMS were spliced. they have not been spliced for quite a while and my cable is of the newer kind.
one piece.
shades.gif Andy
PRS914-6
QUOTE(SirAndy @ Feb 6 2008, 12:40 PM) *

QUOTE(PRS914-6 @ Feb 6 2008, 06:58 AM) *

While similar to Patrick's my inner cable is one piece and not spliced together.


just to be clear, only the very first cables from PMS were spliced. they have not been spliced for quite a while and my cable is of the newer kind.
one piece.
shades.gif Andy


That's good. I bought one not that long ago and it was spliced. The crimp sleeve they used would catch on my clutch clevis. Didn't care for that much and made a new one. Look at the picture and you can see the splice in the circle.

Andy, look at the arrow. Is yours straight or bent?
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SirAndy
QUOTE(PRS914-6 @ Feb 6 2008, 01:48 PM) *

Andy, look at the arrow. Is yours straight or bent?


it came bent ...

but the bend was not the right angle because of the way i routed my throttle cable, so i had to reshape it just a tiny bit ...
bye1.gif Andy

PS: yes, i see the splice. mine is one piece. for the price of that cable, he better not be selling the spliced ones anymore ...
Bee Jay
I just did this with my six conversion that I'm working on. First I ordered a 17" longer than stock throttle cabel with 914-6 threaded ends from Terry Cable. Then I built this aluminum bracket. Works good and I get full throttle.
Bee Jay
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Bee Jay
While testing for full throttle I saw the bracket flex a little, so I beefed it up with this brace.
Bee Jay
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