s14unimog
01-20-2013, 09:21 PM
This issue has plagued my setup for years. I've broken more than 3 S13 OE throttle bodies and trashed one motor from it (see THIS (http://zilvia.net/f/tech-talk/358062-snapped-another-throttle-body-sr20det-pics.html) thread for more details on that). I've asked numerous people about it and for what ever reason, they have not experienced these issues, don't care enough to look into it, or arbitrarily throw out the statement, "you need an upgraded throttle body." Either the case, I'm not here to argue that. I'm here to present my solution.
Now, if you read back in the thread I've linked above, you can tell my setup is no different than most. I installed a Greddy type manifold, picked up an s14 pulley and made a little bracket for the cable. In theory, it looks like a great setup. The S14 pulley clocks the pull point perfectly, the offset works great for the mounting points on the manifold and the OE throttle cable requires no modification; what's to change? Welp.... come to find out, it doesn't work all that well. To put it simply, the s14 pulley lends too much leverage on the center shaft, considering its offset, and despite any best efforts to adjust the cable, you cannot remove the side pull force it puts on the shaft. In short order, the center shaft will break across the screw hole closest to the pulley, the screw will dislodge and your #4 will promptly eat it. I've actually gone so far to machine out a stop for the pedal on the floorboard. No luck.
http://img.photobucket.com/albums/v721/s14unimog/ECA75C46-7058-40B8-8156-99934123A48B-846-00000156704AAA57.jpg
So... What to do? How about this....
http://img.photobucket.com/albums/v721/s14unimog/ThrottleBodyBracket9.jpg
http://img.photobucket.com/albums/v721/s14unimog/ThrottleBodyBracket8.jpg
http://img.photobucket.com/albums/v721/s14unimog/ThrottleBodyBracket7.jpg
http://img.photobucket.com/albums/v721/s14unimog/ThrottleBodyBracket1.jpg
Finally fed up with replacing these damn things, I came up with this. It's a 1/4" piece of 6061 aluminum that is sandwiched between the throttle body and the manifold. I positioned a base point for the cable at the same offset as the pulley and its location ensures a direct line of pull. Also. because it would require a second TB gasket, I designed in machined o-ring glads for sealing each side.
Now.... The point to this thread. Do some of you, in the Zilvia community, want to buy one of these? I will include the part and only the two o-rings - nothing else.
The catch - you have to be competent enough to modify the threaded portion of your throttle cable. You'll need to remove approximately 3/8"-1/2" of threaded portion, without damaging your cable. This means cutting completely around the aluminum threads and then splitting that little piece in half to remove it from around the cable. The hardware is the next part. Because of the part size, you really need longer bolts. For now, I've removed the lock washers for the factory hardware and am using that. Once those are removed, it leaves you with about 5/16" of grip. Enough to hold everything, but you should use caution torquing them down. That's not a lot of thread grip. I plan to get longer hardware for mine through Fastenal. You do what you want.
How much? Not sure yet. I've contracted a local machine shop to produce the part and he's working on pricing. Likely to be around $60-70.
Too much? Don't care. I honestly don't care if a single one of you want the part. The deal is this. I'm an engineer by profession. When my car has a problem, I fix it; simple. This is an extension to those who cannot build such a part. There isn't anything on the market and if I don't get at least 10-20 interested, I'm going to archive it along with my other designs. I only need the one on my car and that one is done.
Thoughts?
Now, if you read back in the thread I've linked above, you can tell my setup is no different than most. I installed a Greddy type manifold, picked up an s14 pulley and made a little bracket for the cable. In theory, it looks like a great setup. The S14 pulley clocks the pull point perfectly, the offset works great for the mounting points on the manifold and the OE throttle cable requires no modification; what's to change? Welp.... come to find out, it doesn't work all that well. To put it simply, the s14 pulley lends too much leverage on the center shaft, considering its offset, and despite any best efforts to adjust the cable, you cannot remove the side pull force it puts on the shaft. In short order, the center shaft will break across the screw hole closest to the pulley, the screw will dislodge and your #4 will promptly eat it. I've actually gone so far to machine out a stop for the pedal on the floorboard. No luck.
http://img.photobucket.com/albums/v721/s14unimog/ECA75C46-7058-40B8-8156-99934123A48B-846-00000156704AAA57.jpg
So... What to do? How about this....
http://img.photobucket.com/albums/v721/s14unimog/ThrottleBodyBracket9.jpg
http://img.photobucket.com/albums/v721/s14unimog/ThrottleBodyBracket8.jpg
http://img.photobucket.com/albums/v721/s14unimog/ThrottleBodyBracket7.jpg
http://img.photobucket.com/albums/v721/s14unimog/ThrottleBodyBracket1.jpg
Finally fed up with replacing these damn things, I came up with this. It's a 1/4" piece of 6061 aluminum that is sandwiched between the throttle body and the manifold. I positioned a base point for the cable at the same offset as the pulley and its location ensures a direct line of pull. Also. because it would require a second TB gasket, I designed in machined o-ring glads for sealing each side.
Now.... The point to this thread. Do some of you, in the Zilvia community, want to buy one of these? I will include the part and only the two o-rings - nothing else.
The catch - you have to be competent enough to modify the threaded portion of your throttle cable. You'll need to remove approximately 3/8"-1/2" of threaded portion, without damaging your cable. This means cutting completely around the aluminum threads and then splitting that little piece in half to remove it from around the cable. The hardware is the next part. Because of the part size, you really need longer bolts. For now, I've removed the lock washers for the factory hardware and am using that. Once those are removed, it leaves you with about 5/16" of grip. Enough to hold everything, but you should use caution torquing them down. That's not a lot of thread grip. I plan to get longer hardware for mine through Fastenal. You do what you want.
How much? Not sure yet. I've contracted a local machine shop to produce the part and he's working on pricing. Likely to be around $60-70.
Too much? Don't care. I honestly don't care if a single one of you want the part. The deal is this. I'm an engineer by profession. When my car has a problem, I fix it; simple. This is an extension to those who cannot build such a part. There isn't anything on the market and if I don't get at least 10-20 interested, I'm going to archive it along with my other designs. I only need the one on my car and that one is done.
Thoughts?