Tony D Posted December 22, 2012 Share Posted December 22, 2012 Why does he TPS HAVE to be throttle-body mounted? Putting it on the crossbar is just as effective... For that matter, you could put it ANYWHERE you got a decent movement with enough degrees of resolution...provided you don't make a sloppy linkage arrangement... Quote Link to comment Share on other sites More sharing options...
nash542001 Posted December 22, 2012 Share Posted December 22, 2012 If you are using megasquirt then you could use a tps from a kia. I think it fits the shaft of the nissan throttle body, can't remember if I modified it any, but you would have to design a mounting plate becuase the mounting holes are not the same. I used one like this http://www.ebay.com/itm/Standard-Motor-Products-TH366-Throttle-Position-Sensor-/230900711053?pt=Motors_Car_Truck_Parts_Accessories&fits=Make%3AKia&hash=item35c2c13e8d&vxp=mtr. Has worked fine for 2 years now. Quote Link to comment Share on other sites More sharing options...
Snailed Posted December 22, 2012 Share Posted December 22, 2012 Why does he TPS HAVE to be throttle-body mounted? Putting it on the crossbar is just as effective... For that matter, you could put it ANYWHERE you got a decent movement with enough degrees of resolution...provided you don't make a sloppy linkage arrangement... You're right, it doesn't. I have put cable actuated, modified GM TPSs under the dash on cars with electronically controlled transmissions that were still running carbs. This was primarily for cosmetic reasons but the resolution was excellent and the functionality was very good and it could be adapted to virtually any car. 1 Quote Link to comment Share on other sites More sharing options...
Xnke Posted December 23, 2012 Author Share Posted December 23, 2012 Because I want a THROTTLE position sensor...not a foot position sensor. For me, it's a distinction. If I could flip the throttle shaft and the TPS 180*, then the problem is obviated and I can move on. I'll experiment with that tomarrow. Quote Link to comment Share on other sites More sharing options...
Tony D Posted December 23, 2012 Share Posted December 23, 2012 There is no distinction. The position of the sensor is irrelevant if the linkage is properly designed. "The lines are our friends, stay within the lines..." Quote Link to comment Share on other sites More sharing options...
Xnke Posted December 24, 2012 Author Share Posted December 24, 2012 Meh. It's going on the throttle shaft, which is where I believe it belongs. The bigger worry right now is the PCV subsystem. It needs a decently large amount of airflow compared to say, the compressor bypass valve actuator. it is NOT a good idea to share the port with the brake booster...gasoline and oil vapors slowly deteriorate the diaphragm and I don't want to buy another one of those anytime soon. I wonder how it's done on a triple carb manifold? I have a balance tube setup already; but I would imagine that the oil vapor pulled through the PCV system would tend to be distributed unevenly in such a setup. Once the PCV subsystem is figured out, Idle control will be handled via a separate block, connected to the manifold via the vacuum log. The jig is being made to allow the injector bungs to be properly fitted to the manifold, properly being construed as "these 3/4" aluminium bosses fit this gnawed out hole in the runner, and point down the intake with minimal direct contact with the port walls." I'm led to believe that port wall contact is to be avoided for the main part of the spray, the better method being to allow as much misting to take place as possible *before* the stream/spray impinges on the floor or wall of the port, but at the same time directly avoiding contact with the back of the intake valve. The reasoning for avoiding the valve is that the intake valve runs hotter than the port wall, but even the port wall, heated by engine coolant, should be hot enough to vaporize the fuel. The hotter intake valve may at times get TOO hot, allowing partial burning of the fuel instead of vaporizing it first. Similar to how heating milk on a stove works...too much heat, too fast, tends to turn the milk....but a warm, controlled heat won't do it, even when the final temperature is the same between the two methods. This seems like a likely explanation of intake valve crud. Quote Link to comment Share on other sites More sharing options...
Xnke Posted January 9, 2013 Author Share Posted January 9, 2013 I have found a TPS! The unit from a 2002 Chevy Cavalier will fit the D-shaft output, rotates the correct direction, and has a common, weatherproof connector. And it's 32$ for a new one. It is clocked nearly 180* from the nissan unit, but not quite. I will have to make an adaptor/spacer plate to fit it but it should serve the purpose quite nicely. Quote Link to comment Share on other sites More sharing options...
Xnke Posted January 10, 2013 Author Share Posted January 10, 2013 So I got the counterbore made this evening, hardened and sharpened up. It's an old-style D-bit reamer, with a pilot on it. I use these things all the time in my gunsmithing stuff. Got the injector bungs counterbored and test-fitted the lower injector seals. More on the TPS sensor this weekend, when I get it fitted up. Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 10, 2013 Share Posted January 10, 2013 Tests at Ford showed aiming the injectors in the mouth of the barrel at a 5 degree angle off dead Center allowing a consistent impingement upon the wall for a consistent Tau layer provided the best throttle response, turn ability, and horsepower. Down the Center was almost impossible to tune. Wetting the wall to stabilise Tau made conventional fuelling easier. Much experimentation was done to arrive t hat point. Each engine is different, one of the few generalities Cosworth was lucky to dispel was that you somehow lose power wetting a runner wall, on the contrary they found that the wetting added capacitance to the AFR allowing easier tuning. How much to wet is the item that takes experimentation. SK Triples had e TPS on the upper shaft (no mounts the ITB'S Body to allow closer spacing)--last mounting tower was taped to accept TPS, end if shaft was a "D" configuration, just like the TPS on a Z! Quote Link to comment Share on other sites More sharing options...
Xnke Posted January 11, 2013 Author Share Posted January 11, 2013 A simple flip of the angle gauge means that the injectors don't miss the port walls as I intended, but instead impinge on the port floor, about middle of the short turn radius, biased to the side closest to the adjacent exhaust port. Lucky mistake, I guess. The view down the injector ports shows the port floor to intersect the flow path about centerline, and then what misses the floor would be hitting the back of the intake valve. We'll see how it works. The GM TPS might be useful for a VW too, I think the EFI throttles use the same 8mm D shaft? In any case, the Cavalier unit is much more compact than the comparable Nissan or Bosch units. It's also got an O-ring seal, to keep water out of the potentiometer housing, so no more wet TPS problems. (I still don't see it as a real problem, unless you're powerwashing your engine or something.) I'm pondering having the finished product powder coated satin black, but I'm worried about how well the powdercoat will adhere to the aluminum. I think at a minimum a phosphoric acid etch would be required, but I'll have to do some research. Quote Link to comment Share on other sites More sharing options...
Xnke Posted February 26, 2013 Author Share Posted February 26, 2013 Here's tonight's work, starting to get vacuum lines routed. Need to drill and tap this cylinder head for external cooling lines, and get them pretty close to the same locations as the ports on my currently installed cylinder head. I'll need to find another 240Z thermostat housing as well, or just machine a billet one. (I am very, VERY tempted...would mean no more weeping adaptors for coolant temp sensors!) The fuel pressure regulator housing is available as a stand-alone unit, if anyone is interested. 2.5, 3.0, 3.5, 3.8, 4.0, 4.5, 5.0 bar regulators are available, as well. They all fit the same housing, and can be changed out with the click of a snap ring.The Whole Shebang:'Cept for these rubber lines, the fittings are all installed where I need them, except the MAP line for the Megasquirt.Here's where those lines that wrap around the back of the head go...compressor bypass actuator control lines. Quote Link to comment Share on other sites More sharing options...
madkaw Posted February 26, 2013 Share Posted February 26, 2013 Just curious of what the measured volume of your plenum is-it seems big! very nice work Quote Link to comment Share on other sites More sharing options...
Xnke Posted February 26, 2013 Author Share Posted February 26, 2013 The plenum is a little under 6 liters, total. I sized it based on industrial roots blower plenums that feed reciprocating booster compressors, best I could figure. it just happened that the plenum material was very close in size to what the formula from one if my 1970s textbooks popped out, and I only had to trim the internal volume a little to match up convenience and the mathmatics. Quote Link to comment Share on other sites More sharing options...
Tony D Posted February 27, 2013 Share Posted February 27, 2013 Powder oat on Aluminium usually has a profile achieved by media blasting, and typical mild acid washing rinse before operation. Every Aluminum Alloy Wheel out there nowadays it seems is powdercoated. Just about anyplace can do it. I've always been partial to wrinkle-paint. Quote Link to comment Share on other sites More sharing options...
madkaw Posted February 27, 2013 Share Posted February 27, 2013 Okay, I have read( which means nothing) that the plenum should be 50%-70% of engine displacement. Quote Link to comment Share on other sites More sharing options...
Xnke Posted February 27, 2013 Author Share Posted February 27, 2013 I looked at it two ways, the first was to treat it like ITB's...the plenum is so large as to be practically infinite from a pressure view. Then I looked at it as an industrial compressor setup, which also suggested a largeish plenum volume. The downside would be fill time, but that's not an issue at all with a positive displacement blower working at 95% VE. (M62 hits 80% by 4000 shaft RPM, 95% by 10,000RPM, and is back down to 80% by 16,000RPM.) The downside to these nice VE numbers is the temperature and thus density of the air...by volume, the roots blower is damned efficient, but by mass...not so much. When I take the manifold into the shop to get decked, I will probably have it bead blasted, then phosphoric acid etched prior to whatever coating I choose. I'm on a deadline, I want to make it to Branson Z Fest this year with the intake and the supercharger installed and tuned! That's a 10.5 hour drive, although I'll make the drive N/A and put the charge pipe and supercharger belt back on once I get there, if the gas milage just isn't there at cruise RPM. Quote Link to comment Share on other sites More sharing options...
Xnke Posted March 1, 2013 Author Share Posted March 1, 2013 Tony, you read my mind. I am thinking more and more that I want a black wrinkle baked-on paint finish, which is still paint but its as tough as powdercoat. I *think* I have enough of that stuff left. Quote Link to comment Share on other sites More sharing options...
Xnke Posted March 5, 2013 Author Share Posted March 5, 2013 Got the fuel rail complete and pressure tested this evening. Complete failure...the reamer used to finish the injector bores cut a perfectly consistant 11.25mm bore...which is NOT enough of a crush fit to seal the injectors. The rail will be bored and have sleeves pressed into place to save it, since I have an integrated fuel pressure regulator on the rail. It's either that, or trade this set of six DSM 450CC injectors for some 42lb 14mm injectors. Quote Link to comment Share on other sites More sharing options...
yellowoctupus Posted March 5, 2013 Share Posted March 5, 2013 What is the injector 'inner' diameter where the o-ring seats? Quote Link to comment Share on other sites More sharing options...
Xnke Posted March 9, 2013 Author Share Posted March 9, 2013 The correct ID for the holes is 10.90mm. 10.75mm is *just* too small. New fuel rail stock showed up today, so I'll just make another rail. Quote Link to comment Share on other sites More sharing options...
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