Zetsaz Posted November 4, 2015 Share Posted November 4, 2015 This head in an N/A build sounds like a party waiting to happen. Turbos are fun, but so is more immediate throttle response Quote Link to comment Share on other sites More sharing options...
softopz Posted November 5, 2015 Share Posted November 5, 2015 I know we cant talk tranny here but how about 3d casting your own bell housing no machine work to be done on bellhosuing (not thats a big deal for you) or no spacer/adapter required. Quote Link to comment Share on other sites More sharing options...
Derek Posted November 5, 2015 Author Share Posted November 5, 2015 3D sand is still foundry sand so the finish is rough. Even printed metal needs some post print machining. Printed sand is still very expensive, so unless you're only going to use one it doesn't make sense in this application. Quote Link to comment Share on other sites More sharing options...
kiwi303 Posted November 6, 2015 Share Posted November 6, 2015 Printed plastic comes out pretty smooth these days, why not print in plastic and use that as a male mould to pour a female refractory cement casting die? Quote Link to comment Share on other sites More sharing options...
Derek Posted November 6, 2015 Author Share Posted November 6, 2015 There are a few things to remember. molten metals shrinks when it cools. Overall shrinkage is controlled with pattern scaling. Solidification shrinkage is controlled with feed risers. The face between the transmission and bell housing is the thickest portion. There are usually multiple feed risers on that face to supply molten metal to that area as it cools. Those risers and surface have to be machined. There are a myriad of reasons what refractory cement wouldn't be practical in this application. Until there is resin 3D printing with the strength of aluminum I'm afraid you're stuck with guy's like me for a while:) Quote Link to comment Share on other sites More sharing options...
socorob Posted November 6, 2015 Share Posted November 6, 2015 How strong are the aluminum 3d prints? Would that be sufficiently strong enough for a bellhousing? Quote Link to comment Share on other sites More sharing options...
Derek Posted November 6, 2015 Author Share Posted November 6, 2015 How strong are the aluminum 3d prints? Would that be sufficiently strong enough for a bellhousing? The technology just isn't there yet. Do a minor amount of google searching and you will see that even the print envelopes are too small. Plus they all need post machining. And it's still crazy expensive. Quote Link to comment Share on other sites More sharing options...
TimZ Posted November 6, 2015 Share Posted November 6, 2015 Until there is resin 3D printing with the strength of aluminum I'm afraid you're stuck with guy's like me for a while:) Well, that doesn't sound so bad... Quote Link to comment Share on other sites More sharing options...
Xnke Posted November 6, 2015 Share Posted November 6, 2015 I think machining existing large A/R T3 housings would work. No need to do a new casting. Quote Link to comment Share on other sites More sharing options...
Xnke Posted November 6, 2015 Share Posted November 6, 2015 I think people are confusing 3d printed sand molds with actual direct printed parts. This is a traditionally poured sand casting, with the actual moulding sand having been 3d printed. Not to mention that the 3d printed metal doesn't have the density of a casting, let alone a wrought part. Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 7, 2015 Share Posted November 7, 2015 This head in an N/A build sounds like a party waiting to happen. Turbos are fun, but so is more immediate throttle response You like camshaft lag? Give me a Turbo any day for immediate throttle response! Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 7, 2015 Share Posted November 7, 2015 I think machining existing large A/R T3 housings would work. No need to do a new casting. But I don't think we need a large A/R necessarily. I've seen a lot of guys give up a lot of bottom end going with a Big A/R because they thought they needed it...then shift at 7,200! Argh... You get the right wheel cut, that AR will move air into the head. You may not make much boost....but go do a pressure-flow test on that runner flowing 310 CFM at -13.5 psi and see what kind of flow it takes passing through it to get up to +3psi even. I think some slip issues will start occurring with the turbine wheel not able to drive the compressor section at lower speeds. Which will be sad.... and THAT is where the VNT comes into play! Quote Link to comment Share on other sites More sharing options...
socorob Posted November 7, 2015 Share Posted November 7, 2015 When I was still building my car a guy stopped by to see it and he did 3d aluminum printing. The company he worked for made parts for nasa. He said the stuff they mainly made using the 3d printing was too intricate to machine and casting wasn't strong enough to use for the parts. Quote Link to comment Share on other sites More sharing options...
budgy Posted November 7, 2015 Share Posted November 7, 2015 (edited) But I don't think we need a large A/R necessarily. I've seen a lot of guys give up a lot of bottom end going with a Big A/R because they thought they needed it...then shift at 7,200! Argh... You get the right wheel cut, that AR will move air into the head. You may not make much boost....but go do a pressure-flow test on that runner flowing 310 CFM at -13.5 psi and see what kind of flow it takes passing through it to get up to +3psi even. I think some slip issues will start occurring with the turbine wheel not able to drive the compressor section at lower speeds. Which will be sad.... and THAT is where the VNT comes into play! Perfect example of why so many efficient engines simply do not need a lot of 'boost'...high PSI levels is not exactly 'good' if it isn't required, its simply a measurement of restriction and not flow. Tony I hate to ask in this thread but regarding the bottom end of your typical stroker L28 is there any real reason why the bottom end cannot be reliably taken to 8500 RPM other than crankshaft vibrations? I know its simply good insurance to get a really good dampener like an ATI, I am just curious why very few people run a stroker crank past say 6.5~7K is it the valve train set up in the factory head that simply has a hard time keeping up? I mean I know most people don't go past there with a mild camshaft because it simply doesn't produce power past that point, but just curious how reliable the bottom end is. Edited November 7, 2015 by budgy Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 7, 2015 Share Posted November 7, 2015 I am just curious why very few people run a stroker crank past say 6.5~7K is it the valve train set up in the factory head that simply has a hard time keeping up? I mean I know most people don't go past there with a mild camshaft because it simply doesn't produce power past that point, but just curious how reliable the bottom end is. Most people "in the USA"... Quote Link to comment Share on other sites More sharing options...
TimZ Posted November 7, 2015 Share Posted November 7, 2015 Most people "in the USA"... _most_ people in the USA... Quote Link to comment Share on other sites More sharing options...
kiwi303 Posted November 8, 2015 Share Posted November 8, 2015 I am just curious why very few people run a stroker crank past say 6.5~7K is it the valve train set up in the factory head that simply has a hard time keeping up? I mean I know most people don't go past there with a mild camshaft because it simply doesn't produce power past that point, but just curious how reliable the bottom end is. Plenty of L series up to 9000rpm around. It's just not so common in the US because most builders there have the Smallblock V8 mindset where displacement and torque determine power. Lotus would have stifled in the US, and TVR... those countries with a culture of small high revving engines are more likely to go for revs. Ever heard an A12 scream at 12000 revs? That's Hayabusa territory, but has been done with OHC old school fours. Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 8, 2015 Share Posted November 8, 2015 ^^^ In fact, I have. Have you heard an L-Series SIX that high up? Mowhahahaha! Corky Bell did a great disservice to builders trying to convince people you didn't need to do anything but slap a turbo on and bang boost to it. For those who want a 'stock engine power curve' just more of it...that works great. If you are bored by a stock L28ET power delivery peaking at 5,300 and prefer the L24 going on a bit higher, or a cammed smaller L24 that pulled to 7,000 then why not turbo THAT profile cam and keep that same rush up top? It makes for quite a different ride than most (_TZ_) Turbo Z's in the USA which I likened to being in a Big Block Vette. Not the feel I had in my VW's, most DEFINITELY not the feel I got in the Turbo Cars I was in while stationed in Japan. 300HP under boost on a stock L28 cranking 18+ psi, and 300HP under boost at 6psi and 7,500 are two VERY different beasts indeed, needing different gearing and driving style. Quote Link to comment Share on other sites More sharing options...
kiwi303 Posted November 9, 2015 Share Posted November 9, 2015 Highest I've heard an L series 6 was my old Laurel L20A at 6K. It came cammed low, took off at the lights like a scalded cat, but fell flat on its face once it hit 110Km/Hr. Cruised just sweet and would go up the bombay hills without dropping down a gear, but it wasn't set up for spirited driving. Quote Link to comment Share on other sites More sharing options...
fuzzy Posted November 9, 2015 Share Posted November 9, 2015 Signed up fresh today - just for this thread. And pretty much the only one I'll need. I'm no mechanic and actually sat thru all 28 pages in a single 4-hour stretch. I don't think I've learned anything new really (since most of the discussions were greek to a layman like me). Amazing stuff. The sheer perseverance of it. Long story short, I want one of these bad. Bucket list kind of bad. It'll take me a bit to figure how much its gonna cost to get it all running, but I know I want one. I'm hanging on the next post until then. Quote Link to comment Share on other sites More sharing options...
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