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View Full Version : CGI or Aluminum for diesel engine blocks


taskbearer
05-23-2005, 11:43 PM
With diesel engines gaining popularity, at least in europe, which construction material do you guys think would be the best?<p>In the late 90's BMW pioneered CGI( Compacted Graphite Iron) blocks. Which had greater structural strenght than their Cast Iron rivals due to their more closely packed structure, hence require less Iron for similar strenght reducing weight in the process. The resulting 740d engine weighed 275kg(a record in its time). The problem with CGI was it was expensive to machine, but recent breakthroughs in manufacturing processes have reduced costs greatly increase wide acceptance.<p>Meanwhile, in the rival camp mercedes pushed for Aluminum in the S400Cdi. This engine employed a wierd 75degree angle to reinforce the strenght of the block as aluminum was not as strong as CGi, but weighed a respectable 245kg while producing more power than the Bimmer. <p>Gast forward to 2005 and its become an all out strugle for both technologies. The Sintercast¬Ě process has made CGI more affordable, and new aluminum techniques have increased the strength of aluminum.Even the CGI pioneer BMW has switched to aluminum. <p><I>Presently in the CGI camp, we have;</I> <br>Audi 3.0V6 204-233hp 220kg<br>Audi 4.0V8 270hp 270kg<br>Ford/PSA 2.7V6 190-207hp 202kg<br>Fiat 3.0V6 250hp 2??kg<br>...soon hyundai V6<p> <I>in the aluminum camp, we have;</I> <br>BMW 3.0I6 231hp 203kg<br>BMW 4.4V8 300hp 242kg<br>MB 3.0V6 190-224hp 208kg<br>MB 4.0V8 314hp 245kg<br>VW 2.5L I5 170hp ?kg<br>Volvo 2.4L I5 125-185hp 165kg <br>Isuzu 3.0V6 170-180hp ?kg <p>The aluminum engines are 10-30kg lighter than their CGI counterparts, So What do you guys think is better?

Superfresa
05-24-2005, 11:35 AM
CGI Is offering a lot more bennefits nowdays. Just look at Ford/PSA's 2.7 Turbodiesel. I know this doesn't say it all about CGI engines but it shows a lot.

taskbearer
05-25-2005, 12:38 AM
The new Audi 4.2LV8 Tdi weighs just 255kg using CGI. Compared to its aluminum rivals, its 10-13kg heavier, but a whole lot more compact than the others. <br>In terms of packaging, the CGI would win. In terms of weight savings, Aluminum is still ahead. But with sintercast process being less energy consuming than pressure forming aluminum, CGI still has an overall advantage. <p>VW is the only comnpany with expertise in both materials using aluminum for their V10 and inlune 5 and using CGI in the audi modular diesel engine family which includes both V6 and V8. <p>I think the two technologies would level out in the future.

Cozz
05-25-2005, 04:36 AM
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>taskbearer</b> &raquo;</i></TD></TR><TR><TD CLASS="quote"><br>VW is the only comnpany with expertise in both materials using aluminum for their V10 and inlune 5 and using CGI in the audi modular diesel engine family which includes both V6 and V8. <br></TD></TR></TABLE><p>I beg to differ. Many companies try both. MB and BMW have labs to test out what is better. BMW opened a place in CA to test out metal materials. This is what they do all day long and now produces blocks for F1. Same thing with MB but in England.<p>Aluminum is the best material for wieght but something not yet mentioned...heat. Aluminum can throw off heat better than most man-made alloys.<p>The aluminum blocks doesn't see as much stress as one would think. These motors uses hardened sleeves in the chambers.

Verdegrrl
05-25-2005, 09:38 AM
VAG GmbH and FIAT spa are generally ackowledged as the leaders in European diesel technology. Fiat for it's ground breaking common rail technology, and VAG for drivability. Fiat was building diesels 90 years ago.<p> <A HREF="http://www.powertechengines.com/" TARGET="_blank">http://www.powertechengines.com/</A> <p>People often forget that VW/Audi was the first to offer civilized diesel cars for the masses (Mercedes did the same for the upscale market). The 3.0 diesel coming to North America in a bit over a year, is a highly regarded engine that has won many awards and is considered the enthusiast's choice among sporting diesels.<p> <A HREF="http://www.germancarfans.com/news.cfm/newsid/2040617.001/audi/1.html" TARGET="_blank">http://www.germancarfans.com/n....html</A> <p>In any case, this thread should probably look closely at what those companies are doing, and then contrast them to newcomers and alternative ideas.

taskbearer
05-25-2005, 10:43 AM
Thanks Cozz for mentioning that wonderful property of aluminum. <br>Audi had to reduce compression ratio to 16.1:1 to achieve their record braking horsepower, compared to BMW and MB with 17.1:1. I think the aluminum had a lot to do with that.<p>Nontheless CGI blocks have a higher torque back-up than aluminum well except for VW V10 which is actually ahybrid block using aluminum for two banks of cylinders bolted to a cast iron tunnel. CGIs still have a cost advantage.<p>Let me not fail to mention smaller engines such as PSA's 1.4 and 1.6L inline fours which weigh both 95kg and 120kg respectively thats a whole lot lighter than fiats 130kg cast iron block 1.3multijet.<p> <br>

taskbearer
05-25-2005, 10:52 AM
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>Verdegrrl</b> &raquo;</i></TD></TR><TR><TD CLASS="quote"><p>In any case, this thread should probably look closely at what those companies are doing, and then contrast them to newcomers and alternative ideas.</TD></TR></TABLE><p>Verdegrrl, thats a good suggestion, but the original intension of the thread was to guage peoples perspectives on what diesel construction material was better, albiet with good reasons. A comparison among different companies diesel program would be for another thread.

Verdegrrl
05-26-2005, 11:59 AM
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>taskbearer</b> &raquo;</i></TD></TR><TR><TD CLASS="quote"><p>Verdegrrl, thats a good suggestion, but the original intension of the thread was to guage peoples perspectives on what diesel construction material was better, albiet with good reasons. A comparison among different companies diesel program would be for another thread.</TD></TR></TABLE><p>I guess what I'm saying is that some companies have a longer history of building diesel engines, and that greater development could either assist in future programs or cause them to put on blinders to new technology. <p>Given the stress a diesel block must take during combustion and that many people expect greater longivity from a diesel engine, my bets are with cast iron.

taskbearer
05-27-2005, 09:39 AM
Interesting, but considering the move towards weight reduction in diesel engines that most companies only have choices between CGI and Aluminum? <p>IMO cast iron would produce a block that is substancially heavier than with the other two technologies. I seem to have observed that companies have stuck to cast iron for smaller engines except PSA, Renault, and Honda who use aluminum. But for bigger engines the cost of shifting to weight saving construction material is justified.<p>What I'm trying to say is you'd likely never see the use of Cast Iron in big engines again, but Iit would still have some presence in smaller engines.

ritmo
05-27-2005, 03:49 PM
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>taskbearer</b> &raquo;</i></TD></TR><TR><TD CLASS="quote"><I>Presently in the CGI camp, we have;</I> <br>(...)<br>Fiat 3.0V6 250hp 2??kg</TD></TR></TABLE><p>Is this the new, forthcoming Fiat-VM diesel-V6?

taskbearer
05-28-2005, 12:16 AM
yes thats it. Don't have too much specs about it yet.