Aluminum block questions
04-05-2012, 08:48 AM
#1
Aluminum block questions
How does the Acura TL 3.7L all aluminum block differ from the Audi Alusil (not the BMW Nicasyl) block? Both are hypereutectic aluminum. The Acura has cast in aluminum cylinder liners so I suspect only the cylinder liner is hypereutectic aluminum. Is this the same for the Audi block.
Any and all info or links to search appreciated!
Any and all info or links to search appreciated!
04-05-2012, 09:42 AM
#2
Curious why you want the info.... ?
The high-silicon aluminum liners are new to the 3.7 for the 4G TL. Idea being that they're better on shedding heat, and because of less expansion, piston/cylinder tolerances can be tighter / resulting in a smaller block with a larger bore (less weight, same power).
The crank and rods are forged steel; this generation gets forged aluminum pistons.
I can't speak to the Audi; I've never seen one run for long enough without electrical issues to invest any time in liking them.
The high-silicon aluminum liners are new to the 3.7 for the 4G TL. Idea being that they're better on shedding heat, and because of less expansion, piston/cylinder tolerances can be tighter / resulting in a smaller block with a larger bore (less weight, same power).
The crank and rods are forged steel; this generation gets forged aluminum pistons.
I can't speak to the Audi; I've never seen one run for long enough without electrical issues to invest any time in liking them.
04-05-2012, 10:25 AM
#4
Curious why you want the info.... ?
The high-silicon aluminum liners are new to the 3.7 for the 4G TL. Idea being that they're better on shedding heat, and because of less expansion, piston/cylinder tolerances can be tighter / resulting in a smaller block with a larger bore (less weight, same power).
The crank and rods are forged steel; this generation gets forged aluminum pistons.
I can't speak to the Audi; I've never seen one run for long enough without electrical issues to invest any time in liking them.
The high-silicon aluminum liners are new to the 3.7 for the 4G TL. Idea being that they're better on shedding heat, and because of less expansion, piston/cylinder tolerances can be tighter / resulting in a smaller block with a larger bore (less weight, same power).
The crank and rods are forged steel; this generation gets forged aluminum pistons.
I can't speak to the Audi; I've never seen one run for long enough without electrical issues to invest any time in liking them.
04-05-2012, 10:28 AM
#5
To the best of my knowledge, the block and heads are high pressure cast aluminum as they've been for years.
I've put 250k+ on a single J32, several hundred thousand miles across various others, and have never had any failure issues related to the block or engine lower internals.
I've put 250k+ on a single J32, several hundred thousand miles across various others, and have never had any failure issues related to the block or engine lower internals.
04-05-2012, 10:31 AM
#6
From: http://www.hondanews.com/channels/28...c-a9004c34bacb
Bold mine.
The etching part makes me think Alusil, per (http://en.wikipedia.org/wiki/Alusil).
If Audi is also using Alusil, it is surely also as a cast-in liner as it would make no sense to make the whole block out of the stuff.
Also, BMW hasn't used Nikasil for a bit now. Nikasil doesn't like sulfur (http://en.wikipedia.org/wiki/Nikasil), ask BMW GS riders who spend a lot of time burning third world gas.
I don't have good resources on specifics of the Audi engine, I found the engine code is CAKA but google hasn't gotten me any useful hits.
Bold mine.
Originally Posted by Acura Press Release, 2010
ENGINE BLOCK
Both the 3.5-liter TL engine block and that of the 3.7-liter TL SH-AWD® are constructed of lightweight die-cast aluminum. The 3.5-liter engine has thin-wall iron liners that are made in a centrifugal spin-casting process that ensures high strength and low porosity. The rough outer surface of these liners makes an effective bond with the aluminum block, enhancing block stiffness and heat transfer from the liners to the block.
The 3.7-liter TL SH-AWD® cylinder liners are made of high-silicon aluminum and are cast directly into the aluminum block. The hard piston ring sealing surface of the liners is created during manufacturing with a mechanical etching process that exposes silicon particles embedded in the sleeves. The aluminum sleeves provide better cooling thus allowing closer piston-to-cylinder clearance than iron liners afford. The alloy liners also improve heat dissipation in the area between adjacent cylinder bores, allowing the SH-AWD® engine to have larger cylinder bores, even though its bore-center dimensions (the distance between the centers of adjacent bores) is the same as the 3.5L V-6.
Both the 3.5-liter and the 3.7-liter cylinder blocks are heat-treated for strength and have deep-skirt designs with four bolts per bearing cap (providing excellent structural support for the crankshaft), thus minimizing engine noise and vibration.
Both the 3.5-liter TL engine block and that of the 3.7-liter TL SH-AWD® are constructed of lightweight die-cast aluminum. The 3.5-liter engine has thin-wall iron liners that are made in a centrifugal spin-casting process that ensures high strength and low porosity. The rough outer surface of these liners makes an effective bond with the aluminum block, enhancing block stiffness and heat transfer from the liners to the block.
The 3.7-liter TL SH-AWD® cylinder liners are made of high-silicon aluminum and are cast directly into the aluminum block. The hard piston ring sealing surface of the liners is created during manufacturing with a mechanical etching process that exposes silicon particles embedded in the sleeves. The aluminum sleeves provide better cooling thus allowing closer piston-to-cylinder clearance than iron liners afford. The alloy liners also improve heat dissipation in the area between adjacent cylinder bores, allowing the SH-AWD® engine to have larger cylinder bores, even though its bore-center dimensions (the distance between the centers of adjacent bores) is the same as the 3.5L V-6.
Both the 3.5-liter and the 3.7-liter cylinder blocks are heat-treated for strength and have deep-skirt designs with four bolts per bearing cap (providing excellent structural support for the crankshaft), thus minimizing engine noise and vibration.
If Audi is also using Alusil, it is surely also as a cast-in liner as it would make no sense to make the whole block out of the stuff.
Also, BMW hasn't used Nikasil for a bit now. Nikasil doesn't like sulfur (http://en.wikipedia.org/wiki/Nikasil), ask BMW GS riders who spend a lot of time burning third world gas.
I don't have good resources on specifics of the Audi engine, I found the engine code is CAKA but google hasn't gotten me any useful hits.
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04-05-2012, 11:28 AM
#8
From: http://www.hondanews.com/channels/28...c-a9004c34bacb
Bold mine.
The etching part makes me think Alusil, per (http://en.wikipedia.org/wiki/Alusil).
If Audi is also using Alusil, it is surely also as a cast-in liner as it would make no sense to make the whole block out of the stuff.
Also, BMW hasn't used Nikasil for a bit now. Nikasil doesn't like sulfur (http://en.wikipedia.org/wiki/Nikasil), ask BMW GS riders who spend a lot of time burning third world gas.
I don't have good resources on specifics of the Audi engine, I found the engine code is CAKA but google hasn't gotten me any useful hits.
Bold mine.
The etching part makes me think Alusil, per (http://en.wikipedia.org/wiki/Alusil).
If Audi is also using Alusil, it is surely also as a cast-in liner as it would make no sense to make the whole block out of the stuff.
Also, BMW hasn't used Nikasil for a bit now. Nikasil doesn't like sulfur (http://en.wikipedia.org/wiki/Nikasil), ask BMW GS riders who spend a lot of time burning third world gas.
I don't have good resources on specifics of the Audi engine, I found the engine code is CAKA but google hasn't gotten me any useful hits.
I did some more research. I guess the Alusil block is hypereutectic throughout. Not sure that would make it better, but would like to know the rationale for the different processes.
http://www.kspg-ag.de/pdfdoc/kspg_pr...v6_v8_audi.pdf
04-05-2012, 11:47 AM
#9
Audi recently ruined their transaxle design to promote more neutral weight distribution, the PDF you linked mentions packaging length being a concern in the engine design phase, probably also dealing with weight distribution.
Unlike the my transaxle example though, I don't think making the engine all Alusil is ruining it, just makes it more costly. In addition, the thermal properties probably make Alusil a reasonable expense in forced induction applications which are MUCH more thermally stressed than N/A engines. ALusil is probably a bit more brittle, crystal-heavy alloys usually are, but this probably is only a concern during knock events, so the expense is probably the primary downside.
Also, I found that not only are the J37A4 crank and rods forged, but the rods are actually fracture-split. That's pretty damn cool, heh
Unlike the my transaxle example though, I don't think making the engine all Alusil is ruining it, just makes it more costly. In addition, the thermal properties probably make Alusil a reasonable expense in forced induction applications which are MUCH more thermally stressed than N/A engines. ALusil is probably a bit more brittle, crystal-heavy alloys usually are, but this probably is only a concern during knock events, so the expense is probably the primary downside.
Also, I found that not only are the J37A4 crank and rods forged, but the rods are actually fracture-split. That's pretty damn cool, heh
04-05-2012, 06:00 PM
#12
6G TLX-S
To the best of my knowledge, the block and heads are high pressure cast aluminum as they've been for years.
I've put 250k+ on a single J32, several hundred thousand miles across various others, and have never had any failure issues related to the block or engine lower internals.
I've put 250k+ on a single J32, several hundred thousand miles across various others, and have never had any failure issues related to the block or engine lower internals.
04-05-2012, 06:05 PM
#13
6G TLX-S
Just wish Acura will do the same to alleviate the front heavy weight distribution on it's sedans.
04-05-2012, 06:23 PM
#14
No thanks. Despite marketing trends, front heaviness is desirable for stability. I'd also rather not have all the extra wiring to contend with, the cost of installing it, the pain of troubleshooting it, the amperage it saps when you're trying to crank, none of it please.
04-05-2012, 06:56 PM
#15
6G TLX-S
Front heavy is the recipe to understeering, especially for FWD vehicles.
I highly doubt we'll see all the above troubles given Honda/Acura's notoriously excellence in reliability and electrical integrity.
Besides, the Acura division is not about stability, it's about advanced performance. Leave stability exclusive only to the Honda division's family sedans.
I highly doubt we'll see all the above troubles given Honda/Acura's notoriously excellence in reliability and electrical integrity.
Besides, the Acura division is not about stability, it's about advanced performance. Leave stability exclusive only to the Honda division's family sedans.
04-05-2012, 07:03 PM
#16
sorry for derail, but IMO I'd prefer it if Acura were Acura, and BMW were BMW, and Audi were Audi, because right now everyone is trying to be BMW and I don't like BMW. :p
Jack Baruth puts it better than I can, http://www.speedsportlife.com/2008/1...t-wheel-drive/
Jack Baruth puts it better than I can, http://www.speedsportlife.com/2008/1...t-wheel-drive/
04-06-2012, 02:11 AM
#17
6G TLX-S
I just don't see how relocating the heavy-ass battery from the front to the trunk of an Acura will make an Acura not an Acura.
An Acura is still an Acura, irrespective where the battery is located.
An Acura is still an Acura, irrespective where the battery is located.
04-06-2012, 09:34 AM
#18
You want them to move the battery to make the car less front heavy.
I don't want the car to be less front heavy. 50/50 weight distribution is not my ideal. Leave that silliness for BMW and the other racecar wannabes.
See?
I don't want the car to be less front heavy. 50/50 weight distribution is not my ideal. Leave that silliness for BMW and the other racecar wannabes.
See?
04-06-2012, 10:11 AM
#19
Moving the battery to the back does little to change weight balance. If it's a major concern; you can pick up a Braille battery or something and keep the battery where it belongs, and still drop 30+ lbs off the front of the car.
And then you put a 2 year old in the back seat and it doesn't matter anyway.
And then you put a 2 year old in the back seat and it doesn't matter anyway.
04-06-2012, 07:45 PM
#20
6G TLX-S
Originally Posted by /www.hondanews.com/channels/acura-automobiles-tl/releases/2012-acura-tl-chassis
WEIGHT AND BALANCE
The addition of a manual transmission, an all-new clutch system and suspension changes yield an 88 pound reduction in weight on the front of the TL 6MT model. The weight reduction not only delivers improved performance, but also generates a more favorable front/rear weight bias. Compared to an automatic transmission equipped TL SH-AWD®, the 6-speed manual version improves weight distribution by 1-percent thus generating a 58/42 ratio versus the 6AT's 59/41 ratio.
The addition of a manual transmission, an all-new clutch system and suspension changes yield an 88 pound reduction in weight on the front of the TL 6MT model. The weight reduction not only delivers improved performance, but also generates a more favorable front/rear weight bias. Compared to an automatic transmission equipped TL SH-AWD®, the 6-speed manual version improves weight distribution by 1-percent thus generating a 58/42 ratio versus the 6AT's 59/41 ratio.
Below are the factory published weight distribution data for 2012 TL's :
61/39 : TL
59/41 : SH-AWD AT
58/42 : SH-AWD MT
Relocating the battery may possibly knock another 1-2 percent of weight from the front to the rear, thus reducing even more understeering tendency.
But not to worry, the FWD-chassis TL will still remain to be front heavy, let alone hitting that 50/50 weight distribution that some people don't enjoy.
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