Astons V8 is a Jaguar engine - or is it?
Discussion
SFO said:
very interesting.
no doubt a wet sump system also creates fmep and pmep .. would a wet sump on the V8 result in power loss of more or less than 20bhp re fmep? any difference on pmep?
yeah, a wet sump system has its own make-up of loss, but a well designed wet sump will limit losses, perhaps to point of very good wet sump and very bad dry sump parasitic loss being about equal? The problem is that in theory what might be best design for each, might in practice not be possible due to package constraints, budget and intellect. no doubt a wet sump system also creates fmep and pmep .. would a wet sump on the V8 result in power loss of more or less than 20bhp re fmep? any difference on pmep?
when the make up of pmep is explained, its mainly split pumping loss variables above piston and pumping loss of gasses below piston (windage / oil churning loss). The latter is very difficult to identify in measurent (from in-cylinder pressure transducer versus crank angle measured at 0.1 degree) from the former even though the kit to measure this costs about £70k brain / hardware and £2k per sensor
Dewi 1 said:
On the subject of V8 blocks, I understand that Aston Martin Racing build their 4.7 engines, by starting with a 4.3 block.
If this is so, I presume that there must be a significant difference, between the 4.3 and 4.7 blocks.
Can anyone explain the background to this, including the reason for not using a standard 4.7 block, when that is the engine capacity required?
wrong info. The racing division takes a 4.7L road car engine from the production line, removes the tri metal tin big end bearing, replaces with more durable lead indium bearing. Removes unnecessary emissions stuff and duly slaps a racing badge on the front of it. The engine is billed @ 445bhp and is why cars fitted with that engine get cained by 'racing engines' prepared outside racing division (as proven by euro gt4 winning champions, uk gt4 winning champions and team who once won Aston martin global challenge). Dont mistake the race prepared engines being outside homologation, they were blueprint, something the racing division could have done if it so wished.If this is so, I presume that there must be a significant difference, between the 4.3 and 4.7 blocks.
Can anyone explain the background to this, including the reason for not using a standard 4.7 block, when that is the engine capacity required?
no difference whatsoever 4.3L block vs 4.7l block apart from the obvious 89mm liner 4.3 and 91mm liner 4.7l.
it is of course possible to craft a 4.7 from 4.3, and if they did, the only reason i can guess is because the supply of 4.7 dried up from factory and racing had a surplus of 4.3, but i never heard of that happening.
cayman-black said:
http://www.pistonheads.com/gassing/post.asp?h=0&am...
Speedrasers post!
Speedrasers post!
Edited by cayman-black on Thursday 27th November 16:24
Isn't this like insisting your engine is from a SEAT and nothing to do with Volkswagen? Why not just accept its origins? It doesn't take anything away from the unit knowing that it wasn't a clean sheet design. Ford are a good manufacturer, nothing to be ashamed of there and I'm pleased of their involvement in both of my cars.
Impasse said:
Isn't this like insisting your engine is from a SEAT and nothing to do with Volkswagen? Why not just accept its origins? It doesn't take anything away from the unit knowing that it wasn't a clean sheet design. Ford are a good manufacturer, nothing to be ashamed of there and I'm pleased of their involvement in both of my cars.
for sure, all of what you say is too true. Without jag experts in design and development the bespoke internal parts would not exist, and without fords purchasing powers or quality hoops they insist suppliers jump through the engine would not be built as good as it is. A great group effort which resulted in a great end product
BamfordMike said:
Impasse said:
Isn't this like insisting your engine is from a SEAT and nothing to do with Volkswagen? Why not just accept its origins? It doesn't take anything away from the unit knowing that it wasn't a clean sheet design. Ford are a good manufacturer, nothing to be ashamed of there and I'm pleased of their involvement in both of my cars.
for sure, all of what you say is too true. Without jag experts in design and development the bespoke internal parts would not exist, and without fords purchasing powers or quality hoops they insist suppliers jump through the engine would not be built as good as it is. A great group effort which resulted in a great end product
I don't see any one denying any of the Jag or Ford heritage!
mikey k said:
I don't see any one denying any of the Jag or Ford heritage!
Impasse said:
Isn't this like insisting your engine is from a SEAT and nothing to do with Volkswagen? Why not just accept its origins? It doesn't take anything away from the unit knowing that it wasn't a clean sheet design. Ford are a good manufacturer, nothing to be ashamed of there and I'm pleased of their involvement in both of my cars.
It's not at all like insisting your SEAT's engine has nothing to do with VW. The SEAT engine is all VW. It's the same thing. The Aston V8 is based on a Jag design, but the finished product shares essentially nothing with the Jag engine -- the parts are unique to Aston, which makes it, to me, an Aston engine. It isn't a clean sheet design, and none of us has suggested that it is. If the AMG V8 is dropped into Astons unchanged except for electronics and exhaust, it will be an AMG engine -- not an Aston engine. IMO, that has no business being in an Aston Martin.
Edited to add: I was, and remain, sad that Ford sold Aston because I think Ford was a tremendously beneficial owner who understood Aston and its heritage -- as evidenced by Ford spending the money to develop Aston-only engines and the Aston-only VH platform. Unlike VW Group, for example, who builds "Bentleys" on VW platforms with VW/Audi engines. And because I fear what may lie ahead with the AMG deal. As I've said many times, it could be great -- if they really develop bespoke Aston engines as they said at the beginning. Or it could be THE END, if they drop off-the-shelf AMG engines into Astons, and who-knows-what further down the slippery slope.
Edited by Speedraser on Sunday 30th November 01:48
Edited by Speedraser on Sunday 30th November 02:08
[quote=Speedraser]
sad that Ford sold Aston because I think Ford was a tremendously beneficial owner who understood Aston and its heritage -- as evidenced by Ford spending the money to develop Aston-only engines and the Aston-only VH platform.
[quote]
Ford under Mulally was the only American major car manufacturer to avoid a bailout fund. So his short term strategy to off load Aston and Jag land rover was either right because Ford lived to fight another day, or was long term wrong because just look at how Jag Land Rover flourishes with new lifeblood and Ford is poorer without them versus if Ford kept them. Clearly available cash is what its all about, because with lifeblood Aston today could have been so different but company was sold to a group who barely managed the funds to buy it and had small change left over to keep it going.
Sad is an understatement in my book. Without Ford ownership from last century there would be no Aston today. And Aston losing ford, well, just imagine the Aston that would be at Gaydon today with continued Ford support over last 7 years. In reality in 2014, that unfortunate saga has meant Aston for 7 years stagnated whilst competitors have accelerated, meaning what aston have to do to release successful new models is not one step but two steps forward in one model cycle, which for many reasons will be more than tough. This is relevant here because the first step realistically might have to be a simple yet well marketed crude 'copy / paste' technology from parent, and the cars created are saviours to enable a tomorrow. Lets hope tomorrow creates the car the enthusiasts want. I dont think its impossible - Indian motorcycles pretty much have followed the same route. It just takes a few good men!
sad that Ford sold Aston because I think Ford was a tremendously beneficial owner who understood Aston and its heritage -- as evidenced by Ford spending the money to develop Aston-only engines and the Aston-only VH platform.
[quote]
Ford under Mulally was the only American major car manufacturer to avoid a bailout fund. So his short term strategy to off load Aston and Jag land rover was either right because Ford lived to fight another day, or was long term wrong because just look at how Jag Land Rover flourishes with new lifeblood and Ford is poorer without them versus if Ford kept them. Clearly available cash is what its all about, because with lifeblood Aston today could have been so different but company was sold to a group who barely managed the funds to buy it and had small change left over to keep it going.
Sad is an understatement in my book. Without Ford ownership from last century there would be no Aston today. And Aston losing ford, well, just imagine the Aston that would be at Gaydon today with continued Ford support over last 7 years. In reality in 2014, that unfortunate saga has meant Aston for 7 years stagnated whilst competitors have accelerated, meaning what aston have to do to release successful new models is not one step but two steps forward in one model cycle, which for many reasons will be more than tough. This is relevant here because the first step realistically might have to be a simple yet well marketed crude 'copy / paste' technology from parent, and the cars created are saviours to enable a tomorrow. Lets hope tomorrow creates the car the enthusiasts want. I dont think its impossible - Indian motorcycles pretty much have followed the same route. It just takes a few good men!
BamfordMike said:
Aston
1 - 5 - 4 - 2 - 6 - 3 - 7 – 8
Jag
1-2-7-3-4-5-6-8
This is the same firing order just two differant cylinder numbering1 - 5 - 4 - 2 - 6 - 3 - 7 – 8
Jag
1-2-7-3-4-5-6-8
Ihe AM and early Jags the numbers went down the right bank then down the left
Later Jags alternated between sides, R1, L1, R2, L2 etc
Edited by NormanD on Tuesday 2nd December 07:17
BamfordMike said:
the car has a dry sump system in name and components, however, in many eyes to be successful dry sump system the engine needs to lose no power from crankshaft windage from interaction with oil / have no parasitic loss. I think from motorsport world the reports came that unlike a successful dry sump system, the system on V8 did have some not insignificant power loss from windage, due to there being an amount of oil always in the sump. Simply put, there isn't a whirlwind going on in the sump to scavenge all the oil out hence becoming know as 'damp sump'. But it does tick the box of another requirement of dry sump, which is to lower bonnet line from shorter engine height. Perhaps because the engine met is power target, and the 'damp' system lowered the bonnet line it was left alone. Good thing knowing this, is there is some free horsepower to exploit should a system that does scavenge sufficiently be implemented by somebody.
On my Ducati engine (V-2, 1.2L, 205bhp) the crankcase is pumped out to give a reasonable vacuum, the reasoning being this avoids air pumping losses although I haven't delved deep enough to see how much those losses are. I suspect with a V-8 these pumping losses may not be the same, but I wonder if this has been thought about for the racing V-8, Mike? One good side-effect is no oil leaks!!BTW putting four of my bike motors together would just about be the same capacity as our V-8 but 820bhp!!!
alpinepass said:
On my Ducati engine (V-2, 1.2L, 205bhp) the crankcase is pumped out to give a reasonable vacuum, the reasoning being this avoids air pumping losses although I haven't delved deep enough to see how much those losses are. I suspect with a V-8 these pumping losses may not be the same, but I wonder if this has been thought about for the racing V-8, Mike? One good side-effect is no oil leaks!!
BTW putting four of my bike motors together would just about be the same capacity as our V-8 but 820bhp!!!
And it would also have just 424lbft at 8750rpm, I suspect it would be a bit tricky in town. Although the ducati engine is relatively torquey for a bike engine, bikes' light weight means they don't need the same torque at low revs, so can concentrate more on bhp.BTW putting four of my bike motors together would just about be the same capacity as our V-8 but 820bhp!!!
But I bet the firing order on that V-2 is easy to guess
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