4.2L V8 | Engine Swap Possibilities
07-29-2018, 08:45 PM
#1
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4.2L V8 | Engine Swap Possibilities
Hi guys I'm looking to buy a spare engine for my car with low miles. I've found several BFM motors for my year, 2004-late 2005.
I'm just wondering, what are the repercussions, if any, to attempting to swap a BAS motor from a C6 A6, or a BHF motor from an S4, or one from a Q7, or a Touareg or a Phaeton, etc.
I would love to rebuild/modify my current engine and get a replacement daily to swap into my car, however with all the options out there I'm wondering if the swaps mentioned above are possible.
What about buying a 4.2TDI engine? I would love a diesel daily.
Excuse my naivety, just curious as to what possibilities lie out there.
I'm just wondering, what are the repercussions, if any, to attempting to swap a BAS motor from a C6 A6, or a BHF motor from an S4, or one from a Q7, or a Touareg or a Phaeton, etc.
I would love to rebuild/modify my current engine and get a replacement daily to swap into my car, however with all the options out there I'm wondering if the swaps mentioned above are possible.
What about buying a 4.2TDI engine? I would love a diesel daily.
Excuse my naivety, just curious as to what possibilities lie out there.
07-30-2018, 07:39 AM
#2
AudiWorld Wiseguy
Diesel no way, Q7 is different engine, as is S4.
A6 motor is a performance downgrade and may have some finicky differences that won’t play nice with the existing electronics/controls.
You don’t see engine swaps in modern cars these days because of the complexity of getting the electronics to play nice.
If you need a new motor for an ‘04, unless you DIY it, the cost/benefit makes no sense. Better off scrapping it and buying a working one.
A6 motor is a performance downgrade and may have some finicky differences that won’t play nice with the existing electronics/controls.
You don’t see engine swaps in modern cars these days because of the complexity of getting the electronics to play nice.
If you need a new motor for an ‘04, unless you DIY it, the cost/benefit makes no sense. Better off scrapping it and buying a working one.
07-30-2018, 09:50 AM
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Planning on DIY
Diesel no way, Q7 is different engine, as is S4.
A6 motor is a performance downgrade and may have some finicky differences that won’t play nice with the existing electronics/controls.
You don’t see engine swaps in modern cars these days because of the complexity of getting the electronics to play nice.
If you need a new motor for an ‘04, unless you DIY it, the cost/benefit makes no sense. Better off scrapping it and buying a working one.
A6 motor is a performance downgrade and may have some finicky differences that won’t play nice with the existing electronics/controls.
You don’t see engine swaps in modern cars these days because of the complexity of getting the electronics to play nice.
If you need a new motor for an ‘04, unless you DIY it, the cost/benefit makes no sense. Better off scrapping it and buying a working one.
The only bit I'm concerned about is the need to go to the dealer to reprogram the ECU.
I found several BFM motors that will fit with miles as low as 70k. However I need to know if it will be plug and play. I'm oversimplifying this but would it be like getting a replacement BOSCH ABS module and having to recode it using the previous model's coding strand?
Also I know the S4 is a completely different engine was just curious to see if it's readable.
In regards to the diesel, what would change/ what parts need fabrication/investment in?
Thank you for the above info on the other engines
Last edited by Automotive_Buff; 07-30-2018 at 09:53 AM.
07-30-2018, 12:12 PM
#4
AudiWorld Wiseguy
Why do you need a spare engine and transmission on hand? The BFM and 6HP are pretty much bullit proof if maintained properly. Certainly they will last as long as the rest of the car.
A BFM and trans from an A8 in your market should be pretty much plug and play as long as you keep your original ECU in place. Trans will need dealer coding though as the TCU is built into the transmission itself.
4.2 TDI was never available in North American market so never type approved. The largely insurmountable regulatory roadblocks aside, you’d have to import everything from Europe. At a guess, at least the engine, transmission (higher torque and different gearing), maybe transfer case and diffs again due to different gearing. All the exhaust system, fuel system, different cooling system, all the ECU’s and wiring loom, and myriad sub assemblies that differ, such as suspension compressor mounts, heat sheilding, etc.etc.
In short a massive and expensive challenge that makes no sense. If you must have one, as you’re in Canada, just wait until they’re 15 years old and import one direct from Germany. It’ll take you that long to convert one, but will be cheaper.
A BFM and trans from an A8 in your market should be pretty much plug and play as long as you keep your original ECU in place. Trans will need dealer coding though as the TCU is built into the transmission itself.
4.2 TDI was never available in North American market so never type approved. The largely insurmountable regulatory roadblocks aside, you’d have to import everything from Europe. At a guess, at least the engine, transmission (higher torque and different gearing), maybe transfer case and diffs again due to different gearing. All the exhaust system, fuel system, different cooling system, all the ECU’s and wiring loom, and myriad sub assemblies that differ, such as suspension compressor mounts, heat sheilding, etc.etc.
In short a massive and expensive challenge that makes no sense. If you must have one, as you’re in Canada, just wait until they’re 15 years old and import one direct from Germany. It’ll take you that long to convert one, but will be cheaper.
07-30-2018, 02:20 PM
#5
The plan when I got this car has always been to get a spare motor and a spare transmission to have on-hand.
The only bit I'm concerned about is the need to go to the dealer to reprogram the ECU.
I found several BFM motors that will fit with miles as low as 70k. However I need to know if it will be plug and play. I'm oversimplifying this but would it be like getting a replacement BOSCH ABS module and having to recode it using the previous model's coding strand?
Also I know the S4 is a completely different engine was just curious to see if it's readable.
In regards to the diesel, what would change/ what parts need fabrication/investment in?
Thank you for the above info on the other engines
The only bit I'm concerned about is the need to go to the dealer to reprogram the ECU.
I found several BFM motors that will fit with miles as low as 70k. However I need to know if it will be plug and play. I'm oversimplifying this but would it be like getting a replacement BOSCH ABS module and having to recode it using the previous model's coding strand?
Also I know the S4 is a completely different engine was just curious to see if it's readable.
In regards to the diesel, what would change/ what parts need fabrication/investment in?
Thank you for the above info on the other engines
08-02-2018, 11:00 AM
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Why do you need a spare engine and transmission on hand? The BFM and 6HP are pretty much bullit proof if maintained properly. Certainly they will last as long as the rest of the car.
A BFM and trans from an A8 in your market should be pretty much plug and play as long as you keep your original ECU in place. Trans will need dealer coding though as the TCU is built into the transmission itself.
4.2 TDI was never available in North American market so never type approved. The largely insurmountable regulatory roadblocks aside, you’d have to import everything from Europe. At a guess, at least the engine, transmission (higher torque and different gearing), maybe transfer case and diffs again due to different gearing. All the exhaust system, fuel system, different cooling system, all the ECU’s and wiring loom, and myriad sub assemblies that differ, such as suspension compressor mounts, heat sheilding, etc.etc.
In short a massive and expensive challenge that makes no sense. If you must have one, as you’re in Canada, just wait until they’re 15 years old and import one direct from Germany. It’ll take you that long to convert one, but will be cheaper.
A BFM and trans from an A8 in your market should be pretty much plug and play as long as you keep your original ECU in place. Trans will need dealer coding though as the TCU is built into the transmission itself.
4.2 TDI was never available in North American market so never type approved. The largely insurmountable regulatory roadblocks aside, you’d have to import everything from Europe. At a guess, at least the engine, transmission (higher torque and different gearing), maybe transfer case and diffs again due to different gearing. All the exhaust system, fuel system, different cooling system, all the ECU’s and wiring loom, and myriad sub assemblies that differ, such as suspension compressor mounts, heat sheilding, etc.etc.
In short a massive and expensive challenge that makes no sense. If you must have one, as you’re in Canada, just wait until they’re 15 years old and import one direct from Germany. It’ll take you that long to convert one, but will be cheaper.
While the original engine and trans are being worked on, I could still drive my A8 around with the newer engine and trans.
Correct me if I'm wrong but is the BGK the 4.2L FSI engine used in 2005/6+ model years? The one that has engine timing chains instead of belts?
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