V10 and V12 TDI Conversion

Civil

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Joined
Jan 22, 2023
Location
USA
TDI
V10
I'm putting a new engine in my car, and the V10 and V12 TDIs looked interesting. With that said, the V10 seems to be a 20-valve, which is suboptimal for airflow, air/fuel mixture, performance, etc. Was there a V10 TDI diesel produced with 4 valves per cylinder? If not, are there 40-valve conversion heads for the V10?
As for the V12, it has 4 valves per cylinder, but an iron block. Are there versions of the V12 TDI with an aluminum block?
 

diffas

Veteran Member
Joined
Jun 25, 2008
Location
Finland
TDI
B5q A4 Avant 2.5TDi+, B7q A4 Avant 3.0TDi
There is basically only one v12 engine and only cg-iron block. I'd rather would look V8 instead than v10. Not sure if the newest 4.0tdi is nowdays alu-block, probably not. Older ones are all cg-iron.
 

altz1

Veteran Member
Joined
Jan 15, 2015
Location
Estonia
TDI
Allroad, A8
Im looking for a extra V12tdi myself right now. Roughly 8-10k Eur to start with. Its a 300+kg engine and rather hard to find any normal transmission to hold the power.
 

Civil

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Joined
Jan 22, 2023
Location
USA
TDI
V10
There is basically only one v12 engine and only cg-iron block. I'd rather would look V8 instead than v10. Not sure if the newest 4.0tdi is nowdays alu-block, probably not. Older ones are all cg-iron.
Why would you go with the V8 instead of the V10 (besides the valves)?
 

adamss24

Veteran Member
Joined
Nov 2, 2005
Location
Great Britain
TDI
audi a4 2.5 tdi 98 quatrro 6speed
Better power to weight ratio to start with, easier to work on, more scope for tuning due to being more compact than a v10/v12 engine and lighter as well !
 

Civil

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Joined
Jan 22, 2023
Location
USA
TDI
V10
Better power to weight ratio to start with, easier to work on, more scope for tuning due to being more compact than a v10/v12 engine and lighter as well !
The compactness for sure. The power to weight however might not be the case. If I recall correctly, VW detuned the V10 as their transmission couldn't hold the torque. It was making something like 300kW+ with 1000Nm+ baseline.
 

adamss24

Veteran Member
Joined
Nov 2, 2005
Location
Great Britain
TDI
audi a4 2.5 tdi 98 quatrro 6speed
You think 300kw is such a high output from a v10 engine ? You can do a pd1.9 tdi to do 400 bhp and that’s with a lot less cylinders. The torque rating is mighty for sure however 600-700 Nm is also possible from a 4 banger and Vag doesn’t have decent manual gearboxes to hold the torque !
 

Civil

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Joined
Jan 22, 2023
Location
USA
TDI
V10
You think 300kw is such a high output from a v10 engine ? You can do a pd1.9 tdi to do 400 bhp and that’s with a lot less cylinders. The torque rating is mighty for sure however 600-700 Nm is also possible from a 4 banger and Vag doesn’t have decent manual gearboxes to hold the torque !
Definitely not, but if you ran as much boost with the V10 relative to the amount of boost the 1.9L TDI needs to make 400hp, the V10 would make >1,000hp. The real comparison should be design-based (i.e., air flow, efficiency, cooling, durability, etc.). Which is why I mentioned the V10's inferior valving.
 
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adamss24

Veteran Member
Joined
Nov 2, 2005
Location
Great Britain
TDI
audi a4 2.5 tdi 98 quatrro 6speed
Even if you feed the v10 enough air it would not take it. As you said, limitations are his breathing- there’s not enough volume to flow trough the tiny passages cast in the head. Hot air behaves in a completely weird way when under pressure- fluid mechanics is wonderful if you care to look ! From that reason alone a 4 valve per cyl, boosted CR engine v6 or v8 is a lot more potent than any v10-v12, not only limitations but parasitic drag trough the system as well ! Also with massive boost long cranks tend to flex a lot and creates a lot of problems with harmonics- in NA form they are awesome smooth power plants !
Apples to apples but I would prefer a short boosted 3/4 cyl engine boosted than a large, gas guzzling engine...I know you guys live in ‘murica where there’s no replacement for displacement but we here are constrained by euro regulations and limitations by design...
 

altz1

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Joined
Jan 15, 2015
Location
Estonia
TDI
Allroad, A8
Definitely not, but if you ran as much boost with the V10 relative to the amount of boost the 1.9L TDI needs to make 400hp, the V10 would make >1,000hp. The real comparison should be design-based (i.e., air flow, efficiency, cooling, durability, etc.). Which is why I mentioned the V10's inferior valving.
Personally i chose v8tdi and next project will be with V12tdi.

My v8tdi is close to (if not more, yet to be dynoed) 600hp and 1200Nm. You could go after even higher hp. Its commonrail engine and imo very tunable. With V12 its the same, just 4 extra cylinders so 1000+ hp can be made. There are 2 projects that i know of, Darkside and one other who have goals set around 800-1000hp with the v12tdi.
 

adamss24

Veteran Member
Joined
Nov 2, 2005
Location
Great Britain
TDI
audi a4 2.5 tdi 98 quatrro 6speed
Altz I respect your decision but-after taking a ride in Bobby Singh a4 a few years ago-I concluded that v6 is enough and after 600 bhp power it’s just a number, the brain has no time to react unless highly trained and/or adrenaline junkie !
 

Civil

Member
Joined
Jan 22, 2023
Location
USA
TDI
V10
Even if you feed the v10 enough air it would not take it. As you said, limitations are his breathing- there’s not enough volume to flow trough the tiny passages cast in the head. Hot air behaves in a completely weird way when under pressure- fluid mechanics is wonderful if you care to look ! From that reason alone a 4 valve per cyl, boosted CR engine v6 or v8 is a lot more potent than any v10-v12, not only limitations but parasitic drag trough the system as well ! Also with massive boost long cranks tend to flex a lot and creates a lot of problems with harmonics- in NA form they are awesome smooth power plants !
Apples to apples but I would prefer a short boosted 3/4 cyl engine boosted than a large, gas guzzling engine...I know you guys live in ‘murica where there’s no replacement for displacement but we here are constrained by euro regulations and limitations by design...
I agree that you don't need more than 400hp, and you don't need more than 2.0L to accomplish that. With that said, I don't find 4 or 8 cylinder engines exciting. If there were an optimized 2L 10-, 12-, or 16-cylinder engine, I'd go for that. As far as what's available, nobody, be they Brit or otherwise, has produced such an engine at a production scale.
With regards to the longer crankshaft, yes it's more likely to bend depending on the application, but all things being equal it's also less likely to shear/break. Also, regardless of valves, the V10 could handle and support >1,000hp relatively easy. With forced induction, the number of valves per cylider affects the efficiency not so much the maximum power. Valves typically become a significant limiting factor for generating power only at the extremes (e.g., a 1,000hp 2L 4-cylinder engine, 2,500hp Viper V10 [2 valves per cylinder], etc.). That said, this back and forth doesn't have to do with the thread.

Personally i chose v8tdi and next project will be with V12tdi.

My v8tdi is close to (if not more, yet to be dynoed) 600hp and 1200Nm. You could go after even higher hp. Its commonrail engine and imo very tunable. With V12 its the same, just 4 extra cylinders so 1000+ hp can be made. There are 2 projects that i know of, Darkside and one other who have goals set around 800-1000hp with the v12tdi.
Nice, Altz. The V8 TDI looks to be like a very solid engine!
 
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adamss24

Veteran Member
Joined
Nov 2, 2005
Location
Great Britain
TDI
audi a4 2.5 tdi 98 quatrro 6speed
Pd 10 cyl engine is a technical dead end... Hard to work on, heavy and still crippled by the need to fire at tdc ! Its potent , yeah but CR is net superior with high fuel pressures available from tick over ! Not being a cheapskate but fuel is still expensive in europe, taxes are very high on large engines and diesel is frowned upon even though is the workhorse found on the road ! As for interesting, reliable diesel engines i wouldnt mind getting my hands on a audi v12 tdi and putting it in a shoe box, folks have done that with large airplane engines since the turn of the century !
As for the old pushrod engines, we are comparing two different fuels, while the engine has a massive punch from large precision turbos, the fuel economy suffers a lot and it becomes plain silly as the car can barely put the power on the road trough the rear tyres on old style automatic gearboxes with lock converters...i drove once an ariel atom on a circuit and that contraption was faster than my brain could think ! The key is being light and nimble !
Boys, i salute you for your determination to push the goals further, tuning right its a very expensive game and speeding is becoming dangerous in my neck of woods with possible prison sentences and lifetime bans...but please keep us posted with your results as these forums are becoming increasingly quiet lately as the veterans are getting "long in the tooth" and busy with businesses and life...
 

Civil

Member
Joined
Jan 22, 2023
Location
USA
TDI
V10
Looks like the Volkswagen petrol V10 has very similar heads to the V10 TDI. With some modification, might be able to use them on the diesel.

 
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