R5 (AEL/AXG/AHY) vs. 4.2 V8 TDI...future conversion project

NoJoke · Jan 5, 2012

Already planning for the future and I need advice. Vehicle of choice will be an Audi A6q wagon not sure which year to get. I refuse to use the 2.5 or 3.0 v6's; not my style even though the new 3.0 biturbo tdi is quite nice.

HP goal is 4-450 and this little voice in my head keeps saying, "there's no replacement for displacement" and the mods would be minimal, turbo's, injectors, remap.

After thinking more the traditionalist says 5cyl+awd=Audi; a VE R5 would require the same steps as an ALH possibly without touching the bottom but vnt control would be a hurdle unless there is a CR alaTDIsyncro method of custom ecu control.

Any suggestions?

JFettig · Jan 5, 2012

I did a small amount of research on this myself when looking for my motor. 5cyl PD motors are hard to come by and expensive - but they do exist. Aligator posted a pic of a golf conversion - it appeared to be cross flow. Not a lot of info on the VE motors on this board except for the few threads you see up toward the top as well as shadowmaker's thread. - should be very similar to AHU mods - VNT control becomes an issue from what I've seen.

I went with a 4cyl PD for my project, I decided that 75hp/cyl isn't very attainable for the VE injection system.

Scott_Dewitt posted a little info about the 4.2LV8TDI project he's working on, sounds EXPENSIVE.

I still wonder about a 12v VR6 TDI project using VE cummins components

injectors and head bolts would interfere.

NoJoke · Jan 5, 2012

JFettig said:
I did a small amount of research on this myself when looking for my motor. 5cyl PD motors are hard to come by and expensive - but they do exist. Aligator posted a pic of a golf conversion - it appeared to be cross flow. Not a lot of info on the VE motors on this board except for the few threads you see up toward the top as well as shadowmaker's thread. - should be very similar to AHU mods - VNT control becomes an issue from what I've seen.

I went with a 4cyl PD for my project, I decided that 75hp/cyl isn't very attainable for the VE injection system.

Scott_Dewitt posted a little info about the 4.2LV8TDI project he's working on, sounds EXPENSIVE.

I still wonder about a 12v VR6 TDI project using VE cummins components injectors and head bolts would interfere.

My findings have been the same, 12v VR6 tdi would be ideal and has been talked about long time ago I'm not sure how much work is needed to produce.

We should know in a week or two whether VE 75hp/cyl is possible

Calling Scott_Dewitt!!! chime in if you can about the V8 and compatible trans. I wanna take a shot at it, thanks.

vwmikel · Jan 5, 2012

NoJoke said:
Already planning for the future and I need advice. Vehicle of choice will be an Audi A6q wagon not sure which year to get. I refuse to use the 2.5 or 3.0 v6's; not my style even though the new 3.0 biturbo tdi is quite nice.

HP goal is 4-450 and this little voice in my head keeps saying, "there's no replacement for displacement" and the mods would be minimal, turbo's, injectors, remap.

After thinking more the traditionalist says 5cyl+awd=Audi; a VE R5 would require the same steps as an ALH possibly without touching the bottom but vnt control would be a hurdle unless there is a CR alaTDIsyncro method of custom ecu control.

Any suggestions?

Perhaps I'm not getting the whole picture here, but what would the VNT control issues be on the 5 cylinder?

Scott_DeWitt · Jan 5, 2012

NoJoke said:
My findings have been the same, 12v VR6 tdi would be ideal and has been talked about long time ago I'm not sure how much work is needed to produce.

We should know in a week or two whether VE 75hp/cyl is possible

Calling Scott_Dewitt!!! chime in if you can about the V8 and compatible trans. I wanna take a shot at it, thanks.

The cat is out of the bag I suppose. The 02 S6 chassis is prepped and awaiting the arrive of it's new powerplant an 2007 4.2 tdi from an A8 with 45,000 miles on it. the transmission will be manual and very custom gear widths increased 2mm on each gear with custom ratios to ring every last ounce of power out of the V8 tdi.

As far as power goes, I'm currently looking at about 450 hp and 800 ft/lbs with 35mpg.

In the meantime the 3.0 liter allroad conversion will get underway as soon as I finish the S8 in the next few weeks.

Keebler145 · Jan 5, 2012

NoJoke said:
My findings have been the same, 12v VR6 tdi would be ideal and has been talked about long time ago I'm not sure how much work is needed to produce.

We should know in a week or two whether VE 75hp/cyl is possible

Calling Scott_Dewitt!!! chime in if you can about the V8 and compatible trans. I wanna take a shot at it, thanks.

Perhaps you should find a way to make a 12v vr6 tdi work. Then I would have reason to stay in the diesel performance area....

NoJoke · Jan 5, 2012

vwmikel said:
Perhaps I'm not getting the whole picture here, but what would the VNT control issues be on the 5 cylinder?

You're right!...we can do a AFN to VNT style conversion that has been done before. The PD might be a better choice than the VE even if its more expensive.

Scott_DeWitt said:
The cat is out of the bag I suppose. The 02 S6 chassis is prepped and awaiting the arrive of it's new powerplant an 2007 4.2 tdi from an A8 with 45,000 miles on it. the transmission will be manual and very custom gear widths increased 2mm on each gear with custom ratios to ring every last ounce of power out of the V8 tdi.

As far as power goes, I'm currently looking at about 450 hp and 800 ft/lbs with 35mpg.

In the meantime the 3.0 liter allroad conversion will get underway as soon as I finish the S8 in the next few weeks.

Is a custom transmission a must with the V8? Not sure if they are traditionally mounted with 6 speeds in Europe.

Scott_DeWitt · Jan 5, 2012

NoJoke said:
Is a custom transmission a must with the V8? Not sure if they are traditionally mounted with 6 speeds in Europe.

It will be nearly impossible to use the 4,2 automatic transmission without major modifications to the C5 chassis. It's going to be easier to modify the ECM than fit the automatic transmission.

As far as the TDI VR6 that would be a very interesting project, you'd just have to redesign the cylinder head and hope the block has enough beef in it to withstand the extra load. You'd need probably 50 grand at least to get a prototype.

But with the 4.2, 3.3 tdi, 3.0, and 2.7 you'd be better to source something already designed.

NoJoke · Jan 5, 2012

Keebler145 said:
Perhaps you should find a way to make a 12v vr6 tdi work. Then I would have reason to stay in the diesel performance area....

I'm not an engineer but if there is one on this board that has an idea on how to make this work then I would be very interested since the aftermarket scene with VR6's is plentyful.

Scott_DeWitt · Jan 5, 2012

NoJoke said:
I'm not an engineer but if there is one on this board that has an idea on how to make this work then I would be very interested since the aftermarket scene with VR6's is plentyful.

At best you will need to redesign the cylinder head to accommodate a fuel injector and glow plug. You might want to look at the direct injection 3.2/3.6 VR6 used in the later cars as a starting point.

You'll probably have to thicken the cylinder walls and install custom pistons with redesigned rods.

Now you'll have to find some way to drive an injection pump or go common rail, meaning you have to design your head around the injectors you want to use.

You'd also likely have to have a crankshaft made from billet or some other very strong material.

All of this assuming that the block and valve train can withstand the additional harmonics and loads imposed by diesel combustion.

NoJoke · Jan 5, 2012

Thanks Scott got the picture about the VR6 haha. Is the 3.3 v8 a good motor? That was mated to a manual.

Scott_DeWitt · Jan 5, 2012

NoJoke said:
Thanks Scott got the picture about the VR6 haha. Is the 3.3 v8 a good motor? That was mated to a manual.

the 3.3 was a pretty good engine from what I understand but it was only used in the A8 for a couple model years, being replaced by the 4.0 tdi. However the 3.0 V6 is very near the same power/weight as the 3.3 tdi, has a single turbo and it quite a bit more popular.

No it was only automatic as well. The only V style VAG manual diesels were the 3.0, 2.7 and 2.5.

3.3, 4.2, 4.0 were all automatics and all longitudinal.

I didn't mean to discourage you about the VR6 tdi, it would be a real cool project but also an extremely expensive project.

NoJoke · Jan 5, 2012

Scott_DeWitt said:
the 3.3 was a pretty good engine from what I understand but it was only used in the A8 for a couple model years, being replaced by the 4.0 tdi. However the 3.0 V6 is very near the same power/weight as the 3.3 tdi, has a single turbo and it quite a bit more popular.

No it was only automatic as well. The only V style VAG manual diesels were the 3.0, 2.7 and 2.5.

3.3, 4.2, 4.0 were all automatics and all longitudinal.

I didn't mean to discourage you about the VR6 tdi, it would be a real cool project but also an extremely expensive project.

Can any of those longitudinal engines be mated to a manual from the VAG parts bin and do a gear swap?

Scott_DeWitt · Jan 5, 2012

NoJoke said:
Can any of those longitudinal engines be mated to a manual from the VAG parts bin and do a gear swap?

I've got transmission in stock that will bolt up to the V6's and am working on adapting them to the 4.2. I've got a method already just need to verify when the engine gets here.

JFettig · Jan 5, 2012

I wouldn't mind fleshing out the VR6TDI as I bet it has potential, there is another thread on it that outlines some of it. Keep in mind that people have pushed 1000hp on stock crankshafts, heads, and blocks, however this could be for another thread. As I see it, it would require a head, pistons, and rods along with the obvious other parts.

Keebler145 · Jan 5, 2012

^ dually note I'll say this and stop to keep the thread on topic. The vr6 was supposed to be a diesel motor until VW realized they couldn't get the compression they needed out of it (I wished I remembered where I read that but now I can't remember/find it)

So the rods, crank, and block are rather stout as it is already. Pistons and head seem to be the weak links.... why waste time with a 2.8l v6 though when a 4.2v8 will fit and still net 50mpg?

NoJoke · Jan 5, 2012

Ok with my simple mind here are bullet points on doing a VR6 and credit to Scott for making suggestions:

Custom Head possibly modifying a direct injected VR6
Custom forged pistons **easy**
Not sure what bore and stroke(custom rods) **easy** stroker?
For fueling and operation use ecu and pump from an existing V6 tdi (possible?)
All VR6 reinforcing items can be sought in the aftermaket

I know I have a lot of blanks but I'm most concerned about timing and fuel delivery of the engine. Everything else can be custom made no problem.

NoJoke · Jan 5, 2012

Keebler145 said:
So the rods, crank, and block are rather stout as it is already. Pistons and head seem to be the weak links.... why waste time with a 2.8l v6 though when a 4.2v8 will fit and still net 50mpg?

Yeah I need a concrete way of mating that 4.2 V8 to a manual 6 speed and the project will be started.

Scott_DeWitt · Jan 5, 2012

NoJoke said:
Yeah I need a concrete way of mating that 4.2 V8 to a manual 6 speed and the project will be started.

I'm 85% there.

Whitbread · Jan 5, 2012

NoJoke said:
Ok with my simple mind here are bullet points on doing a VR6 and credit to Scott for making suggestions:

Custom Head possibly modifying a direct injected VR6

Custom forged pistons **easy**

Not sure what bore and stroke(custom rods) **easy** stroker?

For fueling and operation use ecu and pump from an existing V6 tdi (possible?)

All VR6 reinforcing items can be sought in the aftermaket

I know I have a lot of blanks but I'm most concerned about timing and fuel delivery of the engine. Everything else can be custom made no problem.

Any common rail system could be adapted to work easily. Run it with a Nira or Skynam ecu. Lots of pickup truck diesel companies make custom injection lines so that's not an issue. Run the HP pump with a small cogged belt (like normally used for a procharger or dry sump pump). I know late model duramax or powerstroke injectors are very long and skinny so they would be relatively easy to adapt. Don't need glowplugs, just use a grid heater like 5.9/6.7 cummins motors do.

Although a 4.2L v8 with 2 2260vk's and a 6 speed would be absolutely nuts and have an orgasmic sountrack with an open exhaust. Turbo'ed v8's sound sooooo good. Again, use the Nira or Skynam ecu for most tuneability.

TDIMeister · Jan 5, 2012

V8. Keep me in the loop, please.

NoJoke · Jan 5, 2012

Whitbread said:
Any common rail system could be adapted to work easily. Run it with a Nira or Skynam ecu. Lots of pickup truck diesel companies make custom injection lines so that's not an issue. Run the HP pump with a small cogged belt (like normally used for a procharger or dry sump pump). I know late model duramax or powerstroke injectors are very long and skinny so they would be relatively easy to adapt. Don't need glowplugs, just use a grid heater like 5.9/6.7 cummins motors do.
Although a 4.2L v8 with 2 2260vk's and a 6 speed would be absolutely nuts and have an orgasmic sountrack with an open exhaust. Turbo'ed v8's sound sooooo good. Again, use the Nira or Skynam ecu for most tuneability.

Will have an A8 4.2 tdi front half shipped to you within 2 months. What year Audi body do we need?

TDIMeister said:
V8. Keep me in the loop, please.

http://www.volkspage.net/technik/ssp/ssp/SSP_365.pdf

You got it!

Scott_DeWitt · Jan 6, 2012

NoJoke said:
Will have an A8 4.2 tdi front half shipped to you within 2 months. What year Audi body do we need?

http://www.volkspage.net/technik/ssp/ssp/SSP_365.pdf

You got it!

Due to the size of the engine itself, I'd only look into the larger D2 or C5 chassis. Fitting one in a B5/B6 will be a real challenge if not impossible.

Keebler145 · Jan 6, 2012

Scott_DeWitt said:
Due to the size of the engine itself, I'd only look into the larger D2 or C5 chassis. Fitting one in a B5/B6 will be a real challenge if not impossible.

pfff did you see where he said he was shipping it? Matt is the creator of the impossible....if it can't be done, he'll do it anyway rofl

JFettig · Jan 6, 2012

space frame it.

Scott_DeWitt · Jan 6, 2012

Keebler145 said:
pfff did you see where he said he was shipping it? Matt is the creator of the impossible....if it can't be done, he'll do it anyway rofl

Just offering my advise based on extensive research and first hand know how. But who am I, other than one of the most knowledgeable experts in North America on this topic.

Keebler145 · Jan 6, 2012

haha no mal intent or bashing on your part sir! I was just calling Matt out on the floor for doing some wild and crazy things even if it can't / shouldn't be done haha.

Being a poor college student I only can do what others already have done, I appreciate people like you doing all the leg work for people like me

NoJoke · Jan 6, 2012

Scott_DeWitt said:
Due to the size of the engine itself, I'd only look into the larger D2 or C5 chassis. Fitting one in a B5/B6 will be a real challenge if not impossible.

I'm leaning towards a C5 avant any particular year I should look for? There are so many cheap Allroads out there(suspension problems?)

Scott_DeWitt · Jan 6, 2012

NoJoke said:
I'm leaning towards a C5 avant any particular year I should look for? There are so many cheap Allroads out there(suspension problems?)

The S6 has a larger engine compartment, trans tunnel, and sexier lines, and are more equipped (sport seats, alcantara headliner, larger brakes etc) , however they are pretty rare and cost more.

The Allroad is a good choice, but it has quite a list of standard problems that require quite a bit of money to remedy, suspension is about 4 grand to update to a point where it's not a problem, however they are much more plentiful. The seating sucks, and the Allroad has some weird color options.

The allroads can be had with a manual transmission which helps in the conversion.

I'll let you know how our allroad 3.0 tdi conversion goes in the next few weeks, i discussed a 4.2 conversion but the cost to retrofit and obtain a 4.2 was at least twice what the 3.0 liter was, and the 3.0 liter came with a manual so that headache is solved.

LNXGUY · Jan 6, 2012

Uh, 1000hp on a stock VR6 bottom end/head is a pipe dream. Anything over 400hp and you've gotta start digging into the engine if you want any sort of reliability.

R5 (AEL/AXG/AHY) vs. 4.2 V8 TDI...future conversion project

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