Audi Engine Info

[Chris St Leger-Harris]

Hi Guys,

First post here but been watching what you have been working on for a while and very impressed.

Whilst i admire the GT40 shape, i am assessing the feasability of my own mid-engined coupe design. I am at the very enjoyable but slightly frustrating concept stage when information about donor parts is hard to come by and i am reluctant to purchase bits in case they are unsuitable.

The current powertrain plan (it changes monthly i know ) is to use a Audi S4 V8 engine mounted to a Boxster S transaxle. As i understand it the bolt pattern is such that the two should bolt together without the need for an adaptor plate. I was wondering if anyone could confirm this. I know for Audi promo propaganda that the lump weights 195kg and is 464mm long but does anyone know how wide and tall the unit?

Many thanks and have a great weekend,

Cheers

Chris

[Andy Hills]

Hi Chris

As far as I can tell the Boxster gearbox looks like an Audi 01A gearbox so is should bolt up to the Audi V8, but I can't confirm that.

I can however tell you that a Audi V8 will bolt onto an A4 or A6 2wd gearbox because I have done it. They are available as either 5 or six speed and come up on eBay all the time.

I have got a 1995 -2000 4.2 A8 engine (ABZ) bolted to a 01X 6 speed A4 TDi gearbox and it goes together no problem.


You will probably find the A4/A6 gearbox easier to find than the Boxster unit.

The engine length you quote sounds like one of the newer cam chain engines fitted to the S4, the older units with the cam belt are a bit longer. The weight is about right as I measured mine at 180Kg without oil and water.

The approx sizes of the Audi ABZ V8 engine and gearbox are: -

Total length (Audi ABZ engine + 01X gearbox) = 1200mm
Length of engine (front pulley to bellhousing face) = 490mm
Length of 01X gearbox (bellhousing to rear casing) =710mm
Max width of engine (across exhaust manifolds) = 760mm
Max height of engine (sump to idle air valve) = 660mm
Drive shaft position (front pulley to drive flange) =690mm (or from gearbox rear casing = 510mm)

Hilly

[Chris St Leger-Harris]

Hi Hilly,

Thanks for all the info. I was tempted to use an Audi Tdi 'box since i assumed they would be more available, easier to bolt straight to the engine and would be strong as already build for high-torquer applications. The only thing that put me off was the diesel gearing.

I have done some rough calcs and plotted gear speeds versus road load curves and they should be at the bottom of the post. The TDi gearbox will have a 6th gear that will not have much use beyond cruising and increasing fuel economy. Would be very useful if i had a desire to go beyond 200mph though!

Out of curiousity what is the vehicle that the engine/gearbox combo is being levered into? Many thanks once again,

Cheers

Chris

[Andy Hills]

Personally I think the diesel gearing is much better suited to the V8's NA torque delivery, as it is, 1st gear will spin the rears if you plant your foot at 1500 rpm, wet or dry. Anything lower geared would be even worse....

Agreed, 6th is just for motorway cruising, does make for a quiet drive though.

The engine is in a Lotus Esprit, for the build blog check out
Homemade V8 Espirit

Hilly

[Mike]

Originally Posted by hilly

Hi Chris

As far as I can tell the Boxster gearbox looks like an Audi 01A gearbox so is should bolt up to the Audi V8, but I can't confirm that.

I can however tell you that a Audi V8 will bolt onto an A4 or A6 2wd gearbox because I have done it. They are available as either 5 or six speed and come up on eBay all the time.

I have got a 1995 -2000 4.2 A8 engine (ABZ) bolted to a 01X 6 speed A4 TDi gearbox and it goes together no problem.


You will probably find the A4/A6 gearbox easier to find than the Boxster unit.

The engine length you quote sounds like one of the newer cam chain engines fitted to the S4, the older units with the cam belt are a bit longer. The weight is about right as I measured mine at 180Kg without oil and water.

The approx sizes of the Audi ABZ V8 engine and gearbox are: -

Total length (Audi ABZ engine + 01X gearbox) = 1200mm
Length of engine (front pulley to bellhousing face) = 490mm
Length of 01X gearbox (bellhousing to rear casing) =710mm
Max width of engine (across exhaust manifolds) = 760mm
Max height of engine (sump to idle air valve) = 660mm
Drive shaft position (front pulley to drive flange) =690mm (or from gearbox rear casing = 510mm)

Hilly

Hello Andy.

Do you mind a few questions??

A8 flywheel/clutch ??? Sources??

TDI 5/6 speed what years ??

TDI Shifter for mid engine?? What did you use?

TDI CV bolt pattern/size?

Any help appreciated!

Regards, Mike
mikeyapproved@yahoo.com

[Jeltuh]

I also considered an Audi 4.2 V8. I think you should search for an 4.2 engine with a turbo. Because it is very expensive to get more hp from a 4.2 without the turbo. I don't know which engine you have? Here in the Netherlands are some engines to buy.

[Chris St Leger-Harris]

Hey Guys,

Some interesting points bought up.

Jeltuh: I agree it would be expensive to tune the Audi 4.2 V8 but as the planned vehicle is going to be lighter than a GT40 replica and predominantly used on the road i figured 340bhp would be sufficient. I am also unsure how much torque the Audi/Porsche Transaxle will take?

Hilly: Thinking about it again, the TDI Audi box might well be better suited to the vehicle. Also congratulations as i see PPC are featuring the Lotus next month i see!

Cheers

Chris

[Damon]

Originally Posted by chris_slh

Hi Hilly,

Thanks for all the info. I was tempted to use an Audi Tdi 'box since i assumed they would be more available, easier to bolt straight to the engine and would be strong as already build for high-torquer applications. The only thing that put me off was the diesel gearing.

I have done some rough calcs and plotted gear speeds versus road load curves and they should be at the bottom of the post. The TDi gearbox will have a 6th gear that will not have much use beyond cruising and increasing fuel economy. Would be very useful if i had a desire to go beyond 200mph though!

Out of curiousity what is the vehicle that the engine/gearbox combo is being levered into? Many thanks once again,

Cheers

Chris

Do you have power and torque curves for the engine? It might be a bit more revealing to superimpose them over the road load plot to find out which transmission is better fitted to the vehicle.

[prasanth]

If you want a good selection id try a parts locator. One place that can find you a good short or long block for a Audi engine is TEXAS Junkyards, Junk Yards in TEXAS TX salvage recycler. They have a link somehow to multiples of thousands of recycling centers and will locate the best one for you.

[fostereast]

It sounds like your set on the Audi engine, but have you considered the Ford Modular motor?

The Audi V8 must be almost as big, and the Ford has just about anything you can imagine available for it in terms of upgrades. And it's pretty cheap...