Doesn't the Boxster use what is more or less an 012 gearbox... I believe that there are some limited slip differentials that are shared with the Audi 01A.

The big question is not so much the components inside the gearbox but the casing of the gearbox, specifically the bell housing casting.

For the V8 I'd want to score an 01E gearbox... maybe from scottmandu, he can probably import or build up a nice 2wd one with some gear ratios that will work with the V8.

 

I am curious to hear if there is anything wrong with the motor which is in there? I know very little about boxters, but thought they made a supercharger kit for them. Any reason why this is not attractive?

 

As far as I know the Boxster transmission is an 012. Here's a couple of pics of one:

Assuming they're all the same then the V8 will just bolt straight up to this, just like Hilly's did. You might need to check the input shaft sizes, as the 012 used in the 944 has a different size shaft to the Audi variants. There are loads of clutch options if they are different tho. Just use an Audi flywheel and clutch cover, and the appropriate disk :thumbsup:

Management wise you can use anything you fancy - most use standalone afaik. Someone on here got Megasquirt working on one a while ago, or I'm sure 034 can sort you out with something

Definitely make a project thread if you do this! :cheers:

 

Don't the 986 engines have intermediate shaft failure issues?

 

Yes, my uncle's 986 had a complete failure due to the IMS.

Luckily Porsche took care of him. He had a brand new engine installed in days free of charge.

 

Don't the 986 engines have intermediate shaft failure issues?

M96 motor in the Boxster has a variety of failure modes. Intermediate shafts fail on a number of motors, earlier 2.5 liter motors in 97 to 99 had some casting issues. My 99 had a cylinder sleeve slip and it caused all sorts of havic, broken rod bolt, piston tore everything up, block was a total loss. Some motors have D chunk issues where poor casting allows cylinder to crack in shape of a D. Rumors of oil starvation issues. Newer motors have addressed some of these problems.

To the other question above the M96 due to thin cylider walls and high compression doesnt lend itself to forced induction too well.

I bought a cheap used Boxster motor to stuff in the car while I look at a long term conversion. I'm thinking an Audi V8 is way to go. I think the Audi V8 and Porsche V8 are basically the same motor but there arent many people I know of doing Porsche V8 conversions. Mostly Audi V8's.

I think biggest question with Boxster tranny is related to starter motor and whether its in the right place. I havent seen enough pictures of the tranny or motor to know. I was hoping to find if anyone has tried bolting the Audi V8 to a Porsche Boxster tranny of any kind.

My original Boxster motor carnage pictured below

 

Those two pics I posted are of a Boxster trans. That looks identical to the Audi one I have in my shed which has an Audi V8 bolted to it.

 

Ah the M96 sounds like a disaster of an engine, we don't see a whole lot of those sort of failures on the Audi side of things.

I'm not so sure the Porsche V8 and the Audi V8 are of common origin. While I have not studied the Porsche V8 engines closely I remember something about the early 928 engines being of some relation in bore/stroke possibly valvetrain design to the 944 2.5L I4. If that were true the Porsche V8 is not like the Audi V8, the bore spacings are probably different and as such they are not the same engine. The picture I just dug up of the Cayenne's turbo V8 shows a front mount chain drive... the 079 Audi V8 is chain drive but the chain drive is rear mounted. Audi also used roller rockers on a lot of the V8 engines and in some engines 5v/cyl design heads. Porsche looks to be using lifters in the Cayenne... again signs of different engineering.

The Audi V8 engines can withstand turbocharging, that much has been demonstrated on this forum. Marc Swanson is bonkers for boost and he has been tinkering with the V8 engines, I think he managed over 350awhp from a 3.6L V8... plenty of power for a Boxster.

If you don't have room for the V8 you may be able to fit the V6 or more specifically I'd consider maybe assembling a hybrid. The 2.8 and 2.7T are both 078 engines and you can supercharge the 2.8, and folks use the 2.8 heads on the 2.7T... so maybe if you don't have space for the turbochargers of a 2.7T an Eaton blower mounted in the valley of a hybrid V6 with upped boost pressures (limited by intake air temps and fuel type, E85 might work well here) could yield a potent engine in a smaller package than the V8.

 

Did they fix these problems by the time the 2002 model rolled around?

 

I'm pretty sure my uncle's 986 was 02+ (had the IMS failure)

 

Oh dear...

Maybe we can just never drive ours and let it look pretty in the garage...

 

screw that man, drive the crap out of it. Thats what its made for. If you give them a hard time, Porsche will make good with something like that. They don't want people going around spreading bad things.

 

Did they fix these problems by the time the 2002 model rolled around?

No there are failures with those motors too. Just not as often. There is a great aftermarket developing but its expensive. Resleeved blocks, new IMS bearings that are made to last, etc.

One company is coming along with ways to address issues. My motor even made their hall of fame!

http://www.flat6innovations.com/engine- ... llustrated

 

Ah the M96 sounds like a disaster of an engine, we don't see a whole lot of those sort of failures on the Audi side of things.

I'm not so sure the Porsche V8 and the Audi V8 are of common origin. While I have not studied the Porsche V8 engines closely I remember something about the early 928 engines being of some relation in bore/stroke possibly valvetrain design to the 944 2.5L I4. If that were true the Porsche V8 is not like the Audi V8, the bore spacings are probably different and as such they are not the same engine. The picture I just dug up of the Cayenne's turbo V8 shows a front mount chain drive... the 079 Audi V8 is chain drive but the chain drive is rear mounted. Audi also used roller rockers on a lot of the V8 engines and in some engines 5v/cyl design heads. Porsche looks to be using lifters in the Cayenne... again signs of different engineering.

The Audi V8 engines can withstand turbocharging, that much has been demonstrated on this forum. Marc Swanson is bonkers for boost and he has been tinkering with the V8 engines, I think he managed over 350awhp from a 3.6L V8... plenty of power for a Boxster.

If you don't have room for the V8 you may be able to fit the V6 or more specifically I'd consider maybe assembling a hybrid. The 2.8 and 2.7T are both 078 engines and you can supercharge the 2.8, and folks use the 2.8 heads on the 2.7T... so maybe if you don't have space for the turbochargers of a 2.7T an Eaton blower mounted in the valley of a hybrid V6 with upped boost pressures (limited by intake air temps and fuel type, E85 might work well here) could yield a potent engine in a smaller package than the V8.

I think Boxster has plenty of room for a compact V8 like the Audi motor. I like the 2.7 T as well - have seen it used with Porsche 914's. V8 just has more appeal to me.

When I say Porsche V8 I mean current version in Cayenne. Porsche guys say its very close to Audi, but I think Audi has more aftermarket support.

I just would like to find somone who has actually tried to hook up a Boxster tranny to the Audi motor for a mid engine car to hear what parts are needed. That will save me some time and $$$$.

 

It can't be that close to an Audi engine, as the current bore spacing of even the 4.2L won't allow for much more displacement than that. The whole reason why we have the 4.2L is because Audi changed the bore spacing from the standard 88mm to 90-something. I believe all Audi V8's (3.7, 4.0TD, 4.2TD, 4.2FSI/tt, etc) since the ABH use the larger bore spacing and similar block size, which as I said, doesn't allow for much more displacement. If Audi hasn't gone larger than 4.2L in a V8 since 1991/1992 there is a reason. The V10 had a little room left despite the 88mm bore spacing, which meant it could go from 5.0L (two banks of 2480cc) to 5.2L (two banks of 2583cc IIRC).

 

It can't be that close to an Audi engine, as the current bore spacing of even the 4.2L won't allow for much more displacement than that. The whole reason why we have the 4.2L is because Audi changed the bore spacing from the standard 88mm to 90-something. I believe all Audi V8's (3.7, 4.0TD, 4.2TD, 4.2FSI/tt, etc) since the ABH use the larger bore spacing and similar block size, which as I said, doesn't allow for much more displacement. If Audi hasn't gone larger than 4.2L in a V8 since 1991/1992 there is a reason. The V10 had a little room left despite the 88mm bore spacing, which meant it could go from 5.0L (two banks of 2480cc) to 5.2L (two banks of 2583cc IIRC).

Goog point but exteriors, intakes, etc appear to look very similar. So I suspect that based on smaller bores the Audi motor is a little smaller than the Porsche which would be better. Does somone have all the exterior dimensions of the 4.2 liter Audi V8? Is there a cutaway view of this motor somwhere?

 

Your talking ALOT of body work as the V8 engine is quite a bit taller than the engine in the boxster. You'd loose quite a bit of trunk space, and there would possibly be some intrusion into the passenger compartment.

The Boxster uses a 5 speed very closely related to the 012. The Boxster S 6 speed is of the 0A2 variety.

 

Goog point but exteriors, intakes, etc appear to look very similar. So I suspect that based on smaller bores the Audi motor is a little smaller than the Porsche which would be better. Does somone have all the exterior dimensions of the 4.2 liter Audi V8? Is there a cutaway view of this motor somwhere?

The users I'd ask are a4kquattro, Cbullen and Timmy. They may have that info or be able to provide it.

 

I would find a 3.6 from the boxters bigger brother and drop it in there.

 

AFAIK the V8 in the Cayenne is a direct descendant of the 928 engine. Not related to Audi except in that they're both made by the same company, sort of.

 

Ill go measure a V8 right now

 

OK rough tape measure numbers...

2004 A8 motor: 30.5"w x 22.5"L x 24"H (incl all plumbing, but missing accessories)

2005 BHF V8 motor: 28"W x 22"L x 22"H Total incl all accessories.

Both motors include stock manifolds which are not wider than the heads = widest part.

H

 

04 A8 engine is the last of the 077 engines (front belt drive) These were first used in the Audi V8 which was a large car with an engine bay suitable for an inline five with a side mount radiator. Space galore. These engines range from 250 to 360hp.*edit* 450hp+ for RS6/RS6 plus with turbocharged engines*edit* Some 077 engines were 32v and later ones were 40v.

05 S4 engine is the first of the 079 engines (rear chain drive) These were meant to be smaller to fit in the B6 A4's engine bay and the C5 allroad's engine bay too. These range from I want to say just over 300hp ~2004 allroad to 340ish in the S4 and 420 in the RS4 and R8. Early 079 engines were 40v and later ones were 32v the 32v are FSI.

 

04 A8 engine is the last of the 077 engines (front belt drive) These were first used in the Audi V8 which was a large car with an engine bay suitable for an inline five with a side mount radiator. Space galore. These engines range from 250 to 360hp. Some 077 engines were 32v and later ones were 40v.

05 S4 engine is the first of the 079 engines (rear chain drive) These were meant to be smaller to fit in the B6 A4's engine bay and the C5 allroad's engine bay too. These range from I want to say just over 300hp ~2004 allroad to 340ish in the S4 and 420 in the RS4 and R8. Early 079 engines were 40v and later ones were 32v the 32v are FSI.

Thanks for the clarification Phil, those are exactly what I measured. The S4 motor I have is a 40V, the A8 I presume is also 40V, pulling heads tomorrow so will know for sure.

 

Anytime... Just want to give him an idea of just how varied our V8 engines are, to date I've observed two main groups (077/079) each with two subgroups (valve count). I believe that all three of your engines are 40v.

I'd love to see an Audi powered Boxster... we have some really good engines yet we never got the fun mid engined sports car. Just seems like an all around good idea, till the sheet metal work starts. Maybe add in a turbocharger... they make good mufflers... sorta.