engine conversion 4.2 v8 audi - 986 Forum

tattoo-1 · 12-30-2010, 07:59 AM

after having a few months driving about in my boxster,,, first time i have owned one,,, my son couldnt insure it,, we decided to do a 997 front end conversion,, we managed to get hold of 997 turbo front bumper,splitter, and head lights, we was gona work with every thing else,,lots of work,, this wasnt straight forward were still half way throught the conversion as nothing fits so having bits moulded,, anyway after reading the forums for help iv come across a lot of talk about engine conversions iv read lot of ideas and opions ,, and ive decided that iam going to do a 4,2 v8 twin turbo audi conversion,,,, what iam looking for is there anyone who has done this,, pictures or info,,, lots of people have talked about it but havent heard of it done,,i no theres a ls v8 being done,,and a few others but not a audi, all help would be gratefull, ,

JTP · 12-30-2010, 09:18 AM

IIRC, Brad started out trying to do a 4.2L V8 but it didn't work for some reason. He then went onto the LS1 V8. I don't think he has finished yet.

Adam · 12-30-2010, 09:21 AM

With enough time and money I suppose anything is possible, I mean I've seen cars with jet engines. However I don't think it's very feasible putting a V8 into a Boxster. I'm sure you'd lose operation of the top or more likely the top and the decklid would have to go all together. There would be a major packaging problem. Some major chopping would have to be done to the firewall and body panels, plus all kinds of other custom work. I'd imagine a conversion like this including the engine would cost upwards of 100K dollars.

The Radium King · 12-30-2010, 09:28 AM

long thread on this by brad on the *i think* 914 forum. from what i remember, the intake sits too high on the audi v8 - the engine is too tall for the compartment.

tattoo-1 · 12-30-2010, 10:33 AM

as i was searching the net i came across a forum on this conversion,,,
audi 4.2 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

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?

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.
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.

Boxster motor has big tall intake and a bunch of systems on top of the motor. Audi V8 intake nestles down in between heads. I dont think it would be too tall, but with measurements I will start to learn what will need to be done. There is already a big hole over the top of the stock engine compartment with a removable cover. Tis is located under the convertible top. Firewall also already has a cut out as well with a plate that bolts over the area.

Porsche 914 guys shove Chevy V8's in their little mid engine cars all the time with no or very little sheetmetal mods.

did a lot of measuring and head-scratching for the 4.2L V8, and I'm pretty certain about 2 major points:

1. It fits in all dimensions. It might be about 1" too tall at the back of the intake manifold, but that is not a big deal as there is plenty of room under the convertible top.

2. The transmission from the base Boxster should bolt right up to the V8 and it even has a place for the Audi starter snout. The gearbox on the S would have to be slightly modified, but it should also bolt right up.

pics and al info very much gratful

Adam · 12-30-2010, 10:54 AM

You are talking about a highly specialized and expensive project. You might have to be a pioneer and blaze the path yourself because I doubt anybody else in the world has ever dropped one of these audi engines into a boxster.

tattoo-1 · 12-30-2010, 11:36 AM

as before,, theres a lot of talk and info on the net about,, sizes ,measurements etc,,, but apart from the talk and wondering dont seem to be anyone whos done it yet,,,,,iam not a Mechanic but have done a few projects over time,, ive already clapped eyes on a 1997 Audi A8 4.2 V8 Quattro, complete car,, i also have been offered a bi-turbo set up for this car,,, so looks like iam gona be the first,,, i wont be doing the hard work lol,,, i have a mate who speacializes in audi and bmws,,, so hopefully might make it a bit easier,, conversion is gona take place out of the car,,, once tranny ,and lump up and running then will be slowly,, added to the shell,,, i will post pics as things go with all problems,

just a update on front end conversion,, 997 turbo front bumper is 2inches wider than boxster wings,, 997 lights will not fit boxster wings without making new seatings,, boxster bonnett needs to be rouned in corners to fit 997 bumper,, all front end nearly done,, wings widened,, bonnett rounded,,, seatings for light be fitted,,,
next widening the rear by 4inches a side

jmatta · 12-30-2010, 01:49 PM

If you can make this work, I'm sure many here will be watching. Turbo front won't fit the car without a complete widebody conversion, so I guess have sawzall and go at it. Might as well cut out the center and stuff the V8 in there whilst at it!

tattoo-1 · 12-30-2010, 02:42 PM

thats right you cant add a 997 turbo bumper and lights front onto a boxster wings and bonnett,,, as stated boxster wings had to be widened,,,and new light seatings had to be made,,,in progress ,,,will add pics when into primer stage,, everything can be done with time,,

husker boxster · 12-31-2010, 05:42 AM

Please fill our readers in...

What is it you're attempting to accomplish here? Are you looking for more speed? Or do you want to create some show circuit piece? And what year is your Box?

If you're just looking for more speed, why don't you purchase one of Jake's high buck / big HP motors? It would cost you much less in the long run.

JTP · 12-31-2010, 11:06 AM

This is an ambitious project, though in the opinions of many pointless and unnecessary like the V12 conversion a forum member was attemping a few months ago. I wonder if he ever finished.
I wish you well and good luck though.

tattoo-1 · 06-03-2011, 10:46 AM

wasnt going to add any pics until finally finished but thought it looks different,, how do i upload pics lol

The Radium King · 06-03-2011, 11:28 AM

how well do the 987 headlights fit into the 986 fenders? do they sit relatively flush? how difficult to fabricate the new seatings? i've sometimes wondered if it was possible to put 987 headlights into a 986 and fabricate a jigsaw piece to fill the gap in the fender/bumper.

ps, air (american international racing) sell a set of relatively inexpensive rear flares for the boxster (you noted in a post that you wanted to widen the rear).