Engine swap: Audi 4.2, LS3 or 3.4?

[jpnovak]

So, I have always loved the Boxster since it came out. Financially out of reach.

Fast Forward to now. I have found a local 98 Boxster with what appears to be a D-chunk failure. It may be something else but the hole in the case means bad stuff happened. So there is a car. It has reasonably low miles and needs an engine.

Not being one to keep things stock I have been looking at engine swaps for a while.

here are what might be my options.

1. Audi 4.2 V8. yes, I know this can be complicated. The Audi 4.2 has the same bolt pattern as the Boxster so the transmission is easy to connect. I might have to work out something with the flywheel. Too bad they never sold the A8 with a manual. I would have to work out the electronics but this should be relatively easy as the 98 is a non-CAN car.

2. Ls3. I know, its a Chevy. But this engine makes gobs of torque everywhere in the RPM range, is cheap and reliable. Renegade just released their conversion kit. If its is similar install quality to the 996 variant I think this is a winner. the downside is that the kit is almost as much as the engine.

3. 3.4 swap. This would be the easiest. Simple to install but would require an ECU flash. Then there are still issues with the same problems that plague the M96 motors. yes, it would get an IMS bearing update before going into the car.

4. Stock engine swap. Just buy a used engine and bolt it in. Simple but not nearly as much fun as more power. In such a capable chassis I know I would want more. Turbo or SC kits are not any interest on a stock setup. Just too much stress on an already strained engine.


So, What have others done? How many have done a swap.

[The Radium King]

ENGINE, 99 2.5 40k miles 270hp with/or w/o TPC Supercharger - 986 Forum - for Porsche Boxster Owners and Others

996 911 3.4 engine for sale. - 986 Forum - for Porsche Boxster Owners and Others

[Super 90]

Well... I have an Audi 4.2 V8 in an Audi S5 and it pushes that heavy car along quite nicely, I do say. Can't contribute to your technical questions, but I do love the engine in the car it's made for!

[Cannonball996]

dont get me wrong, I like boxsters, owned a few, but no matter what you do to a boxster its always going to be the next best thing to a 911. for me it would be hard to justify spending 911 money, building a boxter. if it were me I go with a stock replacement engine, do an IMS fix, lighter flywheel and better clutch, and then try and find an LSD for it.

[The Radium King]

911 engine in a boxster is a better car than a 911 for less money. all of porsches best cars were mid-engined (904, GT, 918, 960, 917, etc.). and you can't dis the fit-up, as the 986 shares the same front end and interior as the 996.

i say go for it, then get on the track and suprise a few gt3's. easiest swap is another porsche engine (check out the engine swap article in the tech section of this site); audi will be hack, and the ls swap is going to get expensive as you have to remove all the auxilliaries to make it fit and locate them elsewhere. precision chassis works does a pretty skookum subi conversion that would get you 400 easy hp in a light package.

[jpnovak]

Great comments. Keep them coming. I guess I missed on the dead Boxster by about an hour. It just sold while I was waiting for a return phone call.

I do not see the Audi as a hack. It is still Bosch Motronic based. I will probably have to run a new engine harness or at least a few extra wires for the two new cylinders but everthing else should interface quite easily. The reason I like it is that the 4.2 engine fully dressed with electronics can be found for about $1500 with reasonable mileage. 340HP with low end torque should motivate a Boxster with authority.

Yes, the 996 swap is the easiest. I have read all the articles. Figured I could do it in about 2 weekends.

btw, you forgot the 914 in your list. I have a 300HP WRX powered 914. I figure if I can sort out JDM wiring with non-english manuals then the Audi swap will be no problem. btw, Its fast and raw but not a convertible my wife would drive and it has no AC for the TX summers.

I am still amazed at how expensive 996 motors are. I guess its just demand. I could buy an entire wrecked car for the price of a motor. And yes, I could build a 3.4 powered Boxster for less than a 996.

[mikewood]

If Porsche ever delivered Boxsters/Caymans with 911 type horsepower, the 911 would become irrelevant...

A friend looked into the Subie swap for his early 986, but ultimately decided to go with a simpler 3.4 swap. The LSx is always the right answer, if bang for the buck is the question, as far as I'm concerned.

[The Radium King]

sorry, by hack i meant that there are a few audi conversions out there, but none that have been done cleanly. if done properly i think it would be a good option. sounds like you got the skills; make a kit and the cutomers will come! a search on *i think* the samba will show a long thread on the subject.

[txhokie4life]

996 engines are pricey -- and they suffer some of the similar issues.

They are all M96 engines in the end.

If you have the no how and the will -- hard to argue with the LS depending on what you'll be using it for.

m

[Jeff396]

If Porsche ever delivered Boxsters/Caymans with 911 type horsepower, the 911 would become irrelevant...

Amen to that! And if it's the large luxury back seat of the 911 that keeps them from replacing it with a hyper Boxster.....might I suggest a Boxter with a rumble seat option.

Jeff

[Cajundaddy]

Haha Cannonball996, you funny!


Re: A motor swap, it really depends on your goals. If you want to do any Porsche competition or racing, it probably needs to be a Porsche motor. I have yet to see an Audi V8 conversion that didn't look like a science experiment gone wrong. Scott at Renegade has a recently completed LS3 Boxster but I have not seen it yet. A 3.4 is a sure thing and an LS3 could be fantastic. For either I would choose a Box S roller though. The 6spd trans can handle more power, larger axle, bigger brakes.

[Glasgow 911SC]

Originally Posted by mikewood

If Porsche ever delivered Boxsters/Caymans with 911 type horsepower, the 911 would become irrelevant...

Nonsense!

[The Radium King]

cool video. what makes the boxster better than the 911 is balance and lighter weight. looks like fifth gear went out of their way to find a boxster that was actually heavier than a 911, then they drove it like a 911. of course it lost.