2.7 Engine build options

[KEMLIN]

I have a 2001 Boxster with the 2.7. I've been considering doing an engine swap to an Audi variant of some type and doing research as to what it takes other than the nuts and bolts. It hits me that the easiest solution to my lack of power would be to do a performance build on the 2.7 in the car versus swapping in something different and dealing with the electrical side of things. There seems to be little to no support for making real numbers with the 2.7 or performance builds that I can find reference to. Any thoughts on why there are no good go fast options?

[Hasdrubal]

Is it easier though? Since the 911 engines fit the same, there's not much incentive to bore/stroke the 2.7, and the compression ratio is already pretty high, so new pistons probably won't help unless you want to run race gas. Fabspeed offers some exhaust options that look and sound great, but I'm not spending that much compared to the purchase price of the car. I've seen people swap later model airbox/intake parts, but there's not a lot of room to mess with the airbox, probably easier if you drop the engine.

My plan is if my engine goes for whatever reason, then swap in a VW 1.8t and build that for more power. Supposedly you need a new front engine mount and a fairly simple conversion harness, and it's lighter than the stock engine.

[ike84]

This is a very loaded question. It all depends on your goals, both performance numbers and what you want from the final build.

Widely available bolt on upgrades make trivial differences. God forbid you sink a weeks paycheck into that stupid ipd plenum.

Swaps for bigger m96 motors are possible and have been done. Forum sponsor documents them well. The one thing that EVERYONE misses with these swaps though is that the 2.7 intake and exhaust are not properly sized for a 3.4, and many a poor soul have walked away from a $7-10k 200hr project with only 260hp.

Overhaul of the intake and exhaust can be good for an extra 25-30 hp on the 2.7. Yes, it's true. I did it. Woody did too. It's not anything close to stock, but it can absolutely be done (and it's not terribly complicated from a build standpoint).

After that, get two turbos from a Mazda speed 3 and plumb them up. Run at 5 psi the setup should be good for close to 400hp and the flattest torque curve you've ever seen. The internals will handle this, but do not go any further despie how ready it is to keep torquing that knob on the waste gate. When FI kits were being sold for these cars, there were plenty of heartaches for those that got greedy (the rods won't hold).

You can push it farther than that by dropping the compression ratio and jacking up the boost, but be ready to spend a fortune on upgrading internals. Not to mention the poor 5 speed... (It's good to 350ish, maybe 400hp hp according to the one guy in NA who really truly knows them inside and out.

Guys have successfully performed all sorts of engine swaps - LS, 1.7t, 2.0t, Audi V8, and V8 twin turbo (yes, you read that right). It's never been done, but a w12 will work too. Keep in mind though that there are no commercially available kits to accomplish these tasks, and it is an ill advised undertaking for anyone isn't a baller fabricator AND a whiz with wiring/ecu/sensors, etc.

I spent over a year of my life careening down the very slippery slope of this rabbit hole. Be careful which pill you choose sir.

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[Homeoboxter]

I would just buy a Boxster S 3.2 engine, swap that in and go from there. My understanding is that it does not require any modification. You will probably have to install a third cooler though, but that`s recommended anyways if you're thinking of squeezing out more power from your stock 2.7.

[KEMLIN]

I'm getting slowly closer and closer. I've done a number of swaps over the years and had to go as far as security bypasses and entire wiring harnesses that were new/handbuilt. That's a PITA to make a wiring harness. I really like the idea of a 2.0T for performance numbers as well as weight. I'm under the impression that the 400 mark is very attainable with the readily available mill. The big question is in controlling it, is there a stand alone controller that will work and is a plug and play type of getup? Also a Subaru 2.5 seems like a logical choice but I'm battling the same issues with the controller here also.

[78F350]

I like Ike('s) suggestion that the best HP per $ power increase for a 2.7L comes from an intake and exhaust mod. I drove Woody's build that had a 2.7L engine with a 996 intake, exhaust, and tune. I don't have numbers to quantify it, but it felt like a big improvement from a stock 2.7L and is a lot cheaper than putting a full 996 engine in.

For an Audi swap, I don't think you can do much better than what truegearhead did with a twin turbo 4.2L. Time Trial Build Thread (aero, widebody, any other nonsense)


WizardSmokey took a beater Boxster, cut through some unneeded metal on the back end and put a Maserati engine in.


If you want significantly more power that's affordable by just adding some simple bolt-on parts, you have the wrong car. If you are willing to do your own research and create your own adaptations, there are a lot of possibilities.

[Hasdrubal]

Look up Home built by Jeff on youtube, he has a whole series on trying to put an Audi V8 into a Boxster. Very thorough, but not documented like plans to follow. Kind of put together and modified as needed.

https://www.youtube.com/watch?v=qyDBHhwCHJY&list=PLnidW9Wb_Djzz1q9DZcbO9Kena81b1GuY

Also here's a long thread on an Audi V6 turbo swap, lots of modification and then it caught fire, but looked great to me along the way.

https://audisrs.com/porsche-boxster-s-986-audi-2-7-bi-turbo-engine-swa-t61757.html

[KEMLIN]

HASDRUBAL do you know of a place that makes the conversion harness?
ike84 Where does a guy go for tuning? Can it be done on a factory controller or would I have to go to a standalone ECU?

[ike84]

Originally Posted by KEMLIN

HASDRUBAL do you know of a place that makes the conversion harness?

ike84 Where does a guy go for tuning? Can it be done on a factory controller or would I have to go to a standalone ECU?

Stock tunes are all you need. if using a standard TB (which I would NOT) then a 986 tune either USA or row depending on whether you have precats if using an 82mm TB, you MUST flash 996 fuel maps (again either USA or row depending on cats). All you need are the maps, not the full flash.

Don't do aftermarket tunes. I could write paragraphs about why they aren't worth it.

If you want more power, you need more fuel. To do that, you need more air. To do that, she has to breath in and out.

There are a few reasons why aftermarket tunes would help (FI conversion, running catless and enriching afr, etc), but that's a different level than even what the "out of the box" idiots sell.

I don't use that term lightly btw. I did my research, I've talked to their "experts", just trust me in this (if it's possible to trust a random stranger on the internet lol)

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[Hasdrubal]

Sadly nobody seems to make a conversion harness, there's a thread somewhere on here that shows a custom front engine mount, and the guy who did it said he made his own harness but is not interested in selling them. He did say it's pretty simple if you have the pin out diagrams for both cars, then you just match up the signals from one side to the other. I'm at work now but I'll look for the thread when I have some time..

[KEMLIN]

Does anyone have any experience with TOAD tuning software or have one they recommend for remapping this car?

[ike84]

Originally Posted by KEMLIN

Does anyone have any experience with TOAD tuning software or have one they recommend for remapping this car?

Kemlin, I just messaged you back

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[Hasdrubal]

Forgot about this, sorry-

https://rennlist.com/forums/boxster-and-boxster-s-986-forum/1149877-1-8t-boxster-6.html