Boxster Subaru conversion interest? (Now with Audi V8 content)
 

I'm doing a Boxster/Subaru engine conversion and I was wondering if there is an interest in a build thread here. Not sure what the demographic is here or whether most are purists, but if people are interested in watching, I'd be happy to post up some information/pictures as I go along.

Boxster engine in a Subaru or Subaru engine in a Boxster? :)

Sure, there's always SOMEONE interested. If you are talking a Subie engine in a Boxster, I'm sure there would be more interest than the other way around. Are you gonna try a WRX motor or a Legacy H6 motor? You would probably have less trouble with a 3.6R swap as you would not have to worry about intercooler placement. Either way, it sounds like it will be quite the project. Keep us informed.

Steve

I'm a "purist", but I think a swap like this would appeal to a number of folks out there as an inexpensive alternative to a blown M96 engine. Plus it is a "boxer" configuration, so it's far better than some domestic transplant :eek:

I'd like to see this!

If it's a Subaru engine in the Boxster, what engine are you using? I don't think I'd like the 2.0 turbo from my WRX in my Boxster as much as I like my 3.2. The Porsche engine has a much wider torque band and has so much more character. The Impreza engine, as fun as it is, is more like an on/off switch in comparison.

I'd also think the gearing of the Boxster would need to be altered. The WRX has short gearing and it's still easy to catch the engine off boost going around sharp corners. The Porsche has taller gearing in general.

Just to clearify, I will be putting an STI motor, into a Boxster S that I bought with a blown motor. Why anyone would go the other way around is beyond me... :confused:

Interested. I look forward to seeing more.

Yup. Interested!

fyi, there is a thread in another forum (914 i believe) where a capable-sounding fellow was looking into putting an ls1 v8 into the boxster. while that may sound a bit silly, the ls1 is about the same weight and dimesions as the m96. most of the thread goes on about all the work required to modify/fabricate bell housings and starter locations, but one of the interesting side notes of the whole thing is that the cayanne and audi v8's are both direct bolt-ons to the boxster transmissions. the author of the thread actually admits that an audi or cayanne conversion would be much simpler, but didn't pursue it as he couldn't afford to buy the engine (an ls1 is much cheaper). apparently the audi or cayanne would be less expensive in the long run given that transmission modifications are not required.

long story short, have a look at putting an audi v8 in there - might be easier.

very interested. keep us informed

If you are talking about Brad Roberts, I know him and I know he's working on the LS conversion into a Boxster. We have talked at length about it. Bottom line, he is going that direction, and I am going the Subaru direction. The problem with the Audi/Porsche V8 is they are HUGE with their DOHC 32 valve design, and massively top heavy. Also, engine management could get expensive. In both of these cases, the Subaru and even LS motors are better for the Boxster than the German V8. No don't even get me stated on the cost of replacement/upgrade parts... :matchup:

It sounds like there is some interest in atleast watching the project here so I will post up some pictures as I go.

A Cayenne engine in a Boxster sounds interesting. A V8 Audi engine sounded interesting until I spoke to my Porsche Indy who could not have more bad things to say about their engines after I mentioned an interest in buying an R8 once the prices had come down.
Subi Boxer engine would be pretty bad ass. A guy in one of the many autocross clubs around here made some exhaust mods to his and it sounded like a .50 caliber cannon.

Cayenne V8 = Audi V8. It's the same thing.

I wanna see this

very interested in a build up with pix!
-Jimmy

Very interested as well. I own a 2008 Subaru Legacy GT, which has the exact same engine as the STi except with a different turbo (and obviously engine management).

The 2.5 liter Subaru engine is capable of safely putting down 350awhp without modification to any internals and with a mildly upgraded turbo , as long as it's got plenty of fuel and is running a solid tune. The only real soft-spots internally-speaking are the pistons & piston rings, which seem not to like detonation as much as perhaps some forged pistons would :)

In stock format, with an opened up exhaust and conservative tune, 280-300whp is easily accomplished with no other modifications.

At the same time, expect peak torque (of about 300+ lb/ft) to be delivered by 3000rpms and power to stay on until 5500-6000 rpms.

I think Porsche purists would miss the buttery smoothness of the flat six engine and how it never gets out of sorts, even at very low rpms in higher gears, but otherwise the engine is a great replacement if someone can make it work.

I'm not worried about the intercooler...plenty of ways to make that work....but I'm curious about the transmission adapter, starter mounting, and electronics.

Also, I think the boxster 5-speed's gearing is actually ideal for this engine. The taller gearing means the turbo will get a higher load, which means earlier spool while giving some nice long-pulling times. Combine that with the drop of ~300-400 pounds + 2 less wheels to drive, and I think the engine will drive like a dream.

Good luck to you. This is one swap that's been waiting to happen.

Interesting discussion going on here. I have an 08 STI with a TBE and a stage 2 tune. It is putting down 340 HP to the wheels and 390tq. This is my second STI, started with an 06. I also just got a 2011 Spyder. The 2 cars are totally different, my STI is my DD and the Spyder spends most of the time in the garage covered. The STI is an in your face kinda car, it's ruff around the edges and just want to be driven hard all the time. It is the funniest cars I have ever driven, that is until the Spyder came along or along came the Spyder :). The STI handles very well and I love to drive it when the roads are wet, it slides through corners with total control.. IMO the high roof line makes it a little top heavy and at limit driving does under steel some. The Spyder on the other hand is the cut above the STI in every category , the most neutral, balanced, smooth car I have ever driven and that includes a GT3/RS. The handling is almost like the car reads your mind, it's like you move your eyes and it's there. Putting and STI motor in a boxster would be cool, you might have some fit issues with the motor and as you mentioned the trans, but I think the idea is a good one. That would be one bada$$ car. Good luck with it if you decide to do it.

pcw

It's not a question of whether or not I'm going to do it. It's already started. I have a donor car already (a 2000 "S" with a blown motor) and I already have the first adapter plate finished. Here are the initial pictures of the project...

Nice work! I didn't realize you were the guy that did the Subaru engine in a 911. I saw your site a few months ago and saw your videos on your exhaust also. Nice work on those as well. With a race prep shop at your disposal this conversion should move right along. Looking forward to see the progress.

ot - where did you find those rear flares?

Ahh, look at those banjo bolts. Makes my eyes water.

Make sure to check the Banjo on the turbo side for a filter INSIDE the bolt. Remove it, if it's there. Subaru used it on some models, and has since regretted that decision.

Wow this is an awesome custom Porcharu! That adapter plate is so clean! Did you make it yourself?

I have done some Subaru conversions in the past as you guys have stated. This one is going to be the newest, and I believe, the best. The adapter plate and flywheel are all my own design and the complete kits will be manufactured in-house. Basically, we will be making two forms of the Boxster conversion... a street version, and a race version. This first test car is going to be a race car so that the components and systems can be tested under the most severe conditions prior to being released to the public. I didn't want to come on here and start name dropping my business because I'm not a paid advertiser, so I figured I would just post this as an informational thread, however, I will answer as many questions as I can without giving away any proprietary information.

Sorry man, I didn't mean to expose you but the photo of the car in front of your shop window was a dead give away!

Oh I don't mind being "outed". It's one thing for you guys to say something, but it's something completely different if I come on there and start trying to "sell" stuff without being a vendor.

P.S. maybe a moderator can contact me about becoming a sponsor... :rolleyes:

Test fit the engine today to see how it fits. It's almost like it was meant to be. It almost looks like the turbo might be able to fit in the stock location on the engine, although that's not what I will be doing on this car. There is almost 6 inches between the crank pulley and the engine bulkhead which is WAY more than the stock M96 engine.

Next is motor mount fabrication.

http://i180.photobucket.com/albums/x...z/IMG_5475.jpg
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That's awesome. Will you loose and ground clearance with the Subaru oil pan? They hang pretty low. Are you using the Porsche axle shafts? What's the weight difference from a 3.2?

Freaking amazing!! :cheers:

LOL I thought I was pretty good swapping out the transmission in my 325i lol. :dance:

This is top shelf work man. That adapter plate is gorgeous, I definitely envy your metal skills! :D

Nice job! This is going to be ridiculous!

The 3.2 engine that I pulled out weighed 450lbs. This Subaru engine should weigh about 320lbs which includes the turbo, exhaust, and intercooler.

The oil pan doesn't really hang down much lower than the stock M96 pan, maybe an inch or so depending on where I decide the final location of everything will be.

what a great project!!! flat four turbo in a boxster ! I want one !

Finally, a Porsche with a reliable engine!! :D

100+ pounds lighter. This keeps getting better.

Earlier I noted some of the engine charactoristics that I like better about the 3.2 than the 2.0T. I've never driven an STi. I imagine the low end torque off boost is better from the 2.5L engine than it is from my 2.0. Is that your experience if you have happen to have driven both?

Prototype motor mount/cradle is finished. It mounts using factory hardware locations, and requires no chassis modification or welding. The bottom of the cradle also acts as a skid plate of sorts since the oil pan sits about a half inch lower than the stock oil pan.

http://i180.photobucket.com/albums/x...z/IMG_5556.jpg
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Wow, pretty darn cool. Subscribed, and definitely interested...

What a great project! I've seen a wrx engine in a 914 before, but never in a 986! I'll be keeping an eye on this project for sure. Keep up the good work, this is extremely interesting.

SB

You don't really need to access the oil filter :)

That oil pan is pretty heavily "messaged"

I think this project you're doing is awesome, but gotta ask...in the original engine, there was a steel rope like device that is used to prevent the engine from breaching the firewall in case of a rear end collision. Will you be adapting something similar as a safety feature?

the oil filter will be relocated. I never did like how Subaru placed the oil filter right next to the exhaust. Also, this car will be using an Accusump anyway.

Oh, and that oil pan, that's the way they come from Subaru. The '06 and new egines had that weird shaped oil pan. In the Subaru, it actually makes it easier to get equal length headers.

haven't addressed this yet, but it has been considered