Impressive! Bummer about the axle though.

Thanks Bruce! Went over to the shop today and fixed it, took about an hour. This time it actually sheared the axle right in half!! :p

I figure if you are not breaking things you are not trying hard enough!

http://986forum.com/forums/uploads02...1463344348.jpg
http://986forum.com/forums/uploads02...1463344366.jpg

Hi John,

nice video, thanks.

Well, seems to be you car is an axle eater. :D Maybe you have to look for a kind of GT2 axles. :D ;)

Regards, Markus

Thanks Markus!

Yeah they definitely seem to be the weak link. I've contacted a few companies and I know it can be done, it is just a matter of cost. I know one company can do them, but cost is like $2800 which to be honest is more then I'm going to spend on a solution for now - i'll just not drag race it anymore in the mean time :)

Hello John,

well, 2.800 USD is a lot of money. The OEM 986S axles should be able to handle around 500 Nm in normal street use. But on the drag track that might be different, because of a different grip situation - less slip.

Also maybe it's good that the axles are the weak part, because if you always would need a new gearbox or differential this might be much more expensive journey. ;)

Regards, Markus

Yeah from the research i'm doing the factory axles "should" be good for about 550HP, but considering I am trying to get the car tuned and will be making very close to that number I really need to find a better solution. The good news is that used gearboxes are fairly cheap so if that breaks I can get one for like $1200, cheaper then upgraded axles!

Oh yeah so the #1 company on the list for upgraded driveshafts quoted about $3500 for a custom set of axles. F-that. i'll break a few dozen more cheap ones for that price. UGH.

Hello John,

i don't think the HP is the main problem for the rear axles. It's more the torque. 500 Nm is equivalent to approx. 370 ft.lb.

Regards, Markus

Axles
 

John it's more the angle of the axles causing the problem. What does Renagade use to prevent the problem?

Haha well I'm way past that already so another solution is indeed necessary!



No I don't think it's the angle, it is not much steeper then stock.

Renegade didn't have any solutions other then changing them out every 3000 miles at the time. I have decided not to waste any more of my time talking with them. They were moderately useful during the project and that's about it. Lots of run around and vague answers.

The problem is the components are not strong enough to support the power the car is making under race conditions. Mind you these axles were OK for the last 3000 miles under relatively normal street use. I think the multiple hard first gear launches and even harder shifts into second just killed it.

I am talking with another company and see if they can come up with a solution, otherwise i'll just keep using cheap axles and won't drag launch it in first gear! :eek:

Thanks
J

How much different are the 996 turbo axles?

Just thinking aloud here, but I wonder the effort involved in swapping to a 996 turbo rear hub. I ass-u-me that the bolt pattern to the trans is still 120mm, so all you really need to do is get that axle though the bearing... which typically requires machining out the hub for the larger outer diameter, or just swapping the whole knuckle.

I've never seen a 996 rear hub or knuckle, so I have no idea how far into left field this is is...

The knuckle are a lot different due to the achitecture of the 996 rear suspensions.
I'm sure you can find ones for less than what the 1st company quoted you :)
Good luck !

I thought about going down this route, but to be honest the though of acquiring the parts alone turned me off due to cost, it all adds up really quick.

I am talking with another company who has a great reputation, if they come up with a good price then i'll go with them, otherwise I'm going to piece a set together myself using Porsche 930 CV parts. Lots of stuff readily available out there as they use the 930 transmission in a lot of off road and dune buggy applications.

Yup it would require quite a bit of work and added expense which is what I'm trying to avoid! Hopefully this company I'm talking with can come up with a reasonable setup.

How much is reasonable you ask? Well that all depends of course! To build them right with what I would call "the good stuff", I think If I can get them done for $2500 or just under.
It all depends on the parts you use though, I know I can build them for less and probably save $500 or so, but how long will they last?

Nice thing is if I build them then I can rebuild them easily enough and then I could upgrade whatever fails later.

Either way I'm kinda broke right now so we will see, hopefully my ebay stuff starts selling! Anyone need a 3.6 Liter 911 engine?!?!?! :D

Crazy idea, maybe the front carriers from a 996 TT? Since the base boxster uses the same carriers front and back and S uses the same style but beefier in the back, maybe that could work?

Yeah thats kinda getting back to the more effort then it is worth category, plus parts etc. definitely would not end up cheaper~


So regarding the axles it looks like the best solution is going to be to make a custom set using 930 CV joint setup. They are commonly used in off road conversion and high HP applications. Many different parts available but it could be done for as little as about $1,600... That includes custom stub ends, "high performance" 930 CV joints,bolts pre-drilled for safety wire, flanges & boots and would use a chromoly axle shaft.

Me, I'm a do it once kinda guy so if I were to do it i'd prefer to use all the high end stuff. This of course bumps the price up quite a bit by about $1000~, biggest differences being upgraded CV joints and stronger axles.

Either way, for right now given my current budget for I think the best thing to do is just not drag race it with first gear launches :D Just gonna leave the inexpensive axles in for now~

Exhaust finale wrap up video~
 

Greetings everyone,

So I finally decided to strap the mufflers back onto the V8 car and made a final video here to compare the 2 systems. It takes less then an hour to swap them out once you know what you are doing, although i'd love to build a valved system for it one day, this will have to do for now!

The sound is a bit harsh from the bumper cam but you get the idea. The car is so much more civilized with the mufflers and i'm sure my neighbors appreciate it :p

It still has that great v8 sound but for the unknowing they will probably think the ol' Boxster has got a misfire going on or something.

Anyway I made a video with a little bit of straight pipe vs. mufflers comparison, hope you enjoy it! Still uploading till about 11PM EST so give it a few more minutes and the link should be working~

https://youtu.be/1sc4haWY1L8

Thanks~
J

Hello John,

well – i think you need an exhaust with a flap. So you can regulate the noise level. And i totally agree that the straight though pipes are too loud. My neighbours would kill me immediately. ;)

So a flap with a little extra muffler might be a good idea – just soundwise.

Regards & thanks for the video
Markus

John,
I've been following this thread and just noticed some GT3 CUP axles for sale on rennlist: 996/997 GT3 Cup Motorsports Axles - Rennlist Discussion Forums

No idea what it would take to use these, but figured I'd pass it along.

Ok so I did a bit more research today and one of my buddies at work pointed out something I had not thought of, the ABS ring. DOH>

So to answer all the 911 axle thoughts, no, they will not work. Mainly due to the ABS ring being in the wrong spot. If you don't care about ABS it may work, but i'll let you find that out.

So I tore apart one of my factory axles today and cleaned it up to see if I could use it as a 930 stub. For the record the CV that connects to the transmission is a 108mm joint, same as on the old 930 Turbos which is perfect because those are the joints I want to upgrade to!

The outer joint however is like 104mm and now I have to figure out a way to adapt a 108mm CV to it. I just went and looked and I think it would have to stay the same size until the end then have it flare out to 108mm in order to clear the wheel hubs. Next problem is a clearance issue with the sway bar link because the 930 joint would be so much further inboard then the stock joint. UGH.

I have a few ideas... The first and most expensive would be to have someone 3D scan the stub end, modify it accordingly then CNC it out~ That just sounds expensive. The second idea which my boss came up with is to slightly machine down the stub, then press a something like a 5mm collar that is 1/2" long onto the existing stub so it can be drilled and tapped out to accept 10mm axle bolts.

Once we have the stub in place the rest should be easy, just measuring and building the rest of the axle. heh. should be easy!

Here is what I'm working with, the 986 outer stub and a 930 cv joint cover:
http://986forum.com/forums/uploads02...1464233904.jpg
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Hello John,

i have a stupid question. The axle itself is fixed with a circlip at the transmission side and at the outer side you can also disconnect it (did it when changing my axle boots). Isn't it maybe possible just to change the axle itself and take the inner and outer parts as they are?

Regards, Markus

Part of the problem is the CV joint Markus, the stock joints are wearing out very fast, like within 3,000 miles the joints are worn enough to cause vibration while accelerating.

I am still in the discovery phase so if I can figure out a way to build a good axle setup then great, if not i'll just sell it as-is and let the next guy worry about it.

Thanks for the info, John.

Well, i have to admit that i have no idea how to solve that in an easy way.

Regards, Markus

Hey JJ did Steve have a good solution for your axle problems.

Did you get the video links and pictures I sent you?

Hey Randy,

Yes I did, very cool!

I spoke with Steve and while I'm sure what he does will improve the situation, I'm not sure i'll be 100% happy with it. Basically supplying factory axles which he would then be "race prepping" the outer CV joint. That is all he wants to do which is basically changing to a chromoly cage and put in "good" axle grease. Not sure that is going to solve my problems, but rather buy a bit more time.

A big part of my concern is the wear on the outer CV housing as this is causing me to wear out the axles in about 3,000 miles or less. Steve basically said I could expect to get 3x more life out of them which is roughly 9,000 miles, then I have to find a new set of factory axles, rinse and repeat.

I am going to talk to fabrication shop near by and throw some ideas at them to see if I can come up with a better solution. By better I mean longer lasting, stronger and easily replaceable or able to be rebuilt by me rather then having to send them back off to Colorado or wherever.

I am also going to talk with them about producing V6/V8 conversion parts. I've been looking around lately and am thinking that the newer 3.6L V6 from the 2012+ Camaro could be a good replacement for bad 986 motors. They make 323 HP, are pretty compact so hopefully the conversion could be done without any cutting of the existing structure and from what I can see used motors are fairly cheap and plentiful. Just be a matter of the full integration with wiring etc. which means you likely need a throttle pedal etc. and I don't think Chevy makes a plug and play type setup for the V6 motors like they do the V8s. I'll start another thread on that once I gather a bit more info.

Thanks
J

A v6 swap would definitely be a good idea!
Lighter, smaller, sounds good (to me at least), plenty of power, and probably cheaper to get!
And you'll get the Cv axle more aligned since the engine will be shorter!

Thanks for the feedback Ben,

Hopefully the axles wouldn't be an issue! It does look like an interesting opportunity as it "should" be an easier install etc. Right now Chevy does not seem to be offering a "crate" version but used ones seems to be available for around $2K~

Plus you could still get crazy if you wanted as it looks like the mounting for the V6/V8 would be very similar so if you wanted to upgrade later that could be an option... Of course I found a company out there who is making a twin turbo kit for the Chevy V6 and making 575HP so that could be an option too!

I'm definitely spinning the wheels on this one so any other feedback would be appreciated.

Thanks!
J

Well I went over and talked with my engineering/CNC guy and looks like my initial "economic" thoughts are pretty much out the window :( I'm about to give up on this, I don't know if there is going to be any inexpensive way to completely solve this.

Does anyone know what size the outer CV joint are on later model Boxsters/Caymans? Mine is about 104mm and I need to be able to fit a 108mm in it.
Would later model rear suspensions/wheel carriers stuff bolt up to an earlier car?

Does anyone have a low mileage set of factory S axles laying around? Mine are shot but may be able to get some 60K~ axles, if anyone can do better then that get in touch.

John - I did a little research on the GM V6 (Camaro) motor after our call today.

2012-2015 Camaro V6. 'LFX' 3.6L aluminum motor/aluminum heads DOHC. It makes 323 HP @ 7200 rpm and 278 Lb-ft @ 4800 rpm. I couldn't find the weight on the motor but my guess is that it's lighter than the stock Boxster 3.2L.

I'll see if I can find some dimensions on the V8 so we can compare them to the LS. This could be pretty sweet build :D

I found the weight. GM claims 345 Lbs and Porsche show the boxster motor weight at 399 lbs. So, the LFX looks to be about 54 pounds less...

I agree, I think it would be a great replacement option! Finally got a call back from the V8 Miata guys and they are pretty tied up with other projects until later this year. I was told they have already come up with an adapter plate setup which is there own custom doing and not a Kennedy Engineering piece, although that is about all I got from them. I've got a message in to their Engineer who is up in Tennessee so hopefully he will call me back.

I also put a message out to Kennedy Engineering but no word back yet. My fabricator could definitely come up with a good mounting system but an adapter plate and clutch setup may be asking a bit much.

Next step I think is to figure out some dimensions as I'm pretty sure there will be some height clearance issues. See how bad we are off and figure out options to correct it. Might be as easy as modifying the engine cover or may take a redesign of the intake manifold.

Between the adapter plate and clearance I think those are the biggest issues. A few other variables to work out with regards to the fuel system etc. but nothing major I think.

I think it can be done. Let's figure it out :)
J

Looks like Kennedy Engineering has an adapter plate setup and clutch available, but you need a special tool to modify the transmission apparently which they have available to rent so it is do-able.

I'll try and stop by my fabricator guy and see what it may take to come up with a mounting system for it...

John, I noticed in another post that you talked about doing the LFX swap in a non 'S' boxster. I like that idea because there are so many more non 'S' cars out there and the prices are getting super cheap. Other than the 6 speed tranny, why would the 'S' car be better for the LFX? In my opinion, you're going to upgrade the brakes anyway and then a suspension upgrade is probably a close second in any car...

You would also need to upgrade the cooling but I see where you are coming from. Renegade actually used a non-S car for their prototype.

At this point I don't think i'll be pursuing any more Boxster projects, i'm already in the hole to deep on this one. Unfortunately I don't have an endless bag of money to try new things, and personally I have no real interest in a "V6" boxster, just thought it would be a good option for people to keep these cars going.

V8 car is going to be put onto Ebay soon to hopefully find someone who will enjoy it as much as I have. Hopefully they will have the time and money to finish off the gearbox/drivetrain then the car will be 100% awesomeness.

While i've had my fair share of cars I know i'm not the most experienced out there, but I've put almost 5000 miles on the V8 car and must say, it is the best car I have ever owned.

I appreciate everyone following along on my crazy little adventure. Hopefully I've been able to help some of you out along the way, either with your projects, or your decision to take it on at all :D This is the end of the road for this project... I'm tapped out.

:cheers:
J
http://986forum.com/forums/uploads02...1466858527.jpg

Project V8 Boxster
 

Thanks John for everything I learned a lot from your build. I was gonna do the same swap to, but since you had some troubles and the cost I decided sell boxster. I have now purchased 996 which is cheaper to do , has less problems and can handle the power.Again your post gave me a road map on how the swap is done. good luck.

You are quite welcome. Unfortunately this is the exact reason I have lost interest in pursuing further modifications/kits for the Boxster. Reality is that spending that much money on a Boxster just does not make much financial sense for most people as they are not/do not hold their value like a 911 and never will.

Even though IMHO the Boxster/Cayman is a much better platform, now that Porsche has started to wise up and offer some engines with a reasonable amount of power in them the V8 swaps make less and less sense. Although there is no replacing that V8 sound, which reminds me I need to take off those stupid mufflers, the car is so much more fun to drive when it is loud as hell :D

I imagine a 911 swap would be easier, hopefully I can sell the V8 Boxster and get to figuring out the next project soon. Not sure if i'll do another swap or just try and build a fast fun car with a 996TT, or a Cayman set up for 1/2 mile drag racing? Who knows~

Hello John,

if you will start another project and document it i would appreciate if i could follow it. Always liked this thread and the 986 V8 and even the V6 idea.

Hope you'll find a new owner for the V8 986 rocket soon.

Regards from Germany
Markus

JJ I think you hit the nail squarely on the head - the Boxster swap is too costly. I was seriously looking to have you do a swap until I started adding up the numbers - shocking

I bought bought a 2013 Boxster S instead. A one owner PDK car with 4340 miles and 16 months warranty remaining. I bought the car for not much more than what the V8 conversion would have cost.

I have talked to several other folks that convert tired Porsche's into V8 monsters - the 911 platform is the ticket and to a lesser extent the 914. None of them use Renegade they do their own stuff.

Many thanks for sharing this build with us - it was enjoyable and sadly an eye opener. Let me know what your next project is.

FWIW...Audi V8 starter is on the passenger side, under the motor mount. Stock Boxster starter is on top of the stock motor, which means the starter opening for the Audi engine needs to be on the side, where it is not on a Boxster...gonna have to use an Audi transmission with that v8 Ccnversion...and aside from O1E manual trans, you might as well use the Audi automatic.

After looking into it more, I think that there more issues. I think you could modify the bell housing on the 6 speed to work with the Audi starter or just use the VW/Audi/Boxster five speed. Personally, I would never do an automatic.

The height of the Audi V8 for one would pose a problem, or more precisely the distance from the crank to the top of the engine. Although total engine height is very close, the M96 has the crankshaft much higher vs. the Audi engine. This MIGHT be a good thing if it would be possible to lower the transmission on the Boxster a few inches. While the Audi V8 is short, it makes up for it by being pretty tall and wide. The width at the bottom is not an issue with a Boxster, but the top end may be.

There just doesn't seem to be very many good engine swap options for Boxsters with the M96 that is fairly short lengthwise, short in height and very wide.

While I don't know much about them, I wonder if a tweaked Subaru 3.6 (EZ36D) would be a viable option <ducking> The design of that engine is much more like the later Porsche engines with a single front mounted timing chain, closed deck block, 4 valve/cylinder, variable intake and exhaust timing, mounts in the right place, etc. I bet it would even sound right. You can find them for $2k or less. That might make an awesome lemons Boxster...

A Cayman S box bolts up to an Audi V8 with the starter in the right place. That's what i'm using on my Audi 2.7T build.

So Audi has built only one V8 engine ever and Porsche has only built one gear box in the Cayman S ever.

And these both fit together.

Hm. :D

Regards, Markus