BoxsterLS376 introduction - LS3 conversion :)

[BruceH]

Impressive! Bummer about the axle though.

[BoxsterLS376]

Originally Posted by BruceH

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!!

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

[Smallblock454]

Hi John,

nice video, thanks.

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

Regards, Markus

[BoxsterLS376]

Originally Posted by Smallblock454

Hi John,

nice video, thanks.

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

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

[Smallblock454]

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

[BoxsterLS376]

Originally Posted by Smallblock454

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.

[Smallblock454]

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

[shockandawe]

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

[BoxsterLS376]

Originally Posted by Smallblock454

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

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

Originally Posted by shockandawe

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

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!

Thanks
J

[Bayley]

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...

[Ben006]

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 !

[BoxsterLS376]

Originally Posted by Bayley

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...

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.

Originally Posted by Ben006

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 !

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?!?!?!

[steved0x]

Originally Posted by Ben006

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 !

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?

[BoxsterLS376]

Originally Posted by steved0x

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 Just gonna leave the inexpensive axles in for now~

[BoxsterLS376]

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

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

[Smallblock454]

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

[Stroked & Blown]

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.

[BoxsterLS376]

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:

[Smallblock454]

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

[BoxsterLS376]

Originally Posted by Smallblock454

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.