BoxsterLS376 introduction - LS3 conversion :)
 

Greetings Boxster friends!

My name is John and I'm addicted to projects~ :)

I have been around the Porsche scene for a bit now mostly working with 911's & 944's, and currently work for a small restoration shop in Marietta, GA called Check Point Auto. I recently finished my last side project so I need a new one to keep me from getting fat and lazy... If any of you are into older air-cooled cars you know that the Porsche market has gone completely nuts and finding good classic project cars for a good price these days is just about impossible!

So I was surfing the auction sites, Copart actually on this one and came across a Nice little 2000 Porsche Boxster S that had "Mechanical Damage". Right up my alley, i'm not a bodywork guy. Well this one appeared to be in good overall condition, Grey/grey and a bit of a sleeper as it didn't have a Boxster "S" badge on the back... (Now that I have it not so much a sleeper as it has a 2 FT long "BOXSTER S" sticker on the spoiler, oops ;) )

I always liked the Boxster but personally think the 2.5 has no guts whatsoever and the 3.2 is merely adequate at 250~HP...Project wheels set in motion!!

I got the car, coolant was a bit oily but oil looked OK and so I fired it hoping for the best and... Fired right up! No crazy IMS noise or anything, so far so good! Car appeared to have a new water pump and t-stat so I was hoping a new oil cooler would take care of everything, put it on and ran it for a few days only to find that now not only was there oil in the coolant, but coolant getting into the oil :( WAH WAH WAHHHHHH :( So I figured it probably needs a head gasket at minimum, probably a cylinder head and who knows what else... i've been doing this long enough to know it can be a very slippery slope!!

Needless to say I'm not very excited about fixing the motor that is in it, so I think we should make it better ;)

BEGIN PROJECT BOXSTER LS376-480!!! Unlike some people while being fairly mechanically inclined I am no rocket scientist and would prefer not to reinvent the wheel - I'll just use someone else's!! If all goes well I plan to use the car as somewhat of a shop demo car with the possibility of doing these conversions for customers in the future... While I'm sure you could probably do this conversion cobbling parts together and buying used stuff that's just not my style - that being said, here's the plan!


I have ordered a Renegade Hybrids conversion kit with all optional parts... in reality I'm not sure why they list this stuff as optional unless you are building a race car, but whatever~

Power will be supplied by a LS376-480HP GM Crate motor with Hot Cam! IMHO this is the only way to go, shopping around I can get the whole power plant with new harness, gas pedal and a few other bit I need for about $8,000. Not cheap but consider buying a used LS1, rebuilding it, adding more HP etc. you will still be in it for $5-6K... plus with the crate motor I get a 2 year warranty!! :)

Factoring in the car, the conversion kit, the new motor, fabricating an exhaust and a few extra parts I have set a budget of $20,000 for the whole project which will likely go over because I will probably upgrade some other bits along the way but that's a pretty solid number.

Well the kit should be here in about 3 weeks so I have gone ahead and pulled the 3.2 from the Boxster and am looking forward to sharing this project with you all!

Sorry for the long winded introduction!!!
John

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There will definitely be some interest in a proper LS conversion. What people will be interested in is how it will integrate with all the existing systems without unacceptable compromises at a reasonable cost. So far there really hasn't been anyone that has done this to my knowledge. Good luck.

Tag
 

I want to watch this. I see you are in GA, i'm in AL so I want to see how this goes.

WOuld love to see it after you have finished

Watching this, sounds an awesome project. Would be interested on how you are going to fit it all in.
Are you going to use the original transmission.?

Thanks everyone,

It will definitely take a bit of work, Renegade says about 70 hours for the install but we will see about that.

I definitely want the car to operate as it would if Porsche would have done it themselves which is why I ordered the Electric power steering, electric water pump etc. because otherwise compromises would have to be made elsewhere.

It does utilize the factory transmission which I'll probably crack open and take a look at while it is out to make sure there are no outstanding issues but it felt fine. I also ordered the upgraded clutch kit as they told me the stock clutch would "work" but would likely slip so no freaking point it putting it in if you know it's not gonna work :/

Integration is my biggest concern as I would like all the factory gauges to work. While it seems like Renegade has the mounting of the motor worked out I'm not feeling overly confident right now with regards to instructions on doing it all as I keep getting told they "have lots of pictures"... hrm... we will see!

Thanks!!
John

best wishes and good on you!

I believe Renegade has done many a 996....very similar gauge pack to the 986. There seems to be very few issues in the gauges working there so hopefully you will be fine

How did you decide upon the LS3 rather than 6 or 7. I guess things to consider are: chassis twist/strength; drive line durability; handling and max tire sizes; drivability; suspension. I would think anything over 500 BHP would be very hard to make use of and scary in a boxster chassis

I wish we could get a look at some of the directions for this kit ?

I hope you can share some of that with us without any legal infringements

Looking forward to your progress! Thanks for sharing your project. Good luck and welcome to the forum:cheers:

Yeah I am hoping everything works out, mostly just rewiring some things and adapters for certain sensors etc. but keeping my fingers crossed.

My engine choice was not really based on chassis twist or anything like that as they have a 600 HP LS7 in one and although I don't know the long term effects, seems to handle the power fine. Basically came down to several things but after running through the options it really made sense... let me share my logic...

1. Used LS1 - good motor but low mileage ones from a vette run about $4000 with harness, you could get one from a Camaro then your down to 305 hp and barely worth the effort. I would rebuild and clean it and of course try to get more HP out of it while it was out, figuring I'd probably spend another $1k-$2k easy doing that plus all my time...

2. LS7 Crate motor - Great motor, fantastic internals forged titanium goodness, but the dame thing only makes 505 HP and costs $12,000 so just didn't sit well with the overall project budget.

3. LS6 - old Z06 motor based on LS1 - again too expensive for what you get, people get a premium for them simply because they were only in the Z06.

4. LS3 Crate motor - Brand new, 2 year 50,000 mile warranty, plug in the harness, add gas and go - no time spent rebuilding. 430 hp from the standard motor, but add the GM hot cam and you get 480 HP for about $7500! 25 HP less then the LS7 but $4,000 cheaper! A bit more expensive then rebuilding and modifying a used LS1, but no time spent, brand new and has a warranty!!!

Heh, yeah well if I get some instructions with it i'll let you know!! As I said I have asked a few times now about this and have been told that they have lots of pictures... sooo not really sure what to expect but I'm certainly not going to publish anything here unless they give me the OK, but i'll be glad to ask.

Thanks Bruce! Nice to see a community of Boxster enthusiasts which seems to be fairly active. I'm on Pelican, LS1 tech and a few others but this seems much better. I'll definitely keep you posted on progress!
Thanks!
J

Look forward to watching your progress
 

Thanks for sharing your project. Great choice on the hot cam edition seems like the best deal per pony. Good luck and can't wait to watch your progress.

Makes perfect sense to me and 480 seems like it would be workable top end for the chassis. Looking forward to seeing your progress, costs, and work. Hopefully the LS3 isn't too heavy as compared to the 3.2

Are they close ?
 

This shouldn't be too hard to find out..what are the net weights of each ?

Renegade says they are very close....but they are also selling the kits !!

This is exactly the thread I have been waiting for. I talked to Scott at Renegade Hybrids a couple of months or so ago about doing the same swap in an S. The choice of the LS3 does seem to be the sweet spot. Weight wise the difference is almost negligible. Performance wise you will have the power of a Porsche Turbo with LESS weight, the reliability of a small block Chevy (bulletproof), same or better fuel economy (who cares) and the handling of a Boxster. Done right, you will have an incredible, no compromise car. Sure, purists will give you a hard time, but they already look down on 986s, so who cares. For the price of building another disposable M96, you will have a super car.

I have concerns about a few details with the swap. First off, with this swap you leave in the original engine ECU (DME, whatever you want to call it), and share the crank sensor with the GM ECU. That keeps the gauges and immobilizer happy. Kind of kludgy IMO, but it works. I guess you just remove the check engine light, as the Porsche ECU will have LOTS of faults in it. I have been researching a bit on how to eliminate the Porsche ECU, but that would be a big project. I like to have things super clean, and I wish there was a way to either "teach the GM ECU to speak German", so to speak, or get the gauges, ABS and alarm/immobilizer to work without the Porsche ECU. The first option would be the cleanest, the second the easiest (IMO). My business is automotive electronics, and this stuff is right up my alley. Ideally, I would want to use a normal Corvette ECU so you would have a car that doesn't throw any fault codes and could go through emissions without any issues.

Second, I'm not sure why they don't use the original power steering pump or a different mechanical pump. I guess that will become apparent as you get into it. There is nothing wrong with using the electric pump (probably Toyota MR-2 setup I will bet), but it is added complexity. From a "cleanliness" point of view, I don't like this detail. I think I would get over it after a few stop lights though.

Next, the intake. Keeping everything under the original engine cover seems to be an issue. Turning around the intake manifold so that the intake is at the back is a no brainer, but that also doesn't leave much/any room for the throttle body. That needs to be adapted to turn 90 degrees if you want to keep the intake from going into the trunk.

I think you will also run into some issues with the driveshafts as it looks like the transmission will be moved back a bit. I bet Renegade has a solution.

If you want some good ideas on how someone else made a "short" LSx conversion, here is a link to an Audi RS6 that got a LSx engine. They the same issues with that conversion that you will have with your Boxster.

I can't wait to see how this progresses.

Yeah I'm sure they are not too far off, LS3 weighs in at 466 pounds, can't seem to find a weight on the 3.2 off hand, but I'm sure it's a good 400+.

The wiring will be interesting, you sound like a handy guy to know for this sort of project! :) I am going to try and make the install as clean as possible, but getting the Porsche and Chevy ECU's to jive will be the hard part. It would be nice to eliminate the Porsche ECU but not gonna happen without lots of work. The guys at Renegade say they can make it all work so I'm going to lean on them quite a bit when it comes down to it.

The steering pump is one of those "optional" things which is not really optional if you want to have the power steering. No room for a standard PS pump on the motor, I'm sure it could be done but in an effort to save space they do use a Toyota electric power steering setup. I just hope it doesn't make things feel funny but I think it will be ok.

I went out to visit and checked out the intake setup. They are working on a custom 90* piece which we route back into the stock airbox so it pulls cold air. Of course it is not included with the kit so time to dust off the ol' welding skills and put them to the test :) Not to worries about keeping it under the original cover as additional bit will have to be cut just to accommodate the throttle body and intake, I'd like to come up with a plexiglass or lexan lid for it to show off all my hard work - to far away from that to worry about it right now!

Axles are a concern but they do not have a solution just yet... I know the cheap Chinese axles are pretty cheap though so I may just stock up on a few sets :D

Thanks for the feedback and link to the other thread, I know I'm going to need some help with this one!
Take care,
J

You might be interested in this:

http://986forum.com/forums/408687-post4.html

Subscribed!

I assume you've seen the other topics on this. Here is a post from when I was out in Nevada visiting Renegade...

http://986forum.com/forums/367504-post15.html

When do you expect your parts to arrive from Renegade? So looking forward to this project build.

Fun project! Scott is a friend of mine and he has done a bunch of 996/986 conversions now. The chassis is talking to the motor just fine on them so you should have no problem with that. Toyota 12v PS and WP are the only way to go. The LS3 is certainly a tight fit but doable and it is a sweet powerplant with monstrous torque.

You may be able to use a Cayman engine cover to fit over your intake. It is a little taller and some have done this successfully. Forget a plexi cover. The way a Boxster breathes by pulling air up from the road surface makes the engine compartment look like a nasty chicken coop after about a week of driving. It ain't pretty and this is actually part of the ground effect in addition to cooling the accessories, trans and rear brakes.

I have considered this conversion but Nazi emissions regs in Comiefornia make a street conversion risky. I would have to register the car at Scott's house in NV and run the CHP impound gauntlet while living here in CA. Too much PITA for me unless it was a dedicated track car.

How is the drivability and handling of the Boxster with the LS3 if I may ask.......I guess one feathers the throttle to get back to where it was originally as far as traction and balance....would you need a huge leep / amount of seat time to handle it? Have wheel widths been changed..square? I have been on track in a Cayman R (I think the engine was stock) and found that to have just an insane amount of momentum.....well it was the old Mosport, lots green and yellow traffic, R comps....anyway it felt way way over my head even in the power department.

What do they do for the exhaust system ?

Exactly my thoughts for CA. I still think that if I blow my 3.2, this would be the best route. make it a dedicated track car and have a blast..

It is amazing. All the standard handling that you get with a mid-engine Boxster, but now you have the power to pull out of corners or kick the backend out. Yes, you can now get yourself in a LOT of trouble, so throttle management will be key. And shifts come a lot quicker :-)

While I don't have this (yet), I have ridden in Scott's car in a spirited drive around Las Vegas...

I find all this very intriguing
 

But this is a lot of "stuff" to stuff up the butt of a Boxster
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Well, that is an Audi V8 along with an automatic, not a Chevy LSx. Audi V8s are pretty short, and will bolt up to the Boxster transmission with the right flywheel, so you may not have the same issues with the firewall that you do with the Chevy LSx.

Integration of the Audi engine with the Porsche electronics is actually pretty easy. Likely even easier than the Chevy, even with the GM Performance engine harness and ECU. I just so happen the proper engine ECU for V8 with manual transmission and no immobilizer sitting on my desk as I type this. You just have to make sure to get the right engine. You would want the 40 valve 4.2 from an '02-'03 A6, S6, A8 or S8 with the Bosch ME 7.1.1 ECU. The S cars will have a bit more hp. Those engines are also pretty light and I would bet you could use the AC compressor and power steering pump as is on the Audi engine, with just some adaptation needed on the lines. Those engines are getting cheap ($2k complete, sometimes less) with everything.

The down side is that the Chevy engine will be easier to make a lot of hp with. With the Audi V8, you will get maybe 350hp, and not much more no matter what you do. Both engines are reliable, but the Chevy would be cheaper to keep with parts available anywhere. I would say that the 40 valve V8 is probably one of the best engines Audi ever made, but if things do go south, you are looking at Porsche-like prices to fix it. The Audi engine will be a bit higher rev'ing and may match the stock Boxster gearing a bit better than the LSx. Hmmm, another interesting option.

I favor the big fat torque curve driveability of the LS3 over a 951 or 930 that hits you hard when the boost comes on and if you are not steering straight ahead, tosses you unceremoniously into the weeds. Like a GT3, Z06 or any high hp car, wisdom suggests we ramp up our speed gradually and avoid running around stabbing the throttle unless we like buying a lot of fresh rear tires.

Greetings everyone,

Sorry for the delayed reply, been busier then normal at work tearing down a 1965 911 to send it off for major bodywork and rust repair. Plus my grandma had a stroke a few weeks ago so I've been spending more spare time at the hospital then I would like. She's doing better now but lost most use of her left side so things will never be the same :(

Ok sorry again for starting off on a downer! That being said I have not heard from Renegade yet and tomorrow marks 6 weeks since ordered, although i'm sure they will call as soon as it is ready, i'll reach out to them today. I still need to send off my power steering lines which I just pulled off this weekend so they can make the appropriate lines for the electric steering conversion too.

Also need to go ahead and get the motor coming which i'm going to try and order today. Hopefully they are still in stock and can probably have it by the end of the week.

Since the car had a coolant/oil failure I really need to clean out the cooling system too and make sure there is no guck in it. I have been thinking about it and may go ahead and upgrade the radiators since I have to pull all that crap out. Any of you tried the upgraded radiators from CSF?? I can get them for a little under $400 each and think it's a good "while you're in there" upgrade.

I also appreciate the PM's and emails I have recieved from a few of you and will try to get back to them all. Very excited to get started on this project!!

I'll definitely update again hopefully in a few days when things start to show up!!
Thanks!
J

EDIT: Just spoke with the folks at Renegade and looks like they are just waiting on a few small bits and the kit should ship out later this week or early next week!

Got some stuffs today :)
 

Haven't had time to go through it all yet, but most of the stuff from Renegade showed up today! w00T w00T!!
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Wow
 

Somehow I expected a lot more stuff

Well that is not quite everything, still waiting on the electric water pump stuff and steering lines, but otherwise that is most of it. Plus it is all still wrapped up in cellophane so a bit hard to see everything. I'll get some better pictures this weekend.

It all looks very nice, mounting pieces all powdercoated black. Although right now it looks like just a mess of parts, hopefully once the LS arrives it will all start to make more sense!

How is the Ls conversion coming? I am very interested in how complicated the conversion will be. Does the kit require welding and or extra fabrication and do you think this would be over a weekend warriors head?

Greeting everyone,

The conversion is just about to kick off in full swing as Fedex is currently lurking around with my new LS3 crate motor which should be here today! I have also finally recieved the remaining bits from Renegade so i'll get some pictures up ths week. The car is currently torn down and ready to get started with the major surgery which should begin this week.

Boxster 50 - to answer your question simply, no, probably not, but that depends on the tools and skills you have more then anything. This is MAJOR surgery and definitely more then initially expected.

It is a lot more then just nibbleing away some of the firewall to make room for the valve covers, you have to cut out a section about 2 feet long that hollows out the frame then you have to weld in the "optional" side plates and reinforcement brace, which also serves as the new place to mount the emergency brake bits, which also have to be relocated.

***BREAKING NEWS*** MY MOTOR HAS JUST ARRIVED!!!!!!! Now to figure out how to get it out of the back of the truck! Can you believe there are 480 horses in that little box! BTW shipping weight on the LS3 is 556 pounds for those of you keeping score.

Sorry about that! Ok so to say the least there is a good bit of cutting/welding so it is not a project for the faint of heart.

I'll be back with more updates soon and some pictures of the progress once I start cutting its guts up this week. Although I must go ahead and say that I do wish Renegade offered a bit more guidance on the install process. The only actual instructions recieved came with the Kennedy engineering adapter plate. Otherwise I recieved about 40 pictures from Renegade and that is about it. :( Plus nothing was labled which for the most part it is somewhat self-explanatory, but would it really be that hard to come up with a few labels for this stuff?

Also if you are looking to purchase the kit, don't pay any attention to the "optional" listing section, NOTHING IS OPTIONAL. Ok I say nothing but if you want the car to retain normal creature comforts such as A/C and power steering, oh yeah and the alternator... then nothing else is optional so just go ahead and budget the $6800 for the whole shebang because while you "can use the stock clutch", it won't hold the power.

For those who have asked about the motor etc. I did a bit of shopping around and I ended up buying my motor from Scoggin Dickey Chevrolet in Lubbock, TX. Travis helped me out and was VERY knowledgable about the motor and the hot-rod aspect so I would recommend talking to them. I bought the LS376/480 with the optional GM Hot Cam, along with the ECU/harness/gas pedal assembly and total on it all was $7,836.79 including shipping.

Be back soon!
Thanks!
J
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Great news John. I'm really anxious to see what all is involved and will give you a call soon to set up a time for a visit. I'm only about 10 miles from your shop.

I'm going to look at a car Friday and have started my search for the best price on a crate motor. I'm leaning towards the LS 525 which may be over kill but it's hard to imagine too much power :-)

Just remember you still gotta get all that power to the ground through the clutch, trans, and axles that were engineered and designed for 250hp. Powerful cars are great. Powerful cars that always break... not so much. Choose wisely.

This is great! The engine sounds like a great deal for what you get.

I saw the Kennedy Engineering flywheel and adapter plate setup, and they look like very nice pieces. A local guy is building what he calls "street rails" using a tube chassis with various engines and Boxster transmissions. He just got an LS1 from a Corvette and a Boxster S six speed transmission to put in his latest "car". From what I can see, the LSx + adapter is significantly longer than the M96. I was a bit surprised to see how thick the adapter plate was to accommodate the starter. It looks like some clever engineering or notching of the bell housing could save an inch there. It will be interesting to see how that all bolts up.

I can't wait to see more!

I thought the S 6 speed was good to about 450hp

The Boxster S gearbox is plenty stout. This one is handling over 600 HP.

LS V8 Boxster Conversion From Renegade Hybrids! - YouTube

The flywheel, clutch and pressure plate are replaced with stronger components.

Sorry but the Boxster S transmission was designed for far more than 250 HP. It is essentially the same box as the 996 series cars internally.

Renegade has a running car with over 600 HP and the transmission is fine.

And FWIW I know all about getting the power to the ground. :)

Looking forward to the pics. I do have experience with fabrication and welding and have the tools. Plasma and welder. It does make me weak in the knees to think about cutting up a perfectly running and driving car.... I am hoping the kit comes with a template for alignment purposes. I would think alignment would be key to keep unnecessary bind off the axles and of course for fitment. This is the first I have heard of tampering with the e brake. Will it be unsightly ?

Originally Posted by Topless View Post
Just remember you still gotta get all that power to the ground through the clutch, trans, and axles that were engineered and designed for 250hp. Powerful cars are great. Powerful cars that always break... not so much. Choose wisely.

When I spoke with Renegade they said the trans was holding the power from a LS7 but the axles were the weak link. He also said the car with the LS7 was a track car so you know it has been ran hard with many hours. He did say they have a fix coming for this by the way of after market axles.