944 S2 - LS3 & T56 Conversion

Ive been really wanting to take pictures, and make another good post just havent had the time... so here is a mini update.

The car was moved to my work location a few months ago, where all my tools are and access to fabrication tools (welder, metal saw etc). I completely redesigned the transmission mount because original version just isnt going to fit now that the whole drivetrain was moved back about 2 inches from mounting the engine on TPC motor mounts.

The new mount is 3D modeled and a test template/mock version out of wood will be made once time permits. I will be taking inspiration from XChop's mount (thank you sir) but it will not be the same... but it will be mounting on those 2 bolts he used... as well as others farther down on the perimeter of that same extension housing. Probably 4 bolts total, with a removable loop tying it together underneath. Basically where the hatch/trunk floor ends at and the top of the backseat begins... I will be running a brace across the width of the car on that seam... and having the mount drop straight down from that location to the transmission/diff extension housing. It will be two pieces, one stays mounted to the trans... and then the main brace/mount will be solid mounted at the location discussed. It will incorporate two poly link-flange/isolator bushings with 1/2 bolts that stab through to tie it all together... similar to what XChop showed.

If I had access to a nice tubing bender I could make a mount similar to my original design/oem design... mounted to the original C5 mounting location on the Getrag Diff. Without a tubing bender though... I just cant clear the gas tank and feel comfortable with how it would be. A lot of the weight would be offset/overhung off the actual mounting point of the brace and I dont like that idea.

Other than that, there has been a little design work/modeling done in other areas. I have the entire trunk/hatch area and rear suspension roughed out in Inventor 3D and will be working on the suspension/trailing arm designs after the trans is mounted. I have plans to incorporate additional camber adjustment as I know that the oem suspension setup doesnt allow as much adjustment as most want/need.

I did install the $40 Daystar 911 spring plate bushings... and yes they required some machining to make them fit right. It will work, but honestly I dont really like it... and I have since decided I am converting the spring plates to a large Heim/Spherical Rod End... very similar to what you see on the VW Dune Buggy Coilover conversion kits. It will consist of two pucks/cylinders that fit inside the outer aluminum spring plate housing and inner torsion tube recess... they will sandwhich and have a large bolt/pin running through the center where the 3/4 or 7/8 rod end will mount/rotate.

Watching this one closely, thanks Slpr.

Thank you!

Big update coming soon... cliff notes below.

Gutted the rest of what was left of the interior and being prepping it for welding. Use a combination of wire brush, aircraft stripper and sanding pads to get it cleaned up.

Made wooden template for trans mount plate, figured out some of the missing dimensions and re modeled with new poly bushings etc.

Ordered another rear axle carrier/torsion tube to simplify making the suspension brace/crossmember.

How's the bulk going? Any updates

kevin924kevin wrote:How's the bulk going? Any updates

My apologies for disappearing for a while... I havent checked your thread or anyones in months and months. Had many big life changes going on, honestly havent had much time to focus on the car other than a little design/conceptual work. Moved houses, moved the car to where I am living now and moved jobs. I am focusing on getting settled in and then I will start working on the car again later this year/early next year. I have access to a nice tubing bender now though and other heavy machinery/fabrication equipment... so thatl be a big plus when I can get back into it. Mark my words though, this project will get done... I dont give up, its just going to take as long as it takes.

*drumroll*

I am bringing this thread back from the dead for a very important update! I had to put the project on hold a few years ago due to a new job and day to to day life getting in the way. I never gave up on making this a reality I just needed to come back at it fully prepared and ready to get it done for real this time.

As of yesterday the car has been moved out of storage and into my 2 car garage. I have been buying tools and preparing the garage for months now and finally have a great solid place to work on the car. More importantly I have the tooling I need, at home ready to go whenever I want to. It really is a thing of beauty and its the best setup I have ever had at home.

I am currently working on finishing the final shop layout, setting up equipment and misc tools etc. I have cleaned and organized the entire contents of the garage. If its still in the garage... its purely devoted for working on the car (minus one small corner for yard tools).

I already had a ton of mechanic oriented tools but needed a bunch of fabrication tools to do this project. Here is a list of tools/equipment/supplies I have bought over the past 6 months or so in preparation for getting this party started! Keep in mind I am trying to do this on a reasonable budget and limited space. Ive taken my time and picked equipment with good reviews that will do the job and not break the bank

• Alpha Tig 200AMP AC/DC Tig Welder
  
• 220CF Argon Bottle
  
• Dual Flow Meter (For back purging)
  
• Upgraded TIG Foot Pedal
  
• Auto-Darkening Welding Hood
  
• Welding Gloves, Shirt & Caps etc
  
• Welding Tables
  
• Extra Consumables (Tungsten, gas lenses, cups, collets etc)
  
• Tungsten Sharpener
  
• 3/16 & 1/8 ER70S-2 Steel Filler Rod (10lbs of each size)
  
• 3/16 and 1/8 ER4043 Aluminum Filler Rod (5lbs of each size)
  
• Propane Torch (for pre-heating)
  
• 8" Tekton 360 Swivel Bench Vice
  
• Bench Grinders
  
• WEN 4225 15-Inch Variable Speed Floor-Standing Drill Press
  
• Evolution Power Tools R255SMS 10" TCT Multi-Material Sliding Miter Saw (wicked little saw)
  
• D1050 Diablo 10" Cermet II 50-Tooth Steel Cutting Blade (2 pack to get started)
  
• US General 26" Top Chest (other top chest was literally falling apart)
  
• Misc tool organizers, tool box labels etc (my tools are more organized than ever)
  
• Extra 4 1/2 Angle Grinders
  
• Variety of abrasives (sand disc, flap disc, cut off wheels etc)
  
• Uvex Bionic Face Shield
  
• Bunch of Safety Glasses
  
• Eye Wash Bottles
  
• AND 1 BIG ASSSSSSS FIRE EXTINGUISHER
  

Another thing to note... I have decided to ditch using the stock rear suspension and bought an entire C6 rear suspension setup with 10k miles from an 06 C6. I also purchased the rear frame rails cut out of a wrecked Corvette to help with solving all the guess work in the suspension geometry. It really is going to simplify the build in many ways and ultimately I think is the best thing for getting the power down to the ground reliably over the coming years.

Many pictures and updates to come my friends... progress will no doubt be slow but there will be a lot of progress this year. I am going back to square 1 with the project and starting fresh. Over the coming months I will be finishing up the garage/equipment setup and planning exactly how I am going to graft the C6 suspension into the vehicle. Once I have everything designed, modeled, mock fitted etc I will get into the nitty gritty fabrication work.

After that is complete I will move my focus to doing only what is needed to get the vehicle running and driving reliably. All interior, exterior and EXTRA stuff will come later. I really want to focus on getting this thing on the road... and then ill have a project car that actually moves under its own power. As with any project like this, there is a ton of EXTRA stuff I want to do but if I try to do every little thing right now, who knows when it will actually drive. For instance this may mean buying a temp junkyard engine until the 6.2 can be fully built the way I want it. It may mean... no wide body right now, no new interior, no new paint, no full roll cage. I am talking about meat and potatoes... a reliable driveline, good brakes, good seats... fully road legal.

If all things go well, I hope to be doing some celebratory birthday burnouts January 2020 for my 30th.

Wish me luck!

Slpr948...very much interested in your C6 transaxle swap. I too was "off project" for about 4 years as life happens. In my project I started with the engine build which I completed in late 2014...fast forward to 2019 and I'm about to begin the swap.

Good luck with your project... I'll be following!

Raymond-P wrote:Slpr948...very much interested in your C6 transaxle swap.  I too was "off project" for about 4 years as life happens.  In my project I started with the engine build which I completed in late 2014...fast forward to 2019 and I'm about to begin the swap.

Good luck with your project... I'll be following!

Thank you

I think there are a lot of people out there that have thought about doing this... but very few that make it happen for obvious reasons. I hope I can help you and others that want to "see" more before they try it themselves.

I got antsy and did some mock fitting earlier this week. I started with removing the gas tank because it clearly wont fit right now... although it does look very possible to relocate it back about 10 inches and retain the factory tank setup. Then I cut the spare tire well out, making room for the corvette frame rails and possibly the fuel tank relocation. Then I cut more of the back seat out, basically flush to the frame rails. Overall as you will see it fits very very well... granted I know I need to go up a few more inches... which 100% for sure is going to require notching/modifying the stock frame rail to clear the upper control arm and shock mount points. Based on the axle/diff alignment and position of the differential mount, I am confident the cradle is within an inch or two of where it needs to be centered in the wheel well.

I am using a C5Z differential... with a C6 cradle and will have to make an adapter for the differential mount. Ive seen some vette guys do it, and I will have to weld in some aluminum plate to the cradle... and then drill some holes and reuse stock mount or go with an aftermarket.

Why did I buy the C6 cradle vs the C5 you may ask? Availability/condition and pricing... also the C6 control arms push the hubs supposedly 5/8 of an inch to the rear more. This is one of the ways the engineers lengthened the wheel base of the C6 vs the C5... the other is supposedly the Torque tube being longer. I cant really confirm any of that yet, but I have researched it and that seems to be the most accurate information to my knowledge. If I run into issue a C5 cradle is $80 right now shipped to my door... which I honestly will probably be buying anyways just to have if needed... and the entire C6 suspension can be mounted to the C5 cradle. For now I am going to keep the C5 torque tube, but if needed/possible I may do a C6 torque tube to lengthen the wheel base of the car a little bit... ill cross that bridge when I do wide body etc. Which may be sooner than later, depending on wheel fitment.

Anyways here are some rough mock fitment teaser pics...

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I hope this build is still happening. I've been researching an ls swap with the t56 trans for a couple years now. The trans and rear suspension was my area of debate for most of that time and was stuck between custom trans axles or just putting an entire C5/C6 rear suspension in. Stopped researching due to not even owning a 944 and knowing I'll have to cross that bridge when I start a build. I am now picking my 944 up next weekend and since it will be driveable with a couple minor parts, I will be starting to compile all of parts for when I'm ready to immobilize it and start building. I was really leaning towards the C5/C6 rear suspension was unsure how it would effect the geometry.

Not dead, its sitting in my garage and rolls on the C6 suspension... everything fits. I have an amazing garage setup now but finding time to work on it is difficult between side work for friends/family etc. Currently I am finishing up the fabrication for the rear suspension.

I really want to delete this thread and start another one, because IMO this thread is a great example of what happens when youre not ready to take on a project of this scale. Its also snowballed into the entire rear suspension from the C6, metal wide body, custom fabbed TT setup on a cast iron 6.0. A lot has changed since my last updates... I feel like a clean thread with a link to this thread as the precursor is what will come soon.

I didnt have the devoted space, tools or plan needed to execute something like this in a timely manner. Ripping it apart, test fitting, buying things and progressing to where I am at currently where I can fabricate anytime I want has been the majority of why this project isnt done. Obviously life, money and things have slowed it down too. Its been my sheer will power to finish the project at all costs no matter how long it takes that has kept me going and I do see the light at the end of the tunnel.

I want to say from the get go I would have absolutely LOVED to of been able to do this entire project in round tubing with a bender etc but it just wasnt in the budget. While the route I went will no doubt weigh more, have stress risers/design flaws and probably way overkill... it will be strong and it will work. Later on if need be I can do a second revision if need be with full tubing... this car isnt getting sold. Full disclosure I am not an engineer, ive never done a project of this scale and someone else could do it better. I have years of experience at a machine/fab shop and I am applying those skills and years of theory/knowledge. This is my biggest hands on project and I am learning/pushing my boundaries all the time.

That said, here are some teasers... I have tons of photos and will upload more in a proper thread.
I am subscribed to this thread so if anyone ever has questions just ask I would be happy to help.

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Really glad to see this is still a work in progress. I completely understand how life happens. I've been researching this swap for 5 to 6 years now, and because of life, I'm just now picking my 944 up this weekend. I am of the same mind set with this project, I will do this. I am now drawing my plan up. Thankfully with just a new fuel pump and battery, mine will be up and running giving me plenty of time to compile all of my parts. I'm definitely a few years behind you, but I will following all of the progress.

Very cool, congratulations on your new 944. What year/model?

One of the best things I can say to help which you already mentioned is plan plan plan.

Make lists, think about work flow and what order the build will be done in.

Setup your garage/work area, acquire tools, materials, organize the area etc.

Ive been balling on a budget but have some really good tools for the $$$... obviously nothing name brand. I have an Alpha TIG AC/DC Welder that works beautifully. The $220 Evolution R255SMS Miter saw has been amazing... clean, precise, compound angles, very little prep needed for welding, amazing for TIG prep (IMO better than a band saw for this kind of work). The Wen drill press I have has been great too, affordable... solid for what I need it for. I am going to also be buying a budget big well reviewed MIG welder w/cold welding for sheet metal, and other dirtier welding like bonding to the factory sheet metal/structures with seam welder you cant get out because its on the inside.

Think about what you need to be, street legal. Prioritize what you need to come first, spend money on extra stuff later unless you have the budget and its convenient to do it. Leave a lot of the extra stuff for later IMO so you can have a driving car sooner. This doesnt mean cut corners in the areas you are focusing on... do it once do it right.

I would also try not to purchase things before you actually NEED them because things can and will change.

Know what you want the car to do, is it going to be an autocross NA setup, Jack of all trades street machine, TT Drag car or something wild? Determine that first, then plan how you build everything based around that.

For instance I wasnt originally planning on fabbing a TT setup... or I would not have bought the LS3 aluminum block. I dont want the weight on the nose, but its not going to be the end of the world. I am going to have to balance the car out anyways with the amount of structural changes I have made. I mainly plan on straight line stuff for now and want reliability for the boost. Ill run the iron block for however long cause its cheap and gets the car going and when able I will do a built LS3 Darton Sleeve setup.

Holler if you need anything

Getting a gray 89 S2. The best part is there is absolutely no body work to be done on the exterior. And I couldn't agree more about planning. I have a plan for plan that's for my plan. I've spent the last 3 years getting all my tools in order. I still need the miter saw so thank you for the recommendation. I'm planning on doing everything in stages. Structure of the rear end is my primary concern for trans and rear suspension stage of my. And I will be only buying the parts I need for each stage of the build as I'm in that stage. Just from my planning over the last few years I've already been changing my parts list multiple times which why I decided I'll only get what I need for each stage as I'm in it. I know I still have a few unanswered questions, but with how much information I've been taking in on the subject, I'm slowing down and reworking my plan one more time. Thankfully I already have a full time daily driver and an empty garage, so I have nothing but time to make it right.

Very cool, I really loved driving my S2 til the engine gave out.

As for exterior body work. If you dont want to leave the wheels exposed and the back end jacked to clear wheel arch lips youl need to do cheap flares, a wide body kit or metal wide body. I am going metal wide body route like this awesome guy. I dont like kits, flares, fiberglass etc in general so not even considering those as an option. The way this guy T cut the fenders and widened it is perfect.

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Custom wheels will help you tuck the wheel a lot, with a super super high offset but Its still going to be near impossible to tuck them under the stock wheel well without modifications. I have c5 18x10.5 +58 rears right now and they stick out about 2 inches at stock porsche ride height with the ballast in the car. The C6 front 19x10 +79 wheels are probably the best cheap, corvette wheel to tuck the tire as much as possible... playing with offset calcs it would move the lip of the wheel in about 1.06 (27mm) farther in than my current wheel. So youl still be hanging out about 1 inch. I think its going to be hard even on a custom wheel to get something with a higher off set/more tucked than the c6 front wheel.

One other thing to consider which I have not posted about is how much time I spent positioning the c5/c6 rear frame rails/suspension assembly. Some people leave it lower so the top A arm clears the oem Porsche frame during compression. you can actually set the porsche frame directly on corvette frame/suspension assembly weld it in just like that if you wanted... and I saw someone do that in another thread where they had a "shop" finish the work.

Not trying to criticize there work but the issue with that is at center/oem c5/c6 suspension height... youl have about 2 inches between the top of the tire and the wheel well arch (i tested this). Thus to get your ride height lower/tuck the wheels, youl have to lower the corvette suspension adjustment all the way and or do coilovers which shortens suspension travel. once you do that, you cant adjust it much lower cause youre already deep into your compression travel of the shock, not leaving much room for pot holes or rear squat. in doing so you dont have a lot of choice in having ideal shock travel rebound/compression position and i DONT like that. I want it to function as if it was in a corvette, in ideal position with full adjustment options.

I think its very important that the c5/c6 suspension assembly is put in at neutral travel, and oem height for the porsche... which ironically is VERY similar to corvette height. I did the homework to find out corvette rear suspension ride height/suspension travel/shcok travel rebound/compression position. Then I compared it to Porsche and put it in the center... matched the ride height of the porsche. The corvette suspension has a little more travel than the porsche too... which is going to give you the ability to slam it or raise it high anytime you want.This requires cutting into the porsche frame rails to recess it higher. Obviously thats a big deal and most dont want to do it... but if youre going this far with a project... do it imo.

Anyways im rambling a little but its critical to factor this in...

I like that "t cut" technique on the fenders too. But what a same to go to all that work and then put the hood vents in the wrong place...

That is looking really good! I did this same swap and I also wish I could improve on my fab work but for now the car is fun to drive!

yamamtx wrote:That is looking really good!  I did this same swap and I also wish I could improve on my fab work but for now the car is fun to drive!

Badassss, see I know theres several of these lurking around... people just arent talking about it much except here.

Are you located in TX?

Thanks bud, its been a slow process but not giving up!

Rich L. wrote:I like that "t cut" technique on the fenders too. But what a same to go to all that work and then put the hood vents in the wrong place...

Seems like he nailed the low pressure area based on this diagram... about center or little behind front fender opening centerline.

Where would you have put them? More central behind the radiator? Elaborate please...

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Interpreting that image isn’t as simple as it seems. For starters, on the lower graph “Unterdruckbereich” translates to negative pressure area. So that means where the line travels above the X-axis represents the low pressure zones (counterintuitive). However, and this is the key, the line on the lower graph does not map onto the drawing of the car directly. The numbers on the X-axis of the lower graph do map onto the dots placed on the exterior surface of the drawing of the car. So that red shaded hump on the lower graph is the negative pressure area on the hood, and it exists starting at dot 10 on the drawing of the car, peaks at dot 12 on the car, and then the pressure drops off quickly after dot 14 on the hood and is no longer a negative pressure are by around dot 16 or 17. So the shaded area on the graph represents the negative pressure area that exists between the two dots I’ve circled on the drawing of the car. Hope that makes sense.

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"However, and this is the key, the line on the lower graph does not map onto the drawing of the car directly."

That makes sense and is exactly what I over looked. So yes given that information the person who did those hood vents did do them too far rearward on the hood.

I appreciate you explaining and when I cross that bridge Ill be sure to get better placement.

Thank you!

Sorry I've been MIA for a while. Been having a lot of stuff going on with my other way off topic projects. That's actually nice to know about ride height. Personally I really like the oem height and didn't want to lower it at all. The brakes and front end/front suspension is where I think I'm starting. I am very fortunate that my buddy is going to let me take his 5.3 once he get's his IROC running. So I'm also gonna start working out the placement of the engine and other engine bay components. I was able to locate all the c5 parts at a local junkyard, but unfortunately they're closed right now. So just slowly working on some of the prep work and spending a lot of time on these forums.

I would highly suggest buying Texas Performance Concepts engine mounts. Theyre very high quality and bolt right in, takes all the guesswork out of that area and it will locate the rest of the driveline in the car. It also supports the website... and will save you a bunch of time.

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As for ride height, I also want OEM 944 height with the ability to lower the car. The beauty of the Corvette suspension setup is that it has adjustment already built into it via the level screws on the leaf spring and the total suspension travel is more than the OEM 944 travel. So when centered correctly in the chassis you can drop the vehicle more than OEM and raise it more than OEM. Really gives you a lot of adjustment for the future and if need be you can also install some C5/C6 coilovers then do away with the rear leaf spring.

Cheers bud, keep it up... one day at a time!