Hello there,
Welcome to my project blog! My name is Vlad, I'm a Mechanical Engineer from Toronto, Canada. Please follow me on this quest to convert a Porsche Boxster S roller into a V8 beast!

Boxster V8 conversion

SPEC Clutch

I can’t thank the guys at SPEC enough for rebuilding my clutch disc. The store where I had bought it from miss advertised it as a sprung hub, when in reality it was a rigid design. Took only about a week to get my disc back. Shipping it back to the store for a refund would have sucked.

Old Clutch

SPEC Stage 2 Clutch w Sprung Hub

Instead of flexing, the plastic clip on the release bearing just sheared off when I put it in the clutch fork. Not sure if this was a defect, but the plastic seemed much more brittle than on the old one. I didn’t want to take any chances on such a cheap part, so I called Downtown Porsche to pick up a replacement. The guy on the phone told me it would be $260 PLUS TAX! WTF?!?! The whole clutch kit cost me $620… At this point I decided that I’d rather keep my money. The old bearing was in pretty good condition, so I swapped out the plastic sleeve from that one. Not an ideal solution, but hopefully it will do. I did check the sleeve ID for wear and it was the same as the new one.

Good clip

Sheared clip

The tolerance on the SPEC splines seem to be much tighter than the OEM disc. Putting the transmission on was nearly impossible this time; we struggled for a couple of hours to get it on by hand. At first I thought we weren’t getting it into the pilot bearing, but then I realised it was just the friction of the clutch disc splines (yes we did lube everything prior). Once we got some spline engagement, we put a few transmission bolts on and slowly tightened them diagonally. Each time I checked the gap using a vernier caliper to make sure the transmission was going in level.

Throttle Cable

Today I tested an early 986 Boxster throttle cable to see how it would work with the engine. From what I’ve read on other blogs, the cable is too short and the pedal travel only gives you about 60% throttle. The only alternative is to run a drive by wire setup, which requires some fabrication to mount the GM pedal and a lot of money to buy the whole setup. I would have to get a C5 corvette ECU, harness, TAC module, and pedal. This setup is about $800 used if you can actually find it. I was able to find a cable and pedal setup from an early 986 Boxster for $50, so I decided to give it a try first (these are rare, but believe some pre 99 models came with cable throttle).

There are no mounts on the new chassis for the cable, but it’s easy enough to bolt on. The cable is perfect length and you get about 90% throttle without any modifications. If you grind down the pedal stop you can go up to about 95%, which I am happy with. I will have to figure out a custom throttle cable bracket, but that’s pretty much it. The other issue is the space for intake hoses, but thats a whole other project.

Fitting the engine

Today I finally managed to bolt in the engine for the first time. This was a very frustrating experience, especially trying to do this on my own using a set of stands and a pallet jack. At first I thought I could just roll the whole assembly in together and just bolt it all in inside. I played around with it for a few hours and failed miserably. There’s just too many things to get in the way and too many holes to line up in one shot. 

Today I partially disassembled the engine mounts and tried fitting everything piece by piece. This was still a huge pain in the butt, but at least I managed to put it all together. The clearance seems to be pretty good, and I don’t expect to be doing much more cutting. I am a little more concerned about the air intake situation since there’s only 6.75″ of space between the manifold opening and the firewall.

The engine is in

The way it is now, the engine is slightly tilted towards the front. I may have to add some spacers to the engine or transmission mounts to level it out.

Putting the engine together

Hey guys,

Sorry for the lack of updates recently. Last week I put together the engine and tranny. I am using a low profile LS2/LS3 oil pan for ground clearance. At 4.75″, this  is the thinnest OEM wet sump  pan available. I had to get a new o-ring (blue) for the pickup tube, which cost a whoppig $14 from the dealership. I believe all LS pans are interchangeable, so there was no trouble there.  

I am also using an LS1 intake manifold. The intake is rotated 180 degrees for clearance. I’ve heard of issues with the oil pressure sensor getting in the way with LS3 engines, but mine seems to be ok. Nonetheless, I plan on mounting  both GM and Porsche oil pressure sensors on a 4 AN line remotely (I will make a post on this with a complete parts list when I’m done). 

The Kennedy engineering adapter and flywheel look amazing. The adapter plate was slightly damaged during shipping, but it was nothing serious. The kit comes complete with hardware and instructions. I didn’t purchase the optional KEP clutch, so I had to buy the pressure plate bolts myself. These are longer than the OEM Porsche bolts, so please give KEP a call to find what size you need. 

I was told that the Boxster S clutch will work for a 5.3L swap, but Kennedy Engineering suggested that I upgrade to a sprung hub disk. The new flywheel is no longer a dual mass design, hence a rigid disk might be a bit too harsh. The KEP clutch is amazing, but its close to $1000, so I had to downgrade to a SPEC Stage 2 clutch for $650. As I was putting everything together, I realised that I was actually sent a rigid disk. The online store where I had made the purchase admitted their mistake and offered me a full refund. I decided to give SPEC a call directly to see if I could just make swap with them  instead of shipping everything back to the store. They told me that the Boxster clutch normally only comes rigid, but they could make a sprung disk for me free of charge if I just paid for shipping. I guess for now I’ll just bolt up the tranny without the clutch to see how everything fits together.

I used a pallet jack to line up the transmission to the engine. This is pretty easy if you have the right equipment, but I would still suggest an extra set of helping hands.

The Renegade Hybrids kit wasn’t so straight forward. All the hardware that comes with the kit is mixed in one ziplock bag. It’s not that big of a deal, but it still takes a while to figure out which bolt goes where. I was short a few washers, a harmonic balancer spacer, and a belt pulley. Either these parts were never put in, or they fell out the massive hole in the box during shipping (Steve promised me that the replacements would be on the way shortly). The Wevo transmission mounts which you must purchase separately come with a the bolt and washer for the stock setup. I replaced mine with a 75mm bolt and ground down the square protrusion on the washer. 

I had no issues with the rest of the Renegade kit except for clearance around the oil pan. I opened up the bolt holes a bit to allow for some extra clearance.