Thought I would document and share my little journey here. Test subject is an 89 iroc with a 383, t56 magnum and 9" rear that is mainly a street car, but I also do some autocrossing for fun. I built the engine a year and a half ago, and have put 10,000 miles on it in that period. Its a 1 piece rms, 4 bolt main block, eagle forged crank and rods, mahle forged pistons, compression ratio is 10.92:1. AFR 195 street port heads, comp xfi292 cam, miniram intake. I'm using efi connections 24x kit, running a fitech ultimate LS ecm. Engine runs phenomenally, haven't dyno'd it, but I expect it's in the 530-550 hp range. When I built the engine, I had in the back of my mind I would stick a procharger on it one day, which was why I went with forged internals. That brings me to present day, still planning a procharger deal, but after some debate, both in my head and with friends, I decided to give turbos a try. Initially I was researching one big single, but my caveat was that I absolutely have to retain air conditioning, the stock hood and full exhaust. Packaging all that began looking like a difficult task, I wouldn't say impossible, but certainly not easy. So I began looking into twin setups, with the intention of building my own, when I ran across cx racings twin turbo kit. Their kits have been documented here with reviews being mostly positive. I know its cheap stuff, but I doubt I could build something as good my first try at it and it would save me tons of fab time. I also knew that retaining ac on a kit that specifically says it won't work with ac would require some mods, but I don't mind a good challenge. I ordered the hot side piping only, as well as their intercooler kit. The parts are actually decent, welds look good, but aren't back purged. If they crack, I'll fix it, but overall, it's a great base. I went with VS racing 61/62 .82 ar billet wheel turbos as well as a pair of VS 44mm wastegates. My goal with this block is around the 750 hp range. If it scatters its guts, I'll go wild with a dart block, but in the mean time, I'll use it all as a learning experience and have some fun. It's a t4 flange, 3" v banded outlet. The downpipes go under the headers and run the wear a typical long tube header would run on each side. However my car is extremely low, and with street driving, there's simply no room to run that style exhaust under the car. Not a big deal, I'm routing it under the oil pan in the factory location, to my existing mufflex 4" exhaust. I plan on wrapping the downpipes, still undecided on the headers, simply for the fear of them cracking. I may run them bare at first, if heat is an issue, I'll wrap, as well as running turbo blankets. Spark plug clearance is...ok. I'm running LS coils and already had them mounted down low, at the front of the engine, so I'll be able to keep their location. I'd feel bad for guys running a distributor with this kit and having to run the wires. The ac compressor was another problem. The factory has that thing hanging off the side, in a totally different time zone, right where the passenger side waste gate goes. Totally by accident, I stumbled upon Eddie Motorsports s drive setup. Absolutely perfect. Open in the middle in front of the throttle body, ac compressor tucked in real close, quality parts. Done deal, one problem solved. I'm also well aware that cooling this thing will be a problem. I already had a derale dual fan and shroud setup on the factory radiator, which worked great, but temperatures would creep while driving while using the ac on hot days. it's never been over 205, cutting the ac off briefly would bring it immediately down to 190, and it can idle all day in stop and go traffic at 180, however, I know sticking an intercooler in front of everything would really tax the system. I already had a Dewitts dual core radiator on order before I even planned going boosted, but the covid has slowed their production. I anticipate it being in within the next few weeks. Turbo oil feed lines will be pretty straightforward, just a T off the port next to the distributor and a line to each turbo. Drains are a bit more of a challenge, since the turbos are mounted relatively low. I'm using -10 ptfe line, dropping them through the battery trays, through the framerail on the passenger side, and under the frame and steering box on the drivers sideMy canton oil pan has threaded fitting on each side, one for a temperature sender and one for a level sensor. I'm simply running the drains to those existing holes. Yes, I know they're below the level of the oil in the pan, if its an issue, I'll back up and punt, weld fittings to the oil pan and do it correctly lol. I'll need to upgrade the fuel system, currently just a 255 pump and hotwire kit, as well as modify the fuel rails on the miniram. I have 66 lb injectors, which will put me pretty close to the edge of my power goals, but I'm also running methanol injection, mostly due to my higher compression, if it also works as a crutch for my smaller injectors, it's a win.



Accessory drive installed, first mock up of the turbos. I ended up installing solid motor mounts, as the worn out originals had the engine sitting down about a half inch, causing the downpipes to lay on the k member.





Everything mounted. The hot side is actually stupid easy to assemble and disassemble.





Began building the y pipe. Some straight sections, some pie cuts, some pieces pirated off the cx downpipes to a 3" to 4" merge collector located where the factory cat would go

 

That brings me to this weekend, I had a free saturday to pull the engine, gap the rings, new, thicker head gaskets, dropping the compression to 10.5, and then sending it all back home. After 10k miles, bearings and cylinder walls are perfect, accessories are compact enough to pull the engine without touching the belt.



My left side coil mount can be seen behind the power steering pump





My clutch won't be long for this world, its a ram powergrip hd, rated for 650 hp. It still looks good, I'll certainly upgrade if it starts slipping....

Still have a long list of items to take care of, oil lines, fuel system, relocating battery, wiring, finishing the downpipes, heat wrap and tape for days...

 

Sweet! That kit looks good!

 

Realized I never updated this. Between work, life and other projects this summer, I really feel like I haven't accomplished a ton of progress, but in reality, I have many, many hours into it. From where I left off, my radiator came in from Dewitt's, it's a very nice piece, perfect fit, and the top sits low enough that my intake pipe clears, with room to close the hood. I also completely cut out the center of the core support where the pipe comes through. It looked pretty slick partially cut, but left me no access to get to the clamps on the coupler. I'll box it all in and brace it up once I get everything finalized. I had previously ran the turbo drain lines into existing holes in the oil pan. I wasn't too keen on the idea at the time, and the more I thought about it, the worse it got. The final straw was when the fitting ended up being in the way of the drivers down pipe. I pulled the oil pan and welded a bung on each side in the front of the pan. The hoses now have a better, more direct path, above the oil level in the pan. I have more hours in the downpipes and exhaust system then anything else I have done to the car to this point. The cx downpipes off the turbos put them very close to my spark plugs, so I ended up completely cutting them up and re-angling them. The left crossover pipe I posted previously was a mixture of good pipe, cheap pipe, bad welds and wrong angles, so I cut it apart, got better at welding stainless, completely remade it, and added a flex pipe to each side to allow for some movement and thermal expansion. All piping, and the flex pipes, are from stainless brothers, so I feel they should hold up well. I ran the pipes in the factory routing location, as that would give me the best ground clearance. The pipes are in a few different pieces, with v-bands strategically placed for ease of disassembly. The piping off the turbos must be removed in order to access the spark plugs, so I spent a lot of time with clamp placement and making braces to hold the exhaust in place to make it a simple, repeatable process. Where the pipes run behind the RF control arm, to the y-pipe, I originally planned on another set of v-bands, but there simply wasn't room. Instead I opted for 2 high quality band clamps that can be simply slid off and the pipes dropped down. Beyond the y, it goes from a dual 3" to a single 4". Ground clearance there in the past was an issue, so many hours and over a dozen pie cuts later, I had it nicely tucked up in the factory cat location, with another v-band, again, for ease of access should any work need to be done. All that leads to my existing 4" mufflex system. I wrapped the headers and downpipes, and built a heat shield for the starter. Being something that I plan on driving anywhere, I put a lot of effort into heat protection. I decided to put the wastegate pipes through my hood vents, easily reversible if I end up not liking it.

I had previously notched the derale fan shroud to clear the steering box, the new, thicker radiator required a bit more clearancing. It also puts it very close to the accessory drive. I mounted it in a way so the shroud is easily removable from the top, should any work need to be done with the belt or accessories.

 

On to some exhaust fab. Learning how to weld stainless as I go. I had made a muffler delete out of stainless in the spring, it turned out ok-ish, but the more I practice, I feel the better I have got.

 

Brackets were made out of simple sheet metal, with nuts welded on, some in multiple pieces, again to aid in disassembly and reassembly. Multiple pieces can be removed, and everything else remains perfectly stationary. I still need to make a mount for the parts after the y-pipe and rear-most v-band.

Starter heat shield and a peak at the strategically placed v-band for the right upper pipe.






Just barely enough room for adequate plug clearance and the steering shaft. But it fits!










Still have a few small things to button up before firing the car up, but I can finally start to see the finish line. Although I'm kinda bummed about finishing the exhaust. I really put a lot of time and effort into it and although it took a loooong time, and was frustrating at times, I thoroughly enjoyed doing it.

 

What accessory brackets are those?

-- Joe

 

They're Eddie Motorsports S drive