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so 4ish years ago I decided to start a project car. I had always wanted to build a car and was at a point in life where my garage was busy enough, I just moved into a lightly bigger workshop so had a spare ramp and figured why not, now or never!
I set about looking for a base car, new I wanted something RWD to begin, knowing I was going to guy whatever car I purchased I didn’t want to spend tons (hate to think how much I have since spent 😭
trawling through the inter webs I decided an rx8 was a good shout, much to the disgust of the rotary community! Anyway I found a 2007 with blown oil cooler and pipes that was going for £300 so I loaded up the truck and head off to pick it up. It was in surprisingly good condition except some bodywork dings and scuffs.
now I had the car so whilst starting to strip it out for parts and selling stuff I was researching what engine to bolt in. I found a company making the rx8 gearbox adapters and basically went through the list of compatible engines and decided on a b204 from Saab. Strong engines that make good power and also cheap to pick up compared to Japanese engine that all seem to have drift tax bolted onto everything!
By the time I had sold the engine box and interior I had a chunk of cash to go buy an engine. Found a complete engine with ancillary parts for £250
after doing a bit more research I started to read the rx8 box didn’t like north of 300bhp or torque! Whilst researching the Saab tuning/ building groups I found a company an hour away from me that makes adapter plates for bmw gearbox’s! So job one on the list was get the engine and box mated and in the car!
So there we have a b204 Saab motor bolted up to a getrag from an e30 bmw slotted in a hole. Happy with its positioning I set about making mounts and adapting stuff to fit! I’ve not really done a whole lot of welding/fabrication stuff before this so it was all a learning curve!
started off with engine mounts, I found RWD conversion plates that bolt to block and then a company that make RWD mounts. Took a bit of head scratching to get the correct angles but eventually got it done. They are pretty solid!
originally I was trying to keep the stock sump on engine hence notching so much of the subframe out but I’ve since strengthened that up with the steering rack mounts that I’ll get too. next up was the gearbox mount. As you guys know the rx8 used the PPF, I modified that to mount the diff although that might need to change but I’ll get to that later!
I put a couple of strengthening plates on floor and then built a mount with the rubber bobbins like the factory BMWs use.
you can see in this picture the custom prop shaft and adapter plate to mount it all.
The PPF I chopped in half and made a big flat plate to bolt to floor, welded it all up and got it powder coated.
these are the only two pics I can find of it!
Will continue the thread when I next get a free hour tomorrow! Lots more pictures to get through 😂
originally I was trying to use factory Saab sump but once I managed to get that to fit it just took away to much metal! So started to brace it up and figured it would be an ideal time to get started on the steering.
The plan was always to build it track orientated and build the whole car from scratch inc. the wiring loom so the green electric rack was out , plus it didn’t really fit with the engine in the bay. Decided on a purple tag bmw rack, and wise fab do a direct fit UJ so got that in and worked out positions and made the following mount.
with this all welded in the subframe got all its rigidity back and all was well again. Next was to sort the tie rods and ends. The Mazda track rod ends are different threads to bmw tie rods so this was next on the puzzle.
eventually settled on using BMW inner joints and then made some outer pieces. Rose joints and some thick steel tube and threaded ends, this was my first ever try at TIG welding so let’s hope they hold up!
ive drilled the hubs so I can nut and bolt ( have some high tensile bolts fitted now these were just for mock up) I can also add spacers so once on the deck I can hopefully limit any bump steer, the steering rack mounts a very similar height to factory one so 🤞🏻
last piece of the steering puzzle is the pump, will be using a Vauxhall hydro electric pump I can remotely mount and run hydraulic lines to rack.
I think going forward with the thread I will break it down into each section like this until I’m up to date with where am I with it all!
this is a very interesting build project, can't wait to see how it turns out!
what kind of HP / Tq numbers are you expecting from it when it's all said and done?
should be right around the 375bhp mark, would only need to change turbo to get bigger numbers but trying to go more for overall drive than just big numbers if that makes sense!
It’s not a million miles away from running, electrics was always going to be the longest bit to sort out. I’ll keep these posts going until I’m up to where i am now with it now 👍🏻
Next instalment!
Between all the brainstorming and building stuff I was using my spare time use clean, wire brush and melt off all the sound proofing and underwear inside and out. When I get to that point I’ll tough coat everything , probably in white is the current plan. Stripped rear subframe and had it powder coated. All the hubs were vapour blasted and cerakoted in clear for rears and black for front. All new suspension arms on rear and new lower on front.
Full poly bush kit ordered up and I think I will either re zinc the bolts or buy fresh. The front uppers didn’t have any play in them so just vapour blasted them and they came up brand new. They were silly money to replace and Mazda only!
I read some good reviews on the HSD coilovers so ordered a set of them up too
once the hubs were all in and I could see where things were landing I started work on ARB and links. The engine sits forward of stock one so had to make custom mounts, put captive bolts inside and used factory clamps. Updated roll bar all bolted up and switched the drop links so I just flip them and bolt straight in. They lean forward a bit so might have to extend roll bar but that’s a job for when it’s moving and testing it!
Inlet and exhaust time! One of the guys over on saabworx built the inlet manifold for me. I’ve never attempted alloy welding and didn’t fancy trying to learn yet!
it’s based off the stock b204, chopped in half with velocity stacks inside then an evo style plenum on top. Originally I was going to go stock t5 ecu but as with everything else it’s snowballed so went to stand-alone and want anti lag so I’ve since swapped from cable throttle to Bosch electric throttle .
To the hot side! I did 90 % off the exhaust manifold, got a buddy of mine to do the final weld as he makes manifolds for high end cars for a living so could back purge and keep everything square!
managed to get a flange in stainless, a load of sch10 bends and merge collector inc. wastegage exit. It’s all v banded, will eventually be cerakoted when we get to that point.
so after building manifolds I got to buy some go fast parts.
decided on a pulsar gtx2867r with a 45mm turbosmart wastegate. Fingers crossed for a fast spooling 350/375hp
so far I’ve only made the 3inch down pipe on the exhaust and went with a spicy through the wing/fender screamer pipe. Although if I want to get on track I’ll probably make a second pipe and loop it back into the Down pipe!
I made the boost pipes out of steel for now as it was easier for me rather than getting someone to come over and mock them up on the car. Might go alloy once it’s all together and running.
mishimoto intercooler up front. Can’t remember the size, g series from memory?
Originally I had the mac valve under bonnet but moved it behind the dashboard to tidy things up under bonnet.
Big ram air filter that I will be enclosing also.
the intercooler and radiator mounts are done up the top and when I get to the splitter I’ll incorporate some mounts in that.
the factory b204 pump is quite a big bulky unit, wanting to tidy everything up and running an electric steering pump I went Davies Craig electric pump .
originally mounted on the top of the chassis rail but decided to move lower down to prevent any air locks. Massive radiator from speeding performance parts, I rate a lot of the stuff from them!
with the electric pump it gave the option to lose the thermostat also. The factory b204 stat housing would of been pointing toward bulkhead so I made one up and incorporated the rad cap into as it’s the highest point on engine and close to the overflow bottle.
the stock pump bolts up to the block with a little sleeve// tube thing so had to make something there. Bit of tube that I turned in lathe so the connecting tube fit nice a snug, welded an AN fitting on and a bracket to bolt up to block. Seems solid enough but will have to be tested at end.
ive yet to buy a fan for radiator and the controller for pump needs mounting and wiring up yet.
Started to duct up the radiators and have cut a hugeeeee hole a carbon vent from a VAG car!
mounted an oil cooler up front and grabbed a stock b204 housing with AN fittings already welded in then ran all the lines, pretty happy with how all the hoses landed, kept my OCD in check!
I think that covers most of the cooling stuff, it’s all a trial though so I will have to see how it works out when we do some road miles!
06-09-2024, 03:21 PM
