Nix's Engine Swapped Golden Nugget

My GFB EX44 wastegate arrived so I started off by working out how I was going to fit that, Initially I was hoping that I keep it down below the chassis leg but there just wasn't enough room. I coped and trimmed a 90 degree bend to fit nicely into the hole I'd previously cut in the manifold and tack welded everything in place. and then test fitted the wastegate.





The wastegate currently sits a bit higher then I would have liked but I was a tad concerned about its proximity the the plastic valve cover, I may yet trim it down slightly but other than that it all looks good. I've still got plenty of room to snake the wastegate pipe down and back into the downpipe. I will probably end up making the wastegate pipe removable and join into the downpipe via a Vband otherwise it'll be nearly impossible to get the downpipe in and out.


I also started work on the core support, I decided to entirely remove the standard core support to give me more room for the rad and intercooler and replace it with some 20mm steel tube. I need to weld some brackets to it for the headlights and bonnet pins and I need to fabricate some brackets for the radiator when I get chance to grab it out of my storage lock up and start test fitting it. I also wanted to retain the 2 L brackets that link the core support to the crash bar on the front so need to cut some steel plates to tie those back in as well. Originally I had planned on making the core support removable to make it easier to get the engine in and out but as the front crash bar is not removable I didn't see any point as it doesn't really give any additional clearance so I TIG welded it into the car and TIG welded the cut ends of the core support back together. If I have room once the radiator is in I'll add some gussets to tidy it all up.



I had previously taken the gearbox out the last time the engine was out and hadn't put it back in so first up we threw it back in the car and and then welded the captive nuts to the gearbox cross member. Whilst the car was in the air and I was working on the gearbox I figured id also sort out the gear linkage. At some point I might CNC a custom one from some aluminium but for now I just modified the OEM linkage. so cut, extended and then sleeved the linkage, the steel I used for the sleeve is definitely a bit overkill but it was what I found in the offcut bin and the ID was the perfect fit. Also the chassis mount short shifter I have is crazy short so we'll see that goes once the car is running. I may also need to change some of the shifter bushing things (can't remember what they are called but standard Tailgate McNoIndicate thing on these gearboxes) in the gearbox as there is a little too much slop when its in gear for my liking.



After that I wanted to crack on with the front end so started by making the bosses to weld onto the new core support that hold the upper front bumper mounts and the headlights. Then it was onto getting the intercooler and radiator in. The intercooler was fairly straight forward as the upper mounting bosses sit just below the level of the core support however its size did make fitting it a bit tricky. I went with a 600x330mm intercooler core as that is what most of the Tailgate McNoIndicate guys run on this engine and turbo combo.


The radiator, being a Tailgate McNoIndicate e46 radiator required some modification to mount, firstly I removed all of the funky Tailgate McNoIndicate mounting brackets as I have no idea how the hell they work (they are just a bunch of angled tabs, so I'm guessing its supped to slide into some kind of receiver on the chassis). Next up I welded some aluminium pins onto the bottom so that I can mount the radiator in a more traditional way and then made some brackets with grommets to hold the bottom of the rad.



I didn't get round to making the top mounting brackets as I'm not entirely happy with the height of it yet. I plan on Modifying or remaking the lower brackets so the rad sits about 15-20 mm lower so that I have room for some decent bracket at the top. I also test fitted the new radiator fans and there is just about enough room for everything. I originally wanted to use standard Tailgate McNoIndicate hoses for the radiator but they aren't going to work so I'm gonna modify the inlet/outlet of the rad and see what I can squeeze in.



There is about 40mm between the crank nose and the radiator and about 70mm between the front of the turbo and the radiator. So as long as I position the fans strategically and use a low profile filter it will all fit... Just!. After that I decided to jump into something else and start work on the downpipe. It might seem that I'm kind of jumping back and forth all over the place and to some extent I am, but I'm trying to work out some of the tricky nd slightly concerning bits first. The downpipe is fairly straight forward in terms of routing, It comes out the back of the turbo and then twists up and in slightly to clear the engine mount and steering shaft then back and out around the bell housing. That is where it starts to get a bit tricky, there is so little room around the gearbox as the exhaust is on the wrong side. So I wanted to work out the routing now in case I need to change anything.


So I fired up the bandsaw and started pie cutting. The downpipe will be all 304 stainless and will be fully pie cut (no mandrel bends here).



whilst I had the car on the lift I took some measurements so that I can find and order an air filter that will fit and it suddenly occurred to me that I won't be able to run a draw through MAF If I whack the filter directly on the turbo; But as I have no choice but to mount the filter that way I'll need to find another solution for the MAF.


Now I initially thought there are a couple of options, I could obviously try and run the MAF in a blow through setup and stick it after the turbo but I'm not about to spend hours of my life trying to work out the perfect position for the MAF to get accurate readings, build all the piping to suite and remake the piping again later when I ditch the MAF. So as far as I'm concerned that's a no go option. I know the MS42 ECU's for this engine support running in Alpha/N but that ceases to be the case if you slap a turbo on the engine as the ECU can no longer estimate the air volume; so that's also out.


So it looks like I'm going to have to run an aftermarket ECU straight away instead of using the standard ECU. Oh well needs must. I spent some time today having a look at ECU options and decided that initially I'm going to run a Speeduino based CORE4 ECU as DIY-EFI now offer one for a Tailgate McNoIndicate M52TU/M54 engine and just like the MX5 version it bolts into the case of a standard ECU. If it works out ok I may stick with it, if it doesn't there are a couple of other options I'd looked at that would work (although considerably more expensive).


I'm a little a way away from wiring or getting the engine running so don't really need the ECU yet, but will probably order it at the end of the month.

I was able to spend a few hours after work working on the car again so I wanted to focus on the downpipe. Initially everything was going well and until I realised that it was impossible to get the downpipe on and off without first dropping the turbo (which is a pain in the butt). At this point I stopped and had a look and decided that I was making things way to complicated; My initial design had curves in both plains as I was trying to get some more clearance around the steering shaft. In reality it didn't give me any extra clearance and it made the downpipe an absolute pain.


So I decided to cut the downpipe at the point where it kicks up in order to get over the engine mount and continued from there. After some trial and error I ended up with this:



After that I threw it back into the car and then added a tap to brace it to the bellhousing.

  

for some reason when I ordered the steel for this I ended up with brushed stainless instead of polished, it doesn't really make any difference it just bugs me slightly that the first part of the downpipe is polished as I was using some leftover from another job and the rest is all brushed. Once its all wrapped in heat wrap no one will even see it.

Well I'm still waiting on some parts to arrive to continue on with the exhaust so I decided it start mounting the diff but to do that I need to get the axles out. I'd tried whacking the axles out have a BFH when we took the old diff out and got nowhere so after some advice from Zed I decided I'd start by making some sort of hub puller style thing to push the axle out. I threw some 10mm steel plate on the CNC plasma and then made this



Well I bolted it onto the hub and started cranking the bolt down with a breaker bar and a piece of scaffold pole but it eventually just started to bend the bolt. So I conceded that I'd have to chuck it in the press and press it out. I knew this also gonna be a pain as the lower control arm bolt in the hub had seized. So I unbolted the caliper, the coilover and then dropped the hub and lower control arm in one piece, and then it started going south. So I undid the nut that holds the LCA to hub but as it could toward the end of the thread at stripped all the threads off the end of the bolt. I continued on regardless and used the press to get it out, once it had popped it was easy enough to get it out with the impact. This is the state of the bolt



so now I need to order a new LCA Bolt. I cut the axle in half with a grinder to make it easier to get onto the press and then set it all up with some extra steel plates to level things out.



well I maxed out the press and applied nearly 20 tonnes of pressure and the damn axle didn't move at all. God knows what's holding that thing in but it definitely isn't coming out. So looks like I'm going to be buying a pair of replacement rear hubs as well.

So I gave up on getting the axles out of the hubs, I tried putting them in a press, smacking them with a big F**king hammer and tried using a massive hammer drill to get them out but nothing worked... So I gave up and bought some replacements along with replacement lower arm bolts.



this lot came to about £115 and considering I've probably more time than that trying to get one axle out its money well spent as far as I'm concerned. I removed the dust shields from these hubs as they were slightly worse for wear and I would have had to trim them at some point to fit bigger disks when I get round to upgrading the brakes. So I threw this lot on the car and then started trying to get the propshaft mounted. The Tailgate McNoIndicate propshaft is a 2 piece propshaft so I needed to make something to hold the center bearing. I bolted the prop to the gearbox, took a bunch of measurement and threw together a mount; I ended up having to mount the prop bearing at a slight angle as there just isnt enough room in the tunnel for its full width.



up until this point I was hoping I'd luck out and the prop would just fit but unfortunately its too long so I'll need to send it off to be modified. After the centre bearing carrier was done I was initially a bit stumped on how I was gonna mount the diff without a prop that's the right length but I couldn't shorten the prop without knowing exactly where the diff sits. After some head scratching I came up with a solution and whipped up a jig.



So the Jig mounts onto the centre bearing carrier and aligns with the output of the gearbox to set the correct position for the front flange of the diff. I don't have a gearbox jack at present so I settled for throwing the diff on a stack on toolbox's with blocks of wood to get it in position. I used a digital level to get the correct propshaft angle and then bolted the jig to the diff to hold it in position. After that I started making brackets to hold the back of the diff into the subframe which was actually pretty straight forward.



I only tack welded the the mounts in for now as I'll need to drop the whole subframe out to properly weld them. So after that I started working on the front mount for the diff which is slightly trickier as I wanted the front mount to bolt into the subframe so that I didn't have to take the whole subframe out out to press the bushing in. After more head scratching, some grinding, plasma cutting and a lot of welding I came up with this



So the bottom of the diff sits slightly lower than I would of liked but its a pretty big diff and its position was partly dictated but the correct propshaft angle. The bottom of the diff sits at the same height as the lower subframe brace so its still an acceptable height but between the size of the diff, the location and the mounting ears on the diff, sneaking a 3 inch exhaust around it is gonna be a massive pain.


So that pretty much it for progress for the moment, I did do a bunch of test fitting of various things and I came to the conclusion that I've got no option but to run a scavenge pump on the turbo. Either the line would have to run virtually flat the entire way to get to the rear part of the sump or it'd have to be really short to the point of being nearly impossible to get on and off. It wasn't an unexpected discovery but it is an expense I was hoping to avoid.

So that's pretty much up to date, I have made some progress over the last day or two so I'll post another update either this evening or later this week.

Sorry if some of context or tense is off all of this happened in the past and over a period of a month or 2 across several other posts on another forum

Very nice, I've seen a few of your posts on the Facebook pages. That turbo's really tucked down in there, almost wouldn't be able to tell it had one Look forward to seeing how this progresses.

I thought that car looked familiar...I test drove it in Dec 2019 before I bought my Mk1! Are you somewhere near Kent where I drove it?

Awesome work, and a brilliantly crazy idea. Been thinking of turboing my car and have an old TD04 from my WRX hanging around...

That’s some fantastic work you’ve done there. How much weight difference between the B M W & Mazda engines?

so (I think) the Mazda BP4W I pulled out of the car, fully dressed weighs about 130KG and the Tailgate McNoIndicate M52TUB25 is about 158KG fully dressed. The gearbox is also about 10KG heavier and the diff is probably 5KG heavier; So at about 45-50KG its a fair bit heavier but seeing as it should be outputting 3-5 times what a stock BP4W puts out and probably twice what my turbo setup put out I'm ok with it.

That looks properly tight. Hats off to you for getting it in there though. There’s a few ‘5s floating around with a Civic radiator that’s 1/2 the width, just a though as it might help with heat soak into the turbo. The air filter possibly looks like it might be a bit restrictive? Is there any space to mount it behind the bumper ahead of the inner wing & pipe it in? I did something similar with mine mounting the air filter behind the headlight & piping in a cold air feed from the fog light hole.

So I recently hit the first real hurdle in this project and as of yet I haven't settled upon a solution. When I first planned this project I knew that I'd need to sort something for rear axles and I had planned on having new shafts made up. But this is pretty expensive and I've had quotes from about £450 a pair up to £700 a pair. Its not outrageous but I also wanted to look into other options so I'd spent a lot of time looking through a CV joint suppliers catalogue and found an outer CV that should fit onto the Tailgate McNoIndicate shaft and then slide nicely into the MX5 hub.


The hub in question was from a Mazda 626 mk3 and has the correct outer 26 spline, the correct 25 internal spline for the Tailgate McNoIndicate shaft and the correct seal diameter. It did indeed fit perfectly into both the hub and onto the shaft but when I disassembled the Tailgate McNoIndicate axle I realised something. Tailgate McNoIndicate use an outer plunging cv joint and a fixed inner cv joint, Mazda use a fixed outer and a plunging inner joint. So what this gave me was a driveshaft with virtually no plunge whatsoever (or near enough, the inner Tailgate McNoIndicate CV joint, does has some movement, I think its about 16mm) which is pretty useless. I also realised here that If I had have spent a bunch of money on custom axles I'd still be in the same position.


I spent a bunch more time trying to find a 100mm CV joint that has enough plunge and it appears that they just don't exist, GKN list one with +-20mm plunge but nobody actually sells the damn things.


As the Tailgate McNoIndicate axle is virtually the exact length I need I had considered trying to use a Tailgate McNoIndicate wheel hub on the rear, the only issue is that the MX5 hub shaft diameter is 40mm where as the Tailgate McNoIndicate hub shaft is 42mm. Even though the hubs are induction hardened, in reality the material can still be turned using carbide lathe tools so I could turn it down to the correct diameter. The main issue with this solution is that I'd be stuck with a 5x120 stud pattern on the rear and that really, really limits my wheel selection (no one and I mean no one make a 15 inch 5x120 wheel) as It limits me to wheels with custom drilled PCD's. And then brakes could also be an issue on the rear as I'd need to find new disks that would work.


I have also considered using a different diff but trying to find a diff with a ratio of between 2.9 and 3.1 is proving to be tricky.


Well I'm gonna put the diff and axle issues on the back burner for the time being as I could always just throw an MX5 diff and axles back in to get it driving. The 4000RPM at 70MPH is gonna suck though.


To get over this rather annoying blow I opted for some retail therapy and bought fuel injectors ready to start work on the fuel system. I had originally spec'd out 630cc Siemans Deka injectors as they flow more than enough fuel and come highly recommended in the Tailgate McNoIndicate community. However they were out of stock everywhere so I opted for an alternative and upgraded to the 875cc versions instead. These are direct plug and play for the M52tu engine and at about £300 for a set of 6 they are an absolute steal!.




I'll probably get them in the rail and start work fitting the manifold to start working out the intercooler routing this weekend whilst I'm waiting for the rest of the plumping parts to arrive.

Also as I'm likely to be doing a bunch of random buts today, I'll probably just post them as I go along...