R-Sport B21AT turbo build

Spac

I think that it is cool, but only because they will be your headaches.

Yeah so as hinted in photos and Spac's comments, this is going to be a B21AT build, utilising the R-Sport carby turbo kit.

It's been quite a ride so far. The original TB03 turbo is trash (let's face it, it's a crap turbo). I'm going to be running a new GT2252S.

The R-Sport kit I bought from @Spac in 2015 I think, and I bought the B21A from @Angus242164 also in 2015, and the whole lot has sat in my garage ever since.

This is very much a desire build, I'm not chasing crazy power, it will make like 5psi because I'm pretty sure the Zenith CD175 won't flow enough fuel to go above that.

I'm deleting the mechanical fuel pump as the original boost-referenced pump is too hard to come by and I honestly can't be bothered modifying one. This will be a conversion from K-Jet so the car will already have a return system and I'd rather run an electric pump that can utilise that, so that I don't have to re-plumb the fuel system.

Okay, aux shaft bearings finally turned up. For the record, the Skandix ones (which is what IPD sold me) are finished and do not need to be line bored.

Polished crank:

Main caps installed. I used some plastigauge to check clearances, the front journal was a bit large but juuust in spec, and everything else was good. I also measured axial clearance at about 3 thou which is a tad high but I've gone full send on turbo blocks with 4+ thou and not had any trouble so not concerned really.

I'll complete the bottom end over the weekend. The top end is still some time away so it may be a hot minute before more updates roll in. I have a 405 head on my B21E but it needs new valve stems and if my memory is accurate, it probably needs some corrosion ground out and TIG welded. Just when my machinist thought he was finally rid of me.

I also need to hand-make new oil cooler hardlines to reproduce the original R-Sport hardlines, which are different in design to the 740 Turbo hardlines. I have braze-on banjos and fittings on order just need to pick up some steel pipe.

So I tore down a mechanical fuel pump to see how difficult it would be to boost reference it, and basically I can't be bothered. The car already is plumbed for a return system as it's currently K-Jet, so I'm going to instead use a modern pressure regulator. I think I've settled on a Fuelab 515 which has a pretty nice range of adjustment and will not look too alien in my engine bay. This means the fuel tank and pump are all going to remain as-is, which is nice, as if I ever get over this setup I can go back to K-Jet with minimal hassle.

That aside, today I finished off assembly of the bottom end, barring a couple of fasteners and the oil pan, as I don't have any more M8x16 bolts. I'm waiting on a bunch of fresh fasteners.

I can't start work on the top end just yet, so I am next going to be looking at reproducing the original R-Sport oil cooler hardlines. This is what I have presently:

And this is what I need to end up with:

Other turbo redblock Volvos use a slightly different setup with hoses and hardlines in different places. The bracket you see in the photo above is the one from a 740 Turbo, GCP had them for sale for $not much, and comparing it to the diagram you can see that aside from the actual pipe clamp, it's the same part (the part numbers are different though). I can live with that!

So, I have braze-on banjos and fittings on their way to me from the UK. I have a pipe bending tool but all the same this is probably going to take me a few goes. I may also take this whole setup off the new engine and fit it to my existing engine as I need to make sure these pipes stay clear of the steering column.

Fasteners and banjos turned up. I'm going to try and see if I can use some steel tubing I already have, it has some bends in it already but I think they might actually match up pretty neatly with what I need, so hopefully that will save me some time/the need to buy more steel tube.

Okay so this is what I'm aiming for. I mocked it up with some old 740T hardlines. When I get a chance I'll tack everything together and then see if I can find a shop that can fab up fresh pipe to match.

Ex850R

Is it worth buying a reasonable tube bender?

If you have other use for it or others maybe?

I have a tube bender, but it can't do these kinds of tight radii, the smallest it can do is maybe a 50mm radius, these are about 30mm radius. Benders that can do those kinds of bends in steel pipe aren't cheap and honestly I have no need for one, if this was any other build I would just use aluminium hardlines and be happy with larger bend radii, but this build is all kinds of crazy attempts at reproducing the factory finish.

@Ex850R you can see here the radii I want vs the radius my bender can achieve

Okay mockup pipes are finished. Now to figure out how to make/have someone make the actual ones. Anyone have experience with this sort of thing?

Okay so I went down to Pirtek today and they can do 12mm steel pipe with a 38mm radius. The bends you see in these photos are about 30mm. They wanted about $80 for the two pipes so I left it with them to make a copy. The guy who does it will be in tomorrow, I asked him to give me a call beforehand and I'll see if he wants me to bring the block down so he has a fixture to work with.