Project bB: Breathe In, Breathe Out

If there’s one thing that Project bB has taught me over the course of the build, it’s that custom turbocharging a naturally aspirated platform is far more challenging than the ‘chuck a turbo on it’ notion first seems.

Sure, if you’re working with a popular vehicle and engine base, and have access to a quality bolt-on turbo kit, the conversion is likely to be pretty straightforward. If you’re not, as I have been, it’s exponentially harder, and you’d be silly not to expect your fair share of mistakes and setbacks. There have been a few of those along the way, but thankfully, I’ve had some very talented people supporting the build, and with every challenge that’s been thrown up a custom solution has been found. It’s been frustrating and so rewarding at the same time.

In this update I’m going to tick another couple of jobs off the long and seemingly ever-growing to-do list that accompanies Project bB, but truth be told, we’re actually a lot further along with the build than what this post will lead you to believe. So basically, I just need to pull finger and bring you a bunch of updates in short order to get you all up to speed, at which time I think we’ll pretty much be there.

First, the intercooler system…


Although some of the turbo kits you could once upon a time get for the JDM bB and its USDM derivative the Scion xB were sold without intercoolers (they were often an option to add), the thought of not running one never entered my mind. I researched a range of options, both top-mount and front-mount, aftermarket and OEM parts bin, but ultimately found what I was looking for in Vibrant Performance’s catalogue.


The Vibrant name should be familiar will all Speedhunters readers, as performance products from this Canadian company – a subsidy of Vibrant Power – have appeared on untold feature cars over the years. Their titanium products for exhaust and intake systems, their fluid delivery lines and fittings, and their clamping systems are all extremely well regarded in the automotive aftermarket. Thanks to Vibrant I’m using some of these other components in my build too, but I’ll delve into those in the next update.


There are three off-the-shelf, ready-to-fit universal intercoolers in Vibrant’s catalogue, and this one is the smallest of the bunch. As I’m running a small 1.5L four-cylinder engine and will be content with 200hp, I only ever needed a compact intercooler, and after mocking up a cardboard template, I was happy to learn that this one had the perfect dimensions to slip in behind the front bumper with minimal fuss. It’s rated for 350hp too, so there’d be no flow problems.


You’ll likely have noticed the four threaded holes in the end tanks, and these combined with the pair of included Vibrant stainless steel ‘Easy Mount’ bracket assemblies made fitting the intercooler, well… easy.


Our chosen location for the intercooler was directly below the front impact bar, which would position it right in line with the lower vents in the bumper. In the JTune Automotive workshop, Kevin welded two bolts to the bottom of the impact bar, allowing to the intercooler to simply be bolted into position.


To refit the bumper, only a tiny bit of trimming on the inside was required.

To plumb it all up, I grabbed a bunch of 2.5-inch aluminium bends (which were cut to size and welded where required), some silicone hoses and stainless steel T-bolt clamps.


Another important piece of the puzzle was this Vibrant Performance aluminium turbo compressor outlet flange, which is designed for the OEM Nissan SR20DET Garrett turbocharger, but is also a perfect fit for the front of my Garrett GT2554R.


We also used aluminium tube for the turbo intake pipe, which draws air through a K&N Apollo Closed Air Intake. This system features a plastic air box with K&N filter within, fed via a flexible hose that draws air from behind the front bumper (you’ll see it a few images down). The K&N air box is a neat, straightforward solution and fills the gap in the engine bay that the factory air box once occupied.


A blow-off valve is another important piece of a turbo conversion puzzle, and for this aspect I turned to Turbosmart. Here’s another company whose reputation for quality and innovation precedes them, and after a quick chat with the gurus in Turbosmart’s Australian HQ about which BOV from their extensive range would suit my application best, we settled on a 34mm Kompact Dual Port unit.


Prior to researching my options, I was under the impression that ‘Dual Port’ meant you just had the option of full vent-to-atmosphere or full bypass (recirculate into the intake) configuration. While you absolutely can run this valve either of those ways using the supplied port blanking plug, what Dual Port really means is that it sequentially does both. That is, it’s staged, with the bypass valve coming on first and then the atmospheric valve coming on second. This means that under normal driving conditions the valve is in quiet recirculation mode, but when you’re on it, you have all the benefits (and noise) of atmospheric venting. This clip explains it quite well.


For ease of initial installation, we currently have the Kompact Dual Port operating in full vent-to-atmosphere configuration, but I think it’s likely that we’ll convert to the sequential configuration down the track. I just need to wait and see how loud it is under all driving conditions first.

With the intake side of the turbo (air) plumbing complete, attention was turned to the exhaust, where we were essentially starting from scratch.


Beginning at the turbo end, a custom down-pipe was a given, so I picked up a Precision Turbo 5-bolt turbine discharge flange and Kevin got to work – so quickly that the next time I saw it the down-pipe was finished and fitted. You can see it here though.

Also pictured is the Vibrant Performance turbo oil drain, but more on that next time.


For the exhaust itself, there was the option of a 2.25-inch or 2.5-inch system. You could argue that the smaller size might have been best, but as I also needed to run a catalytic converter to get the car legal, and JTune had a used Mazda3 MPS (Mazdaspeed3) OEM unit with 2.5-inch inlet/outlets taking up room on a shelf, we went with the latter.

I was up for mild steel, but JTune owner Jacky wouldn’t have a bar of it – hence the full stainless system now under the car.


With the new pipework, I also needed a muffler. Actually, I might need more than one, but for starters we’ve just gone with a Flowmaster FlowFX unit out back. The FlowFX is an imported, low-cost 409 stainless steel muffler with a straight-through design, but on its own is possibly a bit too loud for my liking.

You can actually have a listen, because Project bB is running!

I shot this very average iPhone clip moments after the first fire-up on a custom, start-from-scratch base map that Jacky threw together on the fly in the space of 30 minutes.

It also means that I need to bring you the next instalment of the Project bB saga very soon, and in that I’ll fill in all the other blanks up to this major milestone in the build.

Brad Lord
Instagram: speedhunters_brad



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I remember seeing this car on multiple magazines especially Import Tuner
The idea for this car is much ahead of its time and now you can see the same styling coming on cars like the Kia Soul
I think a subwoofer would be so cool for this car


I still like the look of these cars 20 years after I saw one for the first time in Japan. I think some of Toyota's design cues for the bB came from the second-gen Chevy Astro van, but Kia definitely picked where Toyota left off with this model. Subwoofers for sure – I have two Rockford Fosgate 12s going in!


Yeah they're definitely pretty cool


The Scion brand in the US was heavily marketed with a bunch of modification options that had blessings from Toyota. I fully remember metallic orange and purple Scions with suicide-lambo doors and more woofers than a Pimp My Ride car. Loved it lol.


Oh yeah good times


There were some crazy Scion builds for sure!


This car is hilarious. Vibrant intercoller, flowmaster muffler, austrailian blow off, 200hp. hahaha. Vibrant used to be a joke of a parts maker. as in you were an idiot to buy them they were so bad. Whoever told you that car has 200hp is probably the same guy who sold you a flowmaster as a performance part.


No one told me the car has 200hp; I said the goal is 200hp. The engine has been built to handle a bit of boost, so I think it's achievable with this setup. You definitely sound like an expert though, so maybe I'm wrong...


Why do you have doubts about this being a 200hp car?


surely you meant "breath In, Breath Out"


Take a deep breath, it's time to breathe.


I don't think so?


I think you missed the "bB" from "breath In, Breath Out"


Haha! Well yes, that went right over my head, didn't it! Nice one John, and thanks Muaz!


Love the updates on the bB project. I've got a Scion xB (gold RS5) and they're great cars. I enjoy the "I'm not building a track or show car. This is for me to enjoy" build approach. It's not crazy power or full of rare parts, just a lot of love and time to make something you'll enjoy. This doesn't need an uber expensive intercooler, V-band piping, or exhaust for your goals so why waste a bunch of money on things when it'll just slow the project down.

Love the project. Keep the updates coming!


Thanks for the comment! You're 100% correct – for me this build is all about fun. I love the bB, always wanted to have a car with a custom turbocharged engine, and was looking for something I could stick a loud sound system in to relive my teenage years. This car will tick all those boxes.

Dino Dalle Carbonare

Love seeing this slowly come together!


The bB is cool and all, but what about that Swift in the first pic...


The Swift is very cool; will have a spotlight on that once it's finished. Did you spot the big Endless front brakes?


YES!!! I've been patiently waiting for so long! I love this build series. I love purpose-built race cars as much as the next guy but a unique, low powered but fun street car really catches my attention. I can't wait for the next update. Btw, I'm still feeling your pain back from when you ordered the wrong size pistons lol


Oh man, don't get me started on those damn Arias pistons or that damn ARP head stud kit... But she's a runner, so I'm happy!


It doesn't sound too bad, but I understand personal preferences about the noises it makes.

My question is, how did you search the compressor outlet flange? I was just on the Vibrant website and couldn't find them listed. I have a few bits and pieces of Vibrant stuff on my project, and that is a piece I have been trying to track down in general.


Perfect! Thank you!! This should help move along a few of the next steps of the project!


Nice one, what's your project?


About 5 years ago I put a turbo (GT2860 from an R32) on an Intrepid with a 3.5, drove it a couple years then pulled the car for paint and body work, which was 3 years ago. So now I'm finally getting it back together and ready for the road this spring and getting ready to add an intercooler and clean up the 'cobbled' look of everything since it all had to be by us while putting it in.

*Hopefully* if the weathers stays nice here in the middle of Canada I can get a lot accomplished then start the process of preparing the next steps of it's evolution.


That sounds like an interesting project! – good luck with the next steps!


The 2.5" intercooler piping will add noticeable lag to the boost response. May want to consider 2" or even smaller if you can find it, for this 1.5 motor. You also may want to reconsider the rigid mounting of the intercooler as it will experience considerable vibration. A rubber mount or saddle would be advised. Look to OE applications for these kind of solutions as they are well designed for durability.


I've driven it and the response seems pretty good. Smaller intercooler pipes and perhaps a smaller diameter exhaust would surely help, but I think the current setup is fine for what I want from it. That's a good point re: the intercooler mounting, so will look into some rubber insulators.


Hey, I was linked to this from a scion forum. I've boosted my xb too! Modded the 1nz like yours and i've been driving trouble free @ 8psi for months. On the stock 06 xb ecu! no joke. it handles the boost like it came from the factory! if you get bored i have like a build diary on scionlife