Beyond 6000: Project Volvo V50 t5 awd "more than" Polestar

The Why:

Some time ago, I decided I should buy my wife a car. Why? well... I believe because it was monday! As long as I like the car, I don't need justification. If i don't like it, on the other hand, I find every possible excuse to rule the thing out... So SUV's are immediately out of the equation, 99% of diesel's too and regarding the crap the auto industry is selling out today, 90% of every other car too.

Wasn't going to be easy!

First candidate was an Peugeot RCZ with 200bhp 1.6 THP engine... beautiful, well built, and fun. But she said: 2 kids with chairs + 1 13yo, this is not practical! And so I had to let the RCZ go.

Then a BMW 320D CC came up... it was beautiful (for a women... I'd never ride a champagne colored car), but, once again, it failed the rear seat space test.

I was giving up when a Volvo V50T5 AWD popped on the market. It was wonderful. The V50 T5 is not the best T5 engine, but then again, there are no BAD t5's. It's a Low pressure turbo K04 version of the same block on the S60R, with smaller spec'd rods and pistons. The great thing is that it has VVT on both Intake and exhaust and, since volvo was transitioning from TWR and the R badge cars to the Polestar branding, this series, along with the C30, S40mk2 and C70mk2, where left with a R-design trim option but no juicy stuff as the old R's used to have.

Because of this, Volvo dealers offered a Polestar Optimization Pack for the standard RDesign T5's, that you could buy and request installation.

Guess what else I found online: The map, the specs for the dampers, the wheels and the numbered kit documentation. So, In order to have a very valid Volvo V50t5 Polestar, all I had to do was to kit the car with wheels and suspension, add the map and the 2 badges together with the manuals and certificates.

And guess what: the engine block on this one is a Polestar branded one. Care to guess why?

Well, Polestar was preparing and racing the s60r back then and the 2.5 t5 engine block is shared across s60r mk2, and that block fits the v50... as it apparently did :)

So why isn't it the best T5 out there? For starters the turbo is low pressure meaning that this is capped form factory. Then the rods are not near as tough as the S60R ones, also unlike the S60R, the pistons do not provide high compression.

However, much like the S60r, it's a 2.5 with the same block as the S60R. The Volvo t5 are aluminum blocks, open sleeved design with a hard steel liner about 1 or 2 mm thick(depending on the engine). As the block stresses under boost detonation, the block and cylinder walls giveaway a bit to accommodate, but the sleeves liners, in harder steel, will eventually just crack.

The best t5 is the legendary 4T5 engine on a 2.4l configuration NOT BY BORE, but rather by stroke (long block...or longer that the other 2.4 by bore, low power options).

I knew the pistons are good for almost 500bhp, the rods shouldn't go beyond 330/350bhp and the sleeves, when they are known to crack on standard setups, so having a figure is just nonsense.

I didn't really like the Polestar rims...

...so I decided to go for MAK ones with a better design (particularly for portugal where you can have holes in highways and crack a rim easy.... that is exactly why, for the s2000, I chose the 5Zigens proracer gn+ and not the Typical Volk Cn28).... the MAK have a split mid arm that helps spreading the load across more radius then the Polestars. And price was equivalent, even though the polestarts where 20" and the MAK 18", tire wise it made a difference, and I'm not going go extreme on breaking, so ... 18" is enough.

The rest made into the car. And so a 250BHP T5 AWD was born.

I also wasn't 100% happy with the remap and tweaked it a bit, while installing a 3Inch CAI, aluminum wrap turbo ducts, full decat and a cut-out installed just before the rear box.

The car jumped to 280bhp.

The standard Haldex is a gen2 that BIAS the car towards the front-end... HOWEVER interesting this was for her to drive the car (not too much tail happy), it needed a personal touch. I then installed the Gen3 Haldex controller from the Volvo XC90 V8 and that fixes bias to 60%front 40%rear.. yes it issues errors but then again, as long as the power gets to ground, I'm cool.

The car was fitted with MAK wheels and Bridgestone Potenza Sport, and some polyurethane bushings, so it glued to the road and just powered towards the end of the roads all too fast.

Surprisingly the K04 is good for 280bhp and while one thought the car was quick after remap, the moment VVT kicked in, you would feel a tremendous pull towards the car in front of you... or the next corner. These engines are known for starvation limitations due to turbo size, but It didn't feel like this. Probably it will be perceptible from 300 bhp on, and that is maybe why you rarely see them going past 300bhp without major turbo/injector upgrades.

Was really fun, however, some months into this, we felt an occasional stuttering, as if the gearbox wasn't getting into gear, but it was... strangely!

A week into this occasional stuttering at low speed, the car seized and cylinder number 4 said it was time to go on strike.

I'm still to eval if this was a piston carving (the car used to have bi-fuel BS) and we all know that gas conversion presents lubrication challenges, or a stuck injector... or a MEGA crack as compression was totally lost on that cylinder. But the piston scratched the wall and that means trouble either way you put it.

UPDATE: piston scratched the wall because it was fully cleansed by water from the block and petrol from the injectors. The gasket gave away!

After a small talk with the mechanic, we figured that the torque specs for the that part of the head where WAY OFF... so a hypothesis can be formulated:

Former owner overheated the engine, a leak formed, he asked his grease monkey to tighten the block where it warped and sold. Typical Latin BS. I'd have brought the car if he had told me this, anyway, as some tweaking was to happen... but people are shit! We deserve the asteroid coming our way.

So I had 2 options:

1 - buy an engine and have this fixed in a month

2 - buy parts and forge this thing to 1000BHP capable, set it up to 500 bhp to be very unstressed, and allow the wife to thrash a 400-500bhp AWD Volvo to pick up the kid at school

... hum... decisions decisions.

With me, as you can gather with other articles, there is no decision. Replace factory compromised stuff with tuner or racing uncompromising parts and stop worrying.

So a build it was and a big one it would be.

Well I've just start receiving parts!

K1 I profile Forged Rods

Darton MID sleeves:

Wiseco, HighCompression, Forged Pistons:

ARP 2000 Main studs:

ACL RACE Tri-Metal Rod Bearings:

KING Tri-Metal crank bearings:

Also arrived:

ARP 2000 head bolts

Athena 1.6mm full metal, reinforced gasket

The Turbo is to be hybridized to a K24 core good for 420 to 500 bhp. As a result, I'll look at the injector charts and choose accordingly.

The Idea is to have a dual map with the minimum duty cycle the injectors handle for the minimum pressure on the turbo (IDK 180bhp maybe), and either 400 or 500 bhp for the max duty cycle on the injectors and turbo feeding.

I think the Wife will be pleased.

Stay tuned for more info and pictures. I'll be showing off my friend Fabio's skills during the build, in case you wanna try the same recipe.

UPDATE 1

Finally, after a long wait (first gather all the parts, then waiting for the mechanic to have time to assign to the build), I've got word that, next Thursday (in 3 days) the build will start, and the photos will start popping on the blog. Stay tunned.

She is now dry (engine coolant, engine oil and gearbox oil).

Tomorrow, engine and turbo comes out and off to the machine shop. Weeeeee ;)

UPDATE 2

wow this was a mess... no wonder it failed.

Gasket blew and coolant went into the combustion chamber.

Gasket let go almost 50% of the contact patch... it was a matter of time before we had trouble. You can clearly see how clean and washed it is:

And a bench of parts that (about 50% of'em) will never be used in this engine again.

The rods seam thin if you look from this perspective, but turn them sideways and they look like toothpicks. The 2.5 t5 low pressure options is built cheap to it's very core. Disappointing, but a clear tell sign of economists finding their way into engineering departments.

UPDATE 3

Engine is now at machine shop, and turbo has been handed to the turbo specialist for hybridization... in goes a BorgWarner K04 out comes a BorgWarner K24.

Next step: Full destruction of existing sleeves and making the inserts for the Dartons.

Then the cold/hot resleve.

Then honing under pressure plate at full torque (simulating a head in place)... the proper way to do it.

This next phase is expected to take about 1month...so update could be delayed until full sleeved block and turbo are done.

Will try to post progress IF the work shop sends images back.

Update:

So summer came, people went on vacation, stuff delayed a bit, however:

The block is sleeved and parts are now in weight correction and dinamic balancing for assembly.

With the engine now being dynamic-balanced, its starting to get close to assembly, so the logic step is starting to work of shaft reinforcement and brakes.

As such, a set of s60R calipers front and rear...