How to fit and adjust a MBC

[RAW]

i would say the same think for the B200E in our 740. theres not much urgency in it, but theres bags of torque at low revs, and no need to rev it like the engines in most small cars. it suits the car perfectly.

[gpl1968]

Originally Posted by Eddy Matthews

I don't have a 940 yet Chris, but I am looking for a 940/960 at the moment.... It's just the 135bhp from the standard LPT 2.3 lump sounds like about enough to pull the skin off a rice pudding to me! It's a BIG heavy car!! Though I admit I've never driven one (yet!).

So getting a bit more performance without having to resort to expensive engine mods and the associated huge rises in insurance costs sounds like a viable option.

If you (or anyone else) has some concrete numbers it would be interesting to see the comparisons - But genuine numbers please, not guesswork!

Regards
Eddy

For most people the lpt will be fine. It has plenty of power and torque low down for relaxed motoring.
The thing is that once you rise above it's ~4.5psi, the engine lights up and power rises dramatically.
If you compare the lpt which had 135psi(~4.5psi) with the "sport" model that had 190bhp at ~10psi(inc. turbo+), then if you up the boost to say 12psi you will have more than sufficient even allowing for the car's age.

[Eddy Matthews]

Looking at the figures for the various Volvo 900 models, about 10bhp per 1psi increase in boost prssure sounds around right (approx 7% per psi).

Now it comes down to things such as general engine reliability at these higher pressures, turbo life expectancy, and fuel consumption.... Does anyone have any info on those?

I have to admit that fuel consumption doesn't really worry me - I've had plenty of vehicles that only average 24-25mpg, so I'm perfectly used to that!

Regards
Eddy

[Chris740R]

Fuel consumption will only increase if you make use of the extra boost, otherwise it'll be exactly the same.

[Eddy Matthews]

One thing did strike me when reading your installation post Chris, and this isn't meant to be offensive, I'm just curious!

You said to use vacuum hose to connect the MBC to the turbo - But surely that's designed to resist collapsing when it draws a vacuum, exactly the oppossite to turbo hose which is designed to hold a positive pressure..... I would imagine it may blow apart after a short while as it's taking a loading it was never designed for?

I'd be interested in any comments on that - Maybe I'm talking rubbish? It certainly wouldn't be the first time!!

Regards
Eddy

[gpl1968]

Here is a potted history of the B2xx engine (shamelessly snipped from Wikipedia)

In 1985 a revised, "low friction" design was introduced, dubbed the B200 and B230 (depending on displacement).
The improvements were different, longer rods (152 mm c-c, 7 mm (0.3 in) longer), pistons with a lower compression height, lower friction bearings (smaller in size) ,a crankshaft with 8 counterweights (instead of 4 on the older Bxx engines) and a heavy harmonic balancer in the crank pulley.
However, the robustness of the reciprocating assembly was decreased. The engine rods were thinned to 9 mm (0.4 in), the crankshaft design and fabrication were altered and thrust bearing placement was moved from number 5 journal (B21/23) to the number 3, together with smaller bearings. This low friction design was used throughout the remainder of the "red block" production.

1989 saw an upgrade to the crankshaft, with a relocated axial thrust bearing back to the number 5 journal, bigger main bearings, rods were enlarged to 13 mm (0.5 in) from 9 mm (0.4 in) in 1990. Also introduced in 1989 were 16 valve, twin-cam variants of the B200 and B230, dubbed the B204 and B234 respectively. The B204 was also available in turbo form in some markets (such as Italy) where large displacement motors were taxed heavily. It came in two versions: the B204GT turbo motor operates with a lead resistant lambda probe and puts out roughly 200 hp (149 kW). The B204FT has a catalytic converter and puts out appr. 185 hp (138 kW). Both were the first redblocks standard equipped with oil squirters for piston cooling. Crankshaft, conrods and pistons all forged. Exhaust valves were sodium filled for cooler operation. It has smaller valves and stiffer valve springs than n/a 16V. Crank torque is 290 N·m (210 lb·ft) at 2950 rpm for the GT, and 280 N·m (210 lb·ft) for the FT. Other differences from the normal 16V redblock engine are that it uses a remote mounted oil filter (Away from block on exhaust side engine mount) and a windage tray.

For the B230 engines 1993, piston cooling, oil squirting jets were added to help alleviate piston slap problems on the turbo motors. Another modification was to go from a square toothed timing belt setup to a round toothed timing belt setup which made for quieter belt running. (For this engine the volvo belt service interval shows no change from every 75k KM (47k miles)though this article previously stated it was to increase belt life to 150k (94k miles))

At the end of 1994 Volvo improved the engines again by changing the pistons. What is better about the new pistons is unknown. These engines weren't available in the USA. All cars equipped with the updated M90 5-speed manual transmission have these better engines.

The last redblocks were made in 1998, when the 940 model was discontinued.

As to life expectancy of parts (the expensive ones), turbos should last at least 100,000 miles as should the Air Mass Meter. The dual mass flywheel(found on later cars) can fail and is expensive although mine is fine at 185,000miles.

As regards engine life expectancy at the higher boost levels, it depends.

If you are doing high speed runs on German autobahns then expect problems.

In normal daily driving and at motorway speeds the turbo is hardly being used.
You are only getting boost when accelerating and the extra boost only comes in when you call for it.
Cruising at 70 on the motorway and my boost gauge reads a negative manifold pressure, which indicates the turbo is barely spinning.
when I put my foot down to overtake the boost rapidly rises.
As long as the car is in good order before before hand there should be no long term problems with fitting an MBC.

[gpl1968]

Originally Posted by Eddy Matthews

One thing did strike me when reading your installation post Chris, and this isn't meant to be offensive, I'm just curious!

You said to use vacuum hose to connect the MBC to the turbo - But surely that's designed to resist collapsing when it draws a vacuum, exactly the oppossite to turbo hose which is designed to hold a positive pressure..... I would imagine it may blow apart after a short while as it's taking a loading it was never designed for?

I'd be interested in any comments on that - Maybe I'm talking rubbish? It certainly wouldn't be the first time!!

Regards
Eddy

The hose should be able to whithstand the working pressure whithout expanding, allowing for the high operating temperatures in the engine bay.
Fuel hose, as narrow and as short as practicable, is ideal for this purpose as it is designed to work at much higher pressures.
I used 4mm diesel return hose and metal hose clips (mainly because it was cheap and available) and have had no problems.

[Palmer]

So when i get around to it im setting my b200ft at 10 psi??

[Chris740R]

Originally Posted by Eddy Matthews

One thing did strike me when reading your installation post Chris, and this isn't meant to be offensive, I'm just curious!

You said to use vacuum hose to connect the MBC to the turbo - But surely that's designed to resist collapsing when it draws a vacuum, exactly the oppossite to turbo hose which is designed to hold a positive pressure..... I would imagine it may blow apart after a short while as it's taking a loading it was never designed for?

I'd be interested in any comments on that - Maybe I'm talking rubbish? It certainly wouldn't be the first time!!

Regards
Eddy

No problem good question. The vacuum hose is designed to take both vacuum and positive pressure, its used all over the place on the engine. I've used it on my installation because thats what I've seen most people use on their cars. As you can see from the pictures, taken a few months after my initial installation, the hose is still in good condition.

[Chris740R]

Originally Posted by Palmer

So when i get around to it im setting my b200ft at 10 psi??

Quote from foggyjames

That looks pretty good to me. The pictures are good, too. My only comments would be that 12psi might be a little bit optimistic...I've heard them pinking at 12psi on 95 octane in the summer. Different ECU numbers seem to allow different limits. For example, most B200 turbos seem to have a far more restrictive boost cut than their B230 siblings, but some B200 ECUs allow a ton of boost (regardless of the fuel system's capability to actually deliver fuel correctly for it!) without cut.

I think he might be able to help you on this one. Going to need your Engine code.