Anyone familiar with the Saab B204 engines?

[BT]

Hello chaps.

I am looking for some help from someone who knows their Saab B204 engines.

I am seriously tempted by trying a B204 turbo conversion one one of my little classics but I need some help regards which donor car to buy.

I realise that there are a fair few variants such as..

B204i - N/A? - 130hp
B204E - low pressure turbo? - 154hp
B204L - 185hp
B204R - 200hp

Now I obviously want the engine which responds the best to tuning, but still affordable to buy in a donor form. How can I tell what model engines came in what model cars?

I have found a potential donor, rather local, with tax and test, but I am unsure that it will will have the right engine for me.

The car is a 2000 model Saab 9-3 2.0 SE turbo, the seller has listed it as the 185hp model which suggests it is the B204L but it is branded as a EcoPower on the rockercover. After a brief bit of reading they changed to the B205 in the later 9-3 and 95 models. The engine also has the black direct ignition panel as apposed to the red, does this help identify the engine model?

Can anyone tell me if a 2000 model Saab 9-3 turbo SE will have the B204L or the B205? If it is the 185hp "L" model is this a suitable engine? Does it respond well to tuning? Would it be suitable for an engine conversion?

After some brief reading it seems as though I have seriously under rated the B204 engine, well I've never actually shown it any interest before! After a brief read some people are running near on 300bhp with standard internals and they seem to be a pretty decent engine.

Any help or suggestions would be hugely appreciated.

[DavidB]

Get the B204 - it's 2.0 litre and depending on the letter after the code, will determine what power it is producing. They are either high output turbo or low output - HOT tend to be nearer 200 bhp and LOT about 175 - 185 bhp. The L and the E are 175, and the R is about 200 bhp. The R has an upgraded ECU.
I think the 1999/2000 9-3 SE will have the B204R, which has the HOT and upgraded ECU (they only produced a few of these to a single model year).
B234 is taller than the B204, althrough produces more power. The 20 and 23 standard for cc, and the 4 stands for the amount of shafts (this includes the balance shaft I think?). You can't go wrong with them tbh. If you need wiring help, I can forward you the wiring diagrams (ones I made myself from tracing the whole loom from ECU to engine). Even with 175bhp, that should be enough power! A better turbo, intercooler, ECU remap (remaps are incredibly easy on these) and downpipe will produce a reliable 300bhp from a 175bhp engine. I current have 265 bhp from a B204R after spending 100 pounds on upgrades, which I think is enough.

One more thing - you will need the ECU unlocked if you don't want an immobiliser. There is a fellow on UKSaabs forum called Jules who does this for £50 and also remaps the ECU to stage one. Or buy a CanUSB Saab ECU reader for £100 and do it yourself.

[matty2300]

Jun 10, 2014 19:45:03 GMT BT said:

The car is a 2000 model Saab 9-3 2.0 SE turbo, the seller has listed it as the 185hp model which suggests it is the B204L but it is branded as a EcoPower on the rockercover. After a brief bit of reading they changed to the B205 in the later 9-3 and 95 models. The engine also has the black direct ignition panel as apposed to the red, does this help identify the engine model?

Can anyone tell me if a 2000 model Saab 9-3 turbo SE will have the B204L or the B205? If it is the 185hp "L" model is this a suitable engine? Does it respond well to tuning? Would it be suitable for an engine conversion?

2000 model 9-3 will have a B205 (black ignition module, trionic 7 ecu)

for a B204 (red ignition module, trionic 5 ecu) go for 1999 or before

- don't worry too much about whether its a B204L or B204E, the only difference is an ECU remap and the addition of an electronic boost control valve on the higher bhp variants.

avoid the B205 for tuning, much weaker lighter internals in order to get better fuel economy, older ones are prone to sludge issues caused by blow by - there were a LOT of revisions to the breather system over the years to try and eliminate this issue.

[froggy]

What car is this going in ?

[sonett7]

The B234 is not taller than the B204 - it has the same bore and it's only the crank, pistons and conrods that are different.

The gearbox from the Opel/Vauxhall Omega with 4 cylinders or V6's (not straight 6!) fits the B2X4 without any modifications. The clutch slave cylinder needs to have a spacer to reach the pressure plate of the clutch - or use the flywheel from a Saab 9-5 as it is thicker (and a lot heavier). If you use the oil sump from a ng900/og9-3 together with the gearbox from the Omega the engine with have the stock 7 degree tilt when the gearbox is at level.

[DavidB]

Sorry, stroke is taller, I didn't mean size, they're visibly identical.

[BT]

Thank you all very much for your help, it has all been of huge help. I usually like to reply to helpful posts like this individually but I don't want to drag on!

The original car I was looking at was a 2000 reg 9-3, after some reading it does appear to be a B205, after further investigations due to it being an EcoPower the parts are lighter for the "Eco" element and therefore not best suited to 300hp. I am lead to believe the B204 would be better suited so I've ditched the 205 idea. I also think the B205 runs T7 management which I am told is harder to map?

Unfortunately due to the extended stroke in the B234 it makes the block too tall to fit in the bay I intend to fit the engine into, so I have to write that off.

I intend to use a F20 (2.0 16v C20XE) Vauxhall gearbox, flywheel and shafts, this also means I can use an F20 gearbox mount which will bolt straight into the car I intend to install the engine into.

I have since found another donor. It is a 1995 4dr Saab 900 2.0 turbo. Can anyone tell me if this is a B204? I am assuming it is. What management will this be running?

Thanks for the pointer regards the immobiliser, thinking about it now it probably isn't a bad idea to keep it because the car doesn't currently have one, I'm assuming I would need the key, transponder ring and ECU?

Thank you all.

[ejenner]

As pointed out earlier. On the outside the longer stroke 2.3 engine is the same size as the shorter stroke 2.0 engine. If you want something really small you can use the B202 from the 1984-1993 900. It's canted 45-degrees but is otherwise identical in terms of strength and tuneability. The downside to the canted engine is that you'd have to find a donor car to donate the electronics to run it as the older ECUs off the Saab 900 aren't very modern and a bit rubbish.

The other difference with the not-so-good B205 is the asthmatic camshafts. Again, also designed not to work that hard so the precious fuel isn't wasted.

It's worth pointing out that there is an early cut-off for the 9000. If you go before 1994 then it will have the older B204/B234 which limits your transmission mating options and comes with the earlier Trionic 5.2 which isn't as good as the ideal Trionic 5.5.

Just hunt for ANY Saab, 2.0 or 2.3 does not matter, 1994 onwards, with a turbo and with a red ignition cartridge. After about 2001 all of them would have been black ignition cartridge and trionic 7... which is rubbish engine with rubbish ECU. There's 6 or 7 sweet years in between.

[BT]

Thanks for your help.

I know for a fact he B204 will fit, so if the blocks on the 2.3 is the same as 2.0 then the 2.3 should fit. Maybe a 2.0>2.3 conversion can be done later down the line.

Thanks for that help, central oil cap, hard pipe, red ignition cartridge and I am good to go?

I have found a potential donor, so as soon as I get the chance I will go and investigate.

Thanks once again chaps!

[ejenner]

I did say 2.0 or 2.3 does not matter. It really doesn't. Bung on a juicy turbo and the 2.0 and 2.3 are as fast as each other. All the VERY high performance Saabs use the 2.0 block as it's an over-square design so is better for revving to higher RPMs. The 2.3 will be good up to about 500hp, after that people start looking closer at the 2.0 block. If you want about 300bhp then quite literally, either will do.

[BT]

Jun 13, 2014 13:58:45 GMT ejenner said:

I did say 2.0 or 2.3 does not matter. It really doesn't. Bung on a juicy turbo and the 2.0 and 2.3 are as fast as each other. All the VERY high performance Saabs use the 2.0 block as it's an over-square design so is better for revving to higher RPMs. The 2.3 will be good up to about 500hp, after that people start looking closer at the 2.0 block. If you want about 300bhp then quite literally, either will do.

Thank you very much once again for your help.

300 is a barrier I am yet to break which is why I have said that figure, once I have broken that barrier I am sure the gauntlet will be thrown down for 350 and so on.

Nice to see you're in kent, I am from Rochester myself. Are there any local mappers you would recommend?

[ejenner]

I can unlock the ECU and put a stage 1 map on it. Or a stage 5 map if you want... lol.

With free software which a very intelligent very worthy individual wrote for mapping Saab ECUs you can actually road-tune the ECU using the autotune feature. You can also log your drive so take it out for a spin, check the laptop an hour later and see where you can improve your map. To be honest though, you probably won't require much tuning just to get going. The ECU is very good at adapting so as long as your map is for the correct engine and you've not tried to circumvent boost control then you'll probably find it will work right out of the box. Wastegate actuator should be left at factory tension and the boost control valve will then bleed off pressure to give you boost.

One thing you'll require which is often overlooked is the speed signal input to the ECU. On the Saab it will take the speed signal from the gearbox. Without a speed signal it won't try to provide any boost so it will feel fairly flat without a speed signal input. When we transplant the trionic 5.5 ECU to an earlier Saab 900 we can get a speed signal from the back of the speedo where the cruise control picks up the speed signal. Could probably provide the signal from a wheel speed sensor or if the gearbox you use has a sensor then that could work. The parameter in the ECU can be edited for the number of revolutions per MPH ratio so you can adjust, as long as the correct format of speed signal is provided.

[DavidB]

Ejenner - I get my speed signal from my ABS. I read the ECU reads pulses (just like the teeth on ABS), but I'm having problem with boost.
I've got everything running, but just having that problem, and I haven't actually driven the car yet. Would the boost relate to problems with the car standing still - this sounds like a stupid question, but want to clear that up. Does it need speed signal with the car not moving (v = 0).

I've replaced everything with new stuff to get the car running and I'm at this stumbling block which has stood for about 6 or 7 months.

I'm using a rebuilt Calibra Turbo F28 6 speed box with mechanical speedo (should've used an electronic for the speedo). I'd be glad to give anyone the ECU and wiring diagrams for anyone that needs them (you can't find anything decent online), it'd save the problems I had doing it.

[sonett7]

The engine will not build boost until you drive the car.

If you switch to F28 6-speed you need to change the gearing settings in the ECU since the gear is calculated from actual speed and rpm to be able to have different boost in 1st, 2nd and 3-5th. If I remember correctly you need to set the gearing for 5th gear in the ECU to a value in the middle between 5th and 6th of the gear box since the ECU doestn't have settings for 6th gear.

Assume that you have T5Suite or at least know anyone who do...

[ejenner]

I don't think a signal from the ABS sensor will work. This the relevant extract from the trionic suite manual:

"The ECU needs the vehicle speed signal to determine in which gear we are driving. This signal is a square wave form which varies in frequency depending on vehicle speed. The signal is applied to pinnumber 39 on the ECU."

The VDO speedometer in a Saab 900 is mechanically driven by a cable from the differential. After 1988 that speedo in the 900 came with a sensor attached to the back of it which provided a speed signal to the cruise control. That sensor also produces a speed signal which is perfect for trionic. It would be easy enough to take the gubbins of a Saab 900 VDO mechanical speedo and swap the face plate and needle to make it look like the Vauxhall speedo. I'd say that wouldn't be a bad route to go.

The simple answer to your question has already been provided by sonett7. If you don't have a valid speed signal going to pin 39 on the ECU that will count as a fault with the APC boost control system. If the ECU has any faults in the boost control system it won't operate the boost control valve and you'll have no boost.

T5suite - the program you can use when you have the ECU connected with a lawicel canusb adaptor - can monitor pwm of the APC boost control valve. In other words, if you look at what the ECU is doing to the boost control valve you'll know whether or not it is trying to give you boost. If is isn't controlling the valve then you know boost control isn't functioning. If it is trying to control the valve then the problem is with the wiring to the valve or the valve itself.

[keithyboy]

Jun 11, 2014 12:05:59 GMT DavidB said:

Get the B204 - it's 2.0 litre and depending on the letter after the code, will determine what power it is producing. They are either high output turbo or low output - HOT tend to be nearer 200 bhp and LOT about 175 - 185 bhp. The L and the E are 175, and the R is about 200 bhp. The R has an upgraded ECU.
I think the 1999/2000 9-3 SE will have the B204R, which has the HOT and upgraded ECU (they only produced a few of these to a single model year).
B234 is taller than the B204, althrough produces more power. The 20 and 23 standard for cc, and the 4 stands for the amount of shafts (this includes the balance shaft I think?). You can't go wrong with them tbh. If you need wiring help, I can forward you the wiring diagrams (ones I made myself from tracing the whole loom from ECU to engine). Even with 175bhp, that should be enough power! A better turbo, intercooler, ECU remap (remaps are incredibly easy on these) and downpipe will produce a reliable 300bhp from a 175bhp engine. I current have 265 bhp from a B204R after spending 100 pounds on upgrades, which I think is enough.

One more thing - you will need the ECU unlocked if you don't want an immobiliser. There is a fellow on UKSaabs forum called Jules who does this for £50 and also remaps the ECU to stage one. Or buy a CanUSB Saab ECU reader for £100 and do it yourself.

Jules is a clever lad. He removed the immobiliser from my ng900 and remapped it to around 220BHP for £50 too. I think with T5 cars, just look for the crappest car with the best engine to give up. An LPT can be taken up to 220BHP for about £100. They seem to be pretty indestructible mechanically. Mine has over 150k on it and doesn't use a drop of oil. If you leave it standing for a week, you get a puff of blue smoke on start-up but otherwise it's as good as gold.

Out of interest, have you changed the downpipe to get to 265?

[richycalibra]

Jun 11, 2014 12:05:59 GMT DavidB said:

Get the B204 - it's 2.0 litre and depending on the letter after the code, will determine what power it is producing. They are either high output turbo or low output - HOT tend to be nearer 200 bhp and LOT about 175 - 185 bhp. The L and the E are 175, and the R is about 200 bhp. The R has an upgraded ECU.
I think the 1999/2000 9-3 SE will have the B204R, which has the HOT and upgraded ECU (they only produced a few of these to a single model year).
B234 is taller than the B204, althrough produces more power. The 20 and 23 standard for cc, and the 4 stands for the amount of shafts (this includes the balance shaft I think?). You can't go wrong with them tbh. If you need wiring help, I can forward you the wiring diagrams (ones I made myself from tracing the whole loom from ECU to engine). Even with 175bhp, that should be enough power! A better turbo, intercooler, ECU remap (remaps are incredibly easy on these) and downpipe will produce a reliable 300bhp from a 175bhp engine. I current have 265 bhp from a B204R after spending 100 pounds on upgrades, which I think is enough.

One more thing - you will need the ECU unlocked if you don't want an immobiliser. There is a fellow on UKSaabs forum called Jules who does this for £50 and also remaps the ECU to stage one. Or buy a CanUSB Saab ECU reader for £100 and do it yourself.

[richycalibra]

David just rwad your post and was wondering if i can have a copy of your wiring diagram as I'm put b204 in my calibra and I am struggling to find them online mate

[richycalibra]

David just rwad your post and was wondering if i can have a copy of your wiring diagram as I'm put b204 in my calibra and I am struggling to find them online mate

[DavidB]

No problem, I'll scan them in at some point.
BTW I can't believe nobody has had the guts to post them up yet, seeing as it's such a popular conversion.