Fitting Electronic Boost control to a GTA.

Hi all,

I was wondering if anyone has fitted a Electronic Boost control system to a GTA ?.
I am a ex Saab Master Technician, so i grew up on 900 & 9000 Turbos. With Saabs APC system. (Automatic Performance Control).

http://en.wikipedia.org/wiki/Automatic_ ... ce_Control

Back when R5 Turbo's were everywhere, it was very common to fit Saabs APC system to them. I did about 7 installs myself for various people.
Also the Volvo tuning community fit the APC system.

Saabs APC, as fitted to "Classic" 900, and early 9000 models up to 1988, is a totally separate system. And not integrated with the car. Thus it can be removed with its components and ECU very easily.
From approx 1990, it was integrated into the Trionic Management systems. So was not removable.

The advantage is, that APC will adjust the boost pressure to the maximum it can before Knock occours. Thus it can make use of higher octane fuels, such as V-Power. If knock occours, boost is reduced until knock stops. There is also a safety limit that is fully adjustable, so if anything goes wrong, the fuel pump can be cut off in overboost situations.

The other advantage of APC is that it keeps the Wastegate shut tight until 0.45bar. This has the added advantage of causing faster boost spool-up.

It is definately something i will consider doing when i get a GTA. Since it can be fitted in a few hours. It only requires a few connections, such as power, and a RPM pickup from the Ignition. All other connections are to the Saab Boost Control Valve, and the Saab Pressure Transducer and Knock Detector.

Heres a page where someone has detailed the Saab APC system for fitting to any Turbo car.

http://www.rothfam.com/svo/apc/index.html

Hi Paul,

Yes this is an excellent system. I wanted to get to the heart of the spark ion sensing feedback of the ecu of that generation, and looked at it in a fair amount of depth, but adapting it wasn't easy. I couldn't get signals of note out of the noise floor and just gave up at the time I would still love to have a crack at it, as it's really the only way to go, use the plug as the primary sensor.

As to electronic boost control, yes, and it's easy, many systems out there, and indeed the A610 has it factory fit. However, earning my crust as an electronics engineer, I do prefer to avoid it in my other walks of life, so I prefer going a simple dual port actuator - does the same job! Use manifold vacuum to slam the waste gate shut, works a treat, and with a simple blocking valve you can keep that thing as tight as a clam right up to the pressure you want it to burst open... how needs electronics but then I'm not into smooth torque transitions with turbos myself, I like torque, bucket loads and I like it coming in like a scolded cat..just one of life’s pleasures

Hi,

In the first part of your reply, you talk about the Ionisation within the cylinder and using the Spark Plug as a sensor.
This is what the later Saab Trionic 5 system does. (1994 onwards).
Later replaced by Trionic 7 in the new Saab 9-3 and 9-5.
At the time (1994) Trionic was the most powerfull engine management system in the world. It was proved by the motoring press, that a 9000 2.3T driving through London rush hour traffic, actually put cleaner Air out of the exhaust than what it was sucking in the air filter. So the car effectivly cleaned the air. I am still not aware of any other system that can do this today.
Shame Saab is about to be shutdown.

With regards to rapid "Bang" turbo boost rush.... the only problem with that is the shock of the Torque through the drivetrain.
My 1997 Saab 9000 Aero 2.3 Turbo, was modified by Maptun Performance to stage 3. Running 24 PSI (1.4 bar) of boost, giving 330bhp.
Boost was brought on gently by mapping the Trionic system to do so, thus limiting the shock on the gearbox.
Otherwise i would have needed a pile of spare gearboxes in my shed !.

... sure, sure components need to be rated for the duty & why my Fiat Coupe runs an Integrale gearbox and major parts of the transmision, 320fwhp 1 bar 2ltr - faulksie stage 1, Stage 2 being developed, as the Coupe community has surpassed me , I built it 6 years ago.. into 400s now, so 450 it has to be

It was proved by the motoring press, that a 9000 2.3T driving through London rush hour traffic, actually put cleaner Air out of the exhaust than what it was sucking in the air filter. So the car effectivly cleaned the air. I am still not aware of any other system that can do this today.

Well to be fair, air quality in London has improved since then

Actually slmost all modern petrol engined cars on a really hot smoggy day will do that.

These days it's all about carbon dioxide

[/quote]

Well to be fair, air quality in London has improved since then

quote]

ah that will be down to zee '9000 like you know, running around cleanin the air

why didn't they make taxis then and imported them into China?

Seriously though, it was a good system, and yes I was only talking about the ecu with ion sense and knock sensing – massive RD. The analogue signal-conditioning version (early system) can be adapted to other engine applications reasonably easily too.

MFaulks,

You might like this video.
Its a training video i remember seeing when i did my apprenticeship at Saab.

http://green.autoblog.com/2007/11/13/vi ... s-the-air/

[mettersl]

I think the A610 knock sensors only retard the ignition and don't cap the boost. Don't know if the GTA also have these, if not that would explain with GTA turbos look simpler that A610's in the wiring spaghetti department.
The 610 already has the extra valve to spin up the turbo quicker by clamping the waste gate shut initially too.
It might be interesting to try the APC system on an A610, but does anyone know know far the original map goes in boost? (Mr Faulks...)
An ECU change and remap could make this cheap mod quite an expensive and complex one if the original map stops only a little above std. boost.

I love that video- the Saab 2 stroke must have some of the dirtiest emissions ever- you actually have to mix the oil into the petrol as you fill the car- my father had one and I remember the "discussion" when my mum forgot to add the oil one time. Good for 20 years ago though.

The A610's "boost control valve" is just a metered bleed-off which when off, allows the wategate to operate to whatever its pre-load dictates (ie like any normal turbo). When switched on, it causes a deliberate "leak" in the line to the wastegate which causes the wastegate to "see" a porportion of the actual presure thus opening on higher boost.

This is extremely basic boost control. The same sort of arrangement exists on the Skyline GTS-t but that acts purely as a function of rpm whereas the A610 unit is a function of throttle position, engine temp, and I *believe* also as a safety device if knock is detected.

Thus if your TPS signal is up the creek, the engine does not boost properly. Try going for a drive with the TPS un-plugged - it'll run fine apart from the boost.

All of this I worked out for myself when buggering about with my Venturi - I may be slightly if not entirely wrong . For the record, the connector used on that valve is just terrible and should be replaced!!!

This all comes down to closed loop control, mixture strength, ignition control, and charge temperature if that is also a parameter you can control - use of egr etc.
In fact any modern car with closed loop, lambda sensing I.e. practically 100% now would give you the same result. It's really a marketing play. Boils down to a second stage combustion, but the unburned hydrocarbons from the first must be
Ingested if you like prior to reacting with other oxidising agents, free ions, being broken by UV radiation or cosmic rays.. Ha-ha+ joke, much of the fractions are heavier than air and just get absorbed into the
soil and water system. But given the conservation of matter, the net polution depending on what you measure (key being what you measure- total molecular mass as well as it' resultant forms) and actually count will increase if any fuel is introduced in the second stage combustion. What would be worth talking about is if it did all this with no fuel added, then we would be talking, 'course that is impossible for obvious reasons.

2 stroke turbo charged diesel marine engines are the most efficient fuel burning monsters in the world, about 54%. So on the basis of total world system polution are the cleanest current solution to tanker propulsion, but will be giving it a miss trying to fit to a GTA.. Bit like that other thread photo

Hi Paul,

Can you tell me what bits years and model I need ecu and ignition modules off a SAAB - I want to play with the spark plug ion current sense system for a bit of fun. I think the current monitoring circuit is built into the coil on plug module is that right? Do you have any technical detail and wiring diagrams that could get me going? The rest I'll work backwards. I know they had the one ecu that was virtually analogue electronics and control, and think I have the diagram for that some where - knock control circuit was nice simple implementation, but the later generation with the ion sense must have been digital with some sort of FFT algorithm built into the code.

So pretty please anything you can point me towards, which hardware, and tech info would be great. This is for a 4 pot application.

Thanks,
Martin

I have a HKS EVC IV fitted on my car - works very well if a little complicated. Was fitted by a company so I'm not sure what they did but it looks pretty simple.

Tony, I presume that's knock than ion sensing? I am after ion sensing across the spark plug, using an 80V dc post firing. This was built into some of the SAAB systems, and hence question to Paul.

Mr Faulks,

Sorry i did see your question, but i have not had time to reply yet since it will require a detailed post....

Only just got back from Madrid, and off to Atlanta tomorrow. Not getting a min to myself lately.....

Paul.