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Discussion Starter · #1 ·
Driving with two ECU´s

Is it possible to have both a org. ECU and a tuned one installed at the same time so I can switch between them??
 

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Re: Driving with two ECU´s

nice thought to just flick an in car switch highly unlikely, both would have to share inputs and outputs fed thorough a switch junction, also have to allow for location (and have you seen the number of connections!)invest in PPC system - plug & play(Speedparts,BSR)
change over between programs takes 30mins.

PPC unit is married to your original ecu and can not be transfered to another car.
 

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Re: Driving with two ECU´s

I have seen this kind of system on other cars but not Saabs;
Some Turbotechnics systems had a "grannyswitch"; a button on dashboard made ECU run at a lower power rate.... I think that they piggybacked one ECU onto the original.

Maybe this is an alternative to having two ECU's?Maptun/Speedparts are you listening?
 

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Re: Driving with two ECU´s

It would be difficult to switch between two different ECU's but I have a simple modification fited to my stage 1 9000.


The power supply to the APC solenoid is switchable so, when the button is depressed I get full stage 1 power, 235bhp

With the button switched off there is no power supply to the APC solenoid so I only get base boost & 170 bhp.

As I understand it the ECU system operates the APC solenoid using a square wave control voltage to vary the opening /closing frequency. So basically if you switch the power to the solenoid it closes and allows all of the turbo pressure through to the wastegate.

The good news is that the ECU does all of it's controlling on the 'earth' of the solenoid so it's a simple job to cut the normal power supply cable then run a new fused, switched supply from the dashboard.

I haven't used it often but it has been useful in bad weather conditions , rain/snow etc.
 

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Re: Driving with two ECU´s

I don't understand why you would want to do that? Why not just be lighter on the loud pedal?
 

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Discussion Starter · #7 ·
Re: Driving with two ECU´s

Well actually I am considering the this solution for several reasons:

1. From the 1. May the local police force will inforce no tolerance policy on speeding, and I am actually very fond of my licence!!!

2. The same police force is also very eager to check cars for tuning as the tax man whants 200% in tax on any significant modifications. Not thats its ilegal but it would save me for a lot of trouble if I could reset to standard by pressing a switch!

2. I actually like my standard setup for normal driving, as its very relaxing to drive, and I know for shure that when running with 225 HP would be very stressing not to use it constantly!

3. My whife also use the car daily, and I would prefer standard setup when she is driving.

4. Driving conditions around here is only optimal from May to November, the remaining time its constantly shifting between wet, icy and snow, and it can change in a split sec.. In other words then its NOT the season for speeding.
 

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Re: Driving with two ECU´s

So stick a block of wood under the accelerator pedal!

Seriously, I don't get the issue. I retrained myself to slow down and actually found that I could sit back at 60mph on the motorways when I would have otherwise been the chap racing past in lane 3 at 80+.

Very relaxing and the travel time difference for most journeys is negligible, in fact, you can guarantee that many of those racing past for some reason end up in a queue at the M6 toll and fail for some reason to potter over to the left hand side where I am and I usually beat off the toll booth, most of those that have past me over the past mile or two.



Of course, when I'm driving my Aero again in a few weeks...

David.
 

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Re: Driving with two ECU´s

It would be possible if you wired the ECU inputs in parallel and connected the ouputs of the ECU to a two-port switchbox. Some jap tuners do this, but I've never heard of it being done with a Saab. It wouldn't be a good idea to switch ECU's while you were driving, it would probably cause major engine damage I'd imagine.
 

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Re: Driving with two ECU´s

Originally posted by Jason (Mr Torque Steer):
[qb] It wouldn't be a good idea to switch ECU's while you were driving, it would probably cause major engine damage I'd imagine. [/qb][/b]
Certainly! Furthermore, it is recommended that the battery be disconnected before the ECUs are swapped over.
 

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Re: Driving with two ECU´s

Hello,

It's possible to make a switch on the dash to swap to another map. One dealer in Holland, ASM UTRECHT, does it on their demo cars. The name of the guy who knows about it is Jos Steverink. Try to contact him if you like. I can get you a telephone number if you like

regards,

Sander
 

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Re: Driving with two ECU´s

Probably a solenoid on/off switch.

It is hard to believe to change to another map or something like that. Switching off the solenoid valve will reduce boost to base boost and can be switched on or off while driving...
 

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Re: Driving with two ECU´s

Originally posted by David Taylor:
[qb]I don't understand why you would want to do that?  Why not just be lighter on the loud pedal? [/qb][/b]
Apart from the bad weather consideration the main reason I have my stage one mod switchable is that my better half drives the car occasionally and she doesn't always have both hands on the wheel when she hits the throttle.
I want to keep the car in one piece.
 

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Re: Driving with two ECU´s

I was thinking about this.. although it requires a different ECU or to remove the ROM in my current ECU and replace with a larger memory one.
If you flash an EPROM, say a 2mb one and your flash takes up 1mb (being VERY GENEROUS) then you have to tie the chip "low" or "high" depending where in the memory you have saved the mapping. this means that if you flash a chip with a standard map in the "low" memory area, and flash a performance mapping in the high area, then have a switch which you can flick between tying the chip "high" or "low". the ecu would need to be powered off before the switch is done, but it is do-able. just need a chip with enough room for 2 fuel maps.
 

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Re: Driving with two ECU´s

Sort of like the story of how NASA spent a million dollars developing a pen to write in space. The Russians used a pencil.

Seriously guys, a block of wood behind the accelerator *really* will work too!

There are some complex solutions here to a simple problem, here's another simple solution:-

Impress upon the wife that if she bends the car she will have shopping privileges revoked for n months where n is directly proporptional to the cost of the repair. That'll fix that one for sure!


Also remember that both of the above solutions have no impact upon your insurance. Has anyone with an electrical or otherwise modified system considered informing their insurance company who will no doubt look upon such bodging as a greater risk. They'll take any opportunity you throw to whack up the premium and suggesting that "but it made the car safer for my wife" or "it works better for bad weather" will no doubt stir little positive emotion in the average insurer.

David.
 

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Re: Driving with two ECU´s

Why not fit one of the Japanese boost controllers?
The basic ones only have one solenoid and the more expensive ones have two but as far as I'm aware both types allow you to vary boost from inside the car "on the fly".
 

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Re: Driving with two ECU´s

Originally posted by David Taylor:
[qb]  Has anyone with an electrical or otherwise modified system considered informing their insurance company who will no doubt look upon such bodging as a greater risk.  They'll take any opportunity you throw to whack up the premium and suggesting that "but it made the car safer for my wife" or "it works better for bad weather" will no doubt stir little positive emotion in the average insurer.

David. [/qb][/b]
My insurer is aware of my stage one mod and I did my 'switchable' mod under guidance from my local Saab main dealer - they helped with circuit diagrams & an explanation of how the system worked - they liked the idea & though it could be useful in certain circumstances. Infact they liked it so much they even gave me the dashboard switch that I use to activate the system for free.

If you would be happy to stick a block of wood under the throttle pedal - please feel free to do so -but I think you'll find that there are occasions when one might want to press the throttle a little further than the block of wood allows.

How would the insurance report read
" Well there seemed to be plenty of time to overtake - but the block of sitka spruce under the throttle prevented normal accelaration & thats why I hit the oncoming vehicle. My car is badly damged and I've got spelks in my right foot"

I perfectly understand the need to keep things simple but I've found that, even under moderate throttle, once my car gets to 2500rpm it just takes off. There are times when you don't want that. It can be uncomfortable for passengers too, particularly those of a non-motoring bent.

So I'm quite happy with my system & I won't be introducing an timber into the vehicle. The last time I had a car with any wood in it I was driving a Morris 1000 traveller ( I did so for 5 years) & I sincerely hope it's an experience I never have to repeat
 

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Re: Driving with two ECU´s

Originally posted by black&whitesaab:
[qb]It would be difficult to switch between two different ECU's but I have a simple modification fited to my stage 1 9000.

The power supply to the APC solenoid is switchable so, when the button is depressed I get full stage 1 power, 235bhp

With the button switched off there is no power supply to the APC solenoid so I only get base boost & 170 bhp.
[/qb][/b]
This is the difference. Same effect achieved by different approach to what the question is asking. Switching between two ECUs is more complex than black&white Saab's approach - which does seem pretty good to me
 

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Re: Driving with two ECU´s

Originally posted by David Taylor:
[qb]Seriously guys, a block of wood behind the accelerator *really* will work too!    

[/qb][/b]
The block of wood won't work on my car as it goes more quickly at part throttle than at full throttle! I have the rolling road graphs to prove it too
I was considering the block of wood as a 'performance enhancing modification' but I'm sure the insurance company wouldn't like it, especially when it slips across to under the clutch and brake pedals


Seriously, I don't think that switching the APC will work on a Trionic 7 car, as I found that the loss of APC control doesn't just give you base boost, but the engine management gives you some kind of 'safe-mode' where you get no boost/no power at all. Trionic 5 is OK for the APC switching, but the PPC option doesn't apply does it?
 
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