If I were to put on a 2.3L head, a bigger bore throttle body and bigger bore intake manifold and then some 24lb/hr fuel injectors how would me engine adjust to it? Would it automatically sense the level of the gases and put more petrol into the engine or do I need to do something else?

Wow. Big plans for that saab.
If you were to do all those mods that you mentioned then the engine should respond quite favoably to them.
Just remember to reset the fuel computer by disconnecting it from the battery for about 15 mins. this allows all computers to reset to the base and set up the engine to run.
Then go for a ride and drive the piss out of it and you should have a good setup.
Hope that helps.

Thanks man.

What????

You want to change your injectors and throttle body. but you expect your engine mapping to keep up...

The use of larger injectors means that you will run super rich as the new injectors will flow more fuel for any given pulse-width.

Now your new throttle body will now have far different airflow rates for anygiven throttle position.


Your engine mapping might cope with the throttle body alone however stock ECU will never manage larger injectors.

Please don't beleive that the lambda sensor will take account of the new fueling requirements. They have a range of about 12% (fuel trim) and only at fairly constant engine speeds. As old ecu's have no adaptive learning you will have a very poor running car.

The new head and exhaust manifold shlouldn't cause too many problems alone...

Ok... so where do I pick up a new ECU and for how much?

Smack,
I have a 1990 900 S that I am currently replacing the head, fuel regulator, and injectors. Everything should run quite well when retrofitted. If you want new injectors, you can't go that high with the same old computer, like Fan said. But the computer will be able to manage a more mild up-grade. If you use stock turbo injectors, you get an increase from 18 to 21 psi (I think). Also, good turbo injectors are way cheaper than the custom ones. But if you use new injectors, hence more fuel, you need more air in the pistons, which can be had through a new head. Hope this helps!

_________________
1990 Saab 900S 4-door
1990 BMW 735i (I know, blasphemy)
Luigi DiLioni



<font size=-1>[ This Message was edited by: Lui on Jun 12, 2002 3:11pm ]</font>

Thanks helps a lot.