Hi,

It looks like I'm the first guy trying to modify a Marea car !

Do you have any experience in modifying the 1.8 ELX engine ?

I have completely rebuilt the intake system (except the throttle,
air sensor and intake ports that hold injectors). Now with aircondition on I'm like before with it off (measures show +10hp but I still don't trust them, see my General/gear box post).

Of course I've started with a K&N Air filter, but that was just to prepare the car for farther mods. Alone the K&N brings nothing but a big noise. In fact I've tried the car without air filter at all: a lot of noise, nothing else.

According to my studies (calculations) the engine can have more torque and power (not so strange, 63hp/L aren't so much !).
The air box is very restrictive and the intake plenum is very badly adjusted and manufactured (internal port diameters are 6-8mm bigger than that of the intake runners).
The max air speed (at 6000RPM) across valves is about 40m/s, far from the widely accepted 100m/s limit.

In principle the gearbox is the same as on some 150hp Alfas.

The air mass based engine management seems to accept any modification of the intake Volumetric Efficiency (once again is it the term ?).

The exaust manifold could be improved.

Of course the valve displacement (7mm ?) could be higher (up to ~8.5mm), but I don't think that would seriously increase power (but would certainly increase fuel consumption).

I haven't studied yet whether the engine is managed on the cylinder by cylinder basis, but the ignition advance can probably be increased as the engine never overheats.

Alexei

Hi Alpa,
The modification sound interesting. Can you explain to me (if U dont mind)on how to advance the ignition as the engine never over heats.
I think the igniton system is digital with static advance and timing. So no adjustment can be made.

Cheer

subija

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Hi Alpa,
The modification sound interesting. Can you explain to me (if U dont mind)on how to advance the ignition as the engine never over heats.
I think the igniton system is digital with static advance and timing. So no adjustment can be made.

Cheer

subija
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Yes, it's all digital. There is only an external ignition amplifier connected to ECU.

In fact I'm planning to make an additional ECU that would be between the factory ECU and the engine for ignition and injection. So everything would be possible. It's typically what commercial PowerChips and others do (advance ignition and modify injection mapping).

But in my case I probably won't advance ignition as I've increased the engine's power / breathing capability (by modifying the intake system). So the initial margin that existed in the factory engine is likely to be thiner. I'm rather planning to manage each cylinder's injector separately (if it's not already done, to be studied) and to manage injection while WOT in the 'race' way, instead of the 'street' way (that is to inject only while valve is open and not before).