partial throttle boosting

[sciondan]

My question is being that the eclipse is turbo charged from the factor, does the ecu compensate for partial throttle boosting? My thought was the maf would be able to read the increase in air from the turbo boosting and make afr corrections. Problem is now that I have a wide band I can see the afr not changing under light load/throttle boosting. Car will stay in closed loop with a 14.7 afr. I see up to 5lbs on normal driving conditions.

 

[DeadlyScone]

Do you have an aftermarket boost gauge?

 

[sciondan]

Yes I do

 

[DeadlyScone]

I would lean towards is it calibrated correctly. How much partial throttle are we talking anyway? 10-20% throttle? Does your factory boost gauge work and does it read the same as the aftermarket?

 

[1990AWD]

You're probably just not in the ECU's range of parameters to switch from closed loop to open loop. I can't remember what the numbers are but there are throttle %, load factor, stuff like that.

 

[007jimmy]

Its normal for this. If you are in closed loop low boost or not the ECU is going off of the AFR calculations. Once you get past a certain throttle position or WOT you then go into open loop and the ECU simply adds fuel according to the factory fuel map.

 

[sciondan]

I would lean towards is it calibrated correctly. How much partial throttle are we talking anyway? 10-20% throttle? Does your factory boost gauge work and does it read the same as the aftermarket?

The wide band is calibrated and working as it should. Partial throttle for me being a spirited driver is around 40%. Factory boost gauge mimicks the aftermarket gauge nicely. My concern is how easy it is to build boost with not going wide open. If I drive like an old person I can stay out of boost, but the car is slow and not fun to drive. When I turbo charged my scion I used the split second fuel enrichment box, so this was not an issue. I'm just surprised that a factory turbo car would not compensate. How would the manufacturer expect you to stay out of boost if the engine has a load and not at full throttle?

 

[1990AWD]

Just cause you have some load and some boost doesn't mean you have to go all the way down to 10:1 AFR. As you build boost, more air, more fuel, even though you're still at 14.7 AFR.

 

[sciondan]

Its normal for this. If you are in closed loop low boost or not the ECU is going off of the AFR calculations. Once you get past a certain throttle position or WOT you then go into open loop and the ECU simply adds fuel according to the factory fuel map.

I get this but it doesn't really answer my question. So your saying the manufacturer doesn't address partial throttle boost? I normally wouldn't care, but I register some knock when I part throttle boost and I know this is why.

 

[DeadlyScone]

well its basically what he said above. I would assume its normal with that much throttle on a 14b would generate boost. also assuming you have a 14b. even so with a 16g but i could be wrong sensing i am used to having an FP green.

I get this but it doesn't really answer my question. So your saying the manufacturer doesn't address partial throttle boost? I normally wouldn't care, but I register some knock when I part throttle boost and I know this is why.

It might be time to get ECMlink and get tuning if it bugs you that much.

 

[sciondan]

well its basically what he said above. I would assume its normal with that much throttle on a 14b would generate boost. also assuming you have a 14b. even so with a 16g but i could be wrong sensing i am used to having an FP green.



It might be time to get ECMlink and get tuning if it bugs you that much.

Lol, ya I over think everything, but that's what makes me a good mechanic. If its normal then cool. I just don't understand why the ecu wouldn't want to richin things up a little under those conditions to be safe. I'm used to turbo charging na cars so for me to see 5lbs and a 14.7 afr scares me.

Anyone have any ideas on how to tune out the knock on light throttle boosting? I'm tuning with an safc and log zero knock at wide open on 18 psi, so I'm good there. I'm around 100 fuel trims at all times cruising so my low throttle settings seem good.