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if i install a fcd in car(88t) would it make me run lean? I herd fcd makes the car run lean, need to know
 

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It'll run lean if you boost high and don't have enough fuel going in to match the air you're putting into the motor. I wouldn't get a FCD without a wideband, its there to save your motor and does its job -- if you follow the right upgrade path and tune properly fuel cut isn't an issue.
 

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cre3d said:
It'll run lean if you boost high and don't have enough fuel going in to match the air you're putting into the motor. I wouldn't get a FCD without a wideband, its there to save your motor and does its job -- if you follow the right upgrade path and tune properly fuel cut isn't an issue.

yea the fcd itself doesnt make you run lean. it just removes a safety restraint that is there for a reason. like the railing on a building, if you jump over it without the proper preparations youll be really sorry very soon :sadwavey:
 

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in my car it created a lean spot from 3000-3500rpm. that is where the fuel cut defencer is active. it caused some small detonation once or twice. it was fine for a few more pounds, but when i was boosting 18-20lbs it caused a huge power loss for the 500 rpm that it was active!
 

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Since when does lean = power loss?

Edit: Unless it was extremely lean, where I would think you'd be melting something if you ran it more than once? If you were using the FCD and getting a moment of power loss at that 500 rpm range, you were not tuned correctly and simply removing the safety measure that is in place to protect you from the improper tune. FCD is just a bad idea on this motor, it scales perfectly as long as you stay tuned correctly and is a great safety measure. Shortcuts will only make you end up with a big paper weight in the end :\
 

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if you lean out too much theres not enough fuel to create a uniform burn
 

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MKIIINA said:
if you lean out too much theres not enough fuel to create a uniform burn
Right, thats why I edited my post. But I would really think at a condition THAT lean and 18-20 psi you'd be melting pistons unless you got extremely lucky. And it doesn't sound like he made only one run :dunno:
 

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i agree 100% you took the words right outa my mouth! in my car, i was not properly tuned. that is the problem. you will end up slowly increasing the boost to the limit. heck i did it my self. they say curiosity killed the cat!

hks fcd + no fuel = booooooom!
 

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no, i ran the car for over a year with no major problems. i was always in the boost as well. no melted pistons. however, when i removed the fcd my problem was gone. i had the same issue when it was installed and i ran stock boost. this was for shure cased by the fcd. the hks fcd is only active during a small peak of rpm. that is why there is an ajustment. our computer starts to look for over boost at somewhere like 3000rpm.....the hks dissrupts (sorry for the grammer) the signal for a small window and shuts then off.
 

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yes. it only ran lean for 500 rpm or so. i used a wideband sensor. now im not saying something else wasnt wrong only that i never had the problem when the fcd was unpluged.
 

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DAVID SWEARINGEN said:
no, i ran the car for over a year with no major problems. i was always in the boost as well. no melted pistons. however, when i removed the fcd my problem was gone. i had the same issue when it was installed and i ran stock boost. this was for shure cased by the fcd. the hks fcd is only active during a small peak of rpm. that is why there is an ajustment. our computer starts to look for over boost at somewhere like 3000rpm.....the hks dissrupts (sorry for the grammer) the signal for a small window and shuts then off.
Computer doesn't look for "overboost". It looks at how much air you're bringing in and compares it to a few other factors and cuts off fuel accordingly. Has nothing to do with actual boost.
 

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cre3d said:
Computer doesn't look for "overboost". It looks at how much air you're bringing in and compares it to a few other factors and cuts off fuel accordingly. Has nothing to do with actual boost.
Right, but it does not cut fuel. It cuts the spark. If it cut fuel, you'd have a MUCH bigger problem. Cut will hit at or about 1600Hz of frequency through the Karman Vortex AFM . Once the ECU sees that airflow or higher, it will cut the spark.


The FCD will only make the ECU think that you have much less air coming in, therefore you have less fuel coming in. As boost goes higher, the ECU does not compensate and thus you can have a big problem if you don't pay attention.

If you purchase the proper parts and pieces and have the car tuned right, you should never have a need for a fuel cut defenser.
 

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Trent said:
Right, but it does not cut fuel. It cuts the spark. If it cut fuel, you'd have a MUCH bigger problem. Cut will hit at or about 1600Hz of frequency through the Karman Vortex AFM . Once the ECU sees that airflow or higher, it will cut the spark.
it cuts fuel.
Search for a thread called " Increasing rev limit " its all in there.
 

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SuprAng said:
it cuts fuel.
Search for a thread called " Increasing rev limit " its all in there.
I could have sworn it was a spark cut. I mean really, you have all that air going in, how can you just cut fuel? That would cause some BIG problems unless im just thinking entirely wrong. Are you cutting it at the injectors? at the pump? Where? The only way I thought it could be that abrupt and quick was to just cut the spark and have it go way rich. That way you don't have a lean problem, hence the reason for "fuel" cut in the first place.
 

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if you cut the spark, it would build up too much fuel and could cause the engine to die or cause a huge backfire! now that would cause some damage!
 
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