F.c.d

[podgey]

hi, i fitted my g valve this morning, and got it running at .5 bar, and now i want to fit my fcd so i can turn it up a little more. but the distructions dont make any sense, can anyone describe how you fit it for me? i took it to a local auto electric place this morn, but they wouldnt fit it. :(

i had a go my self, but theres no wires as decribed, just a circuit board..

help!

iv tryd a search, but came up with nowt!

[DeusMR2]

which FCD is it? the twosRus one? Generally fcds have 2 or 3 wires, 2 of them intersect one of the wires going into the ecu and the other is an earth

[podgey]

ahh! thanks i think iv got it sussed. im going to try tomorrow.cant wait!

[Skeete]

which FCD is it? the twosRus one? Generally fcds have 2 or 3 wires, 2 of them intersect one of the wires going into the ecu and the other is an earth

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Deus, What does an FCD actually do ? I have an idea of why you would want to stop the fuel cut, but cant work out how it could do it without removing the rev limit...

Cheers

[KiwiMR2]

It just removes the 12 psi limit on the car. So you can boost over 12 psi without the car cutting off the fuel supply. Usually better the have one that just raises the fuel cut rather than completely eliminating it.

Cheers

KiwiMR2

[DeusMR2]

I think the fcd adjusts the boost pressure signal arriving at the ECU and just makes it appear lower than it actually is, not 100% sure of that but it makes sense!

[Skeete]

I think the fcd adjusts the boost pressure signal arriving at the ECU and just makes it appear lower than it actually is, not 100% sure of that but it makes sense!

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Isnt that how a boost controller works ? By venting the pressure before the sensor ? There seem to be a miriad of things that all seem to do the same thing but in different ways...

What is a VSV and how can you get a vacuum in a turbo ?

Excuse my ignorance, but this is the first Turbo I have owned.

who has a link to a site that explains all of this ? The "how things work" website is a little too simplified :o .

Cheers

[DeusMR2]

Yeps the boost controller does the same thing but only to the wastegate actuator, i.e. the actuator sees a lower pressure than what is actually in the intercooler pipes and inlet manifold. The boost pressure sensor readings come from the inlet manifold so will always read the actual boost pressure, hence why a FCD is needed.

You can get vacuum in because under low load/idle conditions the engine cyldinders are sucking air all the way from the intake into the chambers on their downwords stroke. Also the exhaust gas pressure and temperatures are not high enough for the turbine side to drive the compressor side fast enough for it to create positive pressure, its basically freewheeling at this point and not creating any useful work. The boost pressure sensor and wastegate actuator are all seeing negative (vacuum) pressures at this point

When you put your foot down of course the turbine side spins up and the compressor spins fast enough to increase the pressure in the system, this is when we get positive boost :hokus-pokus:

This site has more information, its based on the 3SGTE for celicas but everything works the same way, my little diagram below is the same system but as viewed in an mr2 engine bay

http://member.newsguy.com/~gtfour/technicl...%20Info%20Turbo

[Skeete]

Your just a fountain of knowledge Deus ! And a little diagram too.. Who are you trying to impress as there are no girls on this forum !

[DeusMR2]

lol just trying to help out mate, I was in exactly the same position as you just over a year ago so its my payback for the help people gave me back then