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View Full Version : FMU Removal Question/Xcal2 Requirements


SuperG
11-17-2006, 09:13 AM
I have an Xcal2 and want to remove the FMU. Do I simply remove the vacuum lines and reconnect the fuel line back to it's stock position? At that point do I need to get the engine tuned again or will the current flash simply take over fuel management?

Thanks for any help!

SuperG
11-19-2006, 12:27 PM
Bump - Need Help!

Pro-Dyno
11-19-2006, 02:59 PM
Yes just reconnect the fuel lines and yes you will need a retune. im assuming the car is s/c have you replaced the injectors?

:)

SuperG
11-19-2006, 04:57 PM
Yes just reconnect the fuel lines and yes you will need a retune. im assuming the car is s/c have you replaced the injectors?

:)
Yes, the car is SC'd and no I have not replaced the injectors. I was planning on doing that whenever I got around to replacing the internals with forged parts.

Do you think the stock injectors are a hinderance now?

Pro-Dyno
11-19-2006, 06:00 PM
Yes

They will not feed enough fuel even with a custom tune. The purpose of the fmu is to raise fuel pressure under boost conditions. It does this by applying pressure to the fuel line. like putting your finger over the end of a garden hose the injector are rated for a maximum flow of 24# an hour when fed with fuel pressure of 39.5psi. The fmu raises this psi and forces more fuel threw the injector than they are meant to run. This is a crewed way to tune but it works. and it made it possible for the sc manufacturers to sell there product to people that canít come to them for proper tuning. The down side is that this method is a ticking time bomb (trick) you never know when the fmu or an injector will fail. And you know what happens when the fuel system fails under boost. So I recommend you install larger injectors and a mass air meter to support the injectors and have a custom tune done so you will have your drivability and safety under boost.:thumbsup:
Just my opinion!
Good Luck
Dan

SuperG
11-19-2006, 06:16 PM
Thanks Dan!

Pro-Dyno
11-19-2006, 08:38 PM
Any Time :)