Has anybody done the Free FMU mod?. I was browsing at Gadget's website and was wondering if anyone here had done this?

 

I have heard a lot of good feedback on this mod and it has been said that TRD even recommends doing it. TRD has actually taken credit for Gadget's find.

 

I know it's a good mod ( or at least a good safeguard), but for the life of me, I can't figure out how to do it.

If anyone can tell me, I'll do it and take some pics.

Mike

 

Even though I don't own a SC truck, I know how to do this. The boost port is on the back of the SC. Look at the installation manual if you don't know where it is. Your FPR is on the back side of the engine on the driver's side fuel rail. The hose that runs to the FPR is normally connected to the Intake Silencer.

Here's a pic:



See the hose on the top right of the box? That is the hose that give the FPR the engine load "signal". Follow the hose underneath the plenum where it attaches to a brass vacuum line. Then you'll see where it comes out on the opposite side near the firewall. That little round thing it attaches to is the FPR.

Disconnect the hose that is currently attached to the FPR. Plug the nipple on the Intake Silencer with a 1/4" Vacuum plug. Then attach one end of a length of hose to the boost port on the SC and the other end to the nipple on the FPR. That's the Free FMU.

When set up like this, the FPR will see the boost pressure from the SC and raise Fuel Pressure at a near perfect 1:1 Ratio of boost to fuel pressure.

Hope this helps.
Dr. Z

EDIT: The size of hose needed is anything from 7/32" to 1/4"

 

Thanks for the info Dr. Z
Another question, I currently have the boost gauge connected to the boost port, do I just "T" it to the hose that will be attached to the FPR?

 

"T" the Fuel Pressure Regulator ( FPR ) into the hose of your boost port. ( Boost gauge ).

Thats what I gather.

Jay

 

What Jay said.

Dr. Z

 

ok...i'll try it this weekend.

 

I'll do it this weekend too!

Mike

 

I'd do mine this weekend if it wans't cold and raining.

note to self: buy a house with a big, heated garage...

 

I checked out my truck tonight and this is what I found. The boost port hose is connected to some relief valve. The hose from the resonator box is hooked up to, I think, the original designed TRD fuel pump, and the bottom of that hooks into the fuel line.

Here's pics.....

 

Line from airbox goes in the side of this.... (the little hose goes to the top of the SC.

 

The newer looking hose with the clamp is the line that comes out of the bottom of the silver fuel pump (?) from the last pic.

 

Yup,

I did it at the time of the install. (although Dr Z asks me this every time I post )

I added a brass tee to give me three boost ports. Currently, one does the FPR (or free RMU), one does the boost guage and the last is plugged.

I put it on from the start in the hope that I may end up with boost driven doodads in the future ...just need Split Second to come up with an ECU that sets the map based on boost...

David

P.S> You can sort of see my boost port set up in my sig pics

 

It looks like you have a 1st Gen SC. That piece is the FMU that came with the 1st Gen SC's. Did the dealer install it for you?

You can still use the Free FMU. Just put a Tee into the boost port line and follow with the rest of my directions I posted earlier.
Hope this helps.

Dr. Z

PS David, shut up.

 

Dr. Z,

Yup, dealer install and first Gen SC. I'll see what I can figure out this weekend.

Thanks!

 

My supercharger kit came with a brass "T" NPT fitting. I screwed that into my boost port, ran one side to the FPR and one side to the boost guage. It works well so far.

 

I received one of these TRD FPRs with my used SC and this is the first hint I've seen how it hooks up. Boost port signal, fuel rail and return line makes sense. The old FPR must come out. Anyone know if this is a worthwhile installation or whether the free FMU does the same thing. The guy I bought it from said he never used this FPR although it IS used.