Hi everybody, happy holidays. I got a 1st gen. S/C and it came with the orig. fmu. I was wondering are people are using the TRD fmu or just the free fmu? I'm gonna put the paper filter and the deck plate back in the box and everything else is stock. I just want more power I don't need the maximum that can be achieved with a properly set-up engine (injectors, ftc and new fuel pump) but maybe some day. I just wondered if the TRD fmu is worth the labor to install or do I just hook up the stock fpr to the boost port? :confused:

 

I see no one has responded. I dont know, I dont keep up with all that stuff. But Gadget may know.

GadgetOnline


Jay

 

If you have the stock pump it does not matter which way you go as no mater what you will end up at 50 PSI.

If you do a pump upgrade then the TRD FMU will kick butt over the Free-FMU. I found 33 HP with that combination simply by reducing the high RPM lean out problem.

If you have the TRD FMU and don't want to install the proper size injectors, then installing the TRD FMU and a pump upgrade is a great second place thing to do.

I have some nice dyno charts on my site showing that combination.

Gadget

www.GadgetOnline.com

 

Is the TRD FMU still available to buy??

 

Yea, I would like to get my hands on one too. Can the dealer get me one?

 

Gadget, i'm a little confused. after reading your website, i got the impression that you recommended the free fmu; however, here u post that the TRD FMU is a bigger gain. could you help explain?

 

If I were to get a new 4Runner and put a supercharger on it I would install:

Split Second FTC
305cc injectors
Walbro 190 LPH fuel pump
connect the boost port of the supercharger to the Fuel Pressure regulator, AKA the Free FMU

That is what I would do because that works the very best under all conditions. If you do not want to install the proper size injectors, then increasing the fuel pressure sky high is of some benifit.

To do this you will need a pressure increasing FMU like the one sold by Paxton, Vortech, or even the junk TRD FMU that used to be included with the superchager kit. To use one you will also need to install a larger fuel pump to go with it. If you do not you will only end up with 50 PSI of fuel pressure at full throttle and high RPM because the stock pump can not flow enough fuel to maintain the higher pressure of the FMU. In that case it is a waist since simply connecting the fuel pressure regulator to the boost port will give you 50 PSI at full throttle at high RPM.

For those of you that have a supercharger kit and do not want to install any other fuel mods then connecting the boost port to the fuel pressure regulator will help reduce the high RPM lean out. It will still lean out just not quite as bad.

If you have the TRD FMU and install a fuel pump to go with it then you can easily find the same 33 HP I did by reducing the high RPM lean out problem. That will give you around 65 PSI of fuel pressure at max boost where the Free FMU will give you 50, or the stock configuration will give you 43 PSI.

The Free FMU is better then nothing, but no where near good enough.

Gadget

www.GadgetOnline.com

 

That makes sense.
Thanks Gadget!

 

Gadget,

Between the Paxton or the Vortech, which do you recommend? You are saying this is better than the Free FMU, right? Do I want a 4:1, 8:1, 12:1, or what? Thanks!

Chris

 

Chris, what Gadget said was that a REAL FMU is better than the Free FMU if you are not going to install larger injectors. Since you are going to install the larger injectors and the Walbro fuel pump, just do the Free FMU.

Hope this helps.
Dr. Z

 

Yeah, this is true. But, I also beleive that if you install one from Vortech or Paxton you'll get 65 psi rather than 50 psi by using the Free FMU at max boost. That's a big difference, isn't it?

Chris

 

FMUs are BANDAID fixes. The proper way to address fuel deliver is to install the PROPER size fuel injectors. When you have the proper size fuel injectors make sure that you connect your STOCK fuel pressure regulator to the boost port so your fuel pressure will always stay consistant in relation to manifold pressure.

I tested and tried a bunch of different FMUs and as far as I am concerned they all SUCK. They are inconsistant, erratic and you NEED a fuel pressure gauge to ALWAYS keep an eye on them because they are so erratic. Most of them need constant fiddling to keep the dialed in. All that just drove me nuts. Once I installed the proper size injectors all that hassle was over for good.

Have fun with your FMUs.

Gadget

www.GadgetOnline.com

 

Thanks Gadget! So am I right by saying that the ratio I need is a 1:1 ratio in relation to boost? If so, would a 4:1 FMU be a bad idea? I know you are saying to run the Free FMU, in combination with the larger injectors an fuel pump, but I'm just wondering if more could be squeezed out by using all the same except running the Paxton, Vortech, or Cartech FMU. I'm not doubting you just wondering if there is any potential performance gain if dialed in correctly?

Chris

 

"...if there is any potential performance gain if dialed in correctly?"

EXACTLY!

Gadget

 

Thanks for everything Gadget as always!

Chris

 

Hey Gadget,

This is probably a really stupid question, but would it be possible to run a Cartech, Vortech, or Paxton FMU in combination with the Free FMU? Just something I thought of when you said that dialing in the above three is really hard to do, and has proven ineffective in your experience. Could the combination help to get the extra 15psi that the free FMU misses out on?

Chris

 

Yes. Band Aid away....

Gadget

www.GadgetOnline.com

 

You always say band-aid away, so what would be the ultimate fix then if the free fmu and regular FMU is still a band-aid fix?

Chris

 

"...what would be the ultimate fix then if the free fmu and regular FMU is still a band-aid fix?"

Forget the Band-Aid fixes and simply install the proper size fuel injectors.

Gadget

www.GadgetOnline.com

 

I'm going to have the 370cc's like we have discussed, so what's the best combo, money aside?

Chris