1FZ-FE scaled injector setup

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

landtank

landtank

Supporting Vendor
SILVER Star
10 Year 15 Year 20 Year
Joined
Mar 27, 2003
Threads
385
Messages
21,267
Location
Groveland MA
Website
landtankproducts.com
Moving along with my SC install I wanted to design a scaled system. My criteria was that it should bolt into the air cleaner, offer an injector upgrade and work with our OBDII ECU.

The basic idea is to increase the ID of the MAF housing which in turn lowers the output voltage for the same volume of air. Then increase the injector flow rate to compensate for that drop in voltage so that in the end you are flowing the proper amount of fuel.

The benefit is that even though you are flowing more air and making more power the MAF sensor is still operating in basically the same range and the max duty cycle for the injectors is close to stock as well.

The main goal was to design a MAF housing that was matched to an injector that would not require any additional hardware to tune it and work properly with our ECUs.

The prototype has been installed for a year while my truck was NA. I first wanted to make sure there was no Fuel trim or drivabilty issues. Then I bolted on the SC.

Right now the truck has 195k on the clock, 4.88s and an OME 3.5" lift, a new HG with no aditional work done to the head and a new set of connecting rod bearings. I'm running NGK BKR7e plugs at their delivered gap.

The injectors I am using as the WRX 3920 blues. They were the right flow rate and small in size.

Attached is some pics comparing the MAF housings and injectors.
maf comparison.webp
injector1.webp
injector2.webp
 
This was common practice in the NA-T SC300 and Supras. They run the LS400 MAF with 440cc injectors to improve on the scaling and then fine tune with SAFC. Some people went as far as using the MAP ECU 2/3 as they both offered ignition and fuel tables that could be altered to flow properly. Very much interested in your findings.
 
while NA I was getting 15 mpg on the highway driving 75mph which is pretty good and the timing pull that is present with the stock system is gone which is really good.

Yes, they have been doing this sort of thing for years. But there isn't a 6.3L engine out there to pull a MAF out of. So I had to design one.
 
Are you going to make this housing available?
Maybe as a kit with the correct injectors?

Is it the same MAF that the other oversized housing uses?
 
a bit of an update:

I ran this setup for a year while normally aspirated and then another while super charged. While doing a drive to Florida last year I was seeing great MPG for two tanks and then things went south. I lost a knock sensor which resulted in a huge timing pull and everything went south.

That has been repaired but long hauls aren't in the future anytime soon.

Not sure if I posted this but I did due some data logging with the intent of documenting the timing issue. I engaged the second start switch and placed the gear selector in 2nd as well. Taking off from a dead stop at WOT I saw 40* of timing at 4800rpm. If some of you are inclined to try this I'd love to see your results.

I also installed a SC on a customers truck who is set up the same as me, 4" lift, 35" and gear. The difference between the two is incredibe and once he drove my truck he whats the upgrade.

Just so it's clear, while I am installing larger injectors it's not about fueling. In stock form these ECUs dump more than enough fuel down the throat of the 1FZ-FE. It's about avoiding a programmed response to retard timing when the MAF crosses a predetermined threashold.

The lack of the timing pull is where all the gains are coming from.
 
inkpot said:
The WRX injectors look a bit shorter than the OEMs. Does the fuel rail drop down low enough to fit into them easily? Are you still running the OEM fuel pressure regulator?
Click to expand...

part of the kit is new spacers and bolts for the fuel rail. There was no issue installing them. And still running the stock FPR.

Another change is that the hose section on the new MAF is larger than the stock one. So 2 90* elbows and a piece of tubing replace the "U" shaped section that goes from the MAF to the throttle body.
 
landtank, I'm about to replace my fuel injectors due to ongoing issues with hesitation while under load on inclines (between 2-3k RPM). I'm interested if you put together a kit for sale.
 
^^ What he said ^^
 
Landtank, this looks like really good work. Curious if there is an advantage to go to this being NA? I do plan to run a SC or turbo down the road, but that is a year or two.
 
LC4LIFE said:
Landtank, this looks like really good work. Curious if there is an advantage to go to this being NA? I do plan to run a SC or turbo down the road, but that is a year or two.
Click to expand...

Thanks, I don't see much of a difference on a NA truck.

later on in the fall when things cool off I'm planning on installing the smallest pulley available, and provided the MAF isn't saturated at WOT, I'll be installing a split second signal calibrator, PSC1-003.

Before anybody starts ragging on me about the calibrator choice, it was given to me new in the box. So I'm plugging it in and seeing what happens.
 
You must log in or register to reply here.

Share this page

Back
Top Bottom