TRD Supercharger Re: DIY_EFI Digest V4 #658

[Scott_Hay at toyota.com]

Ed,

The Vf is similar to GM's block learn and what everyone now calls fuel trim.
The voltage ranges from 0v to 5.0v in .5v incriments.  This value is based upon
the ECM's learned fuel adjustment over time.  If there is no adjustment to the
base fuel schedule, it will read 2.5v.  If the mixure is too lean and the
injectors need to be richened, the voltage will increase in .5v steps up to 5.0v
and lower than 2.5v if the mixture is leaned out due to a rich 02.

I am not sure how reliable this number will be for WOT tuning as there is a time
element to determine this voltage.  It should be a good number for regular
driving though.

I will try to find out more for you from TRD.

Scott


Date: Tue, 23 Nov 1999 12:32:46 -0500
From: "Robert Wimmer" <WIMMERR at gunet.georgetown.edu>
Subject: Re: TRD Supercharger

Ed:

1) Your right that the stock FP on the 3.4 engine is 38-44 psi.  I'm intending
to install a FMU (rising rate FP regulator) along with the supercharger to
increase the pressure to the 60 to 65 psi range.  My major worry is how to set
up the FMU so it does not boost the FP prematurely.

2) Do you know the range of the Vf signal and how it relates to either air or
fuel flow?

3) I think the "Boost a Pump" you mention it triggered by boost pressure, not
RPM.  But I assume it could be modified to also trigger off of RPM.

What I think is necessary for the best driveability and performance would be to
raise the FP in two stages.  First, increase FP 1/1 to compensate for manifold
pressure, and let the AFM and ECU control A/F. When A/F starts to lean out at
high RPM, increase FP to 60-65 psi.

4) I have traded e-mails with two of the 4Runner Webringers with TRD
superchargers.  They have solved their driveability problems by switching to
aftermarket injectors, AFM and ECU.  This solution is out of my price range and
I am not sure it is necessary.

Thanks,

Bob Wimmer


>>> <Ed.Wong at astrapharmaceuticals.com> 11/22 3:40 PM >>>


>>
This assumes a fuel rail pressure of 60-65psi.  Is this correct?
<<

It was my understanding that EFI pressure ratios were
lower - like closer to 45psi. I may be wrong as I am more familiar
with the 22RE than the later V6 engines.

>>
2) Is there a way to determine when airflow will exceed the MAF and ECU's
ability to maintain the proper A/F mixture at stock fuel pressure?  I would like
to have some idea when (RPM @WOT) to begin boosting fuel pressure prior to
installing the supercharger.
<<

Im curious if the later EFI systems still use the Vf trim signal.
If so - this will give you a real close look at what the OEM EFI
thinks is going on and how much adjustment is still avail (or
NOT avail as the case may be).
See if there is a connector marked "Vf" in the check
connector box next tothe fuse box in the engine compartment

>>
3)  Is there a simple way to increase fuel pressure based on boost pressure and
engine rpm?  I would like to avoid running overly rich, due to increasing fuel
pressure based strictly on boost, while still within the MAF control range.
<<


I think there is a "Kenne Bell" "Boost a Pump" device that does this.
Most people on this list appear to want to build their own decives
from chips though.

>>
I guess if I'm really lucky, one of the list's readers will have installed and
"dialed in" one of these TRD superchargers.
<<

Check out the 4Runner Webring. There was at least one site that
had a TRD "dial in" description.
Try starting at the bottom of this page -
fascianting Toyota stuff
There is a 4Runner specific ring but I cant find it right now

Ewong
TIA,

Bob Wimmer