3mm Overbore Throttle Body
Over the years
I have added and changed a few things on my truck. Now it weighs
about 900 lbs more and sits 12" taller than most 4Runners.
This weight and drag has taken a toll on the performance of my
basically stock 3.0L V6. No longer does It cruise down the
highway with the ease it once did.
This month I
installed a D.O.A. 3mm oversized throttle body to help my poor over
worked gerbils under the hood. This unit is made by boring
out the main air way opening, much like boring out an engine to
accept larger pistons. The throttle plate or butterfly is
replaced with a larger unit to allow it to seal in the larger
diameter throttle body bore. The larger throttle body opening
allows more fuel/air into the engine resulting in increased engine
performance.
Installation is about as difficult as changing a
carburetor and took me 45 minutes to complete. After removing
the hoses, connectors and cables the old throttle body unbolts
easily. I removed my throttle position sensor and moved it
over to the new throttle body. I sprayed both sides of a new
gasket with some K&W brand "Copper Coat Gasket Compound".
This stuff makes the gasket real sticky and helps prevent vacuum
leaks. It's great stuff to have around when working on intake
systems. After bolting the throttle body in place and
reattaching the cables and lines I was all done. I started up
the engine and set the idle.
For more information about
throttle bodies and throttle position sensors see Jim Brink's
TPS tech article. Adjustment of the TPS may be needed in
some cases after transferring it to the new throttle
body.
For testing I would have preferred to dyno test
before and after the installation to get an exact reading as to how
much of an increase came as a result of this swap. As it
turns out there are no dynos within 100 miles of where I
live. It would have taken all day and as much as $200 to do
the testing I wanted to do, I just don't have that kind of time and
money so I will just have to give a seat of the pants review of the
performance.
I noticed the change as soon as I drove down the
street, the throttle was more responsive. The increase is
most noticeable coming away from a stop. The truck feels more
responsive and peppy. The truck starts and runs normally both when
cold and hot. Over the years my truck has always surged and
missed just a little bit when cold, many 3VZE engines do
this. To my surprise the "cold miss" is completely
gone. Now the truck runs much better when cold. When
driving up a steep grade at full throttle there is a small but
noticeable increase in power as well.
To provide
some reference for comparison I thought I would rate it against
other modifications I have done to my truck. Hands down I
found it better than the 2.5" cat back exhaust, aftermarket high
performance air cleaner , and aftermarket ignition system that I
have tried. I was not happy at all with the Ignition
system or air cleaner assembly and have removed them as I felt they
did nothing to improve performance.
Overall I am
very happy with the upgrade and feel it is well worth the money.
It's not a huge overall increase but is a noticeable
improvement. Gas mileage under normal driving conditions is
the same as before, no better, no worse.
D.O.A Racing
Engines can enlarge throttle bodies anywhere from 3mm to 6mm
over stock (4-6mm over for racing applications only) and has units
available for fuel injected 22re (and turbo), 3VZE V6 engines and
all Tacoma engines. The cost is $250 plus exchange (as of
August 1999).
Contact
Info:
DOA Racing
Engines Tim Jenkins 6013 Premiere Ave. Lakewood, CA 90712
DOARACING@AOL.COM (562) 867-6336
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