--- Greyson Crowe <[EMAIL PROTECTED]> wrote:
> I remember reading a post saying that our GA16DE's
> had cylinder heads meant for economy. Well I
> thought I might pull my head off and have it
> hot-tanked and replace the gasket, while at the same
> time having it milled down and possibly ported an
> polished. When done I might also add an SE-R
> throttle bodie and fuel pressure regulator to help a
> little.
Unless a JWT ECU is used modifications to the throttle
body are useless because the motor cannot rev to where
the throttle body makes a difference.
For a throttle body to help you need to do all of the
basic bolt on's plus cams and ECU, otherwise the
engine does not breath enough to use the extra flow.
This has been proven through dyno testing.
So don't bother with headwork untill you have all the
basic bolt on mods plus cams, then TB work and head
work are probably going to be benifical.
I will say this again, a SE-R throttle body is useless
untill you get to the 115 hp to the wheels mark, which
is all bolt ons plus ecu and cams. All of the power
gains that a throttle body gives is beyond the rev
range of the stock ecu.
You will feel better throttle response but put the car
on a dyno and you will find zero power gain.
A fuel pressure regulator is useless also on most MAF
equipped cars, the GA16 included. The A/F ratio is
slightly rich to begin with. Upping the fuel pressure
will only reduce power. We proved this by testing with
a Horiba broad band A/F ratio meter. In fact the JWT
ECU is leaner than stock.
See the stuff on engine performance under the
technical section of sentra.net. The modifications
listed are proven and dyno tested and the dyno chart
is avalible to look at also. This should seperate the
hype from the truth over what works for the GA and
what does not.
As for the thread on exhaust pipe diameter, 2.25 is
TOO BIG for an all motor GA16 even if it is built to
the limit of what is avalible now. A 205 HP SR20 lost
power going to a 2.25 header collector and
experimenting with a 2.5-2" cat back made no
difference in top end power. Pipe diameter is dyn o
proven by Mike Saiki and myself and Bob Legere, who
probably knows the most about GA16 power.
For those of you that insist that you have better top
end with no loss in bottom end power, I challange you
to produce a dyno chart that shows it.
So beware of hype and of what people who call
themselfs "experts" tell you unless they can show data
and facts. I am no GA16 expert but I can show you
data, it's all on sentra.net now.
Mike
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