[torsen] Pushing the N/A engine
JShadzi at aol.com
JShadzi at aol.com
Wed Oct 24 12:08:02 EDT 2001
<<What can I do to the NF engine in my '89 90q. I know, I know, swap for a
turbo. Well...assume for now that it's not an option (I have).>>
Ohh, more on this later ;)
<<What are my options here? >>
On the street? Not much, you only have a few options if you are ruling out a
turbo swap or going to the 20v head.
Flow- A cam will help, as will port matching the manifolds and polishing the
ports in the head on in the intake manifold, but you already have the big
valve head. A good exhaust is a must, the stock manifold is pretty good, a
small improvment can be had with the triple outlet manifold from the 4kq.
Not much you can do on the intake side, you could bore the throttle body for
some high end increase, but not much. As long as you are sucking throught
that CIS metering head you are limited. I would estimate a really hot motor
with a well executed porting job, cam, throttle body, free flowing exh
manifold/system would loose some bottom end power, but could probably make
150hp at 6k RPM, a 20hp increase over the stock 2.3 NG/NF output. Still not
a fast car, but might pick of a second or so in 0-60. Cost to do all this,
probably $1k to1.5K after the head rebuild, etc, pretty expensive for 20hp
-Displacement- Using the Eurovan 95.5mm stroker crank, you could create some
additional displacement, about 2.5l or so. Add this to the upgrades above,
and IME you could have about 170hp, with much more torque to boot. This
would be a real stump puller, super long stroke, you would loose some high
RPM performance and smoothness, but have a great bottom end. This one starts
getting expensive, after machining, custom rods, stroker crank etc, you could
easily have another $2000 into it. Of course, this stuff always starts
adding up, well, now that you're in there, the clutch, etc, etc.
So, after these two areas of modification, you could have a quick, peppy car,
very tourqey, with good all around power, for about $3.5k-$4k (probably a lot
more), a 50 hp increase. Remember, the 1994 BMW 325i came with 190hp and
variable valve timing. Those are not considered "FAST" cars, and you would
be lucky to keep up with one of those, and you can pick one up in great
condition in the low teens these days.
My recommendation is to do a turbo conversion, simply by swapping in an MC
motor into your car, but keeping your stock fuel and ignition system, you can
safely run 8psi boost which equates to about 180hp too, with a lot of torque,
especially if you used a K24, turbo lag would be non-existent. This swap
could easily be done for under $1k, get a junk yard motor and replace the
seals and headgasket. Very hard to beat, without all the wiring and fuel
system swap you have to worry about with a full MC conversion.
I ran my 80q like this with a similar conversion for over 30k miles,
performed very well and reliably, and I have assisted others in doing similar
conversions with similarily great results.
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