Re: So Slow

[ejfluhr@austin.ibm.com (Fluhr)]

>I've got an 85 4kq with 150k on it.
>I'm capable of doing a lot of mechanical work, so I'm
>looking for what everyone is looking for: Bolt-on, do-it-yourself,
>in-expensive, go-fast. Got any ideas?

Unfortunately for us, there is not much you can _easily_ do to improve
the power output of the n/A I5.  And you also run the chance of skewing
the power band away from its currently (IMHO) excellent rpm range.

Here are a few options that I consider "easy" or "bolt-on" mods:

1) Advance the ignition timing.  Supposed to help a little bit with the
   low-end response of the engine, and perhaps improve gas mileage a bit.
   (I haven't noticed either effect on my Coupe.)
2) Free-er flowing exhaust...but this may sacrifice a bit of your low-end
   torque.
3) Better camshaft...again this may shift the power band up in the rpm
   range.
4) Fuel injection "black box" or ECU "chip" to increase fuel mixture to
   ~13.0:1 A/F at WOT (this is ONLY effective at WOT, and has no impact
   elsewhere with the FI system).
5) Franco industries variable-cam-timing gear.  As I understand it, this
   adjusts the camshaft timing as a function of rpms (some kind of inertia
   mechanism?).  Having advanced my camshaft forward and back one tooth
   and seeing how it affects the power band, this option appears very
   attractive.  It is not inexpensive, however, and I have not heard of
   any first-hand reports from those who have tried it.
6) K&N air filter.  This one is debatable.  I have one in my Coupe GT,
   and could not tell if it made any difference.  Perhaps at really high
   rpms (5000+) it helps, but the engine doesn't make much power up there
   anyway, so there isn't much use in going there.
7) For those with the KX engine (Coupe GT), the 4Kq exhaust manifold
   is a potential upgrade, if the head is already going to be out of the
   car.  For the perhaps 5hp increase it provides, I don't feel it is
   worth doing for its own sake.
8) Remove the A/C system.  Hey, that is 70lbs. worth of metal.  At one point,
   the list was talking about 12lbs. == 1hp, so you have over 5hp right
   there.  ;-) ;-) ;-) 


There are other options that others on the list are far more qualified to
talk about than I.  If you plan on rebuilding your head any time soon,
then you might look into porting/polishing it, extrude honing the intake
manifold, installing larger intake/exhaust valves, three-angle vavle seat
grind, etc.  Still, these are not "bolt-on" mods, and not particularly cheap.

There are even crazier things to do, but I'll let others talk about that
if they feel like it.  :-)

Later,
Eric
'85 Coupe GT
---
Eric J. Fluhr                                Email:  ejfluhr@austin.ibm.com
630FP Logic/Circuit Design                   Phone:  (512) 838-7589
IBM Microelectronics Div.                    Austin, TX