EFI 5KCSTQ

["Graydon D. Stuckey" <graydon@apollo.gmi.edu>]

Guys,

	I got the EFI running on my '86 5KCSTQ over the last couple 
days.   It runs great!   I still have a considerable amount of work ahead, 
calibrating the fuel maps to make it run better, but overall, so 
far, it is a distinct improvement.

	In case anyone is not aware, I have installed an aftermarket EFI 
system (from Fuel Management Systems) on my 5KCSTQ in place of the stock 
Bosch CIS system.   It is controlling fuel only - the stock Bosch ECU is 
still in control of boost and ignition, courtesy of the the Quattro List 
Chip Club (Thanks guys!)   There was alot of fabrication work that had to be 
done.  I built a fuel rail, a throttle position sensor mount, an air 
cleaner bracket (I used an clamp-on K&N,) a hall effect sensor and trigger 
wheel, and a couple other minor things.   I had to add engine and air 
temperature sensors, an RPM trigger, power to the ECU, throttle position 
sensor, oxygen sensor feedback, about 50 bucks worth of aeroquip to 
plumb the fuel rail, and I had to install an additional wiring 
harness.  This was all alot of work, but the results are starting to 
speak for themselves.

	The fuel rail was probably the biggest single fab job.   It took 
alot of careful design, because the number one injector was VERY close to 
the throttle body, so I had to design the rail as short as I could so 
that everything would clear.  I got it in there.   I used injector 
inserts from a VW Fox, which has the "Digifant" efi system.  They were a 
buck each from the dealer.    That allowed me to pop the electronic 
injectors into the head exactly where the CIS injectors previously were 
located.   That was rather slick!

	Brendan Rudack has been helping me calibrate the thing (Thanks
Brendan!).  Since I don't have access to a dyno just yet, I have to
calibrate the fuel maps on the street.  That means driving it around,
taking load/rpm points until I have enough info to go write a new 
chip.    So far, there are still quite a few points that are too rich or 
too lean, but there are also a few spots where the mix is getting very 
close, and it really goes when I get into those spots on the fuel 
curve.   It starts alot better than it used to (two or three revs before 
firing and settling into a _VERY_ smooth, powerful idle.)   I hope to 
improve startup even more with some more calibrations.

	One of the biggest problems now is that the turbo itself is VERY 
noisy!   Brendan likes it (and I would too if I didn't have a family to 
cart around in this thing) but it is very loud.   The whistle of the 
turbo spooling up is very obvious (kinda like driving beside a big semi 
on the freeway, when they get on the throttle) and when I get off the 
throttle, you can hear the compressor being shut down by the throttle 
plate.   It sounds alot like the TransAm cars on shifting!   Makes it 
quite obvious that I need a blowoff valve.   I will plumb that blowoff 
valve though, so that the noise gets muffled somehow and I am going to 
redesign the air filter to reduce the noise some more!

	So far, I am only running about 14psi, but I hope to get that back
up to 17psi as the maps start to get better.  Even at 10psi though, it is
almost as fast as it was before with the CIS at 14psi.  It also spools up
the turbo alot quicker.  1st and 2nd gear acceleration is very quick 
now.    Off-boost tork is better too - getting off the line is easier.

I probably took 25 pounds out of the front end of the car, so that is 
good, but I also opened up alot of room on the passenger side of the 
engine.    One big side benefit is that now I can see my 3" downpipe 
plain as day.   There is a big hole there where the CIS used to be!   
Lots of room now for twin turbos...    :-)

Later,
Graydon D. Stuckey 
'86 5KCSTQ, GDSstageIII, FMS EFI, 3" exhaust
"Yes, it _is_ a little bit noisy!"
"No, that muffler needs to be raised a little"