EFI on Quattro

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

Guys,

	As many of you already know, I put an aftermarket EFI system by
Fuel Management Systems on my '86 5KCSTQ last year.  Since it is in the
archives, I'll spare repeating the details, but I will add a couple
updates. 

	First of all, for those considering it, the biggest challenge of 
all is the fabrication of the fuel rail.   I probably spent half of my 
total fab time building that thing.   It still isn't perfect, and I have 
collected some materials to build another one.   The biggest problem is 
the very tight clearance between the #1 injector and the cam on the 
throttle body.   I considered using a different throttle body, changing 
the cam, and a bunch of other less desirable alternatives.   In the end, 
I simply made a very tight-fitting rail with very little clearance or 
room for error.   Actually, that part worked out OK, but I placed my 
pressure regulator too close to the intercooler hose, and it has worn a 
hole through the hose.

	Everything else is fairly straightforward for someone who has a
firm grasp of the fundamentals of EFI systems.  I picked the injector size
based on experience and a couple fairly simple formulas.  (mostly
experience :-) It turned out that Thunderbird SuperCoupe injectors were
approximately the correct flow rate in theory, and so I used them.  (No, I
didn't borrow them from my wife's car, although the thought crossed my
mind :-) Practise has so far corroborated that decision.  I get about
1.5ms injector times at idle, and it hasn't gone lean yet at WOT.  My
_guess_ is that it makes about 270hp, which is also pretty close to what I
was realistically hoping for.  So, part of the success is due to the fact
that I've had a couple lucky home runs. 

	I had a ground problem with one of the wires that _I_ hooked up, 
so that caused a miss last fall.   Its fixed now.  My fault.

	I still have a few drivability issues, primarily with 
acceleration compensation, which are evident but not serious enough to 
warrant the time to fix them.   The new lifters are much higher on the to-do
list.   The important thing is that it pulls strong in any gear at most 
any throttle position and boost pressure, particularly WOT.  ;-)   And, 
it spins front and rear tires.  :-)

	I am only getting 20mpg, but that _may_ be my own fault also. :-)

	One of the biggest bonuses (aside from the sheer hp boost) was the
incredibly snappy throttle response.  It makes blipping the throttle on
downshifts much easier.  every stock Audi I've driven since last spring
has felt like a diesel in comparison - no throttle response...  even
Francois's S2. 

	The good news is that the price _may_ be coming down enough to 
make it a reasonable swap for a few folks.   I'll know for sure in a few 
weeks after I try out the new software.

	If anyone has questions, just shoot 'em my way.  I'll do my best.

Later,
Graydon D. Stuckey
'86 5KCSTQ, EFI, 3" downpipe/exhaust, GDS SS Muffler, assorted other toys