Holley 4D experiences

[Mike Jones]

Hello all:

Well, got my boat on the water for the first time with TBI and GT40P heads. 
 What a difference!  Instant starts cold and hot, terrific throttle 
response, much better acceleration and 3 mph increase in top speed (that's 
a lot for a boat.)

Just a couple of minor problems to work through.  One involves a too-high 
idle speed when operating closed-loop.  Should be easily solveable.

The second problem goes like this:  Running at full throttle produces 4000 
rpms.  Backing down to 3800 rpms briefly, and then applying full throttle 
brings up 4150-4200 rpms, which then decays over three-four seconds back to 
4000 rpms.  The high speed jet control is nearly maxed out.  I'm going to 
try increased fuel pressure next.

Mounting the O2 sensor in the crossover passage seems to basically work 
fine.  Acceleration, top speed and part-throttle cruise were all unchanged 
or improved from open-loop (although that placement may be contributing to 
the high closed-loop idle speed.  Something I have to look at yet.)

Hopefully I'll have an opportunity to take it out again this week with a 
friend who's not so antsy to get home!

Mike J.