A lot of you have read my posts about the b5 and jp4 pipe. I wanted to chime in and note that I went out today on a completely different day, brand new 97t plug, and re-confirmed my belief that this pipe and motor are just a bad pair for good low to mid throttle operation. If you tune the LSN to idle well, it is really fat in the mid range. If you try to tune for good low/mid, at idle, the motor idles very erratically because it is so lean and will never load up at all.

For those who are curious, this was the tuning method I used when re-evaluating.

The first thing I do is get it 'a little rich on thebox', meaning I get it to a point on the box where I know it is close, but a bit rich on top/bottom when put on the ground. I do this before any full re-tune. This was a warm and humid day with a brand new 97t plug. First I warmed up the motor, richened all the needles till they were both obviously fat -- there was no top end to the motor and the motor would go fully loaded almost instantly when it came back to idle and rev up like a smoke machine if you sat for a few seconds. Next I tuned the HSN on the box till it cleaned out and didn't sound faster when I blipped the throttle on the box. I then tuned the LSN so that after cleaning out with a few good pulls of the throttle it would idle for about 5 seconds before loading up. At this point, it would high idle for a moment as well, then idle for around 5 seconds, then load up.

Next I tuned the high speed with repeated pulls back and fourth on the street to where it was just nearly at top speed and stable temp wise. Today, on a warm muggy day, that was in the 220-230 range. Next I adjusted the LSN so it would take around 3 seconds to come back from high idle, then around 15 more seconds to drop to a loaded up idle speed. At this point, the motor operated really well, but if you just drove slow in part throttle, it was obviously fat and boggy after a moment and transition to full throttle showed it had loaded up pretty good. Adjusting the HSN leaner makes it run too hot on full speed runs, and djusting the LSN much leaner makes the car run on when returning to idle and idle erratically, never loading up.

In pure race conditions, since you always blip a bit and keep the motor clean, it really doesn't do much, but it will getcha if you need a short take-off where you didn't get to keep it clean. This is a condition that I would just adjust out of a 3 needle carb, or at least improve. I'm hopeful that a 2057 will make this better.