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Craig 930 RS Craig 930 RS is offline
Me like track days
Craig 930 RS's Avatar
Join Date: Sep 2003
Location: Kirkland, WA
Posts: 10,196
EFI is well understood, but there are so many endless (and expensive) instances of EFI 'tuning', that.....

Brian's got it - as of just a couple of years ago, options are here which make CIS pretty tunable.

In my opinion - and (soon) my particular case - one can get so close to EFI numbers that you must question EFI.
...depending on your situation, equipment, and desired HP levels.

(Nathan, I did leave out the RPM switch - thanks)
If Robert wants to go past stock -
RPM solenoid switch by Brian Leask:

IF you need the fuel head (there are cases where you will not, the resultant 'post adjustable WUR install' / 'pre fuel head-AFR install' will let you know), you WILL need the RPM solenoid. No way around it. Your midrange will be so rich that even the adjustable WarmUp Regulator will not be able to compensate.

So what do I mean by all this?
AFRs around 12.0 to 12.2 are ideal.
On my car, the boost really comes on around 2,500 rpm.
See the red line (ignore the RF interference spike)? See it drop like a rock - REALLY rich?

This is precisely what happens when you have the fuel head + adjustable WUR which = extraordinarily rich in the mid range.

Oil-diluting, plug fouling, throttle response sucking - RICH.

The solenoid works in conjunction with the WUR, delaying full boost richness until an RPM determined by the RPM module you insert into the RPM switch.

So I inserted a 5,200 module.
See the blue line? This is what it looks like right now.
That line can (and will, when the rain and snow stop) be 'tuned' by the adjustable WarmUp Regulator.

Note from Brian Leask, maker of the Adj WUR and RPM switch kit:

"You need to richen the mixture in the lower/mid-range slightly. You should try doing this with the idle mixture screw first. If that doesn’t get you enough fuel, a slight decrease in the warm control pressure will also help. You also need to richen the top end. You can do so by adjusting the enrichment insert in the bottom of the WUR. I would guess you need to tighten the adjustment nut/stud about ˝ turn to get you to an even 12.0 AFR between 5500 and 6500 RPM.

It appears from your charts that you used the 4200 RPM module. Is that correct?
Keep up the good work!"
- Craig 3.4L, SC heads, 964 cams, B&B headers, K27 HF ZC turbo, Ruf IC. WUR & RPM switch, IA fuel head, Zork, G50/50 5 speed. 438 RWHP / 413 RWTQ -
"930 is the wild slut you sleep with who tries to kill you every time you "get it on" - Quote by Gabe
Movie: 930 on the dyno
Old 02-28-2007, 02:07 PM
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