AFR results, boost increased

[gttjames]

Well iv had my r5 for 5 years now and today was the 1st time iv gone over 14psi. I followed the guide on here for carb fueling, very informative, and decided to try the following combo
120 main (standard)
1.2mm 2nd stage
1mm AC jet

Boost is now upto 20psi and wow! Bit nervous aswell though, find myself listnening harder for the slightest noise

afrs are now
idle 13.9/14.2
normal driving 13.4-13.9
WOT is 11.0

So im right in saying still abit rich on boost? Could do with bein upped slightly?

Im very happy with 20psi and how it drove today but looking for the best afr's and have read that under 11.5 is abit rich making it down on power. Is the best option to raise boost slightly?

for those who dont know spec is
t25/.47 from crturbo's
500miles into rebuild - polished crank, all new bearings/shells/thrust washers.
standard pistons - new tarabusi piston rings
oil pump checked and within tolerances and cleaned
piper 270 cam
head is 73mm and has had a little bit of the squish area modified to make it slightly more low comp to bring closer to oe 73.5
also has piper valve springs

[GTphil]

It is a little rich yes 11 afr.

My next step would be to get some form of det detection installed, like a steth or if your feeling flush a knock box.

If the engines compression ratio is near standard and not higher then you should be ok with 22psi, but like I said det may be an issue it may not, every engine is different.

Also the ignition timing needs to be at the standard setting also, so make sure the sensor on the gearbox bell housing hasn't be moved towards the bulk head, this advances the ignition, makes it feel more pokey but brings on det sooner.

[gttjames]

standard flywheel sensor fitted in standard position. And i would say the cr is standard, if not slightly lower.

Iv got a stephoscope at work which i can borrow. Im happy to stick at 20psi to be honest, feels more than enough. But will running at 11 be doing any damage or seriously down on power, just searching for the best afr's really

[Markey Mark (BD)]

Try drilling the ac to 1.1mm mate, if your happy with 20psi and it seems well no point upping boost just adjust carb ;)

[Ricardo]

20psi IMO is about the threshold for std pistons, is boost measured at carb top or base

[GTphil]

I thought maybe 1.1 mm A/C might lean it off a little to much, worth a try just to see, they do bob along enough at 20lb boost:D I just can't help myself when it comes to a little pressure increase :laugh::wasntme:

Steths in my opinion are a worth while addition regardless, mine stays hooked up all the time.