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So you thinking an Australia vs New Zealand testmatch?

Whoever burns a hole in their piston first can provide the trophy

Will hopefully get it on the dyno at 5psi sometime in the next couple of weeks.

Getting ever closer to blowing it up. Got a 1:1 pulley for the blower and bolted it together. the belt length came to 1260-1285 range which is not available in a 5pk, so I got a 6pk and cut a rib off it

off for a drive- tinktinktink.

nurse it home.
pull outb 5 deg of timing- bwwwwaaaaatinktinktink

nurse it home.
add bucketloads of fuel to the primary circuit (127 to 140 jet) and pull out another 2 degrees of timing, and add some colder plugs.

bwwwwaaaaaaaaaatinkaaaaaaaahhhhhhbwbwsbswbswsbswsbsw

blowing the flame out through the top end and still some detonation on transition/ through the bottom. making just over 10psi

Pulled out so much timing that it is only slightly quicker than it was at 5psi.

need to close the plug gaps up (or get a better ignition system) get some water injection sussed out, and most importantly, recurve the dizzy for less total advance (if possible) and slower progression of advance.

Don't really want to put a head shim in to decompress it, but It may be an easy/cheap option compared to water injection.

I hear your pain, damn pinging, i agree that winding back the timing really kills performance and makes it less responsive down low, timing makes huge difference to power output, its frustrating because you know there is so much potential left but the detonation gets in the way. By trying a colder plug what does this do? Since your sucking through the blower can you maybe get away with a low pressure pump, eg the best w/wiper motor you can find and use a fine jet, if been thinking that spray bottles (garden/hair) manage to atomise the water fairly well and they wouldnt have very much pressure i wouldnt have thought. May be worth a try? Good luck with it im keen to see how you go!

That is getting up there in boost for a non decomped motor. A buddy of mine with an S/C ca18det in a 1200 coupe, reckons that abadetic efficiency for these blowers peaks around 8psi.
A word of caution too. With rich mixtures and cold plugs, fouling can occour. I couldn't figure out why mine wouldn't run. Sat in the shed all winter, before I figured out what was wrong.

Colder plugs (i think) hold less heat in the tip, so when the engine is running close to the edge there isn't residual glow in the plug to set off the next charge before the nspark is fired..... wiki would probably tell you for sure.

I'm not really keen to run water injection through the carby because you take up space that could be air/fuel mixture. The way I figure, if you put your water injection in after the carby, all the air & fuel that was going to go in is already there so it should be all good. I'm still thinking of a pressure vessel setup @ 100psi........ but more research is required.

I can see how people blow up their rides though- the temptation to boot it, and then the split second of detonation before you back off...... not good.

grunter... you going to the next datto meet?

You could try sticking a fogger nozzle between the carb and the blower. That will sap the heat out of your charge like nobodie's business!