I tuned the carby on my turbo setup myself - via on road testing and a WBO2.

Idles at 14.7:1 and tapers down to 12.5:1 at peak torque (ie max cylinder pressure) then revs out to 13.5:1 so this is almost ideal for a turboed car's fuel air curve. Alas the problem now lies in that this is good for power but unlike EFI the carby wont lean out under a low load situation...meh - she's not a daily.

Also because I'm not using ur typical SU my carbie flat slide is mechanically opened so just pulling out from a dead stop if you just flatten the pedal the car picks up until the accelerator pump shot burns off and because the enigne RPM isnt enough to suck fuel its self at that point it leans outs. This isnt a issue because If you were to launch the car you would do it in boost and crusing wise you dont open the throttle that fast - anyway, the pump shot would need to be 4 seconds long to over come that and would kill the engine when heel toe downshifting. However on road its awesome. Fuel air ratios are great - because I machined my own carbie needle, jets and emulsion tubes (cant buy the right ones to get the fuel air needled for a 1.2L turbo motor to be spot on).

You can use a supercharger on a stock A12 -- 9.0 compression.

Up it to 10 and run E85, have a bit of fun with it. Run moderate boost until you're confident you can wind it up.

Or play it safe and stick to 8? I have a selection of decompression shims that can be used to experiment with.

From what my engine recond guy told me for my supercharged engine on a standard cam, between 7.3 to 7.8 /1 and with boost ground cam I could go higher to 7.8 to 8.3 /1.....so I would say dont go any higher....

cool, the biggest problem i had in my turbo a-series days was the rings, though i think mine and probably many others struggled with tuning. even when i had efi on mine it was never really well tuned.

if you get the tune spot on it should be a hell of a lot more reliable and therefore be able to run more boost/timing/compression etc

Its still a work in progress as Ive had it 20psi with more timing but backed it off to 18 psi and 25 degrees.

I've sorted the jetting but I still need to install my bigger radiator (its a alli 300zx radiator squeezed inbetween the chassis rails and pokes up 50mm above the radiator support pannel). So its pretty much the biggest you will fit in a B310.

Also I will do a write up once I'm finished but I still have to like mentioned; install the radiator and Ive got a gilmer drive to go into it aswell. Then I will look into a stud kit for the head and a cooler thermostat!? Maybe.

By stock gaskets I mean just like the normal paper type ones with the steel rings around the cylinder bores however I got an ACL one and I just call that a "stock" one - sorry for any misleading info.

Really you wont just blow a head gasket untill the head lifts (ie too much boost or warping from over heating) so a good quality paper type headhgasket should be fine - but I'm looking at getting a stud kit for the head so that it wont lift.

Speaking of which; is there that much gain of a stud kit on a A series motor because seeing as the head bolts arnt torque to yeild I'm thinking that torquing them another few Nm wouldnt hurt? Would it?

diymark - any chance of you providing some useful info on your experience

its extremely difficult to even get stock head gaskets these days, are you using ones from nissan or a brand name one?

how long you been running turbo and is it daily driver?

how is it all setup?

there was a European dude running 25psi daily on a stock a series for years successfully so your not alone, though we never got a lot of detail on his setup, and not many people have achieved this. a lot of home turbo converters have struggled over 10psi on budget builds.

So my stock A12 running 25 degrees timing and 18 psi is a ticking time bomb? I dont think so. It has the stock head gasket but I am running water injection (not that really helps the head gasket issue).

Properlly installed head gaskets should hold up quite well.

PS - 18 psi at the inlet runners; not straght off the turbo.

leave it as it is. You'll have a hard enough time keeping the head gasket from blowing as it is.

10.5 compression is i think considered the normal maximum for reliable performance on 98 octane

just bumping the compression does nothing compared to boost in terms of performance. it does help a bit but if your really looking for a drastic gain in power boost it