Carb fiddling query

[Tony Walker]

I couldnt get my AC jet out so id drilled my 2nd stage to 1.4 with normal AC and fueled 12.5ish to 17psi, i wanted more pressure but didnt want it to run much leaner, so i managed to get my AC jet out and soldered and drilled that to .9 now its mega rich on boost, low 10s has anyone else experienced this im now at 18 psi at low 10s afr. i didnt realise the AC jet made such a difference.

[GTphil]

Sounds about right that really. A/C makes quite a large difference;)

I use a .9 ac with 1.4 second stage and at 20psi it's just in the 11's

Do you want more boost or just to lean it off a little?

[Tony Walker]

like you have to ask? i just dont want to up to much without monitoring for det.

[Tony Walker]

ive got an aftermarket tdc sensor too which worries me slightly, ive known the coloured wires to be the wrong way round before now.

[GTphil]

Do you know if your compression is standard or not?

And make sure your ignition timing is standard also.

20Psi should be ok with the above if there is enough fuel.

like you say tho, det is what you need to listen out for most definatly;)

[Dave Reed]

ive got an aftermarket tdc sensor too which worries me slightly, ive known the coloured wires to be the wrong way round before now.

I think bb or gt tuning used to sell them. They give around 6 degrees of advance, not Something you want tbh.. As said standard timing should be fine with 20psi, however getting a set of det cans on is the best way to ensure all is well.

[Scoff]

ac and main jet are very sensitive with the standard venturi :)

the problem with going too rich is that it just brings on the inevitable float bowl emptying that bit sooner, not to mention it chucking away some hp.

[GTphil]

I have noticed a marked difference in performance from say an afr in the low 11's to one in the low 12's.

[Tony Walker]

Easiest to drill out the AC then? My TDC sensor is a std one just I have seen std sensors wired the wrong way before.

[GTphil]

Used to be quite a common mod, on a standard lump/turbo with 10/12psi advancing the ignition by 6 degrees used to give it a fair amount of punch.


I must admit, the idea of mappable ignition is very tempting;)

If you just want to lean it off a little then yeah just open out the a/c a little at a time.

Or just up the boost a few psi first:devil:

[Tony Walker]

lol yeah its very very tempting but without det monitoring i think ill play it safe, mappable ignition i thinks my next purchase. Trackdays are just too tempting for my funds tho lol Oulton parks far too convenient.

[LYNCHSTAR]

go mappable i did and it makes hell of a difference scoff did mine.:)