Dave What carby are you running ? A weber (or Holly with mechanical secondaries) on a turbo will quite often cause this sort of effect when planting the foot.... it's as Andrew said - it gets lean when you slam open the throttle... it gets air before fuel flow has caught up...
A way around this is to use SU's or CD's instead. because they have a piston in them, when you open the throttle suddenly the engine's vacuum lifts the piston as the motor only gets the air it needs... In my 240z, if I ran too thin an oil in the carbies then they would also lift too soon and it would backfire... I found the best oil to run in my situation was motor oil 50 grade - much thicker than the standard SU type oil... But gee it use to suck the oil out of them... running at 23Psi I had to fill them up every couple of days... got a bit tired of that in the end.... On the timing front - I ran a locked dissy with a static timing of 32deg! BTW - what did you do about the front pulley? Regards James PS - how about sending me some pics so I can post them on Ozdat. David Andrews wrote: > G'day, got some questions re tuning my supercharged L28. > > It backfires at high load. I think its high load anyway. Anyway, say > 40km/h 4th then you plant it. It'll backfire. > > Was having a chat to a RACV bloke the other night (he wasn't there for > me), and he said I should advance the timing until it detonates then back > it off a few degrees to help. > > When I got the engine the static advance (on the distributor scale thing) > was off the scale. Like around 23 degrees. I backed this off a bit coz I > was a bit concerned about it. Did I do the right thing? Should i follow > the RACV advice? > > Oh and whats the deal with the dual adjustment on the distributor. Its > got the one with the scale and the entire distributor moves, but then > theres another one high up the shaft and just the distributor moves, not > the shaft. > Where should the top bit be in relation to the shaft. > > Thanks, > > Dave > -- ----------------------------------------------------------- James Fitness Director Data Scribe Australia Pty Ltd http://www.datascribe.com.au Computers, Peripherals and Supplies Ozdat Online Webmaster http://www.ozdat.com --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/membersozdat@;datascribe.com.au/ ---------------------------------------------------------------------
