Tuning a speed density system with mods
 

I'm new to efi systems ever since converting my fastback but since my conversion with MAF didn't work correctly I switched to speed density and it worked better than with MAF. Now my concern is that the mods that I did may cause some problem with speed density. I opened up the TB induction because I'll be putting on a 65 mm tb sooner or later but has a 58 now. The upper and lower were gasket match, the lower was gasket matched to the heads, the exhaust side was ported, long tubes were installed with 1 5/8 primaries no cats with full exhaust is in place, smog equipment was removed. What should I start by checking or playing around with till I get it right? The idle seems to slowly come down after reving it and stays at 1200 rpm then drops to 800 and then back to 1200 rpm after a while then back down. The engine shakes a little but not as bad as when running the MAF. So any tunning ideas? Oh yeah and one last question is the right O2 the drivers side?

well it is EZ to tune a SD not to much you can do I am SD still.

What should vacuum be reading right now it reads around 20 hg if I rev it then it moves to 14 hg and then to 24 hg and back down to 20 hg. Also whats a good starting point for the fuel pressure? How about timing?

i'm still running speed density .........i keep my timing at 15* initial timing and the stock fuel psi seems to work pretty good (39 psi w/vac disconnected)

i'm planing to run it on a dyno in a couple of weeks to see how it's running rich/lean wise........as far as i can tell ,at 39 psi i don't smell it running rich so i think it's pretty close......remind me and i'll let you know how the dyno tinkering does

oh ya ....not sure bout vacuum ,but mine would be different caus of the different intake

I am still speed density..........Easy money..

Should I get an adjustable fp regulator if I can smell it being a little over rich?

fostang ......it might be nessesary to get one ........it depends on what your presuse is doing ,get a fuel psi gauge first then run it and see how its doing rich/lean wise and psi wise

although mine is "set" at stock psi ,with the stock regulator my psi would be different ........do to the vacuum levels being different from mods i've done ......thats my theory any way ......i'm not positive cause i got the regulator before i got the different intake ,.....now if i get an aftermarket cam i'm told i will need the regulator ,cams definatly change the vacuum levels too much for the stock regulator to function properly

btw .....i unhook the vacuum line to set at 39 psi then hook it back up .......with vac line hooked up and at idle it stays around 31-32 psi

also.....it'll probly be a while till i get the dyno tune ,unexpected financial problems ......me's to broke to get it tuned right