Delco tuning for for dummys

[Holden202T]

so that just goes onto a weber type of adaptor or something ?

definatelly alot cheaper than the 4 barrel one my mate got but having said that its probably going to flow a bit less.... don't happen to know the size of the throttle plates do you ?

[Dec_head]

I modified a lynx 4 barrel to 2 barrel holley adaptor i picked up for $5 cut the holes out larger and had to build a section up where the iac flow goes and drill and tap some holes.
welded the butterfly off the stock throttle body on to the holley one and used the original cable.
I am pretty sure it is twin 49mm
Or they do a twin 52mm
http://cgi.ebay.com/ebaymotors/Holley-1 ... 4ced045bd5

[Holden202T]

fair enough ... fair improvement over the stock 65mm TB anyways!

[Dec_head]

What is closed loop and how does it work
i have gone back to 12p i had stuffed the base tune i was using because i edited it in tp5
so i started fresh and using tp4 for editing tp5 with the adx from antus for logging.
anyway i notice that when it is idling in closed loop mixtures look good and it idles smoother but it turns off after 20 seconds or so then goes back to rich mixtures until i give it a rev and it goes back into closed loop and works ok again .

[Jayme]

closed loop means the AFR is looping just above and just below 14.7:1 and it is applying temporary corrections to your VE table in the form of BLMs stored in your ram. look at BLM in the log, if it is above 100% then it is making it richer than your VE table, if it is below 100 it is making it leaner than your VE table.

the ecu only enters closed loop when your target afr is 14.7, anyhting else and it uses open loop

[Dec_head]

Ok cool good to see i am getting somewhere wish i had the nvram this is painstakingly slow erasing eproms but great to be learning something new.

[Holden202T]

anyway i notice that when it is idling in closed loop mixtures look good and it idles smoother but it turns off after 20 seconds or so then goes back to rich mixtures until i give it a rev and it goes back into closed loop and works ok again .

when its in closed loop what sort of o2 numbers are you seeing and what numbers are you seeing in open loop ?

[Dec_head]

open loop is around 7- 800 closed loop is around 4-600 roughly it is hard to tell as it jumps all over the place is that normal ?

[Jayme]

its normal to jump up and down 100-700 or so in closed loop, thats how the ECU tells whether to richen it or lean it out. the o2 sensor can only tell if you are above or below 14.7 so it has to swing it either side to be able to tell

[Holden202T]

open loop is too rich and a dare say closed loop is too rich too but its probably more like that open loop should be so its happy there ....