Tunning a AT?

[OneFastEclipse]

Well, I am ready to start tunning my car with the SAFC II and pocket logger. I notice that you guys make 2nd and 3rd gear pulls when tunning on your 5 speed. Where should I make my pulls on my auto? Should I do them from a stop or should I put it in 2nd and do it from 40mph roll? Thanks guys!

 

[TURFNNSURF]

I have a AT also, and have been street tuning for the last few weeks with my SAFCII. I found that following any of the tuning guides from the VFAQ's are only marginal helpers. Mostly because they are written for 5 speeds. AT's tend to load up the motor low in the RPM bands. If you take a normal start from a light (+/- 35% throttle max) our AT's will shift thru all three gears to 4th by 45 or 50 mph. Upshifts tend to happen around 3500 to 4000 rpm. Downshifts are rare when lightly accelerating as well, even when the turbo spools to 5 or 7 psi. This can be problematic for tuning (at least in my case) because the lower rpm settings on the AFC need to be lean enough to keep the low fuel trim close to 100% but not so lean that knock appears at 25% throttle with no boost when accelerating from 40 to 50 mph. (43 counts)
MY SETUP & LOW AFC SETTINGS for comparison:
2G MAS installed (un-hacked), Dejon tool UICP, 2g TB elbow, Stage 4 TurboTrix cylinder head porting plus 1mm oversized SS valves, Crower Titainium springs/retainers, 1G MT cams, MT ECU, SAFC II, 650cc FIC injectors, Walbro 255, Aeromotive FPR set to 43psi base, Ported EVOIII exhaust manifold, ported Big 16G, RNR 3" O2 eliminator downpipe, 3" SS Hiflow Cat, custom 3" mandrel bent cat back exhaust, MBC @ 15psi, Palm IIIC with MMCd to monitor knock and fuel trims.
AFC LOW SETTINGS: 1000rpm= -5% 1600rpm= 0% 2200rpm= +3% 2800 rpm= +4% 3400rpm= +5% 4000rpm to 7200rpm all +6% HI/LO Throttle set to 45/46
AFC HIGH SETTINGS: 1000rpm= 0% 1600rpm= +4% 2200rpm= +5% 2800rpm= +6% 3400rpm= +7% 4000rpm= +7% 4600rpm to 7200rpm= +6%
When I am tuning for WOT, overdrive is off and I do 3rd gear pulls from about 45 mph(3200 to 3400rpm). Sometimes the car will kick down to 2nd if I drop lower than a 40 mph roll(2800 to 3200rpm). So far i have yet to see my car upshift over 6550rpms and as of now it logs pig rich with NO knock and 19 to 22 degrees of timing during a WOT pull. Im not going to pull any fuel till i can get on the dyno at Turborix for some dyno-tune time with a wideband O2. I hope this info helps you out, and any other AT DSM'er trying to tune their car.

 

[OneFastEclipse]

Thanks for the reply. That is some very help full info. What would happen if I put it in 2nd gear and made WOT pulls from about 30 mph on? Would that work for tunning? I'm gonna try your method regardless. Just looking at all the options. Thanks!

 

[TURFNNSURF]

Im sure a 2nd gear pull will work also. I don't get the chance to do that cause my closest open road is RT 95 and its not safe at any time of the day to drop below 45 mph. I have heard that the best way to race our AT's is to start from a 25 mph roll. Basically that speed puts our cars in the usable power band right away and full boost is achieved quickly.

Happy tuning!!!!

 

[x628x]

i have a question about launching. would i need a high-stall torque converter to hold my idle or whatever when im about to race from a stop?

 

[Jasper16g]

Originally posted by x628x
i have a question about launching. would i need a high-stall torque converter to hold my idle or whatever when im about to race from a stop?

If you are running a 14b like your profile says then you should be able to powerbrake 18-20 psi. When I had the 16g on I could easilly get 20psi by powerbreaking. Now with the 50 trim I get 4psi. Get a tranny cooler as well, powerbreaking is not good for the tranny, and will heat it up fast.

Squigs

 

[x628x]

right now i have the 13g. i was gonna install the 14b but it got stolen so now im getting a small 16g, FMIC, 550s, SAFC, exhaust, intake, cams, IC pipes 5 speed ECU, 2g pistons, fuel pump, boost controller, and probably more i cant think of right now. is there anything else i would need?
maybe i should rephrase my original question. when im about to race at a stoplight, and i think its gonna turn green, i powerbrake. then a lot of the time, theres an arrow so i let off. if i got a torque converter would it put the engine under less of a load so i wouldnt have to let off or not?

sorry to highjack this post by the way

 

[TURFNNSURF]

I'll give you my experience, even though i don't condone this type of racing anymore, I keep it to a track, not the street. If you are going to race from stop lights, LEARN the TIMING of the light you are racing from. Don't race from lights that have "delayed green" signs or "left turn lights" cause you can never predict what the on coming traffic will do.. If you drive the same route every day, you'll learn the timing of the lights. This is one way to get a slight advantage over your opponent. Don't powerbrake till you absolutely have to. Holding the torque converter at high rpms while braking causes increases heating of the tranny fluid, and also causes cavitation in the torque converter, reducing its ability to transfer your motors power to the transmission. Basically you want to time your powerbraking to less than 5 to 7 seconds.
Good luck and be careful