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View Full Version : tuning low to medium load cells - help?



evo442
09-01-2007, 12:59 PM
Ok, so I'm pretty happy with my tune at wot. thanks to a lot of help from evom members, etc. I'm new to tuning but learning a lot.

At WOT in 3rd gear, I'm tuned to about 11.5 at peak torqe then down to 11.2 or so all the way till it gets richer in the end. I first adjusted my afr's then timing, then fine tuned. I'm tuned for zero to 1 count of knock. Most time is spent in the 240-260 load cells. I'm using a MBC.

Now, I want to tune the lower load cells. I've done searches, but can only find bits of info here and there.

1. How do I best datalog in the lower load cells? Its tough to keep things at say a steady boost of 15psi while still trying to drive. Would it work to simply turn down my MBC and go wot?

2. What sort of AFR's should I be aiming for in lower load cells. Same? Higher? if higher, then can you give me a ballpark # to shoot for? ie. At a load of 120 aim for an afr = x at peak torque, tapering to y at redline...

Any help or guidance would be appreciated. thanks.

Alfred@TTech
09-01-2007, 01:14 PM
First you will want to make sure you are getting as accurate a load cell read as possible. I don't know if you're familiar with 2byte load logging, but thats what you want. It allows the log to be precise in regards to what cells the ECU is actually using to operate the engine. You can stilluse the standard calculated load method but it is slightly off.

Its a good idea to experiment with your car and take it slow. If you want to see how its running at 15lbs then just turn down the boost and log the car under WOT. Then progressively raise boost to see your load values increase and watch how the ECU reacts to that. Patience is a virtue here so take your time.

Good Luck and if you need help on the 2byte load let me know.

Alfred

evo442
09-01-2007, 03:41 PM
what sort of afr's should i be tuning for at lower loads? same as higher loads for a given rpm, or what?

milesd
09-01-2007, 06:50 PM
what alfred said is pretty much what i was told when I was learning to tune my aem ems last year.
my o2 feed back is set up like this there is very little fuel added or taken away from my main fuel map with it set like this

14:1 afr @ 0lbs of boost
13:1 @ 4
12:1 @ 7
11.5 @ 10 to 16
11.3 @ 19 to 25

this might be a starting place for you, every car is different I have no knock at all but I am also running alky I could run leaner i think but I am still learning as well so i keep the knock down to 1 volt or less.

down at cruse I run around 14.7 to 15.3 down there you can run it as lean as you can without causing missing problems or spots that are too lean.

take it slow turn down the boost and work your way up, it is the only way to learn your self, it was one of the hardest parts to tune for me and it took me alot of time and i made alot of mistakes but i worked through them and my car runs great now :grin: one of these days ill take it to a dyno and find out how much power it is making but for now ill leave you with this, my car is only in first and second gear 1.5 seconds apeace third takes about 2 seconds on pump gas and alky (that is how i gage how much power I gained or lost by time in gear) so take your time! If i can do it you can to.

nothere
09-01-2007, 07:23 PM
during spoolup you want it lean, in the 13s.
if you have a boost gauge it is easy enough to hold the throttle to keep it in a boost target, if you are on flat road you may have to feather the brakes.
@ 10 psi or something like that for a few seconds, do the same at 15 psi. that should get you a pretty good start.