Originally posted by jtkz13@Mar 16 2004, 11:21 PM
I dont know what the big spike in torque is from, but since it doesnt really follow the curve and the 1st dyno didnt have it, I would say it might be a dyno error. Regardless, it still put down a little over 180wtq and almost 170whp, which is about a 10-15 hp & tq increase over stock. More importantly what is the average tq&hp from each run? Are you running premium with the chip? It looks like the chip leaned out your a/f ratio a little bit, where I'm sure some of the hp & tq came from. Just be very watchful for any pinging on acceleration because 15.0:1 a/f is starting to get decently lean. Optimal a/f is 12.5:1 at WOT, remember during part throttle your a/f is going to be alot leaner than WOT. Its good to see that the a/f doesnt get leaner as rpm increases.
The dyno is accurate. This has to do with the way I re-made the converter lockup schedule to get more power to the wheels. Clearly, the first dyno graph wouldn't have it...
As for the a/f...as I mentioend you cannot pay attention to that. It is not really that lean. There is something off on the MAF or the WB. I do lean it out *some* but it yields very little power from just that. I have made pulls back to back with the 87 octane and you do not pick up too much power from the revised a/f alone, but you up, up some. It is a combination of the things I do that gets those results.
As for a/f, I agree. The car has 12.6 commanded...but as you can see even from the stock trace, there is something not right. Stock, they run that thing way rich and it still "reads" 14 on that trace... It is not really that lean. How much power do you think it would have made at 15:1?
Remember, when a car is too lean, cylinder pressures drop. You get leaner than 16:1 and cylinder pressure and temperature drop dramatically and it's actually safer to run 17:1 than it is to run 12:1. I know some will have a problem with that, oh well, get over, it's physics. Now 15:1 is not yet at this point, but like I said, it is not really commaning that a/f. However, this is mainly an issue with blower cars, where the danger zone is 13:1 to about 16:1. (This range does not apply here since this is an N/A car, but I threw it in here for background info since that is what forums are for). Still it made a lot of power for "being at 15:1"...)
Also, when you hit the "rev limiter' in the newer cars, the EEC shuts off the injectors and you instantly go from your WOT a/f to like 18-20:1...and nothing blows. It hits a "limiter" because you make no power. This is all not really relevant but it is here since I htoguiht it would be a good place for this info. I promised Bob I would post useful info here where relevant.
Anyway, he is not really that lean and as I told him and Bob, we need to find the issue on his end or the dyno's end....Bob suspects the WB sensor and he has his reasons. It was my first suspicion but not my only one. Bottom line is, in this case, disregard the a/f...