I was just looking at my dyno when the car was stock.

I had never looked at the air/fuel until now. It IMMEDIATELY shot up to ABOVE 18 (the chart stopped the peak at 18 or it would have gone in the 22ish range.) and didn't come down to about 14 until 5k rpms. Then it gradually lowered to the 12.3ish range by redline.

I dynod REALLY low at the time. I was quite dissapointed. It was 231/270. The hp is pathetic to me for a stock lt1 and the torque wasn't much better.

What I am asking is how much could it have actually REALISTICALLY given me if I didn't have that incredible spike in the a/f?

 

Hard to say, but it that was truely a legit reading on the a/f, your dyno guy is a dimwit and you should go somewhere. Thats WAY too lean and your car was probably pulling max timing due to detonation. The power loss would probably be significant in that case. You should be pretty much a flat line from the time you stab it through the entire pull and i would guess your car would make max power at 13.0:1 on the a/f NA. If your spraying it, you'll probably want to shoot for around the high 11:1 range for good power and to be safe. Hope you weren't hitting those 18's on the bottle.

Ken R.

 

No, that was BONE STOCK. Absolutely nothing done to the car. 70k mile motor 101k mile car/tranny.

Assuming the A/F was correct, what could cause such a lean condition on a stock car!?

 

could be a number of things, bad fuel pump, injectors, dirty maf maybe?

 

Where did he put the wideband sensor? Did he unscrew one of the stock sensors and put it there?

 

No, he stuck the rod up the exhaust.

I have not done a tune up since I bought the car (don't even know what kind of plugs I have, let alone the gap!). I've got a bad front passenger side O2 sensor that I can't get out. I am planning on replacing the fuel filter soon also. I will probably clean the maf when I seafoam. (also coming soon)

Do you guys think this will help that? I also have a tune now that's obviously different, but I haven't been on a wide band since, so I am sure if it was doing it then, that it's doing it now.

Anyone want to paypal a poor man some dyno money?

 

That method (sensor stuck into the pipe) is not accurate. IF it were that lean you would be giving up huge hp.

Rich

 

..... not to mention pieces of piston flying out the exhaust. If you have cats, he can't "
stick the rod up the exhaust".... the cat changes the O2 content of the exhaust gas.

 

Then what's the point of the rod in the exhaust?

He definitely didn't pull an o2.

 

There really isn't a point on a car with a stock type exhaust system, especially with cats. Too much outside air will contaminte the exhaust stream and give inaccurate readings. We even tried this once on my BB open exhaust big ci race motor. The readings were no good, so we just welded a bung for the O2 sensor in the collector. On a stock system, you can just remove one of the O2 sensors and use that bung. If you want to leave them both in place for tuning purposes putting in another bung takes maybe half an hour.

Rich