Heres why: When I dynoed our 02, most of the pulls were 344, 345 and when the knock retard kicked in, it dropped to 337 or lower. Most members thought I was sandbagging the stock runs, since I was one of the first to dyno an 02 back in August.

The 01s have a more restrictive stock intake system than the 02s to begin with, so the delta should be logically higher. (More restrictive airbox and screened MAF)

The 01 also has larger injectors, which may prove to be fine for the new air without new injectors or the AFR Calibrator.

I had no plans at all to change the injectors, until I reviewed the AutoTap Long Term Trims, and tested them. They put out 255cc/min @43PSI compared to our RC Injectors 310cc/min.

Our injectors are slightly rich for the tables set up in the PCM, but they bring the LT Trims back to -2 to -7 depending on the fuel cell.
Using the AFR we can dial the High slightly lean and the new fuel added to the LT Trims in Closed Loop, bring the cells back to 0.

The reason the AFR works better than programming, is it has a +20 to -20% adjustment. As you add components (NOS) or heads and cam, you can dial in the LT Trims back to 0.

Why is it important to have the Long Term Trims as close to 0 as possible?

The LT Trims are goverened by the average fuel added or deleted in each of the closed loop fuel cells to bring them back to 14.6:1.

No intake, heads, cam, headers, or other custom parts can change the GM factory 14.6:1 air fuel ratio for closed loop fuel cells. Closed loop means that your PCM is monitoring the oxygen level in the exhaust through your first set of 02 sensors and telling the PCM to add or delete fuel.

The short term trims, instantly adapt in each cell, with the average fuel trimming showing up in the long term averages.

When you go into cell 22 (Wide Open Throttle), the PCM quits looking at the 02 sensors for its a/f ratio (That why it is called Open Loop 2). Instead it has a factory fuel enrichment code built into it which starts in the 13s, drops into the 12s and ends close to 13 again. This fuel table is perfect for all applications of fuel in a normally aspirated LS6, under most circumstances. Some additional fuel or leanest does not make too much difference on the dyno, within a certain tolerance.

The problem is that WOT takes a snapshot of the fuel cell you were in JUST BEFORE you enter Open Loop. It then calculates the additional fuel that cell had to add, and adds it on top of fuel enrichment. SMALL DYNO NUMBERS LIKE 12 TO 16 RWHP is the result.

When you add a T-1 to your car (2002), the new airflow is seen instantly by the 02 sensors and new fuel is added. After a few miles, the LONG TERM trims go to around 15 to 20%. That's not a problem, since GM allows the aftermarket up to 23% new fuel before the lean code trips. P0171 or P0174 does not mean your car is running lean. It simply means that for 6 seconds, one of the fuel cells added 23% more fuel to that cell to get the car at 14.6:1

I hope this make sense. It is probably the most important thing to understand, and I have been researching this stuff for over 3 years now.

Why larger Injectors?: The 2002 Z06, with the T-1 has very small injectors. 255cc/min @43psi, which is the same injector size as my 2000 LS1 coupe. When 310cc/min injectors are installed, here's what happens:

The computer is telling the injectors to spray let's say for an example 3ms pulse width for a specific cell. That was based on the 255cc injector. Now with the 310cc injector, that same pulse width puts more fuel into the cylinder, the 02 sensor goes, what's this? More fuel? It backs off the LT Trims from their high of say 20% back down to 0 to -7%.

Now when you enter WOT, the LT Trims does not add fuel on fuel enrichment, which brings the WOT cell into its best power range.

So, when you add new airflow, the Long Term Trims adjust on the + side, which means more fuel to bring the trims to 14.6:1. If that new compensatory fuel goes beyond the computer threshold of 23%, it sends a lean code message (MIL).

When you add bigger injectors, they bring the LT Trims back down to baseline (If they are sized properly) allowing the best power.

The 2001 Z06- The injector size is slightly smaller than the 310cc/min @43psi injectors, which makes me think that they might dial in perfectly with the T-1, without the need for injectors or the AFR.

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this is the kind of information on how our cars produce power that I always found extremely interesting..

I found this and copied it here..

I hope you guys find this interesting.

Those 2002 zo6 guys are looking at a bolt on throwing out 448hp..

Thats some serious power..They got a couple of independant z06 forum members testing these numbers before and after..

I'll keep you guys abreast..if they hit the same 448hp at the flywheel..I think the kit is like 2200 dollars and a total bolt on...

All I can say is thats serious hp! (for bolt ons..LOL )

[ 01-15-2002: Message edited by: JBsC5 ]

Pardon my ignorance, but what the heck is the "T-1"? Or this kit to which you refer? I assume it has injectors.

This is a Jim Hall post, the T1 is his intake system, called also the Sidewinder. The 02' Z06 has 26lb injectors stock, the hot setup is 30lb injectors and having the computer reprogrammed, we will see next week.

I actually thought the process on pcm balancing of air flow and fuel during part and full throttle was the interesting part... closed loop /open loop operation ..

Just some fun..

Actually I don't even know the specifics of the products..

Probably the sidewinder/cobra bridge..the fuel injectors..I don't think Hall changed the pcm programing..

His whole thing is bolt on..

Next week ..he's doing independant forum members dyno before and after ..

Should be cool..

JB, if you find this stuff interesting, you might have a look at Charles O. Probst's "Corvette Fuel Injection & Electronic Engine Management"