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Discussion Starter · #1 ·
1) The stock fuel injectors only flow 31.0 pounds per hour at 3 bar. This is 15% less than L67 fuel injectors.

2) The L32 fuel pressure regulator is not referenced to boost. On L67 cars with stock static fuel pressure of 52 psi, your fuel pressure rises with boost at a 1:1 rate, giving you 58 psi of fuel pressure at 6 psi of boost for example. The L32 fuel system has fixed fuel pressure of about 58 psi. This means that above 6 psi of boost, your fuel system is no longer keeping up with the L67 fuel system, and the smaller injectors listed above become a much more significant issue.

3) We have not yet seen anyone exceed the capacity of the stock fuel pump on the 2004 GTP or GTP CompG. Our recommendation is that unless you’ve used a fuel pressure gauge to verify that your fuel pressure isn’t being maintained at WOT, leave your stock pump alone. Don’t fix it if it isn’t broken.

4) The L32 blower moves a LOT more air. We’ve seen 15.9 pounds of boost through an intercooler with a 3.0” supercharger pulley. No third gen blower with any sort of porting can even get close to those numbers.

For all these reasons, we’re seeing L32 cars max out their stock fuel injectors with only a 3.40” supercharger pulley. If you plan to go smaller than this, you NEED larger fuel injectors, period.

5) The factory O2 sensor in 2004 cars reads substantially differently than previous V6 sensors. See this thread for details:

http://www.3800tech.com/forum/showthread.php?p=6611#post6611

To achieve our recommended target air/fuel ratio of ~ 12.0:1, you’ll need to see B1S1 readings in the range of 990 to 1003 mV.
 

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Why do you think Charles is getting completely different data?
If an when Charles presents information that shows other 2004s are near the target A/F ratio with 920mvs will that be enough to question if it is possible Rich's car is an anomolie?

Are you guys planning to do anymore wideband testing on an 04+ vehicle, or was that it?
 

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Discussion Starter · #3 ·
Why do you think Charles is getting completely different data?
The whole point of the thread is that you CAN'T use the factory O2 sensor to tune, because it is inaccurate at the air/fuel ratios we care about. Not only is it inaccurate, but it is also tremendously variable depending on temperature.

If an when Charles presents information that shows other 2004s are near the target A/F ratio with 920mvs will that be enough to question if it is possible Rich's car is an anomolie?
We're testing cars on the dyno with wideband untrol controlled conditions on a regular basis. I don't believe Rich's car was an anomoly. But I do believe that you CAN'T use the factory O2 sensor to tune.

Are you guys planning to do anymore wideband testing on an 04+ vehicle, or was that it?
Definitely. We're on the dyno almost every week. And sometimes, a half dozen times in one week...
 

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Thanks for the response, that helps. I think I finally get it now.

I misunderstood the part about what targets you recommended. I thought you were recommending that the 04s tune their O2s to 1000mv if a wideband tune is not possible. I guess you just meant the 12:1 A/F is recommended.

12.0:1 – anywhere from 990 to 1003 mV (our recommended target for the L32)
 
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