Rich boost issue

[Joseph Upson]

no way would i even suggest trying to run boost on something made specifically for 1BAR.

That's very wise, but in the early days of boosting computer controlled cars it was done effectively even by big names such as Paxston. I did it for years until more information and access to engine management controls came available. If you understand how the ECM functions along with the fundamentals of engine operation it's quite easy, however, you will be limited in how much boost you can run before richening fuel and reducing timing in the chip at 100 kpa just isn't enough. For me that was 7 psi, but it could have been the result of overwhelming the injectors or fuel pump that put up a wall when I tried to achieve 10 psi.

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[robertisaar]

true, but these days, those comprimises don't have to be made... and for the price it runs to do it right, i can't see someone justifying using stuff like RRFPRs anymore(unless you REALLY need the extra pressure along with proper tuning).

[Cidacious]

I installed the MSD 6AL ignition box and now at first at WOT/boost it is a 10.0 and then as the RPM's increase to red-line the AFR goes up slowly to 12.6 just before I lift. Is this, in your opinion not too lean? what range is goal boost afr?

[robertisaar]

depends on the motor... someone on w-body just had their 5 speed TGP dyno'd and after looking at all of the fuel spikes/dips, it seemed to make the most/smoothest HP/TQ at 11.6:1 according to a WB(not sure if it was a tailpipe version on the dyno or what).

[Cidacious]

hmm, okay how would I know if I am too lean then?

[Cidacious]

The tuner found that it was too lean under boost, and that there were stock injectors. They replaced with beefier ones and deleted the EGR. I was a little disappointed that at 8PSI it was only good for 183/230 on the dyno. The guy that sells the 8PSI kit design one or whatever says his kit is good for 200hp. Maybe the tune on my car is now very conservative.