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I have an '02 with minor mods (see sig), and I just added a V-AFC. I went to the dyno to tune it last week, and my gains were negligable. I did gain some power by lowering my VTEC engagement point, and I extended my power band up top, but that's it. The strange thing is that I did lean out my mixture quite a bit across the entire RPM range.
Below is my dyno plot from my 1st pull (V-AFC fuel corrections all set to 0, VTEC engagement point set to 5600 RPMs) and my last 2 pulls (V-AFC fuel corrections optimized to keep my Air / Fuel ratio near 13.7). My base run yeilded 208 RWHP, and my final yeilded 210. The runs between were in the same range.
Question: Are there any '02's with V-AFC's that have shown significant gains from fuel tuning, or is this just an '00-'01 thing?
Did your tuner make sure that coolant temps were the same for each run? The final tuned run might have suffered if the coolant was 10-20F higher than the baseline.
I was the tuner, and there was an average of about 10 minutes between runs. It was also 67 degrees F inside the shop, hood was open, and I've got lots of cooling mods.
I don't regret getting it. I like how smooth the VTEC engagement point is, and the extended power band. I think it will have more of an effect on my lap times than any of my other mods.
I def think you should talk to UL about this. He is awsome when it comes to this.
I have an 02 with a few mods that i had tuned recently. I was able to pick up 15-18 ponies in certain areas. I also know that the spoon header made me lose a few before i added this.
Seems like your car is pulling pretty hard though with those numbers. I believe your manifold gasket is def a great mod. That is one of my next priorities.
Overall, i topped out at 223 on Dynapack which should be somewhere close to you. Maybe a few more.
Something doesn't match up here...you say you've received practically no gains, and the dyno sheet backs that assertion. However, you also mention a significantly smoother VTEC transition, which the dyno does NOT show. I can think of three possibilities: 1) These are not the latest plots, 2) Your dyno is lying to you, or 3) You've convinced yourself the V-AFC is doing something that it's not.
Considering the multitude of people who have seen large jumps in HP at various points in the rpm range, I would lean more towards 1) or 2).
This dyno was an in-ground roller type from Dynojet with Air / Fuel monitoring. I had a full tank of gas, spare, tools, and air tank in the trunk, and my rear tire pressures were 33 PSI. I don't have any idea what my peaks would have been on a Dynapack.
12-09-2002, 04:10 PM
