incorrect. knowledge is power!

 

[QUOTE=timg,Nov 23 2009, 08:34 AM] Log manifold then 6500-7000 rpm.
Tubular manifold then 4000-6000 rpm.

It all depends on the setup.

 

I'm NA and at 4500 RPM. I think since I still feel it kick in that it could stand to maybe go even down to 4000 RPM.

 

the lovefab mini-me... is that considerred a log or a tubular...?

I think it's a mini-tubular.

 

More like a log.

 

After lots of street tuning and datalog analysis, I've achieved a very, very flat AFR curve at 13:1, VERY smooth road torque curve with no measurable VTEC transition, and a VTEC engagement point of 3600 RPMs. While looking at my fuel maps, I noticed that if I overlay my low speed and high speed fuel maps, they cross at 3600 RPMs. Is this a coincidence, or is this a good way to determine the perfect VTEC engagment point? (same amount of fuel + same AFR + same ignition advance = same amount of power). Am I right, or is this just a coincidence?

 

3600 is pretty low to me for na, but if you like it do it. when my car was na, i did 4kish. cant remember, mighta been 4500. basically i just kept lowering it until power looked linear with no vertical lines LOL. you want power to come on predictably, not like a nitrous shot.

on a dyno its the easiest to see the difference. driving the car, it will feel slower, but it is actually faster. as my buddy says though, you lose the vtec bop

 

3600 is surprisingly low, but I was still feeling a VTEC kick when I engaged it higher. Even if I flash Hondata's Toda calibration, I get a kick at 4100. I would also get an obvious "resonant valley" on my road torque plots above my CAI's "resonant hump" at 3500 RPMs. The resonant valley is now gone.

 

Here is my road torque plot comparing my 3600 RPM VTEC engagement (red) against the 6K engagement (blue). There is quite a bit of smoothing going on to remove "noise" from the plot, but it's clear that I'm still getting gains as low as 3600 RPMs. I don't see any reason to raise it.

 

this is exactly what i do when street tuning since fuel follows torque. the most accurate way would be on the dyno but you can get pretty close on the street.

as far as your afr's are concerned. i'd aim richer. i usually aim for 12.8 on 93 pump gas on the street. if i lean it out and i leave it for the dyno since you're going to pick up a few hp that may not even be noticeable on the street while street tuning.