gamby

Hey all--

I'm just wondering if anyone has any feedback on how to get rid of my VTEC dip and/or offer any other wisdom. I have I/H/E/V-AFC

here goes:


and these are my v-afc settings: http://members.tripod.com/gamby123/id28.htm

go nuts (please)



[Modified by gamby, 3:07 PM 1/12/2002]

HXMan

Hmmmm....it seems every dyno plot of a DOHC VTEC engine there is a VTEC dip....guess it is something you have to live with, just make it as small as possible.

It appears your non-vtec lobes were making power fine...did you try raising your VTEC engagement point?

SIINSI

I gotta work on my dip too Bro LOL

Miguel

Padawan

One pretty simple method I've read about to set the VTEC x-over point is to make 2 dyno pulls. On the first pull, set the x-over at an extra-low point. On the second pull, set the point much higher. You are basically looking to set the points at two extremes of the rev range. After the two pulls, compare the plots. The point where the two curves intersect is where the VTEC x-over should be set.

gamby

Yep, I raised the engagement point to 5500 rpms, but haven't visited the dyno again yet.

The dip sucks, doesn't it, Miguel??? At least you have 50 more wheel horsepower than me to console you!

I couldn't mess w/ the v-afc on the dyno, because we did a group rate/baseline thing where it was 3 runs in a row, no adjustments.


[Modified by gamby, 9:08 PM 1/12/2002]

Mista Bone

Try lowering VTEC point to 4500-4700 rpm. The switchover really screws up the airflow in the intake, get it over will ASAP in rpm band.

gamby

Interesting thought, although much of the stuff I've read has said that there's not much of a gain to be had beneath 5000 rpms.

Hmm...

fsp31

Did the dyno have an optional Air/fuel meter?

I'm glad I coughed up the extra $$ to find out what was going on. I also went to the dyno this weekend to see if some changes I made to the intake manifold and exhaust did any good. Turns out I'm running way too rich above 3500 rpm's. Anybody else noticed how the stock FPR just takes a big dump between 3500-4000 rpm's??? I haven't heard anyone talk about this, but I went from 13:1 to 10.8:1 in less than 500 rpm's. Then it hovered between 10.8 and 11.2 until red line. Is that typical? (d series motor prepped for FSP under Solo2 rules)

gamby

Yep, they had the option of hooking up to their O2 sensor, but I didn't opt for it at the time (it was an extra 35 bucks). I think I will next time, though, 'cuz I have no idea what's going on air/fuel-wise.

Regardless, all I hear is that the (stock) B16 runs WAY rich after the vtec crossover, so I leaned it out a teeny bit up there. I'm playing it very safe for those of you that checked out my settings.