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I just received this from the 5Gen ML:

<font face="Verdana, Arial" size="2">Saturday marked the calendar as my first session for the Lude on a large
wheel dynojet. I have had the car over a year, but a couple friends in our
local import group got a killer deal for $50 for 6 runs with wideband O2. I
have learned a lot, and some of it is scary, so please read this long post
if you have an AFC or flapper valve mods.
Large wheel dynos typically show about 5-6 HP lower on small power cars
like ours, because they are calibrated to accept big power guys (like Nascar
teams) onto the dynojet. For most of you, that is review.. on to the meat
of the topic.
My mods (only listed are the ones that could effect the result): 2000
(base) Prelude 5 speed with AEM cai, flapper valve mod, V-AFC, Greddy PE,
and 15" Volk TE-37s with 205/50/15s resulting in -4% speedo/circumference
(-7% FDR) error. The testing was done in 4th gear. Mods above are good for
consistent 14.7s at 96mph in the 1320.
Flapper Valve: OK, unless you have BIIIIG power early in the rev band,
this mod sucks like crazy. I lost 8 to 4 Tq below 5100 rpm. Reconnecting
it helped Tq AND HP below 5000 significantly. In fact, the flapper bypass
graph curves were NEVER above the flapper connected ones, even in the
"advertised" above 3000 range. Unless you have F.I. or bigger power early
on, reattach that sucker.
VAFC: Unfortunately, I saw V-AFC settings on the net from a very
similarly modded 5th gen, and used them. They were 0 to -4 on LVt and -4 to
-5 on HVt. My rollover was set at 4700rpm. Instead of zeroing it out, I
was curious what these settings netted me. Well, it turned out to be 168 HP
and 136 Tq. Not too shabby for a large wheel dyno with few mods. Well, it
turns out that my settings sucked. Bigtime. **If any of you are running
the -4 to -5 settings that are from the internet without dynoing, you
SHOULDN'T be! Every car is different. In several low and mid patches in
the curve, my car was a bit too lean. This was vexing to me, as my car
blows rich exhaust soot all over my trunklid and bumper (the car is white
and easy to see the soot). Well, the problem was way up top around 6.5k to
fuel cut. We were able to go quite a bit leaner up there. Don't ask me how
lean, because I don't want anyone using my settings and frying their car in
case mine is an anomoly. The revised settings were good for 174.4 HP and
140.2 Tq with a very noticible pick up from 6500 to redline that widened to
up to 10HP at 7400/7500 rpm. I can't wait to hit the 1320, and the car
feels like a banshee on the highway!
</font>


I assume he means the secondary intake runner bypass valves (IAB valves) when he says the "flapper valve mod."

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Billy
North Texas Prelude Owners Group
www.ntpog.org
 

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Well, since I don't have a dyno to go to around good ol' Milwaukee- I'm stuck using the settings posted on the web(-4 and -5). If it is dangerous, please let us know which ones are(or might be, or were for you). I don't care if the settings we are using now aren't the best for HP, but if they are possibly hurting my car- speak up...

Strange thing is- when I set my settings to zero, I can't tell a whole lot of difference. Also, when I set my Vtec kick in to stock, it doesn't kick in as hard as it did (and it isn't as loud as it was) before without the VAFC. Please put up your numbers for us so we can see what ones may need a little revising.
 

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like spocko said, tell us what needs to be changed as precaution for hurting our engines... im also using that simple setting on that aol web site like most people
 

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Another note- I used the same page and settings to start with. I don't have a header or exhaust so I figured I wouldn't need the 5% that was posted. I tried 5% across the board, then 3%, then 4%- 4% felt like it made the most power for me.

I also noticed that when I extended the correction all the way to 9k (the web page only showed it up to 7 I think) I picked up a LOT of power, at least on the butt dyno. Only varying that upper end with such a radical change I think should be a reliable indicator of improvement.

Still need to hit the dyno... and I'm sure I'll play more with the settings until then. I also plan on checking the plugs every 50 miles or show and look for a lean-burn condition, until then.

To all you other 5g guys out there, pull the CLOCK/RADIO fuse and reset the ECU when you change the AFC settings, should help make the changes more apparent or functional. Remember to reset it every few days as well (so the ECU doesn't correct it).
 

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marucci- How can you tell lean/rich conditions by looking at the plugs? And are you saying that you should reset the ECU every few days for the rest of the time you have the AFC? That would be a real pain in the ass.

Brandon
NTPOG
 

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<font face="Verdana, Arial" size="2">Originally posted by LuderSH:
marucci- How can you tell lean/rich conditions by looking at the plugs? And are you saying that you should reset the ECU every few days for the rest of the time you have the AFC? That would be a real pain in the ass.

Brandon
NTPOG
</font>
rich plugs are dark like your exhaust looks and running lean they will look white.
 
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Discussion Starter #9

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Regarding Billy's first post..........can someone tell me WHY you would want to close off that vacuum line? To me it seems that you're keeping the engine from beathing by closing that off. If I'm missing something please....enlighten me.

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AOL IM: Joon525

[email protected]
 

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Guys, ill be getting on a DYNO very very soon to have my car tuned (Cam gears, V-AFC). Ill post up my settings whenever i go. I plan on goin pretty soon.
 

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<font face="Verdana, Arial" size="2">Originally posted by Joon525:
Regarding Billy's first post..........can someone tell me WHY you would want to close off that vacuum line? To me it seems that you're keeping the engine from beathing by closing that off. If I'm missing something please....enlighten me.

</font>
Think it's talking about undoing the vacuum that opens the secondary intake runners at high rpms. It's normally closed at low rpms to help increase velocity of the air for increased tourque, so if you have it open all the time, sort of like it's breathing TOO much, like trying to suck through a straw an inch in diameter. Like he said, maybe it would only be useful to leave it open all the time for turbo/supercharger.
 

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There's nothing wrong with using those -5% numbers. It's a step in the right direction, it's just conservative. The more you lean it, the more power you get, until detonation. Which is what this guy found out. On the dyno I stopped mine after -8% just because because I didn't want to lean it out anymore. You start getting some pretty high EGT's around there and I didn't want to push it.

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DirtyLude
My Car
Toronto Prelude Club
www.hondaprelude.to
 

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How does one join the Prelude mailing list? Is there a website or something? Is it some secret underground Prelude club that is invite only?


Andrew
 
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