Hondata S300 using PLX wideband. I'm at 5000ft altitude and using 91 octane chevron gas.
Stock 240 injectors/str fuel rail/aem adj fpr set to 38psi
Car is used for road racing

N/A B16a w/ CTR pistons/cams
Portflo head w/ flat valves
Neither head or deck has been milled
ITR intake manifold w/ 65mm STR T/B
2.5 cold air intake
Spoolin Header (only new mod to car since it's last tune)
2.5 inch exhaust

Here are two datalogs and the map. Shouldn't n/a a/f ratio at wot be about 13.0-13.5? On one of the data logs, I go hard through four gears from a slow roll.
On the second, I'm crusing along in fourth I think and I just floor it at 5000rpm about till 8500 or so. Give me your thoughts before I make this thing go pop on accident.....

Here is the last dyno chart before new header.

 

Yes! You're running too lean! You should be at 13.0 and 13.5 is the leanest you should see at WOT. Apparently your header is more efficient and you're going to need some more fuel in there for the extra air you're flowin.

 

Thanks brokenojoke, you're the best!

 

No problem man.... now get that dip out of it and you'lll be good to go!

 

Ive tuned my race car around 12.6-12.8 to keep the EGT's down.

I saw no power loss when leaning it out.

Your running race gas? You Ignition timing is very high. And how does the car run/drive, it looks as if only WOT was tuned(the big jumps in load sites usually causes stumbles or hesitations).

 

No race gas.... just 91 octane chevron gas. (Highest we can get up at 5000ft is 91)

I was waiting for someone to say that about the timing.... I thought it was high too but that's where the dyno showed it was happiest and I'm not getting any detonation that I'm aware of at least. I check the plugs often.

Once the dyno showed it was happy with a lot of timing, I backed it off a few degrees untill I lost about 1-2hp. I run it hard on 100* days here and it runs fine. (so far at least) Another thing that might have to be considered here is that I only see about 870mbar of manifold pressure compared to those closer to sea level..... My maps have new resolution for my altitude so you dont' see the part of the map where the timing curve would usually drop off a little bit when you get more manifold pressure. I'm not sure if my map should typically do the same thing even though I'm at altitude, I just followed what the dyno was telling me.... "more timing please."

I did mostly stay concerned with the WOT part of the map, but I smoothed out the lower columns and it seems to be running really close to stoich. No stumbles or hesitation to complain about. Start up is a pain in the *** but that's because I have no IACV so I have to keep the motor revved a little untill it warms up. Once it's warm it idles just fine.

 

where you using the o2 sniffer in the tail pipe or was it the one that goes in the header?

 

In the picture I posted it's the sniffer. On my datalogs it's my PLX. Last time I was there (almost a year ago) my PLX and the tailpipe sniffer were matched up pretty well (within .1-.2). On the datalog the reading is the PLX in my header.

 

Is your distributor set at 16 degrees? Base timing may be way off causing you to run 32ish commanded degrees.

 

Check this out... it's a post from last year about me trying to set timing with the s300 and running into a couple problems....
https://honda-tech.com/forums/engine-management-tuning-124/my-distributor-has-all-way-advanced-get-16%2A-hondata-s300-2333044/

 

wtf? anyone else see that he replied to his own thread, than said hes the best?

 

 

Your ideal air fuel is hard to determine. You need to go to a dyno and find the "sweet spot" for your trims. (i.e. WOT tuning, vacuum tuning etc.) Then extrapolate the data from there.

 

I was waiting for someone to say something about that.... hehehehe

 

Thanks! I'm going back to the dyno here in about a week so I'm going do some trial and error. I've been street tuning it a little this last week and got WOT between 12.8 and 13.2 from 4000rpm to 9000rpm.... So I'll richin/lean the fuel mixture on the dyno and see where it's happiest. I'm also going to try a test pipe and a velocity stack to try and get me to 180 at least.

Thanks for the replies...

 

you arent going to find much power difference between that AFR.

 

From my general understanding of it the power is in the timing.... safety is in the afr. Some I talk to swear 5-10hp just from fuel tuning within the 12.0-13.5 range.... Every motor is different and I guess the only way for an amature to find it is to try em on the dyno.