weee.

been mapping my car myself (b20-vtec, spark racing 84.5mm pistons, stock b16a head cleaned up, itr spec valve seats and itr intake valves, head skimmed 5thou, puts it near dead on 12. compression)

anyway just a question to the tuners on here. i currently have the 29-18 vacuum tables on the low cam mapped to be as near to 14.7 as possible, then increasing to 13.5 (until 6 vacuum )and running to 12.9 on WOT

for the vtec tables i made it 13.5 everywhere part throttle and again 12.9 for wot or the lower vacuum areas.

would you say the afr's were to rich or to lean?or do they sound about right, i would rather it be rich to be on the safe side. car is only run on 98 ron fuel and the ignition tables are dead on stock b16a ones. (no advance at all anywhere, waiting for a dyno to hit more load points and get some ignition timeing done)

for the ignition is it simply just a case of adding timing at a certain load point until it peaks (the torque) then pulling a few degrees back off it? same for the wot, people tell me 13.2-12.9 will usually give the best hp. any tips for when i map on a dyno?

thanks!

thanks!

 

Sounds good. I would suggest trying a slightly leaner mix on the 98 ron fuel while you are on the dyno. I doubt you will yield much of a gain.

Have fun!

 

thanks.

also for steady cruise at say 60-70 mph in 5th i am getting people tell me its possible to lean the car out to 15/16 afr range, currently mine is sat mostly around 14.3 -14.0. normal or is running it towards the 15afr range bad?

one more thing on transitions on wot from low-high fuel table the gauge runs lean for a split second as it engages (go's from 13.2 then jumps to 14 then straight to 12.9). do i need to add more fuel just before it clicks on the low cam table or add more on the high cam table? vtec is currently set to 4300rpm, nice and smooth, not to low and not to high that it kicks hard

 

yeah for cruising at low loads i always shoot for 14.7-15.5:1. I've never worked on something with that high of compression though so maybe wait for some others to chime in. If your worried about the little jump to 14:1 at VTEC just give it a hair more fuel on the low map so that instead of being at 13.2 right before the change it goes just a tad rich. honestly though its probably not that big of a deal.

 

The trick for getting smooth overlap between high and low cam fuel maps is to first raise VTEC to ~7000, then tune your low cam map all the way to that RPM region. You will notice the factory ROM maps have tuned cells all the way to 8000 on the low cam. Then do the opposite for the high cam maps, drop VTEC to ~3500 and tune high cam map. If you are targeting the same AFR, the transition should be smooth.

On a side note, the tuning of the entire low cam map is beneficial for other reasons as well. Lets say you are in the middle of an autocross or track day, and you drop oil pressure enough for the VTEC pressure switch to fail, or your solenoid fails for some odd reason, now you at least have a tuned full RPM low cam map for these circumstances. A friend of mine was doing a time attack recently and his VTEC solenoid failed, because I had the full low cam map tuned, he was still able to complete the lap while giving it all he could.

Your AFR's seem on the safe side, possibly rich for part throttle. Remember that there is a very big difference between lean misfire and knock (or detonation as others call it). A lean misfire is not damaging to your engine in any regards unless you are under full load. Some Hondas (Civic VX/Insight and others) go into lean burn mode during light throttle steady state cruising, where target AFR's transition to 22:1. I always suggest leaning out your steady state crusing cells until you begin to get lean misfire, then add 2-3% and call it good. On my 2.0L ITR that equates to roughly 15.5-16:1 AFR's.

Good luck.

 

thanks map is tuned up to 7000 on low rpm. hence why its a little strange. will try dumping in a tad more fuel and see what it does.

i will also tune the steady cruise back to 14.7, i dont really fancy going lower, i would rather pay for more fuel than build another engine, seeming as the car is cursed :lol:!

what is a safe limit for part throttle/mid acceleration? 14.0? 13.7?

 

for part throttle/mid acceleration i shoot for around 14.7. Unless your running way lean, your're not going to hurt anything by going for 14.7

 

is this key to getting good gas mileage b/c let's say passing somebody 5th gear 14.7 u won't be making a good amount of tq to be able to pass it would feel hesistant also most like a lean misfire.

b/c i have an h23vtec 11.6 cr and i'm in the low 13's in part throttle. But it get's up and go right.