WOT and partial throtle
 

I have quick question but don't flame me it is my very 1st build/tune.
My boost gauge shows 0,5BAR at partial hrottle and 0,5 at WOT but my AFRs at partial are around 13 while at WOT 11,4-11,8.
Is my middle RPM to lean or my TPS is not calibrated propertly OR this is how it should be?
I have T25 so it spools fast - around 2,8K RPM I have full boost.

Re: WOT and partial throtle
 

What EMS?

Sounds like you are experiencing the difference between part throttle (closed loop) and WOT (open loop)

Re: WOT and partial throtle
 

sry for no details - it is chipped ECU PM6 with O2 disabled, T25, DSM 450s - it happens at any boost lvl - i tried 0,8BAR and it is the same.
Only need to know if this is how it is supposed to be or someting is wrong - for me suspicious.
Thanks

Re: WOT and partial throtle
 

are you think that afr's are gona be the same all the time? if thats what you're thinking then you're wrong.

Re: WOT and partial throtle
 

for the same boost lvl I would say yes it should be the same unless timing comes to play then AFRs will likely to be different - more advanced at middle RPMs allows more time for more complete burn so it gives higher AFR, is my thinking correct? J just took spark plugs out and all are nice brownish at the ceramic part what I believe is a good sign. Anyway thanks for replies.

Today after few hard runs at 0,6BAR I have taken sperk plugs again. Below is the pic - my EGT still does not work, so please look at the pic and tell me if they look fine. I guess I am running pretty hot/lean (LC-1 shows 11,4-11,8 under WOT/full boost), but kinda on the edge of safety, no signs of detonation. Any input appreciated.

http://images1.fotosik.pl/204/5e364f6926f4e055m.jpg

Thanks

Re: WOT and partial throtle
 

If you ask me they do look a bit lean, but i don't think that 11.8 AFR is at the edge of safety although i dont know what fuel u're jusing.

I'd say that between 12 and 12.5 is pretty nice. To be honest im also tuning my first car at this moment, but as i drove 12.8- 13 @8psi i didn't have any detonation. I also had like 14.4 @ 2psi (thats way to lean if you ask me)..but no detonation. it might be cause i juse colder sparkplugs and 95 or 98 oct fuel (which is standard pump gas over here).

Re: WOT and partial throtle
 

is your AFR at WOT? good luck with AFR at 12,8-13 at 8 PSI, higher Air-Fuel-Ratio you are leaner, lower Air-Fuel-Ratio you are richer - do it for your engine and add some extra fuel.
Detonation is not the only factor - leaner misture burns at higher temps, so you may not have detonations but you may melt your pistons/exhaust valve/s.
get EGT gauge - my reads 760*C at WOT so it is pretty nice - but still my spark plugs are whiteish what bothers me, I guess I will get NGK 8s, while now I have 7s.
BTW the fuel is VPracing 100 oct. Im from urp as well ;D

Re: WOT and partial throtle
 

part of the calculation when the computer figures out how much fuel to fire is the angel of the throttle plate...

it is possible the computer doesnt figure that is has to add as much fuel at part throttle as it does at full

You need to add more timing and lean out your fuel to 12.0 - 12.5 if you are using VP race gas an you are only boosing 8psi or so...

Re: WOT and partial throtle
 

What I did is retard 1.1* per 1PSI of boost and at 9PSI mi timing seats at 19,3* BTDC AFRs are 11,4-11,8, EGT spikes up to 1400*F.
If I will advance timing I guess it will lean out itself without modifying fueal as there will be more time to burn, it will be more complete.
All above is at WOT, at partial throttle my AFR is at 13-13,5 for 8-9PSI.
What advantages I will get after leaning fueal and advancing timing? Is it for performance or safety?
Also higher octane fuel means only higher resistance to detonation or something else?
I know I am a NooB while knowledge is the key :) thanks

Re: WOT and partial throtle
 

well im no expert that for sure, but as far as i know advancing timing and leaning out the mixture is for performance. With 100 oct gas, and 7 or 8 grade spark plugs you should be allright i guess. Maybe keep the AFR's at the higher boost regions a bit lower for safety.

about the EGT sensor, well i don't know anything about EGT's and what would be reasonable EGT numbers. Why pay the extra money if i don't understand what the numbers say (maybe later).

As for partial throtle, tat the moment im also trying to figure out what the nice AFR's are. I do think that 13-13.5 isnt that unreasonable as its not running at the same load and stress as it does while on WOT.