well its been a humid summer here in NY, it seems as tho i've only been driving my car in 85+ degree humid weather, and i was tuned on a 90 degree day. my a/f on my wideband was always in the low to middle 11's at WOT (15psi on a gt40r). so yesterday nite it was finally a lil cooler out, so i wanted to see if it felt any different power-wise..... so i got on it in 2nd, and thought that it felt pretty good! try it again, look at my wideband, readings are in the mid 12's! off the gas, no more WOT rest of the nite i knew weaither changes would effect the readings, but not THAT much! looks like i need to make some adjustments lol

 

what ecu are you running?

 

i'm running an apexi power fc

 

Why are you worried about it running at mid 12's? I wouldn't worry unless it goes above 13.5, shouldn't start hurting anything until it gets past 14 or 15:1 anyway unless you're running your timing on the edge. It should make the most power around 13:1 anyway

 

because i care about keeping this motor together as long as i can lol

 

There is an AIR TEMP vs INJECTOR table acessable with the DL. The stock table values are **** because they are for the stock engine which had a very small IC and also an inadequate radiator. Mazda made the engine run very rich all over for wamer air temps. Thus when the air cooled off, Mazda actually leaned the mixture to a more reasonable values (but still rich). This table is far from being linear for air density changes due to air temp changes.

When your properly mod an engine where it is safe to run our 11.2AFR @ 15psi boost or 11.5AFR at 12psi boost, this table needs changing. Also at the same time it is best to move the IAT sensor to either the IC outlet or TB elbow where it will not heat soak as much and will give more accurate readngs.

If you tuned your modded engine when air temps were hot or very warm
for leaner than Mazda AFRs and did not change the AIR vs INJ tbale, you will go leaner when the air temp drops. This is another reason why you can not go out and tune for one season. You have to do it across the seasons or else get someone's tested table.

 

thank you cewrx7r1 i'll look into that this weekend. that also being said, does anyone have a "table" for northeastern weather?

 

Just a word of caution, if you choose to push 12-1 afr, I would augment your system with water injection.

 

The table values are the same no matter where you live. It would be best to move your ATS from under the UIM to the IC outlet or TB elbow.

- AIR----- MAZDA Stock----Kevin's true
-TEMP ---------values------by air density
************************************************** ***********
80C/158F-------0.957-------0.930
50C/122F------ 0.984-------0.969
30C/86F--------1.012-------1.031
10C/50F--------1.055-------1.105
-10C/14F--------1.102-------1.191
-30C/-22F-------1.148-------1.289

Kevin's are theoretical. Mine which were done by testing, vary by 1% to 2% from Kevin's.

 

thanks

just to make sure i'm understanding this right, by using kevin's values, it won't necessarily completely correct the problem, but it WILL run richer than it currently is when the temps dip into the 40's at nite?

 

Kevin's table would keep your AFRs linear (constant) as temperature varied.

If you AFR tuned at 30C, at 10C the AFRs would be the same (theoretically).
As I said my tested values were 1 to 2% off which is not bad compared to Mazda's values.

Do the math to compare Mazda to Kevin. Your teachers were correct in saying that algebra would be needed through out your lifetime.

 

Thanks for posting that info, Chuck. I've found my AFRs tend to change quiet a bit with weather.....I definitely need to go in and verify/adjust my values.

 

This is what my current table looks like, do i change the whole thing to the one above that you posted?

- AIR-----
-TEMP ---------
************************************************** ***********
80C/158F-------1.00-------1.00
50C/122F------ 1.07-------1.01
30C/86F--------1.29-------1.21
10C/50F--------1.57-------1.50
-10C/14F--------2.01-------1.87
-30C/-22F-------2.81-------2.57

 

Since you took such delight in correcting my english, I will repond the same with your math... 80c=176f

 

Ackualy it wus nut a math eror, butt a tyyping eror. Notice thet the tabble temparatures very by 20 degrees, exsept the top yone of 80 is 3o deckgrees higher then the yone below. The DL adjecent tabble INJ vs Air Temp and Boost stats at 70C, not 80C. Some have seid thet the first tabble value should knot be 80C but 70C.

70C = 158F.

JACK OFF!

 

I feel like I'm back in kindergarten.

 

You appear to have some ax to grind when it comes to the standard by which you judge or I should say police some of the questions that come up in this forum. However, when that high-powered scrutiny by which you seem to live by, is focused back your way, you retaliated like an injured child. I took exception when you decided to critique with a sardonic tone, retrospectively a poorly constructed question not directed to you. I do believe there are much healthier ways to interact with each other so specifically young guys can ask naive questions and not feel the forum ***** are not going to publicly flog them. Moreover, I am not a young guy and DO NOT take kindly to individuals who feel they can ridicule me. “Those who live by the sword are destined to die by the sword”

 

dude shut the hell up, this was a good thread until you had to post your 2 cents...... take it to pm's if you fell the need to bitch at someone instead of cluttering a technical thread

 

Your right..

 

Too many swinging dicks on this forum. Remember guys, we are all rotary enthusiasts, and as such should help each other out. Look up 'comradery' at www.dictionary.com.

We should focus our efforts on constructively building a community of well running, fast rotary vehicles. What's with all this bullshit negative energy? I think a lot of guys on this forum are projecting their own personal problems onto the forum......

 

I agree on all points and stand corrected for my negitive imput...

 

OK!

 

 

Are you testing A/F in 2nd gear? I would do it in 4th as lower gears are going to give you leaner readings.

Jason

 

it did it in 3rd too so i didn't want to chance going thru 4th..... it did seem better last nite tho, i dunno why that ONE nite was an exception?