platinum00

how much does you a/f change with weather.

if i get my car tunned when it's like 50 out, and then i run it when it is 90 out. what changes are there.

platinum.

99B16Si

as intake temps increase your car will run slighty richer, colder and it will run leaner. with a 40 degree difference id say youll change about a half a point in your a/f ratio

Hammett

are you saying that if outside temp is hot then it will run rich and when its cold it will run lean?

platinum00

so it's nothing to worry about.

if anything, tune the car when it's cold out..

correct ??

platinum.

99B16Si

exactly. its all in the density of the air which is greater when its cold therefore more air is making it into the engine

Bailhatch

my car goes from black smoke in the summer to almost none in the winter. about 60 degrees diff. I should be blowing my **** up within a month or two when it drops another 15deg

if only WB O2s grew on trees, like money...

PM-Performance

if you have a standalone it should make the diff in a/f with weather

platinum00

i have a hondata s200/b , so it will compensate for the weather changes ???

platinum.

reignofchaos

doesn't the IAT, 02 sensor and other stuff correct it on the fly? or is this only in closed loop and open loop it doesn't matter what those sensor say?

falcongsr

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by reignofchaos &raquo;</TD></TR><TR><TD CLASS="quote">doesn't the IAT, 02 sensor and other stuff correct it on the fly? or is this only in closed loop and open loop it doesn't matter what those sensor say?</TD></TR></TABLE>

this is still being debated on another forum that is hacking the honda ecu. we're not sure exactly what affects fuel in open loop.

my suspicion is that yuo will run leaner when its cold out, regardless of the IAT compensating somewhat.

platinum00

ttt

vtec.dc2

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by platinum00 &raquo;</TD></TR><TR><TD CLASS="quote">i have a hondata s200/b , so it will compensate for the weather changes ???

platinum.</TD></TR></TABLE>

i don't think hondata will rewrite its own maps to compensate for weather change.. its a not a bad idea to re-tune and have maps for cold and hot weather.. - thats how i'm gonna go about it.

rjardy

Would the baro sensor play a role here? I know it is for altitude but it measures barometric pressure, and with bad weather the baro pressure goes up. Maybe not enough to effect it though. Im probably over thinking this..


Rob

T-sohctec

No, I think that you are making sense. Since cold air is more dense and that is basically what that sensor is looking at then yea it should be correcting for a more dense charge.

platinum00

there has got to be a way the ecu compensates for this.

or is it just not a issue on a N/A car ??

platinum.

Sonny

The Honda ECU *does* compensate for air temperature. As the air gets hot, you run leaner. As it gets cold, you run richer. It's not the other way around.

When it's cold, the air is more dense, so there must be more fuel to compensate for that.

An easy way for me to see this was with the JRSC on the dyno. On the first pull, the air temp wasn't very hot and my injector duty cycle was around 93% (whoa). After a fun runs to get the air temp up to 180 or so, the duty cycle dropped by ~5%.

I'm sure that other engine management systems do this as well. In fact, I've played with the Haltech E6K system and there is section there at allows you to enter correction values for air temp.

Sonny

Mase

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sonny &raquo;</TD></TR><TR><TD CLASS="quote">
The Honda ECU *does* compensate for air temperature. As the air gets hot, you run leaner. As it gets cold, you run richer. It's not the other way around.
</TD></TR></TABLE>

I dont think you explained that too well.

Basically, w/ most true standalones, you have a Air Temp Fuel Corr. Table. Typically you can change the % vs. air temp.

The colder the air, the more fuel you add; the warmer the air, it takes fuel out.

platinum00

does the hondata system have this option.

platinum.

boosted hybrid

From the datalogs I have taken with Hondata from a few cars tuned in warmer weather, then datalogged a few months later in colder weather there is leaning out in open loop from what I have found. Typically if I tune a car 12:1 on the dyno in the summer time, same tune will run around 12.5:1 in late fall/early winter. There is temperature compensation, but not enough to keep the mixture the exact same. Most of the temp compensation I have seen is in closed loop conditions, where the mixture is almost always fairly consistent. I always tune for 12:1 in spring/summer/early fall so the tunes never lean past 12.5:1 in winter or cold nights.

I dont even want to mention the PITA the temp maps are on Haltech. I spent an entire month trying to get the temp maps worked out when I ran Haltech.

-Trinitron-

I was wondering because they have the "chip" on ebay that lets the computer think that the air is actually 20 degrees cooler than it really is and it is supposed to make powa. Sounds like a load to me but I was jus wunderin.

Sonny

Mase: engrish is my second language.

Jeff: I wonder if the Honda ECU air temp correction is calibrated around stock injectors and must be changed for larger injectors? (kinda how tip-in and cranking adjustment work)

Haltech E6K rules. I love DOS.

Sonny

Mase

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted hybrid &raquo;</TD></TR><TR><TD CLASS="quote">From the datalogs I have taken with Hondata from a few cars tuned in warmer weather, then datalogged a few months later in colder weather there is leaning out in open loop from what I have found. Typically if I tune a car 12:1 on the dyno in the summer time, same tune will run around 12.5:1 in late fall/early winter. There is temperature compensation, but not enough to keep the mixture the exact same. Most of the temp compensation I have seen is in closed loop conditions, where the mixture is almost always fairly consistent. I always tune for 12:1 in spring/summer/early fall so the tunes never lean past 12.5:1 in winter or cold nights.

I dont even want to mention the PITA the temp maps are on Haltech. I spent an entire month trying to get the temp maps worked out when I ran Haltech.</TD></TR></TABLE>


See, this is a good reason why i like the EMS, now yeah, maybe its a pain in the *** sometimes, but instead of redoing the whole fuel map, all you have to do is tweak the air temp corr table and it SHOULD correlate with the correct AFR at any given Temp. Now this is easier said than done of course.

You must also look at intercooler efficiency. that plays a big role in this as well.

basically with hondata, you just have to tune a bit more rich in the summer time (if they arent going to get another tune for the winter), for people who are subjected to colder winters, me living in florida, the temps dont change all that much, but we do see .3 point change without the air intake temp sensor adjustment (from what ive seen w/ my own personal car).

boosted hybrid

I have wondered this as well. From all the cars I have tuned this summer (about 40), most of the cars have no issues when colder weather arrives. I have found that some of them claim to be running richer partial throttle with colder weather, which makes absolutely no sense. I havent been able to datalog any of the cars yet, but I am very interested to see what is going on with their partial throttle maps.

The DOS based Haltech software def. was very easy to use, but a bitch to get running 100% like Hondata. I must have spent 2 straight months of tinkering till I got the car to run really well, then I had some issues with the idle dying out on me that I just couldnt resolve. I ended up selling it just to get rid of the huge headache it created for me. If I wouldnt have insisted using the OEM distributor, and went with magnetic pick/coil pack set-up I probably would still be running Haltech.

platinum00

boosted hybrid.

why dont you come to ohio and tune my car.

platinum.

boosted hybrid

I may come to Ohio late this spring if there is enough interest. I had a bunch of guys interested this summer, but I was swamped at the shop this summer doing installs and tuning.