I know that all motor cars like our b18c5's are affected by areas that are high above sea level, but once you boost it, does it still mater?

I once heard that wrx's and other turboed cars dont get affected by areas where its high above sea level. Is this true?

 

Higher elevation areas have thinner air. In very high elevations, this may become noticeable in your car. By what I mean by thinner air is that in a given volume, there are less oxygen molecules due to lower atmospheric pressure. Because of this, you will run richer than you would at a lower elevation. There will be a power loss, but how much you notice it depends on many factors such as; elevation you were tuned at, elevation you are currently driving at, the tuning itself, motor setup (n/a, s/c, turbo), and your engine & fuel management.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mythias &raquo;</TD></TR><TR><TD CLASS="quote">Higher elevation areas have thinner air. In very high elevations, this may become noticeable in your car. By what I mean by thinner air is that in a given volume, there are less oxygen molecules due to lower atmospheric pressure. Because of this, you will run richer than you would at a lower elevation. There will be a power loss, but how much you notice it depends on many factors such as; elevation you were tuned at, elevation you are currently driving at, the tuning itself, motor setup (n/a, s/c, turbo), and your engine & fuel management. </TD></TR></TABLE>
DAMN!! Brad your the man !!!!!
some good info

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mythias &raquo;</TD></TR><TR><TD CLASS="quote">Higher elevation areas have thinner air. In very high elevations, this may become noticeable in your car. By what I mean by thinner air is that in a given volume, there are less oxygen molecules due to lower atmospheric pressure. Because of this, you will run richer than you would at a lower elevation. There will be a power loss, but how much you notice it depends on many factors such as; elevation you were tuned at, elevation you are currently driving at, the tuning itself, motor setup (n/a, s/c, turbo), and your engine & fuel management. </TD></TR></TABLE>

This is why I always tune my jrsc in the dead of winter, when the cold air is most dense. If your a/f tuning is done when air is very dense, then in the summer when air in thinner, you will be running rich which is safe. If you do the opposite (tune your car in the summer), then come winter time your a/f ratio will be lean, possibly causing detonation problems.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Batoutahell &raquo;</TD></TR><TR><TD CLASS="quote">If you do the opposite (tune your car in the summer), then come winter time your a/f ratio will be lean, possibly causing detonation problems.</TD></TR></TABLE>

And this is exactly why I am in bad need of a re-tune. Mine was tuned on a killer hot summer day, and inside the shop it was even hotter (100 degrees+).

 

does this apply to stock OEM cars as well.. or. dont really have to be stock but tuned from factory.

so i dont really know what time of the year my car was made.. and it was made in japan.. japan and north america oviously has different elevation or whatever..

does it matter or is it only for aftermarket tuned cars?

say if my R was made/tuned in summer time in japan. how is my car still running good in winter in canada. ?
my car should be detonating in winter.. no?

 

The stock ECU features relatively conservative maps to allow for the various different conditions and fuels that the car could potentially see. This is one reason why there are power gains to be had by dyno tuning even if no other changes have been made to the motor.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Padawan &raquo;</TD></TR><TR><TD CLASS="quote">The stock ECU features relatively conservative maps to allow for the various different conditions and fuels that the car could potentially see. This is one reason why there are power gains to be had by dyno tuning even if no other changes have been made to the motor.</TD></TR></TABLE>

Good answer totally makes sence..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Batoutahell &raquo;</TD></TR><TR><TD CLASS="quote">

This is why I always tune my jrsc in the dead of winter, when the cold air is most dense. If your a/f tuning is done when air is very dense, then in the summer when air in thinner, you will be running rich which is safe. If you do the opposite (tune your car in the summer), then come winter time your a/f ratio will be lean, possibly causing detonation problems.</TD></TR></TABLE>

same here, had it tuned during wintertime and it works fine all year long!

 

Well, I think I need some clarification here.

2 scenarios that I have experienced.

1) I took a bone stock EP to Colorado and noticed a SIGNIFICANT improvement in gas mileage. Im not talking like over 50+ miles per tank improvement. How does this correspond with this thread, if at all. BTW, the traveling was done in the summer.

2) Turbo ITR tuned in summer (dry/thin air). Vehicle was relocated to a more colder (now) area and an area with more dense air. Vehicle is NOW running rich. How do you explain this? My AF gauge at highest, reads a 14.00. Cruising at low speeds 3K RPM, it sits at roughly 13.5ish. When I apply a little throttle, it dips down in the high 12s.

Whats the deal?!

Edit: Gained over 50+/tank


Modified by migs at 10:59 PM 1/22/2006

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by migs &raquo;</TD></TR><TR><TD CLASS="quote">
2) Turbo ITR tuned in summer (dry/thin air). Vehicle was relocated to a more colder (now) area and an area with more dense air. Vehicle is NOW running rich. How do you explain this? My AF gauge at highest, reads a 14.00. Cruising at low speeds 3K RPM, it sits at roughly 13.5ish. When I apply a little throttle, it dips down in the high 12s.

Whats the deal?!</TD></TR></TABLE>

in general, a/f ratio change from winter to summer temps should not be significant, other causes besides temperature and elevation can be spark plug gap, valve adjustment, possibly dirty air filter?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by migs &raquo;</TD></TR><TR><TD CLASS="quote">2) Turbo ITR tuned in summer (dry/thin air). Vehicle was relocated to a more colder (now) area and an area with more dense air. Vehicle is NOW running rich. How do you explain this? My AF gauge at highest, reads a 14.00. Cruising at low speeds 3K RPM, it sits at roughly 13.5ish. When I apply a little throttle, it dips down in the high 12s.</TD></TR></TABLE>
it all depends on how good a tune you got. the stock ECU compensates for lower intake temps by adding more fuel. (less fuel for higher temps)
if those values were not set right you will not get the right amount of fuel.

 

stock ecu doesn't adjust anything on wot maps

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Relic1 &raquo;</TD></TR><TR><TD CLASS="quote">
it all depends on how good a tune you got. the stock ECU compensates for lower intake temps by adding more fuel. (less fuel for higher temps)
if those values were not set right you will not get the right amount of fuel.</TD></TR></TABLE>

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtec.dc2 &raquo;</TD></TR><TR><TD CLASS="quote">stock ecu doesn't adjust anything on wot maps

</TD></TR></TABLE>
True the ECU does not run closed loop at &gt;40-60% throttle (TPS and RPM based) but there are still factors that are used.
Among the portions of the factory ECU that have been mapped, ECT and IAT are still factored in at WOT for sure... plus there are still more things that are used in the fuel delivery and ignition routines that have yet to be figured out.