I am picking up my new RX-8 in a few days and in advance I am reading the manual.

YA YA I know I am a GEEK... but thats okay because I love rotary's.

Back on topic...

Here is what the manual says on page 6-7 of the 2008 PDF for the RX-8.

"In the floor, defrost, floor/defrost positions, the air
conditioner is automatically turned on
(however, the indicator light does not
illuminate) and the position is
automatically selected to defrost the
windshield.

This item was also automatic on my Mazdaspeed Protege but someone figured out how to disable it.

See this link - How-To: Disabling Automatic A/C - Defrost modes (http://www.mazdas247.com/forum/showthread.php?t=55382&highlight=a%2Fc)

I know from personal experience that my gas mileage improved when I did this mod and I want to do the same thing with the RX-8... thinking that it will also improve gas mileage.

I am a big enough boy to know how to turn on my a/c when my windows fog, which usually only happens 2 or 3 days a year up here in Winnipeg.

So, the question...? does anyone know how to do this on an RX-8?

looks like I will have to change my sig... humm what to put

It should be the same. Once you get down there you can figure it out.

Anyhow, you aren't going to save any money.

People don't go driving around with there defrost on unlees your in snow country.

Besides it works better with it on.

that "feature" annoys me too... subscribed..

I don't recall, but someone might have already done this. In any case, I find it good enough to know that the face vent setting does not trigger the "like it or not" AC, so there is already a viable way to avoid.

It should be the same. Once you get down there you can figure it out.

Anyhow, you aren't going to save any money.

People don't go driving around with there defrost on unlees your in snow country.

Besides it works better with it on.

There are a lot of us who live in snow country (like myself) and personally I prefer floor, or defrost/floor positions.. ( I hate air blowing on my face when I drive... dries out my contact covered eyes! )

About saving money, I think it will. It worked on my Protege and increased my gas mileage. I think if you can drive your vehicle and avoid the a/c from coming on, that in itself would give you better gas mileage. At least it does on every other car that I know of.

If we can figure this out and it works... WOW wouldn't it be great to get another mile or 2 per gallon...

^ exactly. esp in the winter after heating up the car by blasting the heat through the "face" vents i switch it to the window / defrost position..

As I understand it one of the reasons that cars engage the A/C pump while running the defroster is to give the A/C pump some activity (during winter for example when you wouldn't otherwise run A/C). Inactivity of that pump is bad for it, and if it is inactive for too long, it might no longer work.

It is possible that auto manufacturers have fixed this and it is no longer necessary to occasionally run A/C to extend its life, but I was told this a number of years ago. Something to think about/research.

I checked mine with a CANScan and found that the A/C cycles for a very short period, then has a long time between the next. Say 30 seconds between times when the A/C clutch is engaged and maybe engaged for 2-3 seconds max. Not a big deal.

As I understand it one of the reasons that cars engage the A/C pump while running the defroster is to give the A/C pump some activity (during winter for example when you wouldn't otherwise run A/C). Inactivity of that pump is bad for it, and if it is inactive for too long, it might no longer work.

It is possible that auto manufacturers have fixed this and it is no longer necessary to occasionally run A/C to extend its life, but I was told this a number of years ago. Something to think about/research.It isn't only the warm air that clears the windows. Moisture in the air will cling to the cold windows. The AC removes moisture from the air.

I checked mine with a CANScan and found that the A/C cycles for a very short period, then has a long time between the next. Say 30 seconds between times when the A/C clutch is engaged and maybe engaged for 2-3 seconds max. Not a big deal.

So it's on about 10% of the time? Sounds like a big deal..

What about the floor/face combo position - is the Compressor on then?

What about the floor/face combo position - is the Compressor on then?

Yeah,

I always put mine on "fresh air setting" and face

So it's on about 10% of the time? Sounds like a big deal..

That's just what I remember, I don't have the exact numbers. Since you have a scanguage II why don't you see for yourself?

As I understand it one of the reasons that cars engage the A/C pump while running the defroster is to give the A/C pump some activity (during winter for example when you wouldn't otherwise run A/C). Inactivity of that pump is bad for it, and if it is inactive for too long, it might no longer work.

It is possible that auto manufacturers have fixed this and it is no longer necessary to occasionally run A/C to extend its life, but I was told this a number of years ago. Something to think about/research.

Running the a/c is highly recommended to ensure that the pump does not dry out.

Here is what the manual says... Page 6-1 from 2008 Manual

Run the air conditioner about 10 minutes
at least once a month to keep internal
parts lubricated.

10 minutes a month and I drive about 1200 minutes a month just for commuting to work.

That's .008% of the time I drive.

Way better then 10% while being operated automatically...

Please, someone, find out how we can disconnect the feature....

What about the floor/face combo position - is the Compressor on then?

No,

Floor, defrost and floor/defrost settings only

In the Winnipeg winter, I would pull the a/c clutch fuse (10amp, near the front of the box) then the computer can do whatever it likes, the a/c won't kick in.


S

In the Winnipeg winter, I would pull the a/c clutch fuse (10amp, near the front of the box) then the computer can do whatever it likes, the a/c won't kick in.


S


Interesting solution.... the only thing is, if you want a/c you have to stop, install the fuse... a bit of a pain if the car starts to frost on the inside and you want a quick 30 second a/c fix..

I will use your solution if there is now way to eliminate the auto function.

Just mount a switch somewhere that you can use to break (or not) the circuit that energizes the relay.

In the Winnipeg winter, I would pull the a/c clutch fuse (10amp, near the front of the box) then the computer can do whatever it likes, the a/c won't kick in.


S

I might try this this weekend, got a 4 hour drive to DC so I can see any effect on mileage

If you disconnect it on the RX-8 the air from the climate control system will blow warm/hot ALL the time even with the fan knob turned to the zero position, including in the dead of summer

This is the only thing that bugged me when I had the AC deleted on my STU-class RX-8. If the AC isn't working you can't get cold outside air through the climate control system even if it's cold outside, this car actually uses the AC to cool outside air that must somehow get pre-heated by the engine is all I can figure :dunno:

^ Hey, I have a working AC and half the time the cold air setting will roast me alive while the hot air setting won't heat worth a damn. Fun

I might try this this weekend, got a 4 hour drive to DC so I can see any effect on mileage

Try a drive in one direction with a/c off (Fuse out)

The other direction with a/c fuse in.

I look forward to Mondays results

I might try this this weekend, got a 4 hour drive to DC so I can see any effect on mileage

what brings you down to DC??

I work there and live and maryland :wavey:

Try a drive in one direction with a/c off (Fuse out)

The other direction with a/c fuse in.

I look forward to Mondays results

Yep, I intend to do this.. But I'm there for a week so results will take a while ;)

what brings you down to DC??

I work there and live and maryland :wavey:

I'm taking a training class in VA about 10 minutes outside of DC. You guys have any meets during the week?

Yep, I intend to do this.. But I'm there for a week so results will take a while ;)



No big rush, I will be in break-in mode for the next few weeks...

I'm actually surprised no one else has thought of this... especially the way most complain about the POOR gas mileage the 8's get.

Interesting solution.... the only thing is, if you want a/c you have to stop, install the fuse... a bit of a pain if the car starts to frost on the inside and you want a quick 30 second a/c fix..

I will use your solution if there is now way to eliminate the auto function.

So now you want the AC on in the winter.

Make up your mind.

Using the scanguage 2, something that you can see is LOD (Engine Load).

By putting your car in neutral at stop lights reduces the engine load. Thus that can save gas over time.

Using the scanguage 2, something that you can see is LOD (Engine Load).

By putting your car in neutral at stop lights reduces the engine load. Thus that can save gas over time.

True.. But you should already be doing this anyway if you want your clutch to last. Sitting at a light, in gear and with the clutch in, you are not only burning the clutch, but on the 8 you are putting stress on the weak clutch pedal bracket. :icon_no2:

So now you want the AC on in the winter.

Make up your mind.

My home is so far north that my need for a/c occurs 20 times a year, the rest of the year it's snowy or foggy.

I just want the option of saying when the a/c comes on, not when some Mazda know-it-all Designer in Japan has predetermined it for me.

I'm actually surprised no one else has thought of this...

There is of course, no little solder trace to cut - the '8 computer controls all the functions - selector says 'windshield', computer turns on a/c. Simple yet complex. This was discussed and solved in December 2003, and comes up every three months since then.

We just humor people who bring it up thinking it's new.......:)

S

Funny thing is, when I first joined the forum I read this in January. And then completely forgot about it.

Im so used to using windshield or windshield and feet in winter up here in Canuckville in winter that forgot about it.

I just hate having hot air blown in my face and since Im a smoker (yeah yeah) it alsow throws ash all over the place when its blowing on you, so I just use windshield.

Like stealth said, it makes sense.

I bought mine with 41000km, its a 2005. Ive since started premixing, using UCL or Redline cleaner and changed the plugs. Got a K&N on the way.

Hopefully with all that done, and summer comming around ( I rarely use A/C in the summer, except when it get to 90F + I should see great increase in gas/mileage.

Ive already seen and increase from 300km a tank to 330/350 a tank with the maintenance Ive done so far.

P.S. A/C on in windshield position is pretty common to every modern car (2000+) even my 2001 Nissan Sentra had that. Only on the sentra I could feel the load difference immediately.

I'm actually surprised no one else has thought of this...

There is of course, no little solder trace to cut - the '8 computer controls all the functions - selector says 'windshield', computer turns on a/c. Simple yet complex. This was discussed and solved in December 2003, and comes up every three months since then.

We just humor people who bring it up thinking it's new.......:)

S

I have been a member since March 02 and at that time was deciding on which car to buy. Mazda had a deal on a Mazdaspeed Protege that I could not turn down and from the problems most 8 owners have had with early model 8's, I am glad I got the Protege.

I have posted in here from time to time since I bought my speed, knowing all along that one day I would by a rotary powered car owner. Since Mazda won't make an RX-7, I bought the only option out there.

I take delivery of my 2008 Anniversary edition RX-8 tomorrow and in an attempt to stay ahead of the learning curve I read over the manual.

In there I noticed the a/c always on feature, did a few searches on this site and came up with nothing.

With my Speed, there was an a/c delete cut the wire fix and was hoping someone on here would have found a solution.

You are the first to indicate that everything is controlled by the computer, so if that is true, the solution would be change the programming on the computer.

Got anyone in your phone list with those smarts?

I know I've seen this exact same topic before.

I have been a member since March 02 and at that time was deciding on which car to buy. Mazda had a deal on a Mazdaspeed Protege that I could not turn down and from the problems most 8 owners have had with early model 8's, I am glad I got the Protege.

I have posted in here from time to time since I bought my speed, knowing all along that one day I would by a rotary powered car owner. Since Mazda won't make an RX-7, I bought the only option out there.

I take delivery of my 2008 Anniversary edition RX-8 tomorrow and in an attempt to stay ahead of the learning curve I read over the manual.

In there I noticed the a/c always on feature, did a few searches on this site and came up with nothing.

With my Speed, there was an a/c delete cut the wire fix and was hoping someone on here would have found a solution.

You are the first to indicate that everything is controlled by the computer, so if that is true, the solution would be change the programming on the computer.

Got anyone in your phone list with those smarts?

what i did during winter season was simply remove the AC belts and pulley. i did this when i installed light weight pulley and just recently put the belts and pulley/bracket assembly back on.

this will DEFINITELY disengage AC functions...

on the otherhand...anyone got some R12 that they like to get rid of in socal?

on the otherhand...anyone got some R12 that they like to get rid of in socal?

Ever tried Freeze-12, instead?

I've still got a can of Freeze 12 in my toolbox. Freeze-12 runs at higher pressure in the a/c system than R-12 does. It's nothing more than half R-12 and half Propane.

There were some older R-12 replacements that had propane in them, but I'm pretty sure Freeze-12 is just enough R-12 to carry the oil and the rest is R-134a.

Try a drive in one direction with a/c off (Fuse out)

The other direction with a/c fuse in.

I look forward to Mondays results

Drove down with the fuse out and got my best mileage ever recorded 22.3 (I've been keeping track since I got the car, 20k miles). I'll post details after I do the return trip with the fuse in..

Drove down with the fuse out and got my best mileage ever recorded 22.3 (I've been keeping track since I got the car, 20k miles). I'll post details after I do the return trip with the fuse in..

Somewhere in the future try it with the a/c fuse out and DSC OFF... I think the DSC could also be robbing fuel...

My car is too new and any attempts to get better gas mileage would be an exercise in nothing.

I look forward to the get-home results.

Thankfully, I have a base MT with no DSC...

Again, the DSC thing is another nice comforting myth.

First discussed here in 2003, thousands of owners have tried it, and none have achieved measurable savings........

http://www.rx8club.com/showthread.php?t=8299

S

Again, the DSC thing is another nice comforting myth.

First discussed here in 2003, thousands of owners have tried it, and none have achieved measurable savings........

http://www.rx8club.com/showthread.php?t=8299

S

I certainly wouldn't expect large savings with DSC OFF, but I would expect something.

The link you provided took me to a very short thread, with no conclusive measuring or analysis.

I still think its worth exploring. My theory is, everytime you turn the wheel with DSC ACTIVATED, there is an application of breaks, power and or acceleration assisting the turn. Each one of these actions would rob enertia. I also don't believe that you have to drive like Helio Castroneves to activate the DSC. I believe it is a system that continually monitors and adjusts.

BMW's new M3-coupe gas mileage rating, as posted by BMW was calibrated with their traction control system deactivated. If the system didn't rob enertia and reduce gas mileage, they would have calibrated the gas mileage with traction control ON.

what I wish there was, was a way for the defroster options to be on during winter without needing to draw outside fresh air...having a catless midpipe + non recirc air = the smelly :(

Makes me want to buy a highflow cat.

what I wish there was, was a way for the defroster options to be on during winter without needing to draw outside fresh air...having a catless midpipe + non recirc air = the smelly :(

Makes me want to buy a highflow cat.

eeek... nice to have that smell... NOT

R U registered at www.manitobamazdaclub.com ?? If not, come on over.. My user id there is the same as it is on here.

Drove down with the fuse out and got my best mileage ever recorded 22.3 (I've been keeping track since I got the car, 20k miles). I'll post details after I do the return trip with the fuse in..


Looking for an update on the trip back home....

Give me a second lol... Driving back either friday night or saturday..

Give me a second lol... Driving back either friday night or saturday..

lol... i thought this was a weekend trip... doh

safe travels

eeek... nice to have that smell... NOT

R U registered at www.manitobamazdaclub.com ?? If not, come on over.. My user id there is the same as it is on here.

Yep already a member there, don't post too much there though haha :)

Give me a second lol... Driving back either friday night or saturday..


Any results??

On the way back, with the fuse back in and the air set to the windshield setting, my mileage was 19.4 which is more in line with what I had been getting for the past year. So it seems I may have gotten a 2 mpg bump from disabling the A/C... I'd say that alot more testing is necessary, but I am encouraged by the results enough to pursue this further.

On the way back, with the fuse back in and the air set to the windshield setting, my mileage was 19.4 which is more in line with what I had been getting for the past year. So it seems I may have gotten a 2 mpg bump from disabling the A/C... I'd say that alot more testing is necessary, but I am encouraged by the results enough to pursue this further.

Sweet. I have been driving with the floor/face air and DSC off most of the time but my car is still in the break-in phase.

I am planning a long trip at the end of June which by then the car should be fully broken in.

During that trip I will run some tests with the a/c on/off in combo with the DSC on/off and report back.

Right now I am considering installing a switch that will allow me to disable the a/c from the drivers seat. I will post a DIY when I do it.

Right now I am considering installing a switch that will allow me to disable the a/c from the drivers seat. I will post a DIY when I do it.

This is exactly what I was thinking! Looking forward to the DIY

Surefire way to triple your RX-8's gas mileage:

http://www.businessweek.com/autos/autobeat/archives/Toyota-Prius.jpg

because those things get 67 mpg? riiight...

because those things get 67 mpg? riiight...

It was a joke.

Anyway, plenty of people get 15 mpg or less in the city with RX-8, so yes mr. smarty pants, the Prius will triple that easily, real-world drivin'.

15? Try 10! :lol:

What I am most concerned about is highway mileage though.. Do alot of roadtrips so even a 1-2 mpg bump on highway is noticeable in the long run.

Mr smarty pants over and out

i just noticed that mine turns on today on the way home from work unless in face setting even with off. Although i did just get my 8 to weeks ago. I would think it will help save some gas even if it aint much. I wish i could train my foot to save gas as well.