JPMM

I know this issue has been addressed earlier but I just can't fint that @!#$^@$%&^@ thread. I've got 2 simple questions regarding MPG:

1. Does disabling traction control really improves your mileage by 7mpg or so? Or do you have to disable the stability system too?

2. I have BFG kdw's on mine set at 32 psi by the dealer. Their max is 51 psi. Should I increase the pressure to get more mpg/performance out of them?

mmats69

1. No. I've tried it already and found no difference at all

2. I have the stock Potenzas set at 35 psi and get around 20 mpg every tank.

JPMM

Here's the thread that claims that TCS takes away your MPG:
https://www.rx8club.com/showthread.p...ht=gas+mileage

any subjective opinions?

expo1

DSC / TC has no effect on mileage. There are many wrecked rx-8 that back that up.

JPMM

Sh*t there goes my hope of better MPG. What about tire pressure?

Go48

You may get a little increase in MPG, all things being equal, by bumping up your tire pressures to 40 lbs or so, but it may not be enough to offset the much harsher ride. Depends on your pain tolerance. By all means, don't go higher than that and always check the pressures with the tires stone cold.

Mugatu

iTrader: (1)

HAHAHAHAHAHAHAHAHA

Turning off traction yields a 7MPG increase!!!! BWAHAHAHAHAHA!

JPMM

Keep laughin at my miserable 11 posts and 6 days of RX 8 owenership ... you bastard. Just kidding dude, it is rather amusing though And not at the same time, got 50 mi since last fil up and my tank is 1/4 gone. Its such a drop after my mazda6

Glyphon

~50 miles / quarter tank isn't that far off from normal. this tank will likely be my highest since last november. it'll probably be ~270mile tank, and i'm guestimating a ~13.5gal fillup, which will put me at ~20mpg (3mpg improvement over my winter fuel economy). although, this is all speculation until i get gas after work tonight.

never driven the 6, but this car does suck down gas, espcially on short trips and when idling in traffic.

G8rboy

Dude- you bought a sportscar -- not a Civic hybrid. I seriously hope you didn't buy it for fuel economy, but rather the other 900 things it does really well. Drive it, enjoy it. Life is too short to worry about a few bucks a week in gas.

Glyphon

think of it as your weekly tithing to the rotary gods

ALP22

I was worried about gas mileage (still shopping for an 8), but then started really going over the stats on our current 2004 subaru outback sport (mini wagon). EPA reckons 22/28, but over the past 4 tanks we are seeing average 18mpg for mixed driving (winter). Car was serviced 2 months ago and tires checked every 2 weeks.

We're also seeing about 20mpg average on the 99 miata, not driving the snot out of it, because its too sllippery even with snow tires on.

Guess what, the 8's mileage doesn't bother me any more.

r0tor

iTrader: (1)

1. The only benefit to disableing the DSC is an increase chance of totaling your car in a wreck

2. The tank in the 8 is smaller then the 6. 50 miles on a quarter tank is going to get you about 18mpg... which is what my parents 6 actually averages

G8rboy

True, however people really should learn how to drive without DSC so they know how to handle a RWD car in an emergency situation. I see too many people relying on DSC to overcome bad driving... physics + unplanned events like rain/snow will eventually catch up to you.

Your math is a little off-- 200 miles to a tank is going to get you between 14-15mpg (based on ~14 gallon fill-up).

realdeal

I do believe if you do turn off both the DCS and TCS you do release some hp that the safety systems smother, but it is dangerous to have these off going high speed so I agree with you there.

I think a couple of us measured our gas mileage with the TCS off and found no significant difference. That was like 2 years ago. Even with all the different flashes I don't think turning off the TCS will do anything for mileage. Just shift at lower RPM. There are people in this forum who do get 20 mpg and better.

G8rboy

Before the 'L' flash, I did agree that turning off DSC/TCS helped in a high-speed run... I don't think it was as much about holding back horsepower as it was the transitions between high rpm shifts. After that flash, I can't tell much difference on or off when it comes to accelerating in a straight line (assuming you don't shift so hard in 2nd and 3rd you trigger TCS with wheelspin).

I personally run with DSC turned off if the pavement is dry... part of the fun of owning a well balanced RWD sportscar is being able to confidently hang your tail out on corners. People that never learn how to control and eventually embrace oversteer (intended or otherwise) are asking for trouble when their abilities are surpassed by physics and/or bad road conditions.

yiksing

I only heard of better mileage with the AC off, I think...

unpocoloco

I actually increased my tire pressure from 31-32 to 34 2 tanks ago and am getting about an extra 2 mpg. All other variables are pretty much constant - ie. on these last like 6 tanks I've driven to exactly the same place at exactly the same time in about the exact same level of aggressivness with the same amount of traffic (none, plus 4 DAMN LIGHTS towards the end of my drive that are all of like 500 feet apart). So, I'd definitely attribute the raise to the tire pressure.

r0tor

iTrader: (1)

the 1/4 tank mark on the gas guage (or at least mine) is not really a 1/4 tank. This winter I have been hitting 50 miles on 1/4 tank, and then ~120 miles on an indicated half tank and end up putting slightly less then 7 gallons in ... so its about 18mpg

and i verified the guage is off at 3/4s full when i topped off my tank before a trip once

JeRKy 8 Owner

Well that's not only benefit. The only way you can get within the RX-8's advertised 0-60 and quarter mile times is to disable DSC first and then feather to 7000. Try doing that with DSC turned on...you ain't gonna go anywhere.

Also another benefit of turning it off is when you are slowing down the car/stopping at a light or stop sign...you don't have to worry so much about the steering wheel sometimes jerks itself to the left or right thanks to DSC. DSC causes that occasional nonsense, but I guess I can live with it since everything else about it is designed to keep me alive.

Oh and to the original poster...I had the KDWs once (unfortunately), and keeping them at 32 PSI made the handling pretty disappointing. I had to bump it up to 36 - 38 or so, even though the handling was still worse for me than it was with the stock Potenzas. But this is the wrong thread to talk about that so..

G8rboy

When you said a quarter tank, I assumed you meant a quarter tank... not the badly placed mark on the gauge. The RX8's gauge is one of the most non-linear I've ever had...

G8rboy

I second that... you've got something wrong with your car. DSC should never kick in while coming to a stop unless you're going around a corner and the tail comes around on you. Even when it does kick in, it never jerks the wheel... you should get your suspension checked out.

Labop

Only time I've ever had a car jerk to the left/right while straight-line breaking is on the shitty roads with pancakes in them from the passage of heavy trucks and poor workmanship when laying the road. My 8 didn't have TSC/DSC. I had an 8 for two years on some very wet roads, sometimes under "other than normal" conditions, and never had a problem (till the slick spot on the track).

Sure, the end could walk out on me, but I'd have it corrected in short order. I'd only had it happen a handful of times, and every time was from a standing start with the wheel turned on a wet road (or empty parking lot for fun). Main reason I did it in the empty parking lot was to learn how far I cuold take it, and what the car's limits were, figured it would allow me more confidence if I needed to do it under abnormal driving conditions.

A few of us that up to the track where I lost my 8 discussed if TCS/DSC or 4WD would have helped or not, one of the guys was pretty sure that if he'd hit the sopt in his 4WD evo, the same thing would have heppened. So not sure if DSC is really the end-all be-all for saving the car under other than "normal driving conditions".

Any thoughts?

As a side note, my next 8 will have the TCS/DSC... not taking any chances.

JeRKy 8 Owner

Nah I'm not making this up and it's nothing wrong with my current car, since this happened in both RX-8s I've owned. It's something to do with DSC... I've read other posts complaining about this before...like this one here, and some others that I'm not in the mood to continue searching for right now. I thought it was bad alignment at first when I had my first RX-8...but after I got my alignment checked and still had this happen occasionally, it obviously wasn't alignment related. It's something that occurs every now and then when you have nearly stopped the car..the wheel tilts a little to one side with DSC on. Happened more often when I had the automatic because I had to brake a lot more. Could also have something to do with the RE040s for all I know. DSC isn't "kicking in" or anything...it's just a weird spasm. Nothing too major...more annoying than anything if/when it happens.

Aaah **** it, here are some more threads to show you who's been paying attention, ya bastards:

https://www.rx8club.com/rx-8-discussion-3/braking-problem-80995/
https://www.rx8club.com/series-i-tech-garage-22/lurching-when-braking-hard-30781/
https://www.rx8club.com/series-i-tech-garage-22/serious-brake-steering-problem-10668/