HollywoodHall

holy shiznit! im going to try this. i get a consistant 13-15 mpg tank in... tank out.. and i have even driven like my mother through entire tanks. shifting between 3-4 every time. never taking it above 4.5. and i still cant break 15 mpg. i will do an entire tank. with tsc / dsc off completely and compare it to the mpg when it is on.

stanfordcole

I have done nothing special to mine, left DSC/TSC on, horse around with it off sometimes. I now have 5500 miles on it and the more I drive it the better gas mileage I get. I think the engine just gets better mileage as it gets broken in. I averaged about 16 to 17 when I first purchased it and now I am more around 21/22. Mixed driving of course. in both cases.

doc.marx8

interesting thread, I am contemplating on testing this out, but at the current rate of premiuim gasoline in california, it was 2.65 last night, Ill switch to my rx7 for awhile until the price per gallon stabilizes.

happy rotoring!

Twinturbo2800

sounds good, im gunna try it

Todd Green

im having a hard time following this... ur saying that 87 octane gas is giving you better performance along with better mileage as opposed to 91 octane?

RXGr8

Better gas mileage when driving like a bat outta' hell? Yeah right! Read how fuel gauges work first:

http://auto.howstuffworks.com/fuel-gauge.htm

GiN

Your RX-7 gets better gas mileage than the RX-8? My TurboII gets about 15mpg in comparison to my 8's 21mpg..

Rupes

I don't have traction control, and still can't get over 15 MPG in my hilly area.

-RUpes

RandyP

I tried turning off DSC/TSC last night, and was pleased to find even more performance than before. Thanks for the tip!

MTLbroker

DSC/TCS off can't boost hp. The car's hp is what it is. Spinning tires doesn't mean more hp, just that the electronics aren't applying the brakes in low traction conditions.
Also played around with it on and off, doesn't seem to be an appreciable difference in mpg. I leave it on these days - probably saved my butt a couple of times and I didn't even realize it....

RandyP

There are a number of sources of replacement ECUs and control chips that boost engine performance. You can invalidate your warranty by swapping control chips and producing too much power. People spend good money to buy canzoomer's ECU mods. Obviously, "the car's hp is what it is" isn't correct.

The ECU is in control of everything, and it gets data from DSC/TCS sensors. There are any number of ways the systems could interact... even a bug in the firmware could be in play.

It would be nice if people with access to performance measurement equipment could do some testing. People here have documented improved performance by timing their cars; it's worth examining in more detail.

DRx

Amen,

I got stuck in a snowstorm in Seattle about 1 week after buying my 8 last year (yes it actually snowed 6" here).

I got stuck going up a steep hill, not because I was spinning but because the TC system was cutting off throttle. Go stick some grease on a dyno and try it if you want to reproduce the effect of a snowpacked road

Anyway, it seems kind of odd though that at normal moving speed without any turning or rapid accelleration/braking that DSC or TC would have any effect on fuel mileage. But since my only real qualm with my 8 is that it doesnt even come close to living up to that sticker estimated MPG, I too will be trying this theory for the sake of argument.

Right now I get right around 245-255 miles to the tank with 70hwy/30city driving. I also just got the 'M' chip flash so we'll see if the 2 combined make any difference. :o

aruffell

I found this video somewhere on the web... although it is in some Asian language that I do not understand, you can clearly see the benefit of keeping DSC switched on... performance and fuel efficiency is way less important than your own safety (and the safety of those driving around you). Although I would love to get more mileage out of my car I do not think disabling safety feature a viable option.... just my 2 cents... check the video out!

http://www.alexruffell.com/rx8/DSC_demo.wmv

f1michel

our GS model here in Canada has no traction control at all and the car drives very nicely and is very predictable in any circomstances. I think the DSC thingy is great but it makes the driver feel he can do no wrong, hence the false sense of security.

TALAN7

This is all interesting. I have a 6 spd but no traction control or DSC. Has anyone tested a base 6 spd against a loaded one? I literally bought the 1st one off the lot like last july and it wasn't loaded. I had to have it. How much lighter is it compared to the loaded versions? I don't think you can find one now that isn't loaded down.

f1michel

here in Canada you can... base GS model and loaded GT model !! Only 2 to chose from. You can add nav and roof on the GT, only roof on GS i think

RX8MN

My 8 has TC & DSC a feature that I like for overall safety. I've tried turning it off and really did not notice a difference in performance or mileage. However, the system works by both cutting the throttle and applying the brakes so it may be possible that a malfunctioning system could hurt performance by creating brake drag, a condition that would also hurt mileage! So switching off DSC probably cannot give the engine more power, but it would feel that way if it eliminated brake drag! Also if the DSC was preventing full throttle, a performanc reduction may occur, but this should not affect mileage.

Having said all that, I find that my 8 feels like is does not roll as freely as my other cars. If you coast to a stop without touching the brakes, it has a little lurch like the brakes were applied. It also seems to decelerate very quickly if put in neutral and allowed to coast. Turning off DSC has no effect on this condition and I wonder if I am getting brake drag or if it's drivline friction. Any one else have this impression? I'll try to do some experiments to see if I can verify the drag.

RandyP

I took mine for a drive... I ended up finding out how many intersections are not really level! No problem here, but it's only got 540 miles on it.

Could there be build-up on your rotors, perhaps? The pads contact the rotors even if your foot is off the brake.

affenage

I did a test of the DSC off today. Noticed the pitch of the engine hum seemed to be a bit lower. Didn't have any chance to check the hp, got stuck behind a slow moving smelly dump truck

RandyP

I'm getting a theory on what's up with HP vs. DSC, and I think it's how hard you hit the car. I do curvy roads, and with it off, I've been drifting two curves and on the edge of a few others. That couldn't happen at all with DSC on... so...

I think everyone is right. Those who hit hard feel the full performance capability when DSC is off, those who don't, don't. It may not be an increase in HP, but it could be HP available for the slightly insane, that they can't have with DSC on.


[7/5/04] Another thought occurred to me. I'm running the L-Flash. Is it possible that those who feel no change are running the M-Flash?

RandyP

I try to keep an open mind about things, and I've tried to be fair about the concepts in this thread. I discounted the original claim of "50% increase in mileage" as that's too large to be real. After reading several users test times, I thought there might be something to the claim of increased performance.

I felt it when driving curvy roads on the threshold of traction, and others have reported better results in drag-race type testing. Both of these induce wheelspin, which could definitely result in improved overall performance with DSC/TCS turned off.

I wanted to isolate any real increase in performance (or horsepower, if you will). I came up with a test that removed wheelspin: rolling start in 2nd at 20, measure 25-50... rolling start in 3rd at 30, measure 35-60. Here are the results:

DSC/TCS: ON ... OFF
25-50 #1: 4.02 .. 4.01
25-50 #2: 3.42 .. 3.45

35-60 #1: 5.31 .. 5.31
35-60 #2: 5.28 .. 5.31

I put a Philips ToUCam in the car, capturing tach, speedo and view. These results have been determined using a video editor to choose the first and last frames based on the digital speedo. As you can see, there is no difference at all. If your tires aren't losing grip, running with DSC/TCS fully off does nothing to improve your car's performance. Increased performance only comes when you are inducing wheelspin and have the tires and pavement to take advantage of it.

This book is closed, for me.

greyhound

Interesting. Did your tests involve any gear changes? I read in another thread that with the DSC/TCS enabled it seems like it takes a fraction of a second longer for power to kick in just after a gear change. (I have to admit that although I keep thinking about trying this myself, I have never even tried turning the DSC/TCS off! What a loser... :p )

Thanks for the information.

RandyP

No, they didn't. I intentionally tested without shifting to eliminate subtle changes between shifts in different tests, as well as possible wheelspin in the 1/2 shift. I know that when I want to play, and have visibility and room for things to go wrong, I can turn the systems off.

I almost hit a deer about an hour ago doing some "athletic" driving. It happened just past the apex of a curve as I was accelerating, and I instinctively nailed the brakes. The DSC/TCS systems did their job - I stayed in my lane under hard breaking that threw the weight to the outside front tire in a fraction of a second. Those late-night tests may have saved the deer and my brand new car, so I think I'll have it on 99% of the time and get CZ Stage 1 and high-flow catback exhaust to get some extra kick.

NoPistonsHere

I have read the thread from start to finish. In the begining this dude solved the problem of performance/MPG. Then in the middle of the thread you only get performance, and then in the end of the thread you get NOTHING (BOO), dang I feel robbed. I was hopping to get performance at least. Well I am still going to try it and see how the placebo effect feels like. I have gotten 300 to the tank (89-92 octain) with the L flash and dsc/tcs on, currently have 12000 miles on my 8. I have just upgraded to the M flash, and to make sure I have the m Flash, I did the tap the break 20 times with car off and watched the temp gauge go up and down. I still have to test the car with the M flash with the dsc/tcs on. Well looks like I have another test to due with it off, but thats going to be at least 5 fillups down the road. :D

Like Whoa

I Have the 2004 RX-8 with the Grand Touring Package. I kno i havet he DSC but do i have the TCS?