Quarter mile tips and info!?

[MM BOOST]

Ok got another question. Now I know you guys said to turn DSC off when I run it, but which method. The method where I turn the car on and hold the button down disabling it all together or just press the button to turn it off before I pull up to the line???

 

[Russm]

Good Day
If you want to practice reaction times go to bottom let of this site http://www.greatlakesdragaway.com/
theuy also have HORSEPOWER/ET Calculators
Calculate your vehicle's Horsepower and ET based on several input factors!
Press DSC down and hold before you turn ignition.
Practice, practice practice, went 13.6 / 1o5 with just a MSCAI and a MS CBE.

 

[john blutarski]

Ok got another question. Now I know you guys said to turn DSC off when I run it, but which method. The method where I turn the car on and hold the button down disabling it all together or just press the button to turn it off before I pull up to the line???

Nobody has proven yet that the method of holding the DSC off button while turning on the car makes any diff over just turning off the DSC by itself. I wouldn't worry about that.

 

[FMOS Racing]

Lots of quartermile chat here - http://www.mazdas247.com/forum/showthread.php?t=123702111

You definitely want to pull the lever about 5800-6000. Math and experience both put the best shiftpoints in that range. The torque curve of the MS3 drops off a cliff after 6000 rpms. Learn to powershift - after learning to launch, this is key to probably a solid half-second in a MS3.

I'm personally not a fan at all of lowering the pressure in street radials - it simply deforms the footprint due to the loads on the hard sidewalls. I do jack up the pressure in the rears.

Nobody has proven yet that the method of holding the DSC off button while turning on the car makes any diff over just turning off the DSC by itself. I wouldn't worry about that.

That's interesting. I was under the impression that one method only turned off the DSC, the other turned off the DSC and traction control. I'll definitely have to test it this year. It'll save me having to restart the car in staging when I forget.

 

[LordWorm]

]

You definitely want to pull the lever about 5800-6000. Math and experience both put the best shiftpoints in that range. The torque curve of the MS3 drops off a cliff after 6000 rpms. Learn to powershift - after learning to launch, this is key to probably a solid half-second in a MS3.

would love to see your math... i haven't worked it out for the ms3 yet personally - but most people look at the torque curve, see it drops off a cliff, forget that they are still making power, the gearbox is still multiplying torque, and they are still producing more force at the wheels in an earlier gear than they would in the next one. In almost every single production car I have ever looked at the "math" for, it is best to shift at redline, even though the power and torque are falling off. The gearing advantage is not insignificant in most cases.

you do not shift based on the torque curve. you shift based on the cross over point of wheel torque (that is, where staying in a low gear is no longer producing more force at the wheels than being in the next gear), or redline, which ever comes first (normally redline happens long before "optimum" shift points).

if your math is right, and it shows shifting at 6k is optimum, then awesome.

 

[FMOS Racing]

I'll try to dig it up. It was actually a little painful on the MS3 because of the dual final ratios, but I should still have the spreadsheet somewhere. And yes, I know you pick your shift points based on the torque curve times the multiplication effect of the gear and final drive (as compared to the same number in the following gear at the RPM following the shift). As a matter of fact, when I first started reading here, I believed the same as you, that people were just looking at the power curve and deciding when they needed to shift because, like you, my experience was that it was almost always more advantageous to stay in the lower gear.

But, IIRC, the shift points work out to about 5800 rpm on the 1-2 and 2-3 shift, and 5600 on the 3-4 and 4-5. I didn't bother with 5-6 because I don't see that gear change on the dragstrip. The MS3 has a different set of circumstances than most production cars because of several factors - the way the ECU shuts the throttle blade, the way the efficiency of the turbo suddenly drops off, and the very close spacing of gear ratios (again, IIRC, 2nd is about 65% of first, third is about 70% of second, fourth is about 75% of third and fifth is about 75% of fourth). In the MS3's case, redline is definitely a mechanical limit for the hardware and not a "shift point."

I also have about 80 1/4 mile passes in my car so far, have tried shifting at redline, and can say unequivocally that once it's revved past 6000, the rate of acceleration is definitely slowing down.

 

[LordWorm]

I'll try to dig it up. It was actually a little painful on the MS3 because of the dual final ratios, but I should still have the spreadsheet somewhere. And yes, I know you pick your shift points based on the torque curve times the multiplication effect of the gear and final drive. As a matter of fact, when I first started reading here, I believed the same as you, that people were just looking at the power curve and deciding when they needed to shift because, like you, my experience was that it was almost always more advantageous to stay in the lower gear.

But, IIRC, the shift points work out to about 5800 rpm on the 1-2 and 2-3 shift, and 5600 on the 3-4 and 4-5. I didn't bother with 5-6 because I don't see that gear change on the dragstrip. The MS3 has a different set of circumstances than most production cars because of several factors - the way the ECU shuts the throttle blade, the way the efficiency of the turbo suddenly drops off, and the very close spacing of gear ratios (again, IIRC, 2nd is about 65% of first, third is about 70% of second, fourth is about 75% of third and fifth is about 75% of fourth). In the MS3's case, redline is definitely a mechanical limit for the hardware and not a "shift point."

I also have about 80 1/4 mile passes in my car so far, have tried shifting at redline, and can say unequivocally that once it's revved past 6000, the rate of acceleration is definitely slowing down.

I wasn't calling you out - i was just making sure you weren't one of the many people on forums for all makes of cars who really have no idea of the forces at play. The amount of people i've heard say shifting at 6k, or 5k or whatever on the P5 astounds me, when the maths shows the shift point would be well past the factory redline (lets just say if i could rev my motor to 8k without it flying apart, i'd still be crying for more revs!). I wasn't aware of the dual final drive situation until about lunch time today when I started researching it myself. Compressor efficiency shouldn't play a major part though - as many top flight drag teams routinely run their turbos well past the island of efficiency to chase higher boost - if your cooler is up to the challenge, and you're not choking the turbo out, it can be beneficial (although will inevitably lead to shorter turbo life due to running the thing grossly over the manufacturers recommended shaft speed).

if the speed 3 is anything like the aussie delivered mps3, another problem would be computer controlled boost-by-gear (1st produces a wildly different power, and thus torque, curve than 2nd, 2nd is different to 3rd and so forth) - makes accurate calculation a bit of a pain in the rear end unless you've dyno'd every gear. Not impossible, but not as straight forward as a "traditional" engine configuration.

Another big problem with redline shifting is the faster you rev the motor, the harder it is to slot gears on a synchro box. for most production cars gears just wont engage past 8k - and if power shifting the sudden surge in revs makes it even harder to get the thing to engage. so whilst redline is often best, i understand its not always practical.

sounds to me that the 'simplest' solution (although probably most costly) would be to go to a traditional mechanical throttlebody if possible (most governing bodies would require this for real competition because the fitment of double-return springs on the actuator is a safety requirement once you pass a certain trap speed), and a bigger turbo....the more i read about it, the more the ms3 sounds like an absolute beast -that has been hamstrung and crippled to keep the shopping mom brigade happy .....

 

[FMOS Racing]

Here's a dyno graph of a stock MS3 done by Automobile magazine. As you can see in the graph, at 5500 rpms, the MS3 is making ~200 ft-lbs of torque, so over 80% of its peak. By 6000 rpms this has fallen to ~135 ft-lbs, or 55% of its peak. At 6500 rpms, it has decreased to ~80 ft-lbs, or 30% of its peak, and at redline, it's a whopping 50 ft-lbs, 20% of it's peak.

(Sorry for the image size, I'm just linking to it on the Automobile website)

 

[LordWorm]

there lays the problem with an early and high peak torque point... feels great off the lights...but utterly useless up top.... theres so much wasted potential there its not funny.

would make for a good smoke show at the burnout pad though....

you got the rev-drop between changes handy? be keen to see how much of the power curve is actually getting used once you're up and running.

p.s. hot-linking is rude copy the image and attach it to your post....bit neater that way

 

[FMOS Racing]

Nothing would make me happier than a mechanical throttle body! Couldn't agree with you more.

I didn't consider the different power levels in 1st and 2nd gear because, in the greater scheme of things, those gears are over fairly quickly and are generally chewed up with spin. But, I have felt like I get better passes when I actually short-shift 1-2 by a couple hundred RPMs. That may be because I simply get better traction in second with the power level down, which leads to a better ET.

(I'll fix the image when I get home. "Work" has a bit of reluctance allowing the image upload)

 

[LordWorm]

Nothing would make me happier than a mechanical throttle body! Couldn't agree with you more.

I didn't consider the different power levels in 1st and 2nd gear because, in the greater scheme of things, those gears are over fairly quickly and are generally chewed up with spin. But, I have felt like I get better passes when I actually short-shift 1-2 by a couple hundred RPMs. That may be because I simply get better traction in second with the power level down, which leads to a better ET.

do it then... i don't know how it all works as i've never looked at a disi motor or a motor with a fly by wire throttle from a perspective of making them go fast - but it baffles me that the 2 biggest problem areas (fueling at high power, and the throttle snapping shut) can be cured by taking a rather old school approach. fuel would be solved by running a second fuel line to a traditional fuel system and running supplimentary injectors controlled by a simple fuel controller - this would basically pre-fuel the air charge prior to injection by the disi system, and help cure the fuel problem...throttle would be solved by going to a mechanical throttle....

not insignficant mods, but not reinventing the wheel either - throttlebody swaps are common place, as is the use of supplimentary fueling is very common for both aftermarket turbo systems, and big power rigs where you cannot get enough fuel out of a set of 1200cc injectors (high power methanol efi drag engines routinely run 2, or maybe 3 banks of 1000+cc injectors, staged to supply fuel according to the demands of the motor).

This is way out of the scope of this thread, and i'll do my best not to derail it further....but would be interested in discussing the problem/solution if you're keen....send me a pm and we can have a chat about it.

as for "feeling" better runs...ever get that thing where you "feel" its a great run (no wheel spin, great hookup, nail every shift) and the run turns out to be average....then you back it up with a run you're sure is absolutely sh!t...only to find its a PB the best feeling runs are often the worst runs I have.... i actually get excited by the car bucking like a mule out of the hole and rattling off the hardcut....haha..damn i miss the track... been 18mths since I temporarily 'retired' the car from race duties (waiting on engine build - finances are not great and so on....*sigh*)

 

[john blutarski]

FMOS Racing,

If you're running a 13 flat at 107 with an intake as your only power mod than congrats man... wow.

 

[FMOS Racing]

Thank you, sir! The motor mount and drag radials were both critical to that, though. No way to get this thing down the track cleanly without them. As a combination they were worth ~.6-.7 in ET.

I've bought some shorter drag radials and some lightweight wheels for when the track opens. I also have an EBC, but I won't install that until I see what kind of difference the tires and wheels make. C'mon, April!

(I forgot to fix the linked graph... grrrr)

 

[FMOS Racing]

Nobody has proven yet that the method of holding the DSC off button while turning on the car makes any diff over just turning off the DSC by itself. I wouldn't worry about that.

I tested this fairly well yesterday. The only difference between just pressing the DSC button and pressing and holding it while starting the car is the dash indicators. If you press and hold the DSC button while turning the car on, both the DSC and TC indicators illuminate. If you press the DSC button while the car is already running, only the DSC indicator illuminates. In both cases, the traction control is disabled.

I was able to spin the tires to my heart's content in both cases.

I'm sure glad you mentioned that, John.

 

[RC08MS3]

you should read over this if you have any questions about if DSC has any effect on TC:

http://www.mazda.com/csr/safety/active.html

 

[dbrier]

Another vote for practice, practice, practice.

 

[MM BOOST]

Yeah there is no way I will be able to beat this guy, he just dynoed yesterday at 306 whp and 361 ft lbs...I don't stand a chance unless he screws up driving. So i will just be running to get my best time possible. 2 weeks away.

 

[Circle9]

So did he run a 14.5 stock, or with 306 whp? I know you have quite a bit of modifications done to your car as well, what are they?

I used to beat 350Z's and Mustangs quite often at the strip with my Si. Just because they have more power and are technically faster than your car doesn't mean a thing if the driver can't launch or shift very well.

 

[MM BOOST]

Well he has alot of experience at the track, I have ZERO. But he also isn't the best driver in the world. He did the dyno with intake, muffler delete and mail-in tune. He ran the 14.5 stock.

I have the following installed/going to be installed before i run, some things have changed since I made this post:

-Injen CAI
-medieval Turbo inlet
-TRZ MM
-HKS SSQV recirc
-Turbo XS Stealthback
-Racing Beat catback
-S.U. Boost Tubes
-H&R Springs
-TWM Short shifter + bushings
-18x8 wheels with 235 tires

 

[Circle9]

So you have a intake, inlet pipe, and full TBE, I'm not an expert or anything, but you probably are close to the same power as he. I suggest you go get it dynoed before you run. With your rear MM, springs, and wider tires you should have no problem hooking up. I can tell an amazing difference in traction simply by going to some stickier slightly wider tires. I believe one of the main reasons that the Cobalt is faster than the MS3 stock for stock is the tires.

Find an old road and practice your launches!

Edit: Hey, was just checking out the Cobalt forums to see what it takes for them to put out that kind of power and I found this: http://www.cobaltss.net/forums/showthread.php?t=160740

I think its your friend, note that it was a Dynojet, which are known to read the highest of any dyno.