Power Shifting Question

[Ninkumpoop]

I was told from a friend that power shifting in turbo cars is what you're supposed to do to get fastest drag race times. Is this true and what are the down sides?

 

[Aricjm15]

In the ms3 it will get you some awesome wheel hop. It is very hard on the drive train. Clutch, engine ect.
The car already loses traction bad enough in second and third gear.

 

[Ninkumpoop]

What about with upgraded springs and strut bars?

 

[coyfish]

Will help a little bit. Definately a little faster when you powershift properly but it takes a little practice and its very hard on the tranny no matter how well you shift. Ive tried it once and watching the rpms get jerked around hurt my stomach.

 

[Circle9]

Be nice to your MS3, no need to be beating it around. Its fast enough without power shifting.

 

[eg6motion]

I'd advise not to. And unless your at a track....is it really worth the added wear and tear?? I'd at least upgrade to the WOT box before doing this on a regular basis.

 

[rednofive]

I would argue your friend is only half right because power shifting, while potentially good for getting the boost to rise a bit and stay up without much load, also can backfire on you if you have weak grip.

I've powershifted this car and spun the clutch for seconds, even on downshifts from 6th to 4th. The wheels didn't spin, but the clutch sure did and it stunk for miles. I'm not proud of that, I'm stupid for pushing the car the wrong way.

On the opposite side, I powershifted last night from 1 to 2 to 3 to 4 and got great results, but it was a seriously "feathered" power shift. Honestly, since the boost and torque are the best down low in this car in stock form, it really shouldn't ever be necessary to powershift, only lead the R's of the next coming gear.

I'm no expert, but I think the best for this car in stock form is to turn off the DSC (duh) and launch from 1st at about 4K R's with a feathered throttle (NOT WOT or you'll have wheel hop or a smoking clutch) and once near 4-5K get into 2nd as fast as you can and then press squeeze into WOT until you've hit 5K-5.5K, then hold at 5K while shifting into 3rd (mild power shift) and hold at WOT and shift at 5.5K up through the rest.

3rd gear will resist - it's a b**** without double-clutching and you don't have time for that if you're adraggin but you do if you're footing the bills and time for repairs of your tranny (stick to road-racing and track-days, IMHO, I think they're easier on your car, just not your tires and brakes).

To aid in all this, get a boost gauge and watch it religiously along with your tach and learn to feather everything just enough not to get wheel hop, not over-rev and spin the clutch or tires, and keep the R's just slightly above the last gear you shifting up from so as to keep the boost on a bit...

It's a real art and I'm no artist. I don't think I've ever launched this car the same way 2X in the past 5 months. Half of the time that is my fault, the other half the car is doing something.

Between the ECU and the LSD and the weak clutch disk/pp and the nice but not super-sticky stock tires and the great for handling, but not stiff-as-bricks suspension and the super-peaky low-end boost/torque and the torque-steer...

ugh. you get the picture. That it drives as well as it does is a techno-miracle.

Some cars are easy to run straight fast. My 325, while not very fast, was easy to run straight with power shifts.

I'm no expert. I have no kills or traps to back up my Humble Opinion.

have your friend drive your MS3 and let us know if he thinks his rule-of-foot is still the best for this stock turbo-charged car...

 

[mazdaspeedster3]

By the WOT shift kit. They are cheap and you dont have to worry about the clutch any more. Also, launching at 4k....? No wonder you are getting wheel hop. How are you hooking up at all at that high of an RPM? I launch at 2.5-3.5k and have been getting the hole shot nicely (not now with my AS tires on LOL).

 

[15min5k]

launching at 2500rpms is the way to go. I was pulling 2.0 - 2.1 60ft times with this method consistently. You don't want to unlesh 280ft/lbs by launching at 3k and above in this car. It will only result in massive wheel spin / hop and screw up your car inventually.

 

[opt_ms3]

Everyone hating on the power shifting: read this

The Mazdaspeed 3 is only a bit less tricky to launch than a space shuttle. Most of the runs up the drag strip vanished in excessive tire smoke. Or they deflated when the driver, trying to stanch the wheelspin, inadvertently cued the waste gate. Or grabbed the wrong gear with the spongy shifter. Calls to Mazda yielded tips: Pop the clutch at 2900 rpm, upshift at 6000 — redline is 6700 — and flat-shift through second and third (which means don't lift at all — the mechanical equivalent of dropping a Steinway on the clutch and half-shafts and violating our test procedure).

"Don't worry," the engineers said, "it won't break."

It didn't — even after painting the pavement Bridgestone black with more than 30 hole shots. Working the shifter feverishly — the low ratios in first and second mean two shifts happen before 60 mph — we finally scorched a 5.8-second 0-to-60 time and a 14.4-second quarter-mile at 99 mph.

http://www.caranddriver.com/reviews...anese_performance/2007_mazdaspeed_3_road_test

 

[clos561]

ewww 14.4 is a no no

 

[LukeP]

Lifting to about half works best for me. With the absolutely unfathomable drive by wire throttle in this car, I never lift completely even for regular economy soccer mom shifts. Throttle tip in is too laggy and causes a slight jerk from when I release the clutch into the next gear and when the throttle re-engages, even though my foot is already where I think it should be. In older cars with a cable, the throttle is where my foot tells it to be all the time and that's what I'm used to.

Foot down powershifts are a bit harsh on the drivetrain. The only noticable turbo lag shift is 4-5 for me.

 

[rednofive]

By the WOT shift kit. They are cheap and you dont have to worry about the clutch any more. Also, launching at 4k....? No wonder you are getting wheel hop. How are you hooking up at all at that high of an RPM? I launch at 2.5-3.5k and have been getting the hole shot nicely (not now with my AS tires on LOL).

Well, there's a few things going on and you bring up a good point - my advice isn't that great for launch because I've been driving on Bridgestone Potenza G019 Grid All-season tires for the past 4 months and I'm feathering it a lot when I do that, as in very partial-throttle when the clutch engages.

Since my tires aren't that sticky as stock, this slips a good amount without too much wheel hop.

Sounds like I should be trying 3K more often though, based on all these posts.

 

[clos561]

Lifting to about half works best for me. With the absolutely unfathomable drive by wire throttle in this car, I never lift completely even for regular economy soccer mom shifts. Throttle tip in is too laggy and causes a slight jerk from when I release the clutch into the next gear and when the throttle re-engages, even though my foot is already where I think it should be. In older cars with a cable, the throttle is where my foot tells it to be all the time and that's what I'm used to.

Foot down powershifts are a bit harsh on the drivetrain. The only noticable turbo lag shift is 4-5 for me.

when i shift dd i let the rpms drop a bit after relesaing the gas and disengaing the clutch and it works fine

 

[FMOS Racing]

I was told from a friend that power shifting in turbo cars is what you're supposed to do to get fastest drag race times. Is this true and what are the down sides?

Absolutely correct. Especially in these cars since the ECU reopens the throttle too slowly.

Powershifting is worth about a half second and 4-5 mph on a MS3. After I hook up, my foot never leaves the floor. It's gone 13.6@106 with only a MSCAI, 13.0@107 with the MSCAI, MM and drag radials. You need a rear MM to be able to consistently powershift 2-3.

 

[opt_ms3]

damn impressive

 

[FMOS Racing]

I want to add, a benefit of the way the power falls off in a stock car at 6000+ RPMs is that it's best to shift between 5800 and 6000 rpms, which means that you're not right on the max revs when you shift. Also, the soft rev limiter in the MS3 means it's pretty low drama, with no backfiring or big black clouds.

Powershifting in a vehicle with a spark-cut limiter right at the edge of redline makes for some nice fireballs.

 

[Fat_Dave]

^ what do you launch at??

 

[fructus]

I'd like to know how effective would a WOT box be on our cars, since it only activates with the accelerator pedal fully depressed which means that it'll be only burning rubber in 1st, 2nd, and even 3rd?

 

[Russm]

You may want to consider when getting wheel hop from power shifting my engine has moved so violently that it has broken the bracket that holds the intercooler seal in place to the scope 2 times, it's been replaced under warranty but once warranty is out it will cost you $500+ to replace complete scoop, can't buy the $6 bracket, not to mention the opportunity to hot spot your flywheel and clutch plate , tear up your synchronizers and fatigue your drive line. But like previous post you can run 13.5 at 105+ when done well, about 3 out of 10 times which sure is fun but I don't know if it will be worth the cost down the road.
MSCI, MSCBE