Here's an observation on twin-clutch transmissions that won't cross your mind until you drive an EVO MR. Because this transmission relies primarily on throttle position and (presumably) rate of change of the throttle to determine actions like clutch take-up, gear selection and shift-rate, it can be slow when it needs to be decisive. Here's an example which holds true to most auto-manual style transmissions.
Jab the throttle from a stop to get the EVO moving quickly from an intersection or leaving a parking lot and there's an awkward and uncomfortable delay before forward motion actually begins. Here's what's happening: in roughly a tenth of a second the throttle goes from an idle position to, say, 70 percent open -- an aggressive goose designed to get the EVO away from an intersection with limited visibility and two-way traffic.
The electronics controlling the engine and transmission see this and respond: "Oh crap, he really wants to move quickly." Exactly. "Moving quickly requires power. Power requires boost. Boost -- even with a twin-scroll turbo -- requires time." Uh oh.
Frustratingly, the exact opposite of what you want -- immediate, rapid forward motion -- happens. So dramatic is the effect, that a more subtle throttle opening might actually result in the car being further down the road more quickly since there would be less time spent waiting for power to build.
Eventually, things do begin to happen: The engine builds revs and at some carefully calculated engine speed the transmission begins to feed in the clutch -- carefully, now, so as not to overheat anything. Then, and only then, does the car begin to move.
It requires an undesirable adjustment in driving style to reconcile this. Using a manual transmission, I'd have the engine speed dialed up to an appropriate level to get the car moving as I fed in the clutch. And I'd have far less hesitation in these situations.
The EVO's launch control, too, is lame -- precisely calibrated to never overheat a clutch or, heaven forbid, get moving quickly. For proof, check out the difference in 0-60 times between the EVO X MR and EVO X GSR in our comparison test vs. the STI.
Luckily, the SST is brilliant in Super Sport mode on a racetrack -- completely eliminating the need for a third pedal once up to speed. Too bad I don't live on a racetrack.
Josh Jacquot, Senior road test editor @ 3,880 miles
jasond52 says:
01:03 PM, 09/22/08
Interesting read for someone who has never driven a DSG. Is the same behavior to be found on similar trannys in VW's and Audi's?
I was hoping a DSG might be the answer for me. I want a stick but my wife can't drive one. Maybe the hill-holder clutch found on Bimmers and Subies will have to be the answer...
kurtamaxxxguy says:
01:14 PM, 09/22/08
SST? This acronym popped out of nowhere. It took going to the Technorati tag site and scrolling down to 3rd story to figure out what that meant.
Otherwise, interesting observation and suggests that once again, enthusiasts want 3 pedals and a manual, period.
Would the Evo be a better car if Mitsu offered a switch to turn the AWD into RWD?
m_thrizzle says:
01:22 PM, 09/22/08
Hmm, good observation. These technologies try to 'out-think' the driver, with sometimes the opposite response to what the driver intended.
carlisimo says:
03:24 PM, 09/22/08
I don't quite understand what you mean about waiting for the turbos to spool up. That sounds like normal turbo behavior, not specific to a DSG. What's it doing wrong?
jjacquot says:
04:10 PM, 09/22/08
Actually, the turbo spooling is really secondary to simply building enough revs to get the car moving with authority. The turbo won't make any real boost until the engine is loaded anyway.
So, to clarify, what we're talking about here is the amount of time it takes the engine to rev up -- which, believe it or not -- is significant.
Here's why: Normally, when trying to get away quickly in a three-pedal car, the driver has the revs up and is "at ready" with the clutch. When the moment comes (traffic clears, light turns green, whatever) the clutch is engaged, throttle is pinned and movement begins. Instantly.
In a automated-manual car like the MR, the time for the engine to rev begins after the throttle is pressed. Press deep into throttle and the ECU knows you're looking to leave quickly, which requires more revs. More revs, unfortunately, take more time, thus the delay. Use less throttle and there's no waiting for revs and the car moves sooner, but less agressively. It's an unfortunate tradeoff in the world of auto-manuals.
It's frustrating mostly because there's a distinct possibility that a smaller throttle opening yields more initial forward progress. Ultimately, I think the solution lies in an initially light touch on the throttle followed, once the clutch is fully engaged, by wide-open throttle.
Also, it's been long enough since I've driven a DSG that I can't say if they suffer the same dilema.
Josh
firstwagon says:
05:12 PM, 09/22/08
So in summary...unless you are on a racetrack, a manual is a better manual then a DSG and an automatic is a better automatic then a DSG.
rocklah says:
06:50 PM, 09/22/08
My DSG equipped GTI also takes it time engaging the clutch when heavy throttle is applied from a stop. At least the evo's drive-train grips when the clutch is finally engaged.
jasond52 says:
05:27 AM, 09/23/08
I wonder if the answer is hold the brake and mash the gas right before you're ready to jump into traffic. Once your hole opens up, release the brake and the engine and clutch is ready to go. Not good for the tranny, but at least you won't get squashed in traffic.
bankerdanny says:
06:20 AM, 09/23/08
I was going to make the same comment as Jason.
In my old slushbox equipped Saab 900 turbo, the best acceleration was hold the brake, let the revs and boost build then release the brake and go.
If the Mitsu's computers read throttle position, then a similar technique should produce the faster pick up you were looking for because the TPS won't be sensing 0-70% and the engine computer should already be picking up some boost.
stingray454 says:
07:25 AM, 09/23/08
This is one of the many reasons I prefer V-8's hooked up to a traditional manual. I've got plenty of power right NOW, whenever I want it. No waiting for turbos to spool up, or RPM's to build up to hit its peak torque, or computers trying to save the clutches of a DSG. The biggest issue I have is trying not to roast the tires or getting the car sideways. Good issue to have.
huyracing says:
09:18 AM, 09/23/08
you're just nit-picking... traditional automatics are far from instant, either. (unless modified) would you rather have it like in the Ferrari's where the clutch lasts owners as little as 7000 miles? i don't even like how you have to change the clutch on regular manuals. i like how the clutches will last the lifetime of the car, like how an automatic transmission lasts the lifetime of the car. if i were racing, i'd opt for a manual, but then again SST makes that obsolete. so, it seems Mitsubishi got it right for people like me who drive sanely in traffic day to day and enjoy weekends at the track.
stingray454 says:
12:47 PM, 09/23/08
" i don't even like how you have to change the clutch on regular manuals. i like how the clutches will last the lifetime of the car, like how an automatic transmission lasts the lifetime of the car."
Depends on the car and how you drive, but a traditional manual's clutch could last the lifetime of the car too.
The lifespan of the dual clutches on DSG transmissions has yet to be proven. We'll see how long they last and how well they hold up under severe track use. My prediction is they will not last the lifetime of the car. They are wear items after all.
bimmerjay says:
12:54 PM, 09/23/08
"I wonder if the answer is hold the brake and mash the gas right before you're ready to jump into traffic. Once your hole opens up, release the brake and the engine and clutch is ready to go."
I don't know if the Mitsu does this, but many cars with automated manuals and even full torque-converter automatics do not allow you to brake-torque much, if at all. Regardless of throttle position, if you have your foot on the brake the ECU will angrily limit revs.
That said, with a full manual there are of course no such restrictions.
firstwagon says:
07:11 PM, 09/23/08
"i don't even like how you have to change the clutch on regular manuals"
Even if you get it changed at a dealer, the regular manual is still the cheapest and most reliable transmission to own.
If you think the clutches on a DSG will last the life of the car I'll bet you'll be very disappointed. It will wear out and it will very pricey to fix. And you'll have to take it to the dealer ($$$) as no independent shop will touch it.
Automatics can be reliable but require a lot more maintenace then a manual and rarely last the life of the car.
Manuals normally last the life of the car and the clutch can easily last over 100,000 miles unless you really abuse it. If you want to say some money, you can even change one yourself.
The best choice is to own an automatic for the "stuck in traffic" daily grind car and a manual with the fun car.
I'll bet you could pick up a good used Miata for the cost of the 1st replacement of the DSG transmission.