Subaru STI DCCD And SI Drive Explained - The SIMPLEST Explanation!

[@CosineHyperbolic]

This was actually a better explanation than most, but I will say there was still an extremely common misconception about the technical details- regarding power (torque) distribution: The DCCD does *not* adjust power (torque) front/rear- this misunderstanding is more common than the truth, so I don't blame anyone for it. If you first gain an understanding of the difference between how differentials and solid axles transmit torque, understanding the DCCD becomes easy: It's simply an open differential that is capable of locking from 0-100% (becoming effectively a solid axle)- so for anyone struggling, or who really wants to gain a complete understanding, I recommend starting there. But anyway, what's happening is, when the center differential is open (0% lockup), the torque split is nominal (35:65 through 2005, 41:59 onward). When it's locked, torque will go wherever it can, be it 0:100 (effectively RWD) or 100:0 (effectively FWD)- imagine the front or rear of the car being on ice and the opposite having full grip, the gripping side will receive ~100% of torque, whichever side that is (because the entire output, front and rear, rotates as one cohesive unit). What does it do when it's locked up only X%? Well, good luck wrapping your brain around that. Instead, I recommend simply thinking about it like this: Locking to 100% will result in understeer but maximum grip, where open/0% will induce no understeer and in fact will induce oversteer on acceleration via the rear nominal torque split- where anything in between is a compromise between those two extremes, leaning one way or the other. My only "criticism" in practice would be, in my opinion, holding the VDC button to reach "VDC OFF Mode" is better for having fun than the middle mode with the green light ("Traction Mode"). All we have is a brief paragraph from the manual on what that middle mode does, but it's capable of cutting power and activating brakes, so not likely to be desirable.

[@Autofreakgarage]

Thanks for the very detailed breakdown! I appreciate it.

[@CosineHyperbolic]

@@Autofreakgarage Thanks! Just figured I'd tie up loose ends, but otherwise your explanation was one of the most useful I've seen for people just trying to drive the car with some context to help them make educated decisions- good work! 👍

[@fang4524]

No matter what setting you are on. It’s always 41/59. The auto + of - simply changes the Front and rear diff activation sensitivity.

[@jeffchimienti5901]

Great video. Very informative 👏 love your car by the way. I just picked up a 2015 STI limited and it's my first Subaru, so your content has been a big help. Keep it coming!😎🤘

[@ThatwhiteSTI]

I've used both of these features and I do gotta say, when I drove down to NC I had most of the power to the rear and it was so fun, especially in sport sharp, the car felt so alive, and more enjoyable. Also I think you convinced me to get some Alcantara from the guy you use, it's so clean and looks nice! Also those seats since you can get them with the heating feature!

[@xxraverxxonxtacy]

When I had my GVB Sti I really never did messed with manual diff settings. Only did auto + in the rain/wet conditions and auto - for hooning/spirited drives along with Traction Ctrl Off completely 😎

[@jdstark24]

My 2017 is totally stock and it usually gets to 17.9psi absolute max in Sport. Once I got 18.6 in Sport#. Just my two cents!

[@mariochita9631]

Thank you for this I’m new to this platform but been watching a little over a year of your ownership of the sti

[@David-vn3mi]

one of the best explanations 👍🏼

[@calstri]

I’ve been wondering about this for so long. Thank you

[@ferminfalcon2999]

Question you know what it means when [ I ] intelligent light flashing on dashboard in a 2021 Subaru sti stock engine, no check engine light is on. Just asking around

[@Autofreakgarage]

Could be a number of things but basically it’s in limp mode to protect the car/motor.

[@kreevey33]

Lol. Get into the car and instant muscle memory. Start flippin switches and hittin buttons like a pilot

[@Neeks636]

Just got a v11sti and. Thank you 😅

[@eodninja6]

where did you get that red stitched bezel? that looks awesome around the gauges.

[@Autofreakgarage]

kzbin.info/www/bejne/jGPIk4R9nct8pa8si=vwoohjYYrL8Qqsvq

[@inukist5296]

Didn’t know we had trac mode I’ll give it a shot

[@vinnmiottoo3355]

good video man, really helped, also another note for whoever sees this my engine light was on and i was stuck in sport (s), don’t know why but that’s just how the car rolls. I had to figure that out first week myself and it was really confusing so just giving you all a heads up

[@moisessolano4604]

Sometimes you might need oil, happened to my friend where the check engine light came on and it was stuck on sport mode, car was low on oil and the dealer did an oil change and fixed it 🤝🏻

[@magwich69]

Hello bro, how did you configure the DCCD after putting all the "bolts on" in your STI? I mean, you put the intake, downpipe, bov, etc and how did you do the mapping so that when you select the S# mode it gives you the 413whp?

[@Autofreakgarage]

Each setting is a different boost level. This is was done during the dyno/pro tune.

[@DerbzSTI]

Just got my 2018 Sti thanks!

[@aho3916]

This is very interesting to me now that I have had my Sti for 2+ years and 16K+ miles later. I just clicked on manual for the first time and it was set to the Lock position. I’m assuming since it was always in auto, the differential is not affected unless it’s in manual?

[@Autofreakgarage]

Yes, it would only be in the lock position if it was in manual.

[@crzdori]

That's weird (3:09), my SI-DRIVE stays on [I] mode regardless of ignition cycle, it only reverts to [S] if I was driving S#.

[@jonathanb1987]

That is correct. He never drives in intelligent mode so he probably didn't really notice it. I use I mode when I get into stop and go traffic and/or going to the gate on and off base.

[@crzdori]

@@jonathanb1987 thats good, I thought I needed to take mine to get it checked out!!

[@jonathanb1987]

@@crzdori nope. All good to go.

[@avee1711]

I have a 2021 sti and mine also always stays on I mode (which is my preffered mode) when i turn the car off/on

[@fang4524]

I reached 18 PSI boost when my 2020 STI was stock.

[@colingiles4251]

Doesn’t the SI-Drive Controller on a stock STI just change the throttle mapping curve? I thought you needed to tune it to vary boost levels.

[@Autofreakgarage]

doesn't change mapping at all. It changes the throttle sensitivity and input and boost levels. The mapping is exactly the same.

[@colingiles4251]

@@Autofreakgarage I think we’re talking the same thing with throttle sensitivity/mapping, just with different words for it. Basically intelligent has a linear throttle while Sport and Sport# are more aggressive. But the variable boost levels is news to me. I’ve heard of it on modified STIs but I’m new to the platform myself. Picking mine up on Saturday actually!

[@spilibali]

I'm pretty sure all SI-drive does is change throttle sensitivity. All modes still open the throttle to 100% and the target boost levels are all the same in the stock form too.

[@colingiles4251]

@@spilibali that’s what I thought

[@Autofreakgarage]

Intelligent mode actually does reduce boost. Sport and sport# actually is the same boost level upon further research.

[@donAKAthedonjp]

Off topic, how often should you clean the air filter for the redline intake?

[@Autofreakgarage]

Depends what kind of environment you drive in but I would check it every 5-10k or so.

[@donAKAthedonjp]

@@Autofreakgarage ok cool. I've been a little paranoid about it. Thanks.

[@Theskyhigh1994]

When playing with these settings should you be stopped in neutral or is it ok to put it in sport / sport sharp while driving ?

[@Autofreakgarage]

You can change while driving

[@vstillman1]

Big help. Thanks a lot

[@Subiedoo141]

How can we reset it back to factory settings?

[@moe-df9qx]

kewl video but beaides donuts and fun sttuff for that diff lock what logically would that meed to be used for and i roll around with my trac controller alwayz completly off 🤓 all times

[@supertreme5559]

you have to adjust your handbrake. it shouldnt be that high up. should hold your car still in 1-2 clicks in your garage

[@luckyleon6134]

Where did you buy that SI DRIVE CAP?

[@Autofreakgarage]

It’s by Perrin which has since been discontinued.

[@thatharbik6478]

When I use lock my center diff and I drive slow (reverse, slow turns, go up driveways) with the diff locked, it makes a clunky noise and popping nose, shaking my entire car. Anyone have the same outcomes? I have a 2020 sti

[@jonathanb1987]

That's because all of the diffs are locked. The wheels turn at different speeds naturally. During a turn, the outside wheel needs to cover more distance than the inside wheel. When the diff unlocked it can do this naturally. When you lock the diff the inside wheel is trying to spin at the same speed as the outside wheel. On a dry or paved or dry surface the gears inside the diff will grind when locked. This is what hurts your diff. While locked on a slippery surface like gravel or snow the inside wheel will be able to slip a bit while still matching the outside wheel's speed which will not harm the diff. To sum it up, DO NOT full lock your differentials on paved or dry surfaces. The only time that you would lock the diffs is on a gravel road or a gravel road covered in snow. Here is an old but easily understandable video explaining how a differential works. kzbin.info/www/bejne/r4qkqGpvaJ1pjas

[@SuperJackster98]

Your driveline is completely locked and should only be driven straight ideally as turning will cause drivetrain binding, happens to trucks and suvs while in 4 Lo if you’re locking the diff the drivetrain isn’t able to account for differences in wheel speed while turning

[@jonathanb1987]

@@SuperJackster98 exactly.

[@totaleclipse05]

Only lock the diff on gravel or snow (slippery surfaces) unless you like to buy new differentials all the time.

[@yaffajaff]

Selecting "lock" when manually adjusting the DCCD will only lock the center diff. The front and rear diffs will remain LSD regardless of the DCCD setting. DO NOT lock the center diff for daily driving. It will bind and prematurely wear the transmission, especially on cornering. Locking the center diff should only ever be considered when on extremely loose surfaces (such as snow) to split the torque 50/50 F/R

[@hcolin4165]

Koo!

[@andrewweisse4598]

Thank You once again! Another great video, yeah. Love CDiff Auto - (minus) and getting to love 2 add to press trac ctrl once too. All of course in S# mode. U R THE BEST ScoobyFreak86! -SubaruStiAndrew54115. 🏎️🔥👍😊