drifting AWD

[zrn03]

need help on techniques for drifting AWD, i have a 1990 eagle talon im assuming its possible but going to be very hard

[Tsunami]

Yes AWD is possible, but it takes time and practice to get it right. Just read up on drifting techniques before you try it, and use a big low traffic area to practice in and be careful.

[ACDSupra7]

Use:

[Ghost of Duluth]

Yes the search button will help you out some, there are a couple threads on this but the question is still a valid one albeit an already asked one. Check around on the net some. I have never done one personally I can imagine that high entry speed coupled with rapid weight transfer and standing in the throttle will accomplish what you seek. Good luck.

[mranlet]

[ AWD drift AWD drifting AWD trift tech AWD drift techniques AWD drifting techniques

[ AWD drift AWD drifting AWD trift tech AWD drift techniques AWD drifting techniques

The following are some of my old posts on the subject - it would be great to have them added to an FAQ so that people don't have to search all the time, but whatever...

Welcome to the world of AWD drifting my friend. You have now completed step 1 - finding that every single AWD system in the world is completely different from any other system...

I drifted my AWD 91 Legacy Turbo for years, and it's no easy thing (IMO, much harder than the RWD kind). My AWD was rear biased, so there were things that I could do to hold the drift since the rear wheels were always getting power. However, in a front-biased system like the 4G63T's, your rears will only get power when the fronts are slipping, as I'd imagine you know by now.

Part of All-wheel-drifting is exactly what the name says: all of the wheels drift. If you watch AWD rally cars you don't usually see the front wheels following the "best line" on the course like RWD cars do (for the most part). A lot of the time the midpoint of an AWD car will be following the best line but the fronts and rears will all be spinning and the steering is toggled back and fourth between almost aimed straight and almost fully counter-steered. This coupled with the insanely high rates of entrance speed helps the car to stay sliding through the turn rather than grinding to a hald on gravel. J-blood is right about not turning the steering as much as you feel like you should - sometimes only half of a full counter-steer will be plenty to keep you sliding and a full steer will be too much and will whip you back around to the other side.

Although AWD's purpose is to prevent cars from losing traction, you can really use it to your advantage to keep the wheels spinning. If you recall the "traction circle" that you learned in performance-driving kindergarden, you'll remember that the East and West directions represent steering right and left and the North and South directions represent acceleration and braking (respectively). Now, to make a car lose traction, the load on the tires must exceed their ability in any one of those directions or as a combination of two (or more, but that's a bit more advanced).

Let's consider 2 cars with the same specifications, car A having RWD and car B having AWD. When accelerating from a stand-still, car A will be sending 100% of the power to the rear wheels only. Granted that car A has the ability to load the tires beyond their capacity, it will break the traction circle and spin the rear wheels. If car B were to send 100% of its power to the driveline, it would momentarily go 100% to the front wheels (in the TSi's case) and break the traction circle causing wheel slipage. The slip sensor will detect this and tell the transmission to take up to 50% from the front and send it to the rear. When it does this, the load on the front tires will move to inside the traction circle and the rear wheels' traction circle will look exactly like the front's (ignoring weight and transfer). Simple, right?

Now imagine when a car is going around a turn and power is being applied while there is a constant latteral load on the traction circles of all tires on both cars, during a left turn for example (meaning that the work done on the tires is along the East-West line on the left side). While cornering at half of the capacity of the tires, car A can apply enough power to exceed the traction circle of the rear wheels (the work done by the tires is outside of the traction circle on the upper left side). Meanwhile, the front tires will stay at their half-capacity of lateral load without ever knowing what is happening to the rears. From my unserstanding, once a driver counter steers, the direction of lateral load on the front tires is reversed (to the right in a left-turn drift) and they are now working to prevent the car from going off of the track to the left - there's a split second in a feint where the rear is sliding and the fronts are pointed straight just after the body roll has passed neutral. In our left turn, if the driver does a power-over and applies just enough power for the rears to break traction, he can keep the work asked of the tires just beyond the traction circle and maintain control of it, but if he applies too much power the tires will be overwhelmed and the driver will lose control -- this is why higher-powered drift cars need to have the power modulated in order to keep control and keep from spinning while lower power cars can be floored and stay in control.

Ok, same left turn example with car B and AWD. If the driver applies power in a turn, it may cause the front wheels to exceed the traction circle and transfer power to the rears, which in turn brings both front and rear back within the load limits of the tires, since half of the power is going to the front wheels and half to the back wheels. This would essentially be like driving car A in the same manner but with half the power at the driver's disposal (65hp for a Nissan 240SX, probably not enough to exceed even the stock tires). Even if your TSi has 200hp to the wheels, each set of wheels will see only half of that during a drift, and to get it to slide you either have to be turning harder or going faster to have the work exceed the capabilities of the tires (or use less-sticky tires). Rhys Millen can do some power-overing because his rally car has a whole lot of hp.

Unless you have tons of power, All-Wheel Drifting techniques require knowledge of vehicle dynamics, your drivetrain, your AWD system, your traction circle (the best drivers are subliminally imagining all 4 traction circles of all 4 wheels all at the same time all the time). I find that the majority of the time all wheel drifting is spent trying to find ways to "trick" the computer into giving more power to the rear wheels than they can handle. Rocking the steering wheel between neutral and counter-steered one direction is a pretty good way to keep constant load on the outside tires and to find the best steering angle.

You may also want to try doing a moment of very hard braking during the moment of the feint that has the front wheels pointed straight just before turn-in, and then applying maximum power through the apex. Try also varying this so that you don't feint but do sharp braking before the turn-in at a high enough rate of speed that the rear and will swing out, and then try a small steering angle while applying maximum power.

Try getting up some speed (more than you think nescessary) and cutting the wheel to one side and then counter steering with favor towards a small steering angle.

You may be able to trick the AWD by pulsing the E-brake but not yanking it. If you can, try to replicate the effect that rear-only ABS would have but make sure that you fully release before each pull - if your AWD computer is slow enough, it will see the released portions as an opportunity to send power rear-wards and off of the front wheel. Try this technique with the foot brake as well at various times through the turn, both with and without pressing the gas.

I found that most of the operations in drifting an AWD car were pretty full-on: full on the gas, full on the brake, etc. In racing they say that you should use smooth motions as to not upset the car's tenuous grip at the limit of traction, but in AWD drifting sometimes you will need to wrestle the car out of traction.

Hope this helps and let us know how you make out!

As far as AWD TECH goes...

I wouldn't lower the car until you need to in order to go faster, which shouldn't be for a while. For as hard as you may have to push the car, you'll probably have your wallet pretty empty with replacement parts...

Messing with the suspension could be a mixed blessing: you could take corners faster because your car would handle better, but your traction circle would be bigger because your car would handle better. Eliminating body roll would most likely be the best thing to do, since your instinct will naturally tell you not to push the car when you're sitting on your arm. If you decide to get new rims, stick with something relatively narrow for now (no 8" wides yet) until you have no trouble at all breaking traction, since wide wheels generally mean more grip and a bigger traction circle.

The sensors in AWD usually compare road speed to axle speed and if the axles are going too fast then it transmits power to the AWD. Speaking of which, if you got tires on the front that were smaller in diameter than the origional ones, it might think that you're slipping all the time - even when you're not - and send power to the rears all the time. Of course, you would essentially turn the car into a 4x4 in 4-wheel mode and get crappy gas mileage (esp with 350 horse!).

I'm glad I could help, kinda felt like I owed you one after all the help with the 4G63T stuff - all my buddies think I'm nuts for trying to build a 350hp AWD CRX, let alone take it drifting!

I'd be happy to try and answer specific questions if you have them. BTW - the 4G63T CRX is now going to be an EJ20 CRX... Hope this helps!

-MR

[jsigone]

how much is the EJ20? what made u think of that motor for a platform instead of the 4g63? Or was it the 6spd gear box that u wanted?

[mranlet]

Sup Jsi?

An EJ20 clip is about $4000 for the cheapest one I can find - a bit more than the 4G, but rear-biased.

It's really a mix of factors; I greatly prefer rear-biased AWD, the super-low center of gravity makes for better handling, if I do a V-mount, it will be easier on the low longitudinal engine, the boxer will sound menacing when side-piped. Above all, I've been a Subaru guy for years and just really like the flat fours (or the SVX's six). The EJ20 would be good because it's still being produced, the mileage will be lower on the newer engines and aftermarket parts are readily available. If I have $4500, I don't think I'd be able to pass up a J, but If I come up short, the EH block may be the ticket.

I'm not even nescessarily looking for the EJ20 persay, but really just some good condition Subaru motor - my old EH22 was putting out about 350hp before my Legacy died. That motor was 10 years old at the time and only rated at 150 (or was it 130?) in stock form. I'd settle for the 1st gen Legacy 1.8 as long as I can get AWD for it. The CRX won't need as much power to go fast becuase there's much less of it. 13's in my Legacy will be more like... 11's?

I'm going to be in CT and NY this summer (Subarus make up probably 10% of the cars on the road), which is when the fabrication work is going to be done. I think I may pick up the drivetrain from a wrecked Legacy while I'm up there and use that as a sort of 3-D template to do all of the fabrication. Even if I wind up welding in Subaru mounts while the dinky Honda D15 is still in the bay, anything that I can do to expedite the final swap will make it that much easier. If I can get my hands on a spare ECU and wiring harness, I'll even route all of the electrical lines and wire it up so that the EJ20 be as plug-and-play as possible.

I'll let you know how it turns out...

-MR

[jsigone]

having an EJ in a rex would be sick, the engine area is so small that it shoudl fit fine. Motor and tranny mounts will prolly be the least of ur worried cuz u ahve to hack the firewal in onder to mount the tranny. what type of chassis reinforcing are u planning on doing? Are you gonna make a custome engine cradle for teh EJ motor or u gonna just fab new mounts for the bottom? How many mounts are on the EJ motor? Sounds like u have a good plan, just gonna be a alot of cursing and frustration. Good luck and take pics as u go please.

[mranlet]

If memory serves me right, there are 2 mounts for the motor and 1 for the trans. There really won't be that much hacking of the firewall, since the motor sits pretty far forward and most of the trans is inside the bay. I'm really more worried about room for the radiator and intercooler. I think I might be forced into a V-mount, which may detract from the sleeper appeal. The exhaust tunnel will have enough room for a driveshaft once I sidepipe the exhaust (which may be one pipe on each side, if I go twon turbo !!!), and the rear undercairrage in the back will have to be rebuilt to move the fuel tank and support a differential.

Depending on how much of a problem it will be to fit everything, I may do a pseudo-body drop / frame-lift including an immensely stronger transmission tunnel, engine cradle/suspension mount, and rear differential framing (the classic "dog-bone" found in many classic roadsters and the new Shelby Cobra). The width of a Subaru is a tiny bit wider than the CRX, so suspension members will have to be re-mounted to retain the double-wishbone setup at front and semi-trailing arm in the rear. The Subaru spindles will also have to be worked into the CRX's suspension, which means a conversion from 4x100mm to 5x100mm lugs, but also an upgrade to 10" disc brakes all around.

I'm going to go with the EJ22T from an older Legacy Turbo, which is the very same drivetrain that I had in my old Legacy (which I talk about all the time). I know that I can make 300+ hp on that motor using the same trick I did before, but when it blows I'll just drop in an EJ20T since it will fit the same transmission. Other alternatives are to buy an EJ20 block and build it up with forged crank, con rods, pistons, and such with a 2.5L head. Usually I'd say bottom end construction is a beotch, but in the flat four you can really get to everything right up until you seal it up.

There will be pics a plenty, as this will be the only AWD CRX in the US to my knowledge (and one of only about 5 in the world, including one in Quebec)

[jsigone]

If you get tight on room, U can always opt the FMIC for a good SMIC. I use a stock MKIV supra SMIC that the core is 11x9x5, it works great, very stealth and allows the raditor all teh air and room it needs. Spearco also makes hi effecaint bar and plate SMIC core. I use the supra core cuz it proven, the supra owners don't heat soak til 400-450whp roughly 500hp at the motor. Which is plenty enough for a stock bottom end on almost any car. I'm currently running a T04E 56 trim (T61) and it hold 21psi just fine on pump 91 oct and 27psi on 110oct. The only time I got it to heat soak was when it was 105* out, heatsoaked after 6 pulls on the freeway.

[quickstyleRPS13]

the ej20 has 3 motor mounts 2 on the bottom and 1 on top center. i think the top one is just for stablizing the motor though because of the horizantly inposed cylenders (spelling???). and your going to run in to so many prob. doing that swap its not even worth it.motor and tranny mounting is one thing but the rear diff. thats going to be a doozy. good luck.

[quickstyleRPS13]

sorry didnt read the hole post about all that fab work your thinking of doing.

[mranlet]

Ahem...

Read my quote

-MR