altoid

Welp I figured I might as well stop being an assmonkey and might as well show everyone how the real time four wheel drive system works, not to mention, im pulling an all nighter to get my dammn sleep cycle back on track, lemme know what you think. This is all straight from the 89 civic manual. The CRV RT4WD is merely an evolution of this idea, so it uses the same basic principles but is more advanced in how its done.

General
When there is no difference in speed between the No.1 and viscous coupling unit (No.2 propeller shaft) , power is transmitted to the front wheels through the front differential and the front driveshafts. The left driveshaft is connected to the differential by an intermediate shaft, The power is also turned 90 degrees by the transfer gears and transmitted to the No.1 propeller shaft. Whenever there is any speed difference between the No.1 propeller shaft and viscous coupling unit (No.2 propeller shaft), power is transmitted to the rear wheels via the viscous coupling unit, the No.2 and No,3 propeller shafts, the rear differential and the rear driveshafts.





Front Driveshaft
An intermediate shaft equalizes the length and angle of both driveshafts for easier steering on bumpy roads. The driveshaft end of this shaft runs on a bearing which is held by a holder on the engine case. A constant velocity universal joint at each end of the driveshafts ensures quieter operation and longer life. The front wheels run on an angular bearing for reduced friction

Propeller Shaft
The propeller shaft carries power from the transfer to the rear differential. It is of a 2-piece construction and is supported by two rubber mounted bearings. The shaft has four universal joints: one tripod type and three yoke-and-spider type. These joints permit the shaft to lengthen and shorten, as the rear suspension moves.

Viscous Coupling
The viscous coupling unit is located on the front end of the No.2 propeller shaft. It consists of a housing that is connected to the No.1 propeller shaft by a tripod joint. Inside the houning are 79 plates, which have 0.2 mm (0.008 in.) of clearance between one another, surrounded by silicon oil. The 40 housing plates are engaged with the splines in the housing and the 39 hub plates are splined to the shaft. The plates have holes in them to aid in heat dissipation. The viscous coupling unit also contains approximately 10 % air to allow for the thermal expansion of the silicon oil.

Whenever there is any difference in the speed of rotation between the No.1 and No.2 propeller shafts, such as when the front wheels lose traction, there is friction between the housing plates (drive side) and the hub plates (driven side) .This friction is caused by the resistance of the plates sliding against the silicon oil. This resistance between the plates and the silicon oil is what begins to transmit torque from the housing plates to the hub plates and eventually to the rear wheels. This transmission of torque is proportionate to the difference in the speed of rotation of the wheels.

As the difference in propeller shaft speed continues, the temperature of the silicon oil keeps rising. Due to thermal expansion, the pressure inside the viscous coupling unit is also increasing as the temperature rises.
When the pressure becomes high enough, the housing plates begin to contact the hub plates and the engine torque to the rear wheels increases rapidly, as noted in the diagram below. To reduce plate wear, there are spacer rings to limit plate to plate contact.





[Modified by EE4, 2:15 AM 2/10/2003]

FourthGenHatch

Interesting. So basically it's sort of like LSD but instead of transfering it to the other axel it transfers it to the rear wheels?

miskone

You're saying you could put that on another honda made car like a crx? But have to get the rt4wd from a cr-v.

kyle h.

im sure that will clear a lot of things up for people.

altoid

if thats how an lsd works then it sure is.

The rt4wd also came on the 4wd wagons (ee4) so if you don't plan on pushing over 220 hp you could go with that, otherwise i'd go with the crv drive train.

I Gotta Question

dont you need b series for crv and dseries for ee4? I was looking into the ee4 but if I can use the crv then I will go with that since I will be pushing 260whp.

altoid

yeah you'll have to get stuff refitted, probably get the driveshaft cut, which isn't a big deal, i can get mine cut for 30 dollars, and buy a brand spankin' new one for 100 so its not expensive.

I Gotta Question

so I would have to use the ee4 tranny though right . btw what is your setup?

altoid

nah you could use a b series motor with a manual crv tranny which would use the b series drive shaft, and if you were gunna put that in anything thats not a crv mods like cutting and such would have to be done.

So far my set up is just a sohc zc, but i've got everything sitting in my room right here (almost) waiting to be put in it'll be as follows

exospeed race regind (396 lift 268 duration)
full 2.5" exhaust
d16a1 pistons 11.05:1 compression
prelude 92-96 vtec injectors
arp rod bolts
and y8 manifold

Im estimating 150-160 whp, im hoping for 170-180 but its unlikely


[Modified by EE4, 9:08 PM 2/15/2003]

I Gotta Question

so you have a SOHC zc in a ee4? How does it drive? Good gearing?

altoid

yeah drives really well, the tranny is still the old beast from 160k miles ago, and is pretty strong, gearing is great, 0-60 in something like 7 seconds, not super fast but good enough when ya gotta merge, and I love the 4wd, when i do an occasional drag just to see what i can pull off the front wheels barely slip, and then once they do i can feel the rears just kick in a push the rest of the way. as of now my 1/4 is about 16.5. not too bad for 2505lbs and 120ps/100ft/trq motor. Should be fun once the setup is complete, I'll doing some small time rallies on the weekends too after i get built up

altoid

and in the snow this car is a beast, I can't wait to see what she'll do tomorrow. 2ft baby! im running off stock 14" steelies, they are perfect as far as im concerned


[Modified by EE4, 10:05 PM 2/15/2003]

I Gotta Question

right on!!!!

Francois

How much % is transfered to the rear wheel?

altoid

not a % its proportional

RICE POLICE SIP

iTrader: (2)

4drEF

Post is now resurrected from 2003.
Nice.

goforbroke

Honda tuning did a 4 wheel drive hype R with crv components. A lot of you guys probably already know this though.

ahuff

Can you use a 92-95 Civic EX engine with the AWD wagon without any fitment issues? I suppose you'll need a new ECU from the 92-95 but other than that, will it just drop in? I ask because you say you have a ZC engine but out here in CA it is illegal to use that engine. As far as I know, the only option I potentially have to get more power is the 92-95 civic EX engine. If that engine is an easy swap, then I can also put an edelbrock or GReddy baseline turbo on and still be smog legal.

By the way, thanks for the great write-up on how the AWD works.

~sp33~

Any D series engine can be mated to the EF AWD driveline.

spastik

my good friend Shea did a GSR swap and mated it with a CRV tranny and drivetrain. had to make his own custom rear axles for it to work







more info can be found at idahospeed.com and at hondacivicwagon.com

rexman

iTrader: (6)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by spastik &raquo;</TD></TR><TR><TD CLASS="quote">



more info at idahospeed.com and hondacivicwagon.com</TD></TR></TABLE>

^^^ now that's what i'm talkin'bout.
alot of people don't know civic's came in 4wd,
my subie buds r like w.t.f.???

Slowass2dr

i was originally saving up to buy an rx7, but i might use my money to do this projet, the crv one that is

~sp33~

Ive read about that swap being done.. And from what that guy just posted he makes it sound easy.. But its not. theres ALOT of fabrication and welding. That being said go to the sites the guy mentioned and see for yourself

ahuff

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ~sp33~ &raquo;</TD></TR><TR><TD CLASS="quote">Any D series engine can be mated to the EF AWD driveline.</TD></TR></TABLE>

So just to clarify, the D16Z6 does not require any mounting modification. It will just drop right in without any special brackets and mate directly to the 6 speed tranny?

Will I need the engine wiring harness from the D16Z6 engine? Or, will the D16Z6 ECU connect directly to the D16A6 wiring harness?

Thanks again guys.