Convert the AWD transmission to FWD?

[bnr32jason]

What is the exact process of converting these AWD transmissions to FWD?

Is it just a matter of removing the center differential housing and using a block-off plate like they show here?

http://boldride.com/blog/wp-content/uploads/2013/02/04-Factory-Five-818.jpg

Will that blockoff plate be included in our kit? Or is that something we have to get fabricated?

What is that little part sticking out? Is that safe?

Does it matter if my gearbox has the DCCD feature? Will that make anything easier or more difficult in the conversion to FWD?

Thanks!

[Seniorsub]

Converting from AWD to FWD is very simple Today rebuild a transmission with by the racedriver choosen ratio's I have build alraedy a lot of TM's with FWD only for racetrack use! For connecting the Transmission out to the Front diff I use a Subaru Special tool and a washer from 18x34 with 4mm thickness installation can be done with only to remove the rear cover. Instead of this OE rear cover instal a flat (Bremar) plate. For racinguse it is neccessarry to instal an transmission oil cooler.

greetings

SeniorSub

[PhyrraM]

Everything needed will be provided with the 818 kit.

[RM1SepEx]

something like this... http://www.bremarauto.com/products/subaru-2wd-conversion-kit/

[StatGSR]

the part sticking out the back is part of the shift linkage.

If you have DCCD, i assume you have a STI six speed transmission, which FFR will not be supporting with this kit. 6 spds can be converted, but DCCD wont do anything when only the fronts are powered so it really wouldn't need to be wired up.

as mentioned FFR will include everything that is needed to convert a Subaru 5spd.

[Silvertop]

something like this... http://www.bremarauto.com/products/subaru-2wd-conversion-kit/

Presumably, FFR found a better price (or is making one of their own) than the Bremar product. $400+ dollars? For that? Good Grief !!!

[bnr32jason]

the part sticking out the back is part of the shift linkage.

If you have DCCD, i assume you have a STI six speed transmission, which FFR will not be supporting with this kit. 6 spds can be converted, but DCCD wont do anything when only the fronts are powered so it really wouldn't need to be wired up.

as mentioned FFR will include everything that is needed to convert a Subaru 5spd.

I have a JDM 5-spd STi DCCD transmission from one of the earlier model STi's (1998 or so).

I'm aware I won't be using the DCCD, I'm just wondering if internally there is something different that will make it more difficult to make the transmission work with the 818. I actually have all the DCCD wiring and the two associated ECU boxes, I'm hoping that I can sell all of it off to make some money back.

[PhyrraM]

IIRC, there a differences in the phase 1 and phase 2 transfercase (for lack of a better word) splines. The swap was around the 1999 model year.

FFR has only officially committed to supporting the '02-'07 Impreza line. So I would expect that FFR will only support the later gearboxes.



..Of course it could also be likely that all the spline differences are on the parts that get thrown out.

[Ironhydroxide]

IIRC, there a differences in the phase 1 and phase 2 transfercase (for lack of a better word) splines. The swap was around the 1999 model year.

FFR has only officially committed to supporting the '02-'07 Impreza line. So I would expect that FFR will only support the later gearboxes.



..Of course it could also be likely that all the spline differences are on the parts that get thrown out.


OK, the Phase 1 and Phase 2 Center differentials. there are a few differences, but i'll explain why it won't matter to us.


phase 1 was weaker, and had fewer plates in the differential itself. the OUTPUT to the REAR of the transmission is different, the output to the front diff, and the input from the gearset are the same spline, and diameter.

the reason phase 1 and phase 2 do not mix is because of physical size of the differentials (for those subaru guys wanting the better phase 2 diff,) and the output to the rear. the phase 2 differential physically does not fit in the phase 1 casing, the output to the rear can be swapped. the way the Subaru folk get around this is get an ENTIRE center diff housing, and bolt it up.

so. simplified. EITHER phase 1 or phase 2 transmissions should work with a FWD adapter coupler. The backing plate MIGHT not have the exact same bolt pattern (i've yet to pull them sidebyside and check that fact).


ALSO to note, if you were thinking of doing it... the phase 2 gearsets DO NOT work in the phase 1 transmission casings. (unless you don't care about having reverse)

the gearset bolts in and meshes fine, the reverse gear idler shaft is offset slightly from phase1 to phase 2 to facilitate a larger reverse gear. so, if you wanted to do this, remove the reverse idler gear and shaft.

[bnr32jason]

Judging by the charts I've read, I'm going to assume that mine is a Phase 1. My transmission number is TY752VB5CA and the chart says it's from a V3/V4 STI RA 97-98.

Something that does worry me though is I got a PM from a gentleman from the Netherlands but the English is a little iffy, might be a Google Translate job, can anyone verify this:



But please that for the transfercase of the factory transfercase with the metal 4 bolts cover in top you need to modify the lubrication for the 3-4 and fifth gear needle bearing. Because by remaving the central diff the oil flow to the needle bearings wil stop! Its for 10% sure you will haven seized needle bearings!

My transmission is a 5spd DCCD version. I want the 4.44 final drive and the supposed stronger/wider gearset, if this needle bearing concern is going to destroy my transmission than I'll just swap what internals I can into a non DCCD 5spd.

Any input?

[StatGSR]

I thought you just locked the center diff, not remove it....

[Wayne Presley]

I thought you just locked the center diff, not remove it....

You remove it

[Ironhydroxide]

Judging by the charts I've read, I'm going to assume that mine is a Phase 1. My transmission number is TY752VB5CA and the chart says it's from a V3/V4 STI RA 97-98.

Something that does worry me though is I got a PM from a gentleman from the Netherlands but the English is a little iffy, might be a Google Translate job, can anyone verify this:



My transmission is a 5spd DCCD version. I want the 4.44 final drive and the supposed stronger/wider gearset, if this needle bearing concern is going to destroy my transmission than I'll just swap what internals I can into a non DCCD 5spd.

Any input?

First of all. I WANT YOUR TRANSMISSION, the whole thing. LOL. i've been dying to get a 4.44 DCCD trans for a while to put in my 3 door leone EJ20G project.
Second of all.... I can see where this guy is going. and yes, he is semi correct.

lemme see if i can find pictures. if not i'll have to take some.
http://i757.photobucket.com/albums/xx213/ironhydroxide2/RiggedPerformance/IMG_20130325_224635_zps0a45582c.jpg (http://s757.photobucket.com/user/ironhydroxide2/media/RiggedPerformance/IMG_20130325_224635_zps0a45582c.jpg.html)
here is the center diff, rear output shaft, differential, and differential casing of a phase 2 transmission (2003 WRX specifically)

in the differential casing you can see there is a plastic piece held in by one 10mm hex head bolt. (i will need to take better pictures this weekend, but thats a start)
This plastic piece catches the slung fluid from the 5th gear drive gear, and transfers it to the upper transmission shaft (input shaft) to feed: 5th gear needle bearing, rear input shaft bearing, 4th gear needle bearing, 3rd gear needle bearing.
if you REMOVE this slung fluid, or the Plastic catch/transfer tray, you'll sieze the transmission fairly quickly.

Now note, on the Phase 1 the plastic piece is held in by 2 10mm hex head bolts, and passes through the center "blockoff" in the Center Differential housing. this is because the plastic piece catches the fluid slung by the center differential itself, and NOT the 5th gear drive gear.

i BELIEVE the adapter is still a bathed unit (low enough in the fluid that it will sling fluid) and therefore will still sling fluid to the catch. (i'd have to verify by taking measurements of the adapter and the center diff, then finding where the fluid level usually sits while operating)

but now i think about it, the Adapter ONLY replaces the front section of the center diff and does not extend to the rear section of the Center Differential Housing.


That said, for those wanting to use Phase 1 transmissions, please procure a phase 2 center differential housing, this will ensure the bearings stay lubed, and everyone stays happy.

(pictures to come,)
maybe i'd better start a new thread on identifying the difference between phase 1 and phase 2. hmmmm.

[Ironhydroxide]

I thought you just locked the center diff, not remove it....

for those going RWD in the subie world, they weld the Spider gears in the center differential. then remove the center shaft of the front CV shafts.

this can also work for a poor mans FWD locker. but if FFR supplies the adapter, why not use it and remove the 5+lbs of rotating mass?

[Ironhydroxide]

What is the exact process of converting these AWD transmissions to FWD?

Is it just a matter of removing the center differential housing and using a block-off plate like they show here?

http://boldride.com/blog/wp-content/uploads/2013/02/04-Factory-Five-818.jpg

Will that blockoff plate be included in our kit? Or is that something we have to get fabricated?

What is that little part sticking out? Is that safe?

Does it matter if my gearbox has the DCCD feature? Will that make anything easier or more difficult in the conversion to FWD?

Thanks!

to answer the PO question:
I Know for a fact that you "CAN" use the Phase 1 DCCD transmission (though you'd probably get more $ from selling it as a whole DCCD and buying a non DCCD with the same ratios)
I do not know if you can use the phase 2 dccd, as the Solenoid for the accuation of dccd seems to come from the transmission housing itself.

So, to recap. if your transmission looks like this then it is uncertain
http://www.gotitrex.com.au/home/images/stories/5speed.JPG

if your transmission looks like this then you are good (though I personally would frown upon you for splitting up a dccd transmission, then i would request you sell the DCCD center to myself ;) )
http://a3.l3-images.myspacecdn.com/images02/118/f3d0789049a04aaebe7ca2fe575584bd/l.jpg

[bnr32jason]

This is my transmission.

https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn1/21801_502751726441187_327700872_n.jpg

How much does a complete 5spd with DCCD center, all DCCD related wiring, DCCD ECU boxes, and matching rear diff sell for in the US?

From looking on eBay and NASIOC it seems like it's going to have to sell for quite a bit for me to be able to afford a 02-07 5-spd as they sell for quite a bit. I got this whole setup for $450 and was planning on using it.

I'm now reconsidering my desire for the 4.44 FD as my dad, a good friend of mine, and a guy on NASIOC have all mentioned that the low gearing might actually make acceleration too difficult in our lightweight relatively powerful 818. Anyone else agree with that?

[Ironhydroxide]

Looks like good condition ones go for anywhere from $1500 on up, but that's normally JUST the trans, no wiring, controllers etc.

I also think a 4.44 short ratio, in a 1700 LB (ok 1800, but i plan on doing as much weight savings as i can) car, will be just too much... probably be doing a second, fourth, fifth shift pattern.

My Leone Project should weigh in at about 2100 with me in it, and i'm planning on a 3.90 with semi short gears, making it so I can be in the gear, putting power down longer. rather than losing time shifting.

anyways, point here can be found with some research online. Search Google, Gear ratio Calculator. use it
Using the above TY752VB5CA transmission code. and a tire size of 225/45-17 (i know, but its stock for wrx. so... ) and say a rev limit of 7800 RPM (high spinning 2.0)

RPM 1st gear at 7800 = 42.4 = 5200RPM in second gear.

we can follow this all the way up... but this is enough to make my point. if you have an engine that makes GOOD power from 3500 RPM through 8000 RPM, then you want to USE all that powerband, with only a little overlap for gears. it means you can be in a gear for LONGER putting power down instead of shifting very often, then running out of gears to shift to.



i feel like i'm rambling, so if this is confusing LMK and i'll try and clear it up a bit better.

[bnr32jason]

No, it's not confusing, I appreciate the clarification.

I'll be using a VF36 turbo which should see full boost at about 2800rpm. This compounds the problem that you bring up, as I would be wasting a lot of useful RPM and shifting much more often.

[Xusia]

That 4.44 FD ratio would probably make that an awesome transmission for someone who wants to build a fuel efficient EV (as opposed to a performance oriented EV). It would allow them to use a smaller motor.

[RM1SepEx]

???

I think that you are geared too low at 4.44. The standard wrx ratios may well be overkill losing as much weight as we do from the Subaru to the 818. I thought about higher gears until I ran the numbers and many of us won't pull redline in top gear. (approx 180mph with normal sized tires) So check out your speed in gears here...

http://www.cargister.com/calculator-gear-ratio?rpm=7000&final_ratio_teeths

or use this spreadsheet

http://www.oakos.com/wrx/gears.xls

[PhyrraM]

Just from a 'time in gear' standpoint, I'd be at least thinking about/researching an OEM FWD transmission with a 3.7:1 final drive. IIRC, no AWD trannies came with anything lower than 3.9:1 (I stand corrected, read next post)

If your looking into an automatic build, the SVX had a 3.54:1 final drive that I think would be just about right with the light weight and an engine built with even a smidge of torque.

[RM1SepEx]

From NAISOC forum

5MT transmissions
'02-'05 WRX
- 1.1:1 transfer gear
- 3.900FD tranny
- 3.545FD rear diff

'06-'07 WRX
- 1:1 transfer gear
- 3.700FD tranny
- 3.700FD rear diff


so for an 818R you want to gear for top speed at the end of the longest straight... they may indeed look for that 4.44 diff !!!

[Xusia]

so for an 818R you want to gear for top speed at the end of the longest straight... they may indeed look for that 4.44 diff !!!

Um... I was under the impression a higher number (i.e. 4.44 vs. 3.9 or 3.7) indicated LOWER gearing (i.e. more mechanical advantage). That would mean less top speed. So for a higher top speed you'd want the lowest number (i.e. 3.7). Did I get that wrong, or am I misunderstanding what you are trying to say?

[Ironhydroxide]

Um... I was under the impression a higher number (i.e. 4.44 vs. 3.9 or 3.7) indicated LOWER gearing (i.e. more mechanical advantage). That would mean less top speed. So for a higher top speed you'd want the lowest number (i.e. 3.7). Did I get that wrong, or am I misunderstanding what you are trying to say?



you are correct. a 3.70 final drive will allow you to have a higher top speed (if the engine can overcome the air drag) than if you had a 4.44.

a couple little calculations with the 2006 WRX transmission compared to the above 4.44 Transmission.

First, the 4.44 http://www.cargister.com/calculator-gear-ratio?rpm=8000&final_ratio_teeths[]=&final_ratio_teeths[]=&fdr=4.44&diameter=634.3&ratio[1]=3.083&ratio[2]=2.062&ratio[3]=1.545&ratio[4]=1.151&ratio[5]=0.825&ratio[6]=&speed_in=mph&width=225&profile=45&wheel_diameter=17&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=

Specifically i look here and the graph to visualize it. (warning this is with an 8Krpm shift point) also note, top speed in 5th at 8000rpm is 162.3mph
Gear shift Difference after shifting RPM after shifting
from 1st Gear to 2nd Gear 2649 5351
from 2nd Gear to 3rd Gear 2006 5994
from 3rd Gear to 4th Gear 2040 5960
from 4th Gear to 5th Gear 2266 5734


Second the WRX 3.70 http://www.cargister.com/calculator-gear-ratio?rpm=8000&final_ratio_teeths[]=&final_ratio_teeths[]=&fdr=3.7&diameter=634.3&ratio[1]=3.454&ratio[2]=1.947&ratio[3]=1.366&ratio[4]=0.972&ratio[5]=0.738&ratio[6]=&speed_in=mph&width=225&profile=45&wheel_diameter=17&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=

again here is what i look at, top speed with this ratio is 217.7mph @8000 in 5th
Gear shift Difference after shifting RPM after shifting
from 1st Gear to 2nd Gear 3490 4510
from 2nd Gear to 3rd Gear 2387 5613
from 3rd Gear to 4th Gear 2307 5693
from 4th Gear to 5th Gear 1926 6074

Now, if you click, you can see the overlaps of the gear ratios. On the first graph we can see that at, say we have a turbo spools at 2800rpm, we can be in any of 1st through 4th gears at 40 mph and still make power. (if the turbo will spool through 8000).
the second graph shows us that at 40mph with the same 2800 spool RPM we can be in either first (top of 1st) second (middle of second) or third (very bottom of 3rd). still redundant, but not quite as much.

note redundancy isn't bad at all... options are good when going through corners, depending on if you want to be coming out accelerating, or if it is the first of an element that you need to be slower at the end of, but want to hold speed through the first section. but too much redundancy, can lead to lack of gear utilization.


NOW, lets have some fun and put the 4.44 gearset on the 3.70 final drive :evil:
http://www.cargister.com/calculator-gear-ratio?rpm=8000&final_ratio_teeths[]=&final_ratio_teeths[]=&fdr=3.70&diameter=634.3&ratio[1]=3.083&ratio[2]=2.062&ratio[3]=1.545&ratio[4]=1.151&ratio[5]=0.825&ratio[6]=&speed_in=mph&width=225&profile=45&wheel_diameter=17&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=

and how about the 3.70 gearset on the 4.44?
http://www.cargister.com/calculator-gear-ratio?rpm=8000&final_ratio_teeths[]=&final_ratio_teeths[]=&fdr=4.44&diameter=634.3&ratio[1]=3.454&ratio[2]=1.947&ratio[3]=1.366&ratio[4]=.972&ratio[5]=.738&ratio[6]=&speed_in=mph&width=225&profile=45&wheel_diameter=17&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=&teeths[1][]=&teeths[2][]=




Back to the reality of it, all this is just blabber, some say lower FD is better, some say higher FD is better. not to be discounted is the ability of subaru transmissions to accept WHATEVER final drive you want for WHATEVER gearset you have.... HELL if you want to change the specific gear ratios (1st and second are sets, and 3rd and 4th are sets) you CAN!!! you can do almost anything with a subaru transmission.

I PERSONALLY like the feel of the 4.11 and 4.44 transmissions in subarus, because it makes the 3000lb car feel lighter, though i do feel like it will take a 1800 lb car, and make it an almost useless 1st gear(and consequently third gear), then once you are through launching in second, you'll instantly shift to 4th gear, because you're still in power, and you don't have to shift again two seconds later.

[RM1SepEx]

I'm assuming that these track cars for some sort of spec series won't have more than 300-350 whp so 160+ top speed will be just fine for most domestic road racing venues.
The 3.7 and 3.9 ratios give 180+ mph in top gear at redline and are geared high for fuel mileage, they will be very strong performers on the street and or autocross with 70 in second gear

[atomicjoe23]

the part sticking out the back is part of the shift linkage.

If you have DCCD, i assume you have a STI six speed transmission, which FFR will not be supporting with this kit. 6 spds can be converted, but DCCD wont do anything when only the fronts are powered so it really wouldn't need to be wired up.

as mentioned FFR will include everything that is needed to convert a Subaru 5spd.

StatGSR, could you possibly supply any info about converting the 6-speed STi tranmsissions to FWD only. . .ours is a '17 so it is a DCCD, but the understanding I have is that the DCCD doesn't even need to be wired in and we don't care about the DCCD because that is what is shifting power to the rear when the front wheels spin. . .correct me if I am wrong please.

Thanks!

[Hobby Racer]

StatGSR, could you possibly supply any info about converting the 6-speed STi tranmsissions to FWD only. . .ours is a '17 so it is a DCCD, but the understanding I have is that the DCCD doesn't even need to be wired in and we don't care about the DCCD because that is what is shifting power to the rear when the front wheels spin. . .correct me if I am wrong please.

Thanks!

Wow, way to bring a thread back from the dead.

This should help.

How to convert any Subaru 6 Speed (6MT) to Front Wheel Drive (FWD)
(https://thefactoryfiveforum.com/showthread.php?34577-How-to-convert-any-Subaru-6-Speed-(6MT)-to-Front-Wheel-Drive-(FWD))