4.44 , 4.11 or stock ? and why ?

[oab_au]

The final drive gearing that you use, depends on what type of driving you do. The car was designed with a 3.7:1 diff to be a high speed touring car, that can do interstate trips with good comfort and safely.

The trouble starts when it was fitted with a 3.54:1 diff and used as a city commuter. The higher gearing placed more load on the box that was now rotating slower. Producing more heat from the torque converter, having to work harder to lower the gearing. While the lubricating ATF was circulated slower through the cooler and the gear shafts. The result is overheating of the epicyclic gear sets.

Lowering the diff ratio to 4.11:1 reduces the load on the gears and lets them rotate faster. The torque converter has less work to do so it produces less heat, and as the pump is rotating faster it pumps more cool oil to the gear sets. The 4.44:1 ratio just does this more so. The down side is that the engine now spins faster for the same road speed.

Using the Legacy/Impreza/Outback gearbox can be an alternative as the load reduction can make up for the 1 less plate in the high/Transfer clutches. Where these conversions are put at risk is when the SVX TCU runs them. The TCU will still carry out a soft change, where as the cars that these boxes came from don’t, so they suffer the long sliding shifts. Installing a Quick Change will remove this, returning the box to the same changing conditions it had in the donor car.

To help the box to last longer, the “Power Mod” should be done. It is the easiest way of ensuring that the car won’t be lugged around in too high a gear, as it will change down earlier to reduce the load. If it has a QC fitted, it will prevent the sliding changes that cause much of the band and clutch problems.

Harvey.

[Nevin]

Originally Posted by oab_au

...paraphrasing...a bunch of smart stuff that mkes perfect sense...

Harvey.

So, even on 4.11, 4.44 trannies, etc... You would encourage the power mode mod and the QC for those as well? I think I can see why, but I'd like to get it straight from the horses mouth so to speak.

I was thinking of doing both of these things when I install my 4.11 tranny, but after reading your previous post, there's no thinking about it at all, it's going to be done!

Also, I have the 4.11 TCU, so would you recommend I use it in my conversion, or just use the stock TCU with a quick change? Is the quickchange compatible with different TCUs?

[oab_au]

Originally Posted by Nevin

So, even on 4.11, 4.44 trannies, etc... You would encourage the power mode mod and the QC for those as well? I think I can see why, but I'd like to get it straight from the horses mouth so to speak.

I was thinking of doing both of these things when I install my 4.11 tranny, but after reading your previous post, there's no thinking about it at all, it's going to be done!

Also, I have the 4.11 TCU, so would you recommend I use it in my conversion, or just use the stock TCU with a quick change? Is the quickchange compatible with different TCUs?

I have a Aust. Liberty that has a power mode switch the same as the JDM SVXs have, we drive it in PM all the time, except on the expressway. The SVX got the, 'floor the throttle and hang on' type, which is only good for acceleration. We got had.

This is probably the best and cheapest mod you can make to the SVX. There are a few that have both the Quick Change and the Power Mod, and all the reports that I see has convinced me to convert my Aust. TCU to switchable Power Mod.

You all over there, only have to stick a wire into the TCU plug to a switch to ground.

Use the SVX TCU to keep the higher rev change points.

Harvey.

[Tuck]

Originally Posted by svxfiles

4.44 , 4.11 or stock ? and why ?

--------------------------------------------------------------------------------

the title says it !!
__________________
Regarding 4EATS';
I have installed dozens of 4.44s, and THREE 4.11s.
Every 4.44 has held together,
(except for Chi ke's cracked bell housing)



and all three 4.11s have had issues.

I believe the reason is that the 4.44s last is that with the 4.44 you have lower gear ratios that take our heavy cars up to speed with less strain on the transmission.
A 4.44 (compared to the stock gears) has 37% more torque in first,
31% more torque in second and
25% more torque in third and fourth.

A 4.11 transmission has 16% more torque (compared to stock gearing)
In all gears.

The lower gearing gives us the "Best kick in the pants"
while only turning about 500 RPM higher than a 4.11 at 70 mph.
I have stated in the past, and PM'd on many occasions that I would only install a 4.11 IF it were rebuilt.

The lower gearing gives us the "Best kick in the pants"
while only turning about 500 RPM higher than a 4.11 at 70 mph.

What's this 70 MPH??????

[svxfiles]

Originally Posted by Tuck

The lower gearing gives us the "Best kick in the pants"
while only turning about 500 RPM higher than a 3.54 at 70 mph.

What's this 70 MPH??????

OK, 1000 more rpm at 140 mph.

[Francis]

so after reading all this , since i know i am doing alot of highway i should go with a 4.11 but making sure it has been rebuilt ?

[rvnmaniac]

Originally Posted by Francis

so after reading all this , since i know i am doing alot of highway i should go with a 4.11 but making sure it has been rebuilt ?

Set up a POLL i'm luvin' my 4.44

[Francis]

Originally Posted by rvnmaniac

Set up a POLL i'm luvin' my 4.44

are you satisfied when on highway ?

edit....i mean 80miles trip and over ?

[svxfiles]

I have had up to four SVXi at a time with 4.44s.
I have had them for years.
I have have put tens of thousands of miles on them, drag racing, autocrossiong, long trips, up to twelve hours each way.
These are the gears Subaru SHOULD have used.














Unless everywhere you go is downhill.

[VICSVX]

I'm looking to to a 4.11 swap due the availability of them at my local u pull.... Out of a 97 impreza... And I've read conflicting info about leaving the power mode on. Is the true or.....?

I've also considerrd a 4.44 but haven't sourced one yet. I have a jdm 5sp out of 95 sti with matching the diff and some pedals if anyone is interested in a trade?

And is the 4.11 really that much less reliable then the 4.44?

Originally Posted by oab_au

The final drive gearing that you use, depends on what type of driving you do. The car was designed with a 3.7:1 diff to be a high speed touring car, that can do interstate trips with good comfort and safely.

The trouble starts when it was fitted with a 3.54:1 diff and used as a city commuter. The higher gearing placed more load on the box that was now rotating slower. Producing more heat from the torque converter, having to work harder to lower the gearing. While the lubricating ATF was circulated slower through the cooler and the gear shafts. The result is overheating of the epicyclic gear sets.

Lowering the diff ratio to 4.11:1 reduces the load on the gears and lets them rotate faster. The torque converter has less work to do so it produces less heat, and as the pump is rotating faster it pumps more cool oil to the gear sets. The 4.44:1 ratio just does this more so. The down side is that the engine now spins faster for the same road speed.

Using the Legacy/Impreza/Outback gearbox can be an alternative as the load reduction can make up for the 1 less plate in the high/Transfer clutches. Where these conversions are put at risk is when the SVX TCU runs them. The TCU will still carry out a soft change, where as the cars that these boxes came from don’t, so they suffer the long sliding shifts. Installing a Quick Change will remove this, returning the box to the same changing conditions it had in the donor car.

To help the box to last longer, the “Power Mod” should be done. It is the easiest way of ensuring that the car won’t be lugged around in too high a gear, as it will change down earlier to reduce the load. If it has a QC fitted, it will prevent the sliding changes that cause much of the band and clutch problems.

Harvey.