48 replies to this topic

[LXCHEV]

There's a couple of guys in the EH club here in VIC running TH700's behind early red 6 cylinders. I don't know any details, but believe they used CRS adapters. They seem pretty happy. Next next I see them i'll have to ask for some more info.

[TerrA LX]

I can't see it being any worse than any other auto trans mentioned here.
Holden would not have used them for so long if they were not more efficient than previous models surly.

[EunUCh]

I think most of power drain would appear to come from the fact that most auto's had a tall diff ratio?,they really only drive an oil  pump that deselects/selects gears at the right time,the cable is not a "kick down" cable but works in place of the vac. modulator in conjunction with the governor,this cable needs to be set pretty well spot on or else shift points will be affected or other disasters can happen.

 

Who knows how much they sap but it is called a "torque converter",some people even say that there is a "gain" in torque given how the thing works but i dunno?

 

I should imagine the pump would take some driving and allow for "slippage" in the converter these days is quite good,don't know the figures but coupling points of converters have come a long way?

Not sure on the overdrive of these things but i think they are temp./speed sensitive but kits are available that "modulate" when the thing locks up?

 

One thing should be kept in mind is that when a shorter diff. ratio is used the governor will need some tweaks or else the shift points will be too early.

 

Not sure how much torque the pump would suck out but given that the converter can be spun easily by hand it may not be that much?

 

Sounds like a good thing to try,they are supposed to be pretty bloody strong and they are cheap and kits are cheap as well,and from

what i understand they are easy to work on.

[TerrA LX]

I thought most of the smaller engines ran 3.45 or around that with a th700 or a 4L60.

[EunUCh]

Just going off a stock VP como with 308 ratio on whatever size tires they had on them,first is lowish but i should imagine a 4l60/r700 with a set of 355 or 336 gears on 14's would be quite nice with a tweaked governor and a shift kit.suppose it would come down to wheel size?

Edited by EunUCh, 12 April 2015 - 06:35 PM.

[TerrA LX]

I thought only the 304 and up had the 3.08 standard?

[kiwi-lilj]

Auto's are for poofs

Hey your work ute is an auto. Does that make you a "poof for hire" ?

[EunUCh]

 The daughters VP was 3800,3.08 ratio on 14's,336 would be much nicer,355 even better.

 

lol ,autos are for men who have given up pushing cogs in

 

They are a strong transmission,as already said...a glorified t350 with an overdrive...the torque converter is smaller than a trimatic 6cyl job,a good oil cooler and i wouldn't even bother about the lock up function?

[TerrA LX]

The lock up function gives it it's most efficiency.

[76lxhatch]

I thought only the 304 and up had the 3.08 standard?

Pretty much every Commodore (there are always a few special exceptions) VN-VT1 is 3.08:1 standard in both V6s and V8s
 

first is lowish

That is the one oddball thing, roughly 3:1 first gear which is quite short for an auto. Either annoying or useful depending on your intended use

[TerrA LX]

I will en devour to have a closer look I really thought 3.45 was a pretty common ratio from the VN and on.

[UCgazman]

3.45 was only standard on 6cyl VL's

[76lxhatch]

I will en devour to have a closer look I really thought 3.45 was a pretty common ratio from the VN and on.

Sadly not, even utes had 3.08 diffs. Don't quote me on this but I think 3.45 in maybe the VS GTS-R and possibly one or two other special HSV models but that's about it. You could probably option it I guess.

[Uncle Chop Chop]

I think the VN Group A had 3.45:1 gears because of the 6 speed that was introduced for the first time. It's been 25 years since they were new, so the memory may not be spot on.

[dattoman]

How many choices do you want ?

 

http://www.filedropper.com/diffs

[76lxhatch]

Looks about right, 3.27:1 was the other (not common) HSV option, maybe that was the GTS-R? Never heard of the 3.7:1 being OEM in a Commodore, maybe just a listed option since none of them are shown as LSD? Would like to get my hands on a set in that ratio but they are basically impossible to get (manual Aussie built R31 3L Skylines had them also).

4.11:1 was behind the 4 cylinder Commodores, don't think you guys got them?

[dattoman]

3.73 is still avail new for both the M75 and M78

[Collo]

3.45 and 3.7 are the go to diff ratio changes for the commo guys with standard diffs, which are mostly 3.08's from what I've owned/seen.

[UCgazman]

I've got a mate that ordered his VE with a 3.7 diff, available but not standard. Friggen fast car too...

[76lxhatch]

3.73 is still avail new for both the M75 and M78

Never thought of getting them new... easily found for the M80 for later cars but never seen a second hand set (or diff in a car for that matter) for M75