IRS G series diff ratio help

[1JZ.747]

hi boys and girls.

i am in need of a IRS G seriues diff ratio lower than a 3.7.

im hoping some one knows where i can get a 3.5 or there abouts

need more gearing so i can go run high 160 to 170 mph in the cressida

any help greatly appreciated.

shane

[The Real Roadrunner]

Jase down at living low had a 3.5? G series lying around and just lent it to one of my customers, ill see if he knows what it came out of.

its in a Live housing but its should be easy to adapt to the IRS housing.

Cheers
Linden

[cambelt]

Marks 4WD adapters do the 3.5 G series gears . about $500
I was told they may buy them off predetor??
Dave

[DLA11D]

Jase down at living low had a 3.5? G series lying around and just lent it to one of my customers, ill see if he knows what it came out of.

its in a Live housing but its should be easy to adapt to the IRS housing.

Cheers
Linden

How did you know that? I'm using it at the moment to get me by. He had it in his landcruiser which is using a hilux diff. Depending on how quickly i get mine back i can ask him of he wants to sell it.

[JustenGT8]

LOL i just went thru this so hopefully can save you a world of pain...for the wallet that is.

Some mob the US make the 3.54:1 which are then branded by a number of retailers (including Marks). Around $550AUD unless you are patient and have time to wait for a deal to come up on Ebay.

Now the 1st prob. This CW&P gear set wouldn't fit the low ratio centre....3.9:1 and shorter?

There appear to be 3 different offset centres 3.42:1 and taller. 3.52 to 3.7. and 3.9 and shorter.

Basically the taller ratios have a larger pinion gear which necessitates the larger offset.

So, depending what you started with (3.7 hopefully?) will determ,ine whether the 3.5 is a bolt in proposition.

I got mine to fit with the short ratio full spool but it took some machining to achieve.

Hope that helps.

[cambelt]

Also second hand gears that have run in 1 carrier sometimes will make noise if transplanted into another carrier .
Dave

[cambelt]

Live axels carriers give more ajustment than IRS ones and i dont think it equates to so many different carriers choices.
Sucks for IRS tho unless you get yr hands on the old tall ratio TRD centres . I havent had much to do with modifing IRS diffs as i really only rebuild standard ones for customers.
Dave

[JustenGT8]

Live axels carriers give more ajustment than IRS ones and i dont think it equates to so many different carriers choices.
Sucks for IRS tho unless you get yr hands on the old tall ratio TRD centres .
Dave

Could well be? Diff guy did have a 'tall' ratio live axle center in the shop so there are definitely 2 options....neither of which suit the 3.54 in an IRS

[madmont]

Here are a few pictures of g series 4.375 Hiace gears and 3.7 IRS gears. Measure the offset for yourself .
Pinion gears

ring gears

4.375 gears

3.7 gears

[JustenGT8]

Interesting but not sure it's clarifies to the point needed by Shane? It's well known in live axles mods that one combo of gears/centre needs a 3mm offset spacer added. With the insertion into the IRS centre you need to lose 3mm (actually a little more as you don't have the level of adjustment with the IRS as Cambelt1 pointed out).

I have just done pretty much what Shane wants ie a 3.54 into a G series IRS housing. I used a full spool from a 4.X:1 ratio live axle housing though which need that machining

[madmont]

Here are a couple of pictures to highlight some differences between IRS and live axle centres . The torsen is IRS

[ed]

wait till you try and put a live 4.88 crown onto an irs centre....

[1JZ.747]

my diff started out as a 3.9 cressida diff, i bought a 3.7 diff from an a70 supra and had my chassis shop change it over. so my understanding thus far of my current setup is its bascially an bunch of A70 internals in a cressida housing.

did anyone ever make lower ratios fors A70 supras liike they do the A series diffs in the JZA80's

[madmont]

Pic of 4.88 crown on IRS centre. You will have problems meshing with the pinion if you put
4.88 crown and pinion into a IRS housing

[amichie]

Ask this guy. He is very responsive to emails.

http://www.gearinstalls.com/

[email protected]

Also if you believe this link the Group A had a 3.23 diff.

http://www.turbosupras.com/pages/pag...mechanical.htm