Recomended Diff For RA28

[88_gz20]

I have a friend with an RA28. It currently runs an 18R-G, W50 and a T292 diff.

He is planning to do a SR20 conversion (i tried talking him into toyota motors but to no avail) He would like to know the best diff that will bolt in with the least hassle.

It needs to have discs on it rather than drums to make it easier to get engineered.

Any suggestions?

Thanks
88_gz20

[joecoolmk2]

so sr20det?

i'd just get a couple of spare centres and swap them in if one breaks. i don't know how much a t diff can take, it'd take a bit of a flogging. there's nothing that will bolt straight in with disc brakes. there are options of the mk2 f diff, it's a bit wider and you need to find st141 disc setup or adapt something else. then there is the g diff, but i don't think that'd be needed for an sr20det.

[88_gz20]

thanks, can you adapt discs to the T series?

[jeffro ra28]

A half descent 18rg will break t series diffs with what i have heard! If its a half descent
sr20 then it wont last long.

The most popular diffs that are being used with engine conversions are the G series diff from an Rn25)(or similar era) hilux. They can have rear discs easily adapted and LSD centres are readily available.
You will need to weld on the T series mount tho.

Another option is the volvo diff.

[BigWorm]

Go the volvo diff!
My 4AGTE eventually smashed the T series, it did take a little while though, I think because the single spinner didn't provide enough traction to cause much shock load to it.
No (decent) diff will bolt in, they all need brackets rewelded & alot of them need shortening, so your choices are pretty large. I went with a volvo diff as it didn't need shortening, wasn't total overkill, they're common & cheap to get hold of, have huge axles, and aftermarket LSDs are pretty easy to get hold of.
All up though the conversion cost maybe $2500, as I decided to go with new everything (discs, bearings, seals, torsen LSD, caliper rebuild, pads & shoes, adjustable upper trailing arms, 3" tailshaft to suit etc).
You could prolly get away with $1500 or so if you used a hilux G series diff with standard LSD, drum brakes etc, depending how much work you can do yourself.

[ace]

Have a read of this Volvo Diff Conversion thread.
http://toymods.net/forums/showthread...t=celica+volvo
i'm thinking that'd be the best option, otherwise a 7.5" F series Toyota diff modified to suit the real axles/rear Discs off a ST141 (Avante)/RT142.
I'd personally go the stock diff until it breaks, then weld it up while building the next one but if disc brakes are required for engineering....
Get him to ask his engineer if the standard Hilux drums would be enough for the rear? They're bigger than the standard ones.

[o_man_ra23]

I think the main question is what stud pattern does he want to run, and what offset wheels?? if he wants FWD offset with 4 stud, go the F series with avante discs. easy setup, and Joel (TurboRA28) has shown that FWD offset rims fit under RA28 with this setup quite easily.

If he wants 5 stud and deep dish, get the RN2x diff... unbreakable, ford 5 stud pattern to fit rims from XA-EL foulcans (gotta get ones with big centre holes, not hard really tho), so they are REALLY easy to get mags for. You can then adapt in MA70 rear discs with the calliper brackets which are available from these forums.

both diffs have torsen LSDs readily available.

Tell him to look into the 3SGTE or 1GGTE. Either of these motors will make an SR20 shudder, and both are easy to adapt a W58 behind. Also the 1GGTE has the advantage of being not only cheap, but a piece of cake installation.

Cheers, Owen

[sheepers]

what ever you do DO NOT USE KEYSBROUGH DIFFS!!!!! worst bunch of wankers ive ever delt with.
i wont go into what they did to my car (ra23 with crummydoor LSD)
but it cost 2500 and im still finding things they buggered. oh, and i got a quote to "fix" it (read, throw it away and start again) 1600.
if anyone in victoria wants to throw a brick through their front window you have my blessing!!!
latter,
sheepers.

[hemi twofifteen turbo]

A commodore LSD would be perfect I think, although sorry to hear Keysborough screwed it up. I've not heard many good things about them (keysborough), and they seem to be a rip. It's actually a borgwarner 78 series diff, used in valiants, commodores after VK (1985 ish), Fords, Nissans (old R30 skylines etc, pintaras) and prob more. They are a very good diff, with plenty of ratios around, quite cheap etc. The later models were 28 spline as opposed to 25 spine. I got my 25 spline LSD for $15 from pikapart but eventually blew it up (behind 265 turbo) I still have a mate pushing 300rwkw through a 25 spline LSD but he doesn't abuse it too much. VL turbo's and commodores onwards used the 28 spline diffs and they are running 10's or even 9's now on stock diffs, (VL weighs more than a celica by a bit too). It would be my first choice for a mid-hi HP output which could take a fair bit of abuse. But would require shortening etc.

[o_man_ra23]

The biggest downfall of the ol bog warmer is the fact that the lashing is adjusted by shimming. This is the biggest PITA around to do, and is much easier to do in a banjo style diff (front loading, have a look at any Toyota diff, or Ford 9"). Plus the centres are generally clutchpack style, which can be teh poo for carparks and general driving, as well as wearing out considerably quicker than the torsen style commonly available in the toyota range.

If he wants to stick with the original stud pattern, I would highly recommend an F series. Even if you need to cut it down, it will still be a lot less work than any of the other options. If he wants ford 5 stud, i would say hang the losses in the extra weight and get a G series from an RN2x... changing over mounts is the only major alteration needed for that.

Cheers, Owen

[thomasbl]

What sort of power output is your mate going for with the Sr conversion? Is he building a street, track, drag, daily driver? What sort of budget is he working to? These will also have an effect on what diff he might choose.

[barned01]

going on the assumption a SR20det is more or less the same package as a 3sgte, Ie torque curves would be similar
peak power would be similar.
Look at what people have used behind the 3s engine and go from there.
another thought is
what does the silvia use? 8", 7", 7.5"? If it was good enough for factory nissan, then you should get an idea of what toyota can equivalently provide.


TurboRA28 Would be the best guide for actually putting the diff to the test though.
He has an F series diff which is 7.5" as mentioned already, is pushing 220 odd RWKW and it seems to be performing nice for his purposes.
an SR20 would require similar demands i would have thought to the 3s so that sounds like the best go in terms of weight and ability.

If your mate is really wanting to use the nissan engine though, why not go to the extra trouble and mate the nissan drivetrain to the car as well? Yes it is bucket loads more work, but since we are offering reasonable answers to help him with a diff for his nissan engine, the least he can do for us is a guide on how to put the rear end of a silvia under an RA28.

ps. dibs on the 18rg if he wants to get rid of it cheap

[XR Pilot]

what does the sylvia use? 8", 7", 7.5"? If it was good enough for factory nissan, then you should get an idea of what toyota can equivalently provide.

Its spelt Silvia

They use an R200 viscous LSD, which is designed for an independant rear end, so it would be a hard job to fit, needing to use the Silvia rear suspension cradle, and somehow use the CV setup in the rear. It would be lighter than the borg warner diff though, and handle alot of power, the R200 is used in most rear wheel drive Skylines I believe, I *think* the GTR's have it too. And some of those push 500rwhp on the stock diff no problems.

But big job to fit it I reckon.

Oh I think they are equivalent to 8" I only know Nissan diffs as R160/R180/R200 or H145/H165/H190 (solid rear end diffs) etc, I don't know what they are equivalent too.

[tricky]

But big job to fit it I reckon.

I'll tell ya by this time next year, providing everything goes to plan! But yes, It'll be a HUUUUGE job, and may end up being to hard to set up properly. The go is fully adjustable mounts (or at least easy enough to alter) 'cos the alignment is going to be the achilles heel of this conversion.

[o_man_ra23]

Its spelt Saliva

Fixed for you

Cheers, Owen