3000gt trailing arm install while keeping ABS and 4WS

[cheekychimp]

Are GTO axles any beefier? I really have no experience with GTOs other than the rear swap I did and as stated we used the VR4 axles. So HO5TYL are you suggesting that with some 'massaging' the GTO axles/entire subframe could be made to work? It's an interesting concept. I'm not sure how ratios etc would work out but I was given to understand the rear diff on the GTO is considerably beefier. As has been stated in other posts I think you can try to overcomplicate things but I also thought getting the guts of a GTO transfer case onto a VR4 would be a good move!

 

[H05TYL]

non turbo GTO axles have the same splines (and axle dia) as evo/4-bolt mech lsd. Turbo GTO's have much bigger axles and splines.

 

[cheekychimp]

But realistically could you fit a turbo GTO rear end in a VR4? What would be the obstacles?

Track too wide?
Rear Diff ratio?
Custom Rear Driveshaft section?

 

[raptorWagon]

I think it may be too wide, but here's a couple pics to help with the comparison
GVR4 subframe

GTO VR4 subframe

 

[RedTwo]

The GTO subframe is fairly different. It's longer (north south) and the mounts are wider apart. In your crazy 'let's just fab it up and rock everyone's world' world that shouldn't be too much of a problem /ubbthreads/images/graemlins/rofl.gif

The suspension arms are the same length as the VR4 but they are mounted further from the diff so the axles are longer (a good 35mm each side). In turn this makes suspension a bit funny, the mounts (top and bottom) are the same but now the lower mount is further out.

The diffs come in 3.307 and 3.545 ratio and have a different mounting flange for the driveshaft - that should be easy enough to swap and driveshaft length would be controlled by where the subframe is mounted, see point from above /ubbthreads/images/graemlins/devil.gif

The diff mounts in a convaluted way to the subframe (refer attached picture from ASA): the mustache brace (34225) mounts to the rear diff cover with 3 bolts and then links horizontally to the subframe, where the red arrows are pointing, rather than the chassis like our cars. The two rear mounts in that photo above are integral to the subframe.
The diff body is attached to two supports (34225L/R) which are then mounted to the subframe, a little further towards the rear on the two struts marked with green arrows. There are *no* vertical connections on the diff and *no* vertical connections between the diff and subframe.

I'm sure some fancy welding would solve it pretty easily. /ubbthreads/images/graemlins/grin.gif

 

[cheekychimp]

Yeah even in my crazy 'let's just fab it up and rock everyone's world' world that seems like a little bit too much work. I also don't like changing suspension geometry willy nilly just to get stuff to fit!

I would think if the correct rear diff ratio exists it would be far more realistic to possibly look at modifying the turbo GTO diff housing so that it would bolt to the existing subframe and moustache brace. I'd hazard a guess that the extra strength of the rear end comes from those thicker axles. You are going to be stuffed there as far as I can see if the axles are a different length. Even if you could get past the issue of the remaining suspension components coming up short, 35mm each side (total 70 mm) not to mention the extra track caused by the handbrake assembly in the hub. You are talking I'd imagine upwards of 5 cm on each side! /ubbthreads/images/graemlins/jawdrop.gif

Okay, that's not huge, and you might be able to offset that in part by some careful wheel offset choices, but you are going to need to do something similar at the front if you don't want it to look stupid. Anyway you look at it, it is still a huge amount of work but it would have some merit as a one off modification that allowed you to use stock GTO axles.

But yeah I think the sub frame swap is a non-starter. If I was even going to consider that much fabrication I'd have someone build a custom tubular rear end.

 

[Whoodoo]

Well I did a quick comparison of the wheel axles and the GTO wheel axle is, as you say, quite a bit longer to make room for the drum e-brake. Looks like I'll be needing that big long list of this and that before I crack into this one.

Of course there is the possibility of getting rid of the ABS... I want to keep it because I live in a fairly rainy area of the globe and with them big ole honkin' brakes on there, I want to give myself all the chance in the world to keep it out of a ditch.

Its funny though, I've never actually hit the ABS so maybe its all in my head and getting rid of it won't hurt much.

 

[RedTwo]

Bah, this Dodge Stealth manual is useless, they don't appear to have the same components as JDM cars!
The TT GTO rear diff bearings (outside - where the axle shaft enters the diff) are beefy!
The VR4 (and NA or auto turbo GTO, most Evos, etc) has 72.0x35.0mm (O.DxI.D.), while the TT GTO has 82.50x45.24mm bearings!
Out of interest, the non turbo GTOs have pretty much the same diff components as the VR4 (gears, LSD unit, axle cups) and all GTOs have the same subframe and diff mounts/mustache braces.
So if you fab up a GTO diff to VR4 subframe conversion, you could use any GTO diff. Then you would just need to sort out the axle shaft between the CV joints - sounds like an easy job! /ubbthreads/images/graemlins/jawdrop.gif


Awesome, on a slightly unrelated note, The Japanese Police GTO interceptors are listed in ASA (Z16A MNGF9 and MJGF9), unfortunately smoke screens, bullet proof glass, hand cuffs, sirens and police lights are all aftermarket accessories /ubbthreads/images/graemlins/rofl.gif

 

[mitsuturbo]

Quoting Whoodoo:
Of course there is the possibility of getting rid of the ABS... I want to keep it because I live in a fairly rainy area of the globe and with them big ole honkin' brakes on there, I want to give myself all the chance in the world to keep it out of a ditch.

Its funny though, I've never actually hit the ABS so maybe its all in my head and getting rid of it won't hurt much.


No matter how much "ABS sucks on our cars" i've read and heard, i can't buy into it. ABS saved my ass a couple times, and lack thereof caused some damage to my vehicle once (when it was hot and dry out, nonetheless), and almost again another time. If my vr4 ABS quit working, i'd do everything i could to get it working again. Used/cheap parts are plentiful. IMHO there's no reason to NOT have ABS unless it's a track car, especially where we live.

Relevant sidenote: Is it possible to put a DSM ABS cpu in our cars along with DSM 5lug spindles, so ABS will function properly, or does the DSM system differ too much?

 

[cheekychimp]

Quote:
No matter how much "ABS sucks on our cars" i've read and heard, i can't buy into it. ABS saved my ass a couple times, and lack thereof caused some damage to my vehicle once (when it was hot and dry out, nonetheless), and almost again another time. If my vr4 ABS quit working, i'd do everything i could to get it working again. Used/cheap parts are plentiful. IMHO there's no reason to NOT have ABS unless it's a track car, especially where we live.



Funny that you mention this. My 8G VR4 ABS was CRAP! I literally sailed past and even through junctions standing on the brakes not because I was skidding but because the ABS was 'confused' and I was free wheeling. It did seem to be rough road surfaces that cause the issue and it seemed to behave very well on well surfaced roads but even so I regretted not pulling it because I think it attributed to the final crash and demise of that car.

But despite the fact that I have removed the ABS from my other 6G VR4, I had to stand hard on the brakes in the stock car this morning and I was impressed. Good pedal feel, locked up the wheels hard enough to give good tyre screech but no sliding and I stopped well short of the back of the postal truck pulling into my lane. If that is how the ABS intends to behave from now on, then it is welcome to stay on this car! /ubbthreads/images/graemlins/worthy.gif

 

[Whoodoo]

I believe that is the course of action I will be taking. There have been some who have put a 1g ABS ECU in their G with success and, if the rear sensor is the same between the GTO and GVR4, then I don't think I'll have any issues.

 

[cheekychimp]

Quoting RedTwo:

The TT GTO rear diff bearings (outside - where the axle shaft enters the diff) are beefy!
The VR4 (and NA or auto turbo GTO, most Evos, etc) has 72.0x35.0mm (O.DxI.D.), while the TT GTO has 82.50x45.24mm bearings!
Out of interest, the non turbo GTOs have pretty much the same diff components as the VR4 (gears, LSD unit, axle cups) and all GTOs have the same subframe and diff mounts/mustache braces.
So if you fab up a GTO diff to VR4 subframe conversion, you could use any GTO diff. Then you would just need to sort out the axle shaft between the CV joints - sounds like an easy job! /ubbthreads/images/graemlins/jawdrop.gif




I might have to look into this seriously. I could pretty much pull the rear subframe off the 'Ultimate' build and fit it to the stock car even if I decided to keep the 4WS. I'd have to change a few bits and swap brakes over but the rear diff ratio would work, I'd gain a plate LSD in the stock car and retain 4 bolt hubs so I could retain the ABS as well if I wanted.

I'm pretty sure this could be done, it is just a shame it might need custom axles. The ability to use stock axles would be the real deal maker for me. I will seriously have to lay all this stuff out on the floor and figure out just how wide it would be with a suitable offset. If it could work with stock axles I think custom tubular control arms might be an option. Hell I can see this coming off!

Edit: I suppose it would be wishing for too much to assume that the turbo GTO diff guts would fit into the VR4 housing or that the VR4 housing could be machined to accept the bigger bearings?

 

[doommachine]

I know this is thread necromancy.. but for other readers the differential itself is the same, only the housing differs. So yes, any GTO diff will fit into a galant; if the ratios are different it is not terribly difficult to remove the ring gear.

Additionally; the differentials themselves are manufactured to fairly good tolerances and thus if you reuse the ring gear from your galant diff, so long as the backlash on your original diff is OK you should be able to re-use the shims and have the same backlash. I swapped a cressida limited slip diff into a JZX100 chaser in this way, and the measured backlash was literally exactly the same. Of course make sure you mark which direction and side the shim is from.

 

[EMX5636]

Have you decided what to do with rear struts? RedTwo posted that that the lower strut post is larger on the GTO (his trailing arms came from a Diamante based chassis). I'm considering this swap for my GVR4, but have to see if K-Sport or similar coilover companies would sell just the lower threaded strut body for a 3KGT.

 

[RedTwo]

It may pay to look into GTO rear suspension. They're longer and the top hat shouldn't be too different, if not identical.

 

[doommachine]

But not 2" longer, only a few CM. I guess some slight lowering would be OK but on a hard bump, just how far will the wheel or suspension travel? The body relative to the length of the shock will be 2" closer with the same amount of travel.

Also, redtwo you mentioned something about the control arms, I'm assuming you'd need the 3000gt control arms as well? They look similar-ish..

Actually, with the evo X shocks, surely the bushing can be pressed out and replaced?

 

[raptorWagon]

Talk to English Racing, they put a 3kgt vr4 rear diff under Jeff Bush's drag 1g DSM. /ubbthreads/images/graemlins/wink.gif