IRS into MX62 Cressida?

[floody]

Crazy idea? Possibly pointless, true - but I'm not really interested in that, just whether its hypothetically possible without utterly massive refabrication.
Just from a technical point of view, how different is a MX62 floorpan from a GX6x chaser/mkII etc? Is there a rear cradle that would go close to fitting, maybe MA61?

On a semi related note, would GX61 lights, bumper, bonnet bolt up?

[thechuckster]

(waits for wilbo to chime in here) ... ...

floorpan is very different

just like the RT142 (is that the right model?) IRS into the RA40, this requires surgery to chassis rails, probably surgery to the cross member and lots of fabrication all round.

Anything that 'kind of' fits is a lot of work.. having said that, anything that gives you an F-series diff and potential for good skids is worth looking at

... no idea about compatibility of body parts.

[Norbie]

As above it will be quite a lot of work, so if you go down that path you might as well use decent IRS, eg MA70 or even S13. The semi trailing arm IRS setup used in early 80's Toyotas (Celica, Supra, Corona, Cressida, Crown etc) is crap.

[floody]

Ahh fair enough. I was hoping it would be like an R31 skyline; add the mounting points for the crossmember and bolt in... Apparently not.

Definitely interested to hear if anyone has any ideas on the body parts though. I have access to a quite straight and tidy MX62, I was thinking it could be the basis for an interesting project. As for the IRS, mayhaps I've just looked at too many slammed, mucho rear negative cambered GX62s lately in my Jap car mags - had a vision of it dropped on fat deep dish 14s or 15s, maybe a 5MGE or 7MGE.. Just wouldn't be the same with a live axle.

[gianttomato]

Didn't some Jap models come with IRS? Even the 30 series Cressida coupes (although strictly speaking called the MX41) had IRS. Looked very much like the MA61 trailing arm setup.

Argh...yep GX62.

[floody]

Didn't some Jap models come with IRS? Even the 30 series Cressida coupes (although strictly speaking called the MX41) had IRS. Looked very much like the MA61 trailing arm setup.

Argh...yep GX62.

Yeah that was where I started my train of thought; I had assumed they would be as blase as Nissan in terms of slapping a 4 link rear end in something and packing it off the colonies; apparently they are more thorough at Toyota.

[Robbos_Toyotas]

Yeah that was where I started my train of thought; I had assumed they would be as blase as Nissan in terms of slapping a 4 link rear end in something and packing it off the colonies; apparently they are more thorough at Toyota.

Jag rear end and bolt the whole cage in is one idea....you would honestly have to measure it all up.

However I honestly dont think the conversion is worth your while. If you want good times, both around track and in a straight line, solid rear end is better anyway! And i honestly think, adapting an irs system into the car is not going to make it ride any better, unless you spend big bickies setting it up perfect!!

if you decided to stay solid, (as i know there are no lsd's for the cressida's "e" series), I wouldnt bother with the over-rated F series though. Go straight up for a hiace/ hilux G series rear end, which are proven tough using a ma70 supra lsd centre.

blake

[wilbo666]

MX63 came with IRS. As well as GX6x?

As others have said you will be in for a BIG job trying to put IRS where the stock live axle was!

It would be like trying to put the MA61 IRS into an RA60 (no noe does it!).

Cheers
Wilbo

[Norbie]

If you want good times, both around track and in a straight line, solid rear end is better anyway!

WTF? Straight line yes, but around a track no way. Show me any racing formula where a solid axle is used, apart from those where it's mandated (eg NASCAR or the super taxis). Well designed IRS has very clear benefits, but the issue here is whether those benefits are worthwhile compared to the hassle of a conversion.

[tricky]

It would be like trying to put the MA61 IRS into an RA60 (no one does it!).

Not when you can get an RA65... Not only is it less ugly, it has IRS... albeit the shocking semi trailing arm design toyota seemed to love so much!

Robbo, I'll agree with Norbie here. Live axle for the drags, but no way a well prepared live axle will flog a similarly well prepared (and designed, everything else being equal) IRS around the track. And for street, IRS is definitely king.

Floody, this is an area I have been doing lots of research, measuring, scrabbling around under other peoples cars. Almost any live to IRS conversion is gonna be a serious challenge, and unless you have the time, money and skills to do it properly, the results won't be fantastic. Even if you manage to rig up some adapters for an IRS subframe to your existing mounts, you'll probably have to remove some metal (dunno about your car specifically, but I'm sure it's pretty universal), 'cos otherwise the subframe just doesn't sit close enough to the underbody without interfering with stuff. The other thing is the new cage/adapter should be made with some adjustment, because alignment is the thing that will make or break an IRS conversion.

This being said, it's a challenge that I am willing to address, and nothing listed above is insurmountable. It all depends on how much patience (and $) you have. If you do it, good luck, and make a thread!

[Robbos_Toyotas]

WTF? Straight line yes, but around a track no way. Show me any racing formula where a solid axle is used, apart from those where it's mandated (eg NASCAR or the super taxis). Well designed IRS has very clear benefits, but the issue here is whether those benefits are worthwhile compared to the hassle of a conversion.

supercars have solid rear ends mandatory? they come out with irs factory, so changing to solid for the sole purpose of racing, must have been done for some reason. Surely suspension is where one team could beat another, so i have no idea where this thought come from. Isnt the purpose of racing to beat fast times, meaning utilising the best possible setup for a race?

About the only car racing i know using irs is rally, and the hybrid cars (ie F1, indy etc)

edit: i totally agree for comfort etc around town, IRS is a killer.

[thechuckster]

they change to solid to make the cars all behave the same - otherwise they'd all have fancy, complex suspension setups. Most of the engineering work in those cars is restricted or regulated somehow to make competition a 'level playing field'.

[floody]

Now, this will make the thread's origin seem a bit useless, but to be honest the idea really came about from seeing the typical over the top GX61s a few people had built in Japan; the idea of the IRS conversion was really just to create silly looking negative camber to go with dished rims, stretched tyres etc.
Thanks for the excellent and useful replies though!
Probably more economical to shred the MX62 into bits and import a GX61.

This GX61 here is the car that inspired the original post by the way;


More gratuitous dish and slammage at http://www.gallery-l.com/

[Robbos_Toyotas]

they change to solid to make the cars all behave the same - otherwise they'd all have fancy, complex suspension setups. Most of the engineering work in those cars is restricted or regulated somehow to make competition a 'level playing field'.

I just find that hard to believe, as why wouldnt they just make them use the same IRS setup??? Such as formula 1 cars do....All the same suspension with IRS

[floody]

Robbo, its not just "all the same setup", its literally all the same components, geometry etc.