Ok, Don't Laugh. 4wd Hr31, Is It Possible Or Not?

[HR31COUPE]

Firstly I'd like to state I'm not a 13yr old kid that has just been dreaming all day about this, It's something I have been seriously thinking about and trying to think of ways to go about it so I would appreciate serious replies.

My goal is to try and make my HR31 coupe into 4wd as I intend to use it for track work. I have spent quite a while researching things but as I still have things that I require answers on.

When people put RB26 motors into the R31 they modify the sump, obviously to remove the 4wd component but it is also for clearance issues with the cross member is it not?

Now I know of the R32 GTS-4, and being the closest relative to the HR31 I would assume some things would be similar between the 2.

Are front crossmembers from these vehicles able to be modified to fit into a HR31?

Also from my research I've found that the Stagea was available in a RB25DET Neo 4wd option. Is this factual or not? The reason I want to know this is in theory I should be able to put the 4wd sump from one of these onto my RB25DET neo motor but using the R32GTS-4 crossmember to get the required clearance.

This car is a long term project so $$$ over a long period of time doesn't bother me too much. I just haven't had the opportunity to see the differences between sumps, cross members etc. only what I have read so info from someone with experience in these matters would be greatly appreciated.

[Simon-S14]

yes the stagea comes 4wd with the 25, but it is auto only..

Anything is possible but at comes down to how much money its going to cost!

[BHDave]

It can certainly be done.

In all honesty i think getting the motor and cross member sorted will be the easy bit. Have you though about the differences in the front suspension between the r31 and r32?

I can't remember the site addy but see if you can find the site for "full race". They have developed an R14 (awd s14 with rb26). There will be a lot in common with what you are proposing, particularly front end set up.

[predator]

Wouldn't your biggest problem be getting the center diff to fit into the floorpan?

[GTS4WD]

OH MAN! The ammount of nights I have drempt about a stripped out ATTESSA R31!

Honestly.. Rb25DET out of a stagea.. You will need the whole front cut ie. Engine/loom/ECU/Gear box (make sure it is out of a 4WD ie. it will have a transferbox att. to the gearbox)

Things to consider:

- Front and rear diff. Are they the same Ratio? Will you have to get a different rear diff? From what I remeber.. (dont quote) Staggy = 4.083, R32 = 4.375. What is a R31 diff ratio?

- Front drive shafts should be ok. May need to mod CV joints slightly. Are the splines compatible with the stock 31 inserts?

- The front crossmember may have to be changed to accomodate the front sump. Will it bolt up to stock R31 mounts? Do you even need to change it?

- Floorplan. Do you need to mod the floor plan to accomodate the transfer box?

- The rear AND front ATTESSA electronics.. you will have to find both front and rear traction sensors/electronics etc. You will have to run the wireing around the vehicle. A workshop manual will help you with this greatly.. Gimme a holla if you need one with the neccessary info.

I think thats it..

I dont know if I had missed anything.. but there is ALOT of research to be done man..

If you are drop dead serious about doing this.. the best way to do this is as you go along.. step by step.. See if you can get a blown Auto R31 for a couple of hunge.. 25 for say 2K.. sell as much of the interior as you can.. perhaps the bottom end and the gearbox.. make up some money via this..

Thats the best way of doing it I think..

Give us a yell is you need any help or if it will go ahead.. definately something to keep my eye on!

[Fitzpatrick Speed Works]

a rear wheel drive correctly setup will be faster, as it is far lighter!!

But can be done especially if you would be willing to manual control the 4wd via either a master cylinder or an electronic device that feeds constant voltage to the attessa pump. If you want the computer as well thats where you will hit a really big wall.

[GTS4WD]

a rear wheel drive correctly setup will be faster, as it is far lighter!!

Yeah.. that it true..

Stock 31 Weigh's ~1300Kg..

Stripped 31 ~1100Kg

Attessa equipment ~150 - 200kg

The benefits (depending on what you will be using the car for) are quite minimal.. The fact toy have the advantage of the ATTESSA cancells out the fact you added the extra Kg.

This would be one seriously cool car though! It would be one MEAN drag car!!!

[Bl4cK32]

Things also to remember

The 4wd has a different design of the left front chassis rail to allow room for the drive line to the front wheel.

There is also a hump on the gearbox tunnel on the drivers side to have enough room for the transfer case.

U need to mod the actual chassis / body of the car to make it fit, not just slap in crossmembers.

[Danzzigger]

I'm one of those 13 year old kids you were mentioning (though im actually 17).... anyway I bought a rb25det gts4 engine from an auction (stagea engine) and then it hit me that I can't even use the engine cause of the new laws that will come in place (no turbos). But the 4wd system inspired me and I wanted to see what was involved, here is a link to the thread about it at the r31skylineclub: http://forum.r31skylineclub.com/index.php/topic,79062.0.html

Hope this helps a bit, I didn't press any further on how to do it, otherwise the club would have cracked the shits with me since I clearly dont have the funds to undergo the project.

Where abouts are you located? If your serious about doing it, I have a a stagea engine (no turbo, starter motor or crank angle sensor), and 2 x Auto 4wd gearboxes up for grabs if you need them. And if I could help out in any way I'd like to be apart of it . If you are going to make it a drag car, the Auto's might be what you are after anywayz....

~Danz

Edited July 10, 2007 by Danzzigger

[HR31COUPE]

Cheers for all the information and suggestions so far, It is certainly a hell of a lot to think about and a hell of a lot of work.

And please don't take offence at the 13yr old remark, I just understand that car forums get alot of "Dreamers" making threads about outrageous things that they never intend to ever carry out.

As for the Attesa, I'm not too sure if I want to go the trouble setting that up, I'm wondering if there is a reasonably easy way to make it constand 4wd.

I intend this to be a rather long term project due to the costs and research involved but I thought it would make an extremely unique and fun car.

Might see if I can find a reasonably priced shell to start playing with so that I don't have to pull my current coupe apart until it's time to drop the motor in.

[Danzzigger]

I intend this to be a rather long term project due to the costs and research involved but I thought it would make an extremely unique and fun car.

Might see if I can find a reasonably priced shell to start playing with so that I don't have to pull my current coupe apart until it's time to drop the motor in.

Yeah it would be an awesome car, I saw a gtr cross member on ebay just as I was thinkin of doing it, only like 150 bucks or something.... though your probably better off getting a whole frontcut off a gtr, it'll be pricey though.

And please don't take offence at the 13yr old remark, I just understand that car forums get alot of "Dreamers" making threads about outrageous things that they never intend to ever carry out.

No offence taken

Its cool I know I'm still a n00b when it comes to terminology and stuff with cars, I'm trying to get my head around it all so I'm used to pplz getting pissed off at me when I don't understand something. I just wish ppl would be more forgiving and willing to teach rather than bag thats all.

As for the Attesa, I'm not too sure if I want to go the trouble setting that up, I'm wondering if there is a reasonably easy way to make it constand 4wd.

I was told that the Attesa system is spossed to only be used for about 15 seconds, otherwise the clutch burns out or something, my guess is that for racing use they must use aftermarket sumps or something. If you check out the link I gave you, it'll firstly show that im a noob, but itll also list all of the obvious things you'll need to change such as.... cross member, suspension conversion, cut out of transmission tunnel, changing of rear diff? - (unless you can fit the r200 shortnose senders to the r200 longnose), and rear diff ratio

Edited July 10, 2007 by Danzzigger

[GTS4WD]

Quick point.. to Danzzigger and HR31Coupe.. I couldnt be bothered to read the R31 thread.. so i dotn know if i t was mentioned there.. but if you want to do a 5 stud conversion.. get a VL rear suspension brace.. You can also do this to the front one aswell.. They have a better suspension system AND 5 stud.. cheap as too..

Im with dazz on this too!..

If you need a hand.. give us a yell.. Id be MORE than happy to help.. =]