[seanzook06]

hi all. I have recently acquired a NT LWB maruti, I have big plans for it in order to turn it into a largely capable vehicle for the type of driving I generally do, mostly the hard sandstone rocky terrain in areas around sydney, I want this car to be as capable as possible, but it will be engineered

Here Is What I have in mind
- j20a and auto combination

- sierra transfer with 6.5s

- hybrid toyota diffs comprising of a shaved hilux centre with 60 series tubes, hubs, etc. cut down to 50mm wider than WT sierra

-37 inch roxxzillas on 17x7 p25 rims (not many options available for 17x7 wheel offsets unfortunately, also will only be engineered for 33s)

- 4 link rear suspension, 3 link front. probably using vitara or jimny coils depending on required spring rate.

suspension will be aimed towards maximum stability and predictability rather than hektik flex. also low as is feasibly possible

- mid mounted winch

- vitara power steering

- boatsides

- front clip pinch

- roll bar behind cab,



lots of speed holes to lighten things up a bit.

so far problems I can see are

this is going to be a heavy car. there is a lot of weight in toyota diffs when compared to suzuki stuff, but for the sake of engineering and running a 37 offroad semi reliably i think it is needed,

crawl ratio is going to be very low, around 96:1, which is low for an auto from what I have seen, however 37s should speed things up a bit.

at the end of the day I want this to be as light weight and close in width/length to a sierra as reasonably possible, in order to retain the suzuki capability when compared to other bigger cars.
what I dont want is a sierra slapped on some big wide diffs, with floppy suspension, that is now pretty much just another hilux or patrol

please critique away!

[Brenno]

I think it will be too heavy to be engineered without a GVM upgrade.

Not sure what NSW is like in regards to tyres. Might be able to get away with 50mm increase in the tyre size that came with the axles you are putting under it.

Is 4.9s and 35s a better option. 37s are big!

[seanzook06]

I have been told that tyre size is in direct relation with wheel bearings on the supplied diff, so a 34 is legal on a 60 series wheel bearing in NSW without additional swerve testing provided I stay under 7 inches of added roof height above standard. 35s is an option, but if that was the case I would almost certainly step down to Suzuki diffs.

A 37 is big, but I want to stick with that tyre size, we have a few comps near me and the things that limit Suzuki's in the modified classes is always tyre size, it seems everyone is going bigger, so presence is definitely a 37.

[Gwagensteve]

I’ll reply in more detail later, but where are you getting 7” of lift as permissible? My take on VSB14 was 75mm max.

There are some big 79’s getting around that are apparently(?) legal but that’s not the same as starting with a much lower car with a much smaller tyre.

You’re going to have to look very hard into packaging. Toyota front knuckles are much bigger than Suzuki and this will heavily restrict space between the chassis and the knuckle. Likewise around the sump and chassis for the front axle.

[sideways]

Have you talked to an engineer about your hybrid diff housings? To me that seems the pivotal part of your build. It comes down to their interpretation of the rules.

Would bundera diffs not achieve the same thing? Easy enough to convert to fully floating or narrow down if you like. They'd probably make it simpler to engineer. A bundy diff is roughly 100mm wider than an SJ70.

FWIW solid axle hilux/40/60/70 hubs are essentially the same up to 1999. Same bearings/brakes/cvs/ect.

A 37 on a +25 rim with 1400ishWMS diffs seems to narrow to me in terms of fitting it all in and retaining turning circle. I'm not saying it's impossible but it's going to be some work and compromise.

[Gwagensteve]

Agreed. The packaging around the front end will be very very hard. Also, and engineer won’t accept ANY tyre contact with anything, so you’ll really have to build allowing 25mm or so of clearance ad full flex/lock. With the constraints of a Sierra, 25mm of clearance is a lot to achieve.

[seanzook06]

In terms of addressing both the roof height and the hybrid axles, I have been in contact with rampt customs, and they say that I can get a 34 on hybrid Toyota diff engineered, without a swerve test, provided the overall roof height of the vehicle does not increase by more than 7inches. If that is correct, I should be able to legally run a 33 provided the suspension does not raise by more 3 inches, however my goal is as low as possible certainly less than 3 inches.
In terms of front end packaging I do agree it is going to be very tight, but I think it should fit, if necessary I can widen the housing to slightly wider than wide track sierra width, this should help with the positive offset wheels reducing space up front

[Gwagensteve]

I strongly recommend you read VSB14. The steering and suspension section is here:

https://www.infrastructure.gov.au/sites ... 015_v4.pdf

I don’t know where the reference to 7” (175mm) comes from. VSB14 is very clear that lift above 150mm is not covered under the NCOP and that lift above 50mm requires a lane change test. NSW does still have some unique requirements but they will be documented on your registration authority’s website.

Note page 75 (LS7 checklist) - total vehicle height cannot increase by more than 150mm. Not 150mm +25mm for tyres.

A 34” tyre alone is 100mm of lift. And as that exceeds 50mm of lift, you’re doing a lane change.

Again, I’ll put more time into a reply when I can. Bear in mind I own, have built and drive with a number of cars that are very similar to what you’re proposing.

[seanzook06]

I will take some time to go over vsb14 again.
I look forward to a more detailed reply, part of my inspiration for a build like this is from seeing rigs like yours and built cars from the Victorian Suzuki club in action, and comparing them with some of the built cars in the NSW Suzuki club that I wheel with often.
In terms of capability they are chalk and cheese. we have big engineered sierras, but they are all too unstable, and essentially end up being as big as a Hilux or patrol, and make things look a lot harder than they are. I drive all of the same stuff with minimal fuss in my mildly modified Sierra. Yet People still have the idea that big lifts, spoa, and the like are what make a capable sierra. My goal is to essentially end up with something as close to lwb sierra size as possible, but with the suspension characteristics I want and tyre size.

[Gwagensteve]

Hmm, I thought I had my computer with me but I don’t, I’m stuck on my iPad for now.

NSW has always had a bit of a thing for taller/bigger cars. Back in the day when there was more access to big sandstone steps etc I could sort of see it but I can’t really now. Anyway.

What you’re proposing is a very big and complex build. It’s also expensive once you’re talking about custom axles. Principally though, it’s a long, long project. The longer it takes the more chance your engineer will retire/quit, (this is surprisingly common) the rules will change, meaning the project can’t be completed, or you run out of interest, which is very, very common. There’s also the small issue that, as you have already said, “I drive all of the same stuff with minimal fuss in my mildly modified Sierra”

I don’t think 37’s are practical at a 92” wheelbase. They do not fit in the front clip. The bonnet will have to be cut. They will come up above the top of the tub in the rear. Yes, anything is possible but I don’t think the work is worth the return.

Have to run now but more will come.

[seanzook06]

so looks like 37s are off the cards.
a few reasons for this:
packaging is going to be a nightmare
I have heard from an engineer that cutting into the bonnet is not allowed for tyre clearance.
that ruins any chance of running them without having a much wider car, with heavily limited compression travel,
17x7 wheels arent available in any good offsets and 17 inch wheels are heavy
all of this for 1 inch of ground clearance over a 35
that is too many complications and compromises in my opinion

so now the step is down to a 35 roxxzilla

without the need to run 37s I think it is best to step down to suzuki based diffs if possible. however my one issue with this has to do with the terrain I drive. sandstone and rocks have traction and this put a lot of stress on the driveline, I am not sure if a suzuki based rear end is up to that stress even with full float.
I doubt it would take much to bind up the rear end and snap an axle like a twig.
thats partially why a lot of people up here swear by hilux diffs.
however I havent seen any suzuki based floaters in action nor heard of anyone up here experimenting with that sort of thing
I dont want to build and engineer this car on suzuki diffs only to find out the rear end is unreliable

some opinion on this and experience would be great

so I am thinking these are my diff options

front:
- WT with chromo axles

- Vitara rear with sierra knuckles

- shortened hilux

rear:

- bundera rear full float conversion (cut down to WT width)

- vitara full float

- Sierra full float (ADD kit or similar)

personally I am inclined to go with bundera rear floater and hilux front with shortened tubes,

that is from a point of being able to get hilux diffs being able to run a larger legal road tyre so I can have acceptable road gearing while still having
good low range. and the larger diameter of a hilux axle when compared with a suzuki one for strength purposes

downsides I can see are weight and clearance however.

I am interested to see peoples experiences with suzuki based axles on 35s on high traction surfaces

[Gwagensteve]

Couple of quick things for my lunch break- No answers here, only commentary.

There are loads of good 17" rims for 6 stud cars because high positive offset is now the norm due to cosmetics/handling/brake clearance/IFS steering geometry.

There are stuff all 15" rims in either 5 or 6 stud with much positive offset and you'll run into steering arm and brake clearance issues if you try to go too positive.

Building the axles wide and running lots of positive offset gets the knuckles inside the rim (maximising axle tube length for mounts/clearance), gets the scrub radius down to prevent steering kickback and lowers steering effort.

Vitara rear housings are massively lighter and hilux/landcruiser.

There are issues with axle seals if you're building a custom rear Toyota floater. Landcruiser rear spindles have provision for an oil seal in the nose of the spindle, which rides on a larger diameter section of the 60 series shaft. If you use hilux front spindles I don't believe that provision is there and "broomstick" axles won't have the increased diameter for the seal. I recall there being discussion about this in Toyota circles.

Toyota brakes are very, very heavy. especially drum rear.

You can run a 30 spline Toyota axle with a Sierra or Vitara centre. The carrier bearing journal is the same size between Sierra and Vitara and will clear a 30 spline axle.

With 60 series knuckles you can theoretically run the biggest tyre a cruiser axle can be certed for with a Suzuki centre for the clearance.

If you drop to a Sierra front knuckle the best you can ever hope for on a cert is 31"

Front hub bolts are the weak link with a front Sierra cromo axle/CV

Rear axles are the weak link with a 26 spline full float rear. You will break them with the car set up as you describe. (sticky 35/auto/6.5 transfer)

With a stock LWB chassis, the taper and chassis width aft of the rear axle is a substantial issue for WT width axles. There is no room for a shock outside of the chassis and the springs are far too inboard. This significantly reduces instability. This is something of an insight into how these builds get complex and how end up juggling lots of compromises. (least of which is what the engineer will let you do) Joshyboy's car is radius arm so he has roll stiffness and massive durability regardless of where his shocks and spring are but trades off some flex and flexibility of roll centre placement. When I went from radius arm to 3 link/panhard rear stability went out the window even though the shocks, springs and roll centre didn't change. With a 4 link rear, getting triangulation of the lower arms is very hard and getting roll stiffness back is also very hard. (even getting a swaybar in there is tough as there is little room beside the chassis of you're on a WT track width and don't have crazy negative offset rims.

This is all relevant at this point as rim offset, track width, roll centre and wheel travel/articulation will all force your hand on component placement. This is the stuff that will massively slow the project when you're trying to work with an engineer.

[seanzook06]

commentary is much appreciated
interesting, when crunching numbers on wheel offsets, a hilux diff with p10 wheels has a track width 1mm wider than a wt sierra with n13 wheels, both of which are common readily available wheel offsets in a 15x7.

I personally used to have that track width on my old tyres, and while a little wide for my liking, it did work quite well for the terrain I drive.

this makes a sierra or vitara diff stuffed with 30 spline axles and 60 knuckles, at hilux width with p10 wheels a real possibility, provided the engineer will play along.

thats all for now, reply on suspension ideas will come later

[BlueSuzy]

For reference, My 88 Sierra Lwb was engineered in 2014 on standard width Hilux/Bundera and 35's. Completely custom3/4link on coilovers and swaybars. Hilux ps box, 80 master, 60 booster, Vented discs all round, 6.5's, +++more. So much is similar to this build.

I've been through a lot with my build.

Almost 10 years later, the rules are still the same for NSW but you need an engineer that will want to do it. Further brake testing now though. A lot were running away from 4wds way back in 2014 as the cops were cracking down, VSB's were changing literally in a day, Then going back again, Then harsher VSB's came out, The system then changed with the VCCSC and then later engineers licences were revoked from dodgy engineering. (I know of a Lwb on 60's series that probably shouldn't of been on the road) And so, I was lucky to find one to do the 35"s.

So when are the rules changing again? Who knows, But hopefully not half way through your build like mine was making me question it every day.

Would i do it again? Yes and No. Leaves are easier. I should of picked a better motor when i originally built it.(g16b failures killed my motivation and broke my heart many times, And now good luck finding a good motor)
Would i change anything? Tricky one. I've now changed the motor to something modern and common once again. Thoughts in my mind have been to use a Hilux rear housing, Easier axles to find than Bundera, But Ive never broken anything other than bent tailshafts, rocks... I also like how the bundy pumpkin offset is matching the front for those larger rocks to go under the axle tubes.

seanzook06 wrote:

hi all. I have recently acquired a NT LWB maruti, I have big plans for it in order to turn it into a largely capable vehicle for the type of driving I generally do, mostly the hard sandstone rocky terrain in areas around sydney, I want this car to be as capable as possible, but it will be engineered

Here Is What I have in mind
- j20a and auto combination Getting rare, When an engine goes, where do you find another?

- sierra transfer with 6.5s Cool

- hybrid toyota diffs comprising of a shaved hilux centre with 60 series tubes, hubs, etc. cut down to 50mm wider than WT sierra As far as i know, Everything in the front of a 60 is the same as hilux, but housing diameter, width and centre is bigger. axles, hubs and cv's are hilux size.

-37 inch roxxzillas on 17x7 p25 rims (not many options available for 17x7 wheel offsets unfortunately, also will only be engineered for 33s) Should be able to get 33's engineered on Hilux.

- 4 link rear suspension, 3 link front. probably using vitara or jimny coils depending on required spring rate.

suspension will be aimed towards maximum stability and predictability rather than hektik flex. also low as is feasibly possible Cool, You need swaybars so keep that in the build design

- mid mounted winch Goodluck, Depends on your arms, Auto, Exhuast etc, Theres a lot with not much room left.

- vitara power steering Can work, I went ifs Hilux, 60series+ is another option

- boatsides Cool

- front clip pinch Cool but flare issues and headlight clearance is not going to be fun

- roll bar behind cab, Cool, You wont get one engineered inside.



lots of speed holes to lighten things up a bit. Won't do much

[Gwagensteve]

I agree, I don't think I'd choose a J20 to start with at this point due to size, (they're loooong) age and supply. The catch in finding an alternative engine always becomes the gearbox though, and more modern engines typically have more modern management that requires more time and $$ to work around. Most of the engines we seem to (still) get excited about for conversions are at least 20 years old. More modern engines also tend to be very specifically engineered for their (FWD) application with issues like no side engine mounts and plastic intake manifolds that won't work in a RWD application, for example. More common crate engines broadly supported for swaps/motorsport use tend to be expensive and more engine than a Sierra can handle.

I hadn't discussed the mid mounted winch but I agree they are a nightmare to package and get clean cable runs etc. Also, if it ends up under the car how much work is it to get to and service?

I also hadn't discussed the boat side thing. Again, this might be something that's cool in NSW but not in Vic (although the only mention in VSB14 of state differences were in relation to LS7 and LS8) but locally, engineers will not entertain cutting/modifying sills at all. They can be protected etc but not removed. Any work on them must be a professional quality repair back to original. This is definitely a more recent change.

Pinching the nose dramatically improves headlight clearance. Yes, it does complicate flares.

Speed holes reduce the weight of RHS, for example, by ~30%. I can't fabricate using factory thicknesses so I have to do what I can to reduce the weight of everything.

[seanzook06]

j20 was simply chose, because it is (slightly) newer than g16b and there are gearbox options suited to sierra. I have seen c18det, sr20, k20a or similar 4 cylinder swaps, but never looked into them because Id prefer to stay suzuki based where possible.

so essentially here we are now with the build

Here Is What I have in mind
- j20a and auto combination. or another viable more modern engine (open to suggestions based on experience)

- sierra transfer with 6.5s (keen to stick with a sierra transfer)

- hybrid sierra diffs with 60 full float ends, 30 spline axles. aiming for 1397 between WMS (or vitara rear diffs) anyones experience with sierra 3rd member strength would be helpful here.

- 35 inch roxxzillas on p10 rims 15x7 (purely because this is a common size rim)

- 4 link rear suspension, probably end up being coilovers mounted just inboard of the chassis rail (cant see any other viable solution without chassis cutting and narrowing. big no from engineers)

- 3 link front. probably using vitara or jimny coils (or coilovers depending on how tight things get)

suspension will be aimed towards maximum stability and predictability rather than hektik flex. also low as is feasibly possible. (swaybars are a definite at this point, especially with shocks further inboard than I would like)

- mid mounted winch. (would be nice, but low priority compared to fitting everything else in

- vitara power steering (again, open to suggestions, vitara p/steer is pretty bolt on and easy, why I made that choice)

- boatsides


- front clip pinch. (in keeping this thing low it is required, headlight clearance making flares is just a little more fabrication, certainly not rocket science

- roll bar behind cab

lots of speed holes to lighten things up a bit. (any shaved weight is better than none)

I would appreciate the holes being picked. the more refined I get this idea, the more details I can properly give to the engineer, before getting his opinion on the build

[BlueSuzy]

I'm also really unsure about the hybrid diff housings. Something the engineer will have to work on. Don't be surprised if many say no. If Benji is doing them, He'll have to work with the engineer too, On what the engineer wants. They're all different. We have rules here, but they're all read differently.

Like Simon in Tas with his LWB. Hilux diffs, Engineer wanted the wheels to make it the same wheel track as a sierra.
Like another guy in NSW, Scott from memory, way back before mine was built. It was a Rodeo with Patrol diffs, He was told to shorten the diffs to make it the Rodeo track width.
This is simply wrong as its pretty clear in the vsb files, But they had to do what they had to do...

Roxillas will be a no for engineering. Bias ply. They work great offroad though.

[seanzook06]

The hybrid axles are likely the hardest part to get engineered. I have contacted multiple engineers, but as usual, most don't want to be involved in this sort of build or there is radio silence.
Roxxzillas will definitely not be engineered due to being UTV tires, however I am willing to take that risk anyway and tyres are easy to change if defected

[sideways]

Why go to all the effort of a 50mm narrower diff housing when you could just get some more positive offset rims?

On rocks and in comps with 35s I reckon a suzuki 7" centre wont be tough enough.

[sideways]

I've got different priorities and I don't drive your sort of terrain but I like stuff to be readily available and not to rely on custom fit or special aftermarket parts that may not be available in the future. I totally get building something unique that nails down the perfect set of compromises but I think you're really picking up a lot of cost/time/flakiness compromise for a minor weight saving per diff, half an inch of pumpkin clearance and 50mm of WMS width. Not to mention likely a headache with the engineer.

To pull off this Sierra/Landcruiser hybrid you're looking at:

Custom housings F+R
Custom axles F+R
Custom full float conversion
RD208 ARBs with 30 spline side gears
And you're stuck with either factory second hand diff gears or aftermarket ratios that don't match up with factory available ones (If you break one in years to come will you be able to still buy them?). Last year I had a heck of a time just finding a -good- set of SJ70 diff gears. Wreckers wanted double the price I recently paid for new 8" Toyota gears.

VS Hilux front which is cheap, easy, we know will hold up and everything you could ever want (aftermarket or factory) is available off the shelf. If you wanted to run 37s then you could easily make it tough enough. On the flip side I imagine Bundy housings and axles are very hard to find these days. You could do a custom offset pumpkin 8" housing at 75 axle lengths and have off the shelf parts and the right WMS. I don't know if bundys share that pumpkin offset/axle length with 75s already, there might be enough in it that you can weld 75 rear spindles into a bundy housing and get the lengths right. Chromo 75 axles are available so that's a clear upgrade path if you find you need it.

If you broke it first trip out in the season or first event in a comp I'd hate to be missing out on that wheeling and have the car sitting broken while you wait on custom parts or are trying to hunt down a good set diff gears from the front of a 25+ year old car. A great thing with toyota stuff is I can call up and have seemingly any part, brand new in a few days at quite reasonable cost and that's in country W.A. With a Hilux diff even if you broke a longfield or a locker you can just slot in a stock part and get back on the tracks.

I don't mind the idea of a bunch of custom parts if it's bomb proof but I think you're going to run into the limits of those gears at that tyre size/use.

IMO if you're sticking with Sierra gears then you're better off sticking with Sierra swivels too. The potential of a 30 spline axle exceeds the potential of the 7" Suzuki centre. It sucks to have the diff gears as the weakest part of your setup, not only are they a pain/expensive to replace but they're much more complicated to upgrade than axles/cvs/hubs.

[seanzook06]

You do have a very good point there, personally I haven't heard of a
Properly set up 7 inch centre fail, only dodgy locker installs with improper set ups. But although I prefer to only crawl things. This will also be used In a comp setting, which is a completely different style if wheeling. I have trouble believing a sierra diff will last long with the abuse it will get.

[Gwagensteve]

I wouldn’t advocate a sierra centre with 30 spline axles. They will fail.

I couldn’t accept the weight of a housing designed for a 3tonne+ GVM vehicle in a 1600kg car. 60 series rear brakes weighed 46kg alone.

The only custom parts in my rear end are the broached side gears. The axles are off the shelf aftermarket parts.

A hilux third member will fit in a vitara rear housing with a redrilled pattern and 3mm spacer on the mounting flange.

[Gwagensteve]

Also, a quick word about competition. Comps tend to be very destructive. A car that’s had lots of work put into it to be legal won’t stay legal long if it’s comped either through damage, rule requirements or modifications made to improve competitiveness. Whilst I’m a bit biased as I’m not at all interested in competition, it is worth keeping in mind compared to a recreational car you need to overbuild and conversely the car will have a shorter life.

Just the same as. Are fully reading VSB14, you need to carefully read the rule book for any comp and see whether it’s compatible with your build.

[seanzook06]

I certainly agree with the destructive nature of comps. Most of the local comps require a registered vehicle anyway. They are more a of a two or 3 times a year thing, not regular competition, so while I am building the car to be able to place well at comps, it is not my main focus with the build, it is more about creating the best tool in order to take on the hardest terrain in my local area. For me that means small enough footprint, stability, low cog, big tyres, low gearing, lightweight and just enough wheelbase for steeper steps. I don't like the compromise of running a diff housing that is double the weight of a sierra housing, I also don't see the point of "upgrading" to a bundera rear end when it is still semi float. I am keen on the idea of full float for reliability. Although a hybrid axle will end up being more work and difficult to engineer, I still don't see the point in compromise unless I am forced to

[BlueSuzy]

A Bundera rear will do most of what you need. I found some spare axles not long ago for mine.

I have never broken or twisted my axles twin locked on 35's.

If i was breaking them, My next go to will be cut down standard toyota float axles from a 60/70 full float and adapt the hub/ housing flanges to the Bundera.. There will not be a cop that will know the difference.

Housings aren't double the weight. Check the weights thread on here.


If you want to comp, you need a trailer. Just build it for comps. The comp life will turn it away from being legit, fast.. We've all seen it happen to many cars.

Mine was built to comp if i wanted to, minus the front cage and b pillar extra bars for belts and diagonals. It turns out I've never wanted to comp. I fix enough broken down junk at work.