[tanshi]

People that know me and know my builds know that i like to do things differently,
For a while now ive been looking at build ideas for tuff truck etc, watching videos of it and other crawling events for ideas.
Ive never actually been but im hoping to do so in 2015.

I look at all of these events and to me the cars are all way too wide, too long, and realistically just different to how i would build.

What im hoping for is an ideas discussion, adult, calm. about what works, what doesnt, and why.
Take it as brain storming, no one is right or wrong, so no one needs to get thier panties in a twist.

[Gwagensteve]

This could be the best thread on the board ever.

[tanshi]

Gwagensteve wrote:

This could be the best thread on the board ever.

as long as it doesnt turn into a slagging match like every other potentially informative thread does

[tanshi]

I'll start by giving an example of a build that i thought had good potential, im not saying it wont work, it remains to be seen but i think he chose to go too big.

Steve johns's LJ.
http://tufftruck.com.au/entrants/TTC201 ... Design-Fab

42 inch sticky boggers, 102 inch wheel base from memory. and stupidly wide.
Not to mention the Commodore v6 which every one seems to love for some reason.

Good points,
the tiny body, almost irrellevant weight in the tub, and not too much bar work.
kept alot of the body, though i think could have done a little more to keep the LJ styling

Bad points,
Ick, boggers, yes they are sticky, but they are still a bogger. how many of the top rock crawling rigs in the US run boggers?
42s, seriously do they need 42s? bigger tyres need bigger diffs, bigger diffs mean more width generally.
commodore V6. why? because they are cheap, but how often do you blow a motor and need to replace it?, they weigh almost as much as an LS v8 and have similar power to an H27 suzuki motor

[offroadjack]

can I have input on here as well? or you rather me not to.........i'd be serious tho,
there has been a lot of research done on what works and what doesn't, those guys(tuff truck) spend hundreds of thousands dollars on their competition trucks and it's an ever evolving jiggling and trying out things to improve the ability to finish a run.
it's been interesting to watch how their trucks have changed over the years and where they are now, wide, dual steering, long and low with lots of suspension travel looks like it's proven to work better then previous years.
it sort of makes sense how they are thinking, long and low to keep the centre of gravity down to prevent roll overs but fit massive 44'' + tyres to keep that ground clearance.
haven't really been following it for the last 2 years but there is a good chance i'd go again this year.

[tanshi]

i think that is the first time ive heard you say anything sensible on here.
thank you.

I agree that some width is nessessary. Physics tells us that a wider car is more stable than a narrow one.
But when does it get to the point where width stops helping and starts taking your choice of lines options away.
again with tyres. i agree that bigger tyres make a difference to performance, but when does bigger stop adding to how well you can drive something and start just adding to cost of vehicle and breakages
the trucks that i have seen win before are not exactly what i would call long. 100-110 inches seems to work well, any longer and they seem to struggle with ramp over.

[Marko_SJ]

tanshi wrote:

I'll start by giving an example of a build that i thought had good potential, im not saying it wont work, it remains to be seen but i think he chose to go too big.

Steve johns's LJ.
http://tufftruck.com.au/entrants/TTC201 ... Design-Fab

42 inch sticky boggers, 102 inch wheel base from memory. and stupidly wide.
Not to mention the Commodore v6 which every one seems to love for some reason.

Good points,
the tiny body, almost irrellevant weight in the tub, and not too much bar work.
kept alot of the body, though i think could have done a little more to keep the LJ styling

Bad points,
Ick, boggers, yes they are sticky, but they are still a bogger. how many of the top rock crawling rigs in the US run boggers?
42s, seriously do they need 42s? bigger tyres need bigger diffs, bigger diffs mean more width generally.
commodore V6. why? because they are cheap, but how often do you blow a motor and need to replace it?, they weigh almost as much as an LS v8 and have similar power to an H27 suzuki motor

I think Outbackjack has covered a lot of what you've asked, low and wide with masssive tires, I've never observed TT or scoped out the builds, in any case thats not what I want to talk about.

-----------------------------------------------------------------------------------------

As for the commodore v6, its probably more advantageous than you give it credit for. I dont see why everyone hates it to be honest.

It is very simple, its easy to modify and tune, it is very reliable, they are hard to break and of course, as you said, cheap.

You've pointed out that its deficient in power compared to say a H27, for its output and size that may be true, but theres the power spread to think about.

Knowing Suzuki, the peak torque and power for the h27 probably starts at 3500 RPM, whereas the 3.8 will make it from very low and in a very linear manner. For example, my mates old ute would drive nicely from 1200
RPM and felt almost "electric" and was stupidly easy to drive, I'll give it that.

Don't interpret this as me saying 3800s are a good idea to put in sierra/vitara etc.

[offroadjack]

I can be very sensible Tansi,
knowing how to drive the thing is the other factor, human error is something un avoidable, that's what makes it so interesting to watch.
as for SJ, the H-engines need their revs to make it produce some torque and he be spot on why the trusty old 3.8 com is used so widely, cheap, torqy and easy to mod and tune + every backyard has parts laying everywhere.
but hey, it be great fun building something you think is going to work, on the cheap and just be in it for the fun, no one would stand a chance competing with the big boys that are backed up by their sponsors but why not have a crack at it.

[tanshi]

just so we dont let a good story get in the way of facts, a quick google shows me,

Buick v6, the cast iron one from the VT, VU series.
Kw: 153
Torque: 360nm at 4000rpm
engine weight: 177kg (392lbs)

H27
Kw:135
Torque: 250nm at 3300 rpm
Engine weight: 145kg (320lbs)

LS1 (i'll go with the specs from the first ones as they improved over time)
KW:257 kW at 5,600 rpm \
Torque: 470 N·m at 4,400 rpm.
Engine weight: ~180kg (400lbs)

[tanshi]

Im not saying the H27 is the best engine either, just using as an example that the Buick motor really isnt.

[Gwagensteve]

I'm on my phone ATM and I'll add more to this thread over the weekend, but I'm almost certain the torque figure for the commodore motor you've posted is wrong. I'm convinced they do 305Nm.

[offroadjack]

just coming from what I know and don't criticize me on that, the early VN and VP engines have much more torque for some reason, that was where I worked @holden and dealing with the cops that brought in their new VS (I might be out on what model) comes in for servicing, they were spuwing their new car wasn't producing as much power as their previous models.. ?? (coming from the hors...cops mouth, not mine.)
probably had more to do with tuning then anything else...
the H27 is a great engine but low down it's not doing much..

[tanshi]

sorry my mistake.foot pounds vs NM
edited specs post

[tanshi]

Not critisizing at all, just would like the facts of power weight and torque to back up every thing.

while we are at it i'll add the LS motor as i personally would run an LS over the 3800 v6 every day if i thought that power was nessessary

[offroadjack]

they're expensive tho! and even a g13b can make a 42" tyre comp. vehicle crawl with the right gearing....but then you get into that big $$$ territory again ;-(
all depends on what sort of comps you would like to enter...
in the outback challenge you can scream that H27 to the limiter most of the time but when it comes to crawling?...imo I don't think it'll suit..

[tanshi]

agreed. but your spending $4000 + on tyres and skimping on a $100 dollar motor..??

I dont get why people build the way they do and thus this post

[JrZook]

tanshi wrote:

just so we dont let a good story get in the way of facts, a quick google shows me,

Buick v6, the cast iron one from the VT, VU series.
Kw: 153
Torque: 360nm at 4000rpm
engine weight: 177kg (392lbs)

=0.86Kw/kg - 2.03nm/kg

H27
Kw:135
Torque: 250nm at 3300 rpm
Engine weight: 145kg (320lbs)

=0.93Kw/kg - 1.72nm/kg

LS1 (i'll go with the specs from the first ones as they improved over time)
KW:257 kW at 5,600 rpm \
Torque: 470 N·m at 4,400 rpm.
Engine weight: ~180kg (400lbs)

=1.42Kw/kg - 2.61nm/kg

Added units for comparison. If the 3.8 produces 80% of its torque @ 3300 thats still 288nm and 1.62nm/kg. According to those figures the 3.8 doesn't seem really bad at all compared to the H27..

[offroadjack]

true, but I recon the V6 is quicker and easier to work on then a V8 (looking at being in a comp and something goes wrong, lets face it, you don't have a tech crew doing it for you)
anyway, looks like this is going to be a long tread so you'll draw your conclusions out of it what to go for
(that was for tansi's last post)

[Red89]

I sooo wish I lived on the east coast, I would have been very tempted to compete in a small built Sierra. I have many an argument with guys who believe throwing more power and bigger tyres at their car will make it more capable.

Anyway engine choice may be attributed to not a lot of thought being put into it. A lot of time gets put into suspension geometry, cage etc so when it comes to engine the V6 Commodore is proven to work, cheap and easy to get hold of, the commodore auto can be adapted to the popular twin Toy cases or alternatively the V6 can be adapted to the Toy box easily and both using off the shelf parts. People go for the easiest option because they would rather put my thought into other aspects of the build.

Tyre choice may come down to whatever their particular sponsor is doing the best deal on. As far as sponsors are concerned a car that 'looks the part' gets a lot more attention and is more attractive to one that looks like Tim Hardy's for instance.

[gvzookdriver]

I know what everyone will say but what about a small turbo Diesel engine say around the 2lt size only weigh (dry) about 100-150kg. Would think they would have more torque

[Zook_Fan]

You only need enough power to break traction in tuff truck, once you've lost traction you'll continue to spin them. For this reason I see the engine discussion as borderline pointless. Rhett proved an angry 1.3L was enough for a podium finish. I am using a 3.8 for my build but it is not what I'd build if Tuff Truck was my goal competition but I would be looking for a light V6 for the torque. The H27a does fit the criteria but it is a comparably rare engine, you're not going to find a block in a pinch.

The next part is the automatic transmission. Well auto if you choose that way but you've got no reason not too. How strong is the standard auto behind the H27? Can it stand up to the abuse? What about the transfer? Atlas? How do you adapt it? These could all be simple answers, I don't know. Again I went with a T700. Decent low gearing, with an over drive. Can be built to last and if it doesn't I can pick up a new one for under $200 (probably in a whole car for that).

I think you hit the key notes earlier in this thread and then got distracted by the engine. Width, length and suspension. These are what I consider the keys to be. A few years ago Suzuki's dominated the courses and I don't think any of them had bigger than 60 series diffs for the year I'm thinking. Width needs to be narrower than most think, there doesn't seem to be a lot of sidehilling in Tuff Truck, there's a lot of climbs but width won't help you much there. Length, 100 - 110in just like you said, probably start to middle of that range.

Suspension. Biggest component of the trucks by far and mostly over looked. You mentioned why would you spend $4000 on tyres and skimping $100 for an engine? In my case it was so I can run $6000 worth of shocks. The suspension is what will help a car to crawl, you should be aiming for a 3 link front and rear for the high roll centre and be aiming for average anti squat numbers. Do you need suck down winches? Front or rear? Hydrualic suspension? Will air shocks cover it or will a set of tuned coilovers get you further? My guess is they will, look at every race report from the Ultra4 races in USA. They are all saying "After we got our shocks tuned we could blast through the desert and the car handled the rocks much better too". Going fast or slow, it's the same principle. Soft springs with hard compression, make sure you have preload at full extension on your springs. That's regardless of what type you choose.

I think steering is somewhat underused in Australia. We don't have a junkyard full of Dana diffs that with some mods you can run 45/50 degrees of steering. It's got to help to be able to move the wheels that much when you're on a rock ledge... Do you go full hydraulic or hydraulic assist? Full hydraulic probably makes more sense for a crawler but with a 3 link if you wanted a mechanical connection you won't lose anything using assist. Rear steer seemed to be almost proved useless a few years ago by the winners, I believe it is if your car is the right length.

Tyre size is typical in Tuff Truck. Everyone seems to want the biggest thing there. I'd either go 37" or 40" treps, depending on my axle housing chosen. Compound and traction are worth so much more than height.

In the end it's budget that normally what dictates the compromises.

[tanshi]

the only thing i will dissagree with you on there is the shocks, for tough truck, rock crawling comps, you only need to look at what tube buggies in the states at the top of the classes run.

no speed involved, air shocks seem to work perfectly for what they do.

[offroadjack]

THERE is the magic word, BUDGET...

[offroadjack]

you can go in so much tech detail but your average bloke won't be going that far into it, well, I wouldn't unless I could finance the whole build up and actually aiming at winning....

[Zook_Fan]

Air shocks will work no doubt, but I think coilovers will work better. When crawling I'll accept that there is insignificant difference between the two, hence why all the crawlers in the states use them. But looking at the attempts some people take on some obstacles at tough truck a better comparison would be bouncers. They are mostly running single coilovers at each corner and not very well valved. So much so that when the Ultra4 cars came to compete they flogged them all over the park with hill assaults. So working backwards, my theory develops that well tuned shock absorbers will win out over air shocks that have had oil and nitrogen played with.

[tanshi]

offroadjack wrote:

THERE is the magic word, BUDGET...

Yeah no doubt at all, but with size often comes cost. and bigger budgets.

smaller tyres = less gearing = less $$$
smaller tyres = less diff size = less $$$
smaller tyres + less diff size = less weight
less weight = less traction acually required to move vehicle over obsticle
etc

[Zook_Fan]

How small do you want to go? Are you saying 35's? 33's?

Pick the tyre size and build to that. Rhett's buggy would be interesting on the Tuff Truck tracks as a good indicator if your small buggy idea will work.

With utter disregard to panel damage a long wheel base sierra on 35's with a full suzuki drivetrain might go rather well.

[tanshi]

I think you really have to go with 37s for the sticky compound, unless maxxis come through with a 35 in the not too distant future.

Rhetts micro struggles on really tough stuff, but i think thats actually too long for its width and tyre size.

[Marko_SJ]

Interesting thread. Lots to learn here about serious cars.

What are you thinking of running Tanshi?

[tanshi]

I have a few ideas, but honestly thats what this thread is for, to see what other peoples ideas are of what works.

I have a few hair brained things that almost definitly wont work, like running the lj50 motor just for shits and giggles. this would compromised the performance of the build massively, but i drive one at the moment and it goes ok.

my theoretical build is some thing like,
LJ50 tub
lj50 two stroke motor, (issue is no auto gearbox)
Vitara built diffs centred pumpkin front and rear probably 5.1 gears.
hydro steer, probably try and run a smaller ram to make sure the pump could keep up the flow.
reduction box > sierra case
4 link front and rear
air shocks
35s (if i could get a sticky compound)