Future of KOH 4400 chassis/car development?

[Isdtbower]

Have we run out of ideas? Big ideas take time to digest and test. Maybe it really is the introduction of the lightweight SXS-ish rigs that is making designers and builders thinking, questioning, and re-thinking.

As this goes on, there is a consistent group that does look for every % improvement. There have been big questions about portals but now some old questions and knowledge are being thrown at the "new order." A question exists whether the front axle should be over driven ...but by how much. The general consensus is yes and even OEMS build slightly different ratios for the front vs the rear.

But now portals, and larger tires can change how that over-driven responds. Most of this relates to IFS/IRS. but SA guys should take note.

First we have to look at "CV's". Constant Velocity Joints. When a pair, on a shaft, are PHASED correctly and the angles at both ends are equal, they ARE "constant velocity joints." When one or those joints change the angle then there is a slight change in velocity as they rotate. Not as much as a Cardin joint but it is there. There is a lot of history with Cardin joints and why anything fast or with big angles will be CV's.

IFS is the bugger as the CV's are almost never in angle phase. Articulation, camber curves, wheel regression, caster curves, and turning all affect the "loping" of the outside CV.... and resultant changes at the tire patch. (Resultant torque vibrations in a portal for example and resultant steering feel)

I think geometry has more to do with how well an IFS turns, but if your rear is over-driving the front then the driver will want to kick out the rear more often (A driving style more pronounced in to 2wd.)

Just know that there is this reckoning, and spotted, in the advanced design group. (above my grade level for sure) It might have even been recognized to the CanAm engineers, and that new front design addresses that.

 

['84 Bronco II]

Have we run out of ideas? Big ideas take time to digest and test. Maybe it really is the introduction of the lightweight SXS-ish rigs that is making designers and builders thinking, questioning, and re-thinking.

As this goes on, there is a consistent group that does look for every % improvement. There have been big questions about portals but now some old questions and knowledge are being thrown at the "new order." A question exists whether the front axle should be over driven ...but by how much. The general consensus is yes and even OEMS build slightly different ratios for the front vs the rear.

But now portals, and larger tires can change how that over-driven responds. Most of this relates to IFS/IRS. but SA guys should take note.

First we have to look at "CV's". Constant Velocity Joints. When a pair, on a shaft, are PHASED correctly and the angles at both ends are equal, they ARE "constant velocity joints." When one or those joints change the angle then there is a slight change in velocity as they rotate. Not as much as a Cardin joint but it is there. There is a lot of history with Cardin joints and why anything fast or with big angles will be CV's.

IFS is the bugger as the CV's are almost never in angle phase. Articulation, camber curves, wheel regression, caster curves, and turning all affect the "loping" of the outside CV.... and resultant changes at the tire patch. (Resultant torque vibrations in a portal for example and resultant steering feel)

I think geometry has more to do with how well an IFS turns, but if your rear is over-driving the front then the driver will want to kick out the rear more often (A driving style more pronounced in to 2wd.)

Just know that there is this reckoning, and spotted, in the advanced design group. (above my grade level for sure) It might have even been recognized to the CanAm engineers, and that new front design addresses that.

Over driving the front axle is getting more popular in the rock crawling scene to improve steering, take some bind out when forcing the front into big walls/boulders, and to "stretch" the chassis out to keep it planted and stable on big climbs. I can't think of a situation where it would be beneficial to overdrive the rear. It seems to me that the heavier the vehicle is and the more speed that's involved, the less overdrive you can get away with. With RC crawlers, it is pretty common to run 20-40% front overdrive, I think some of the WE Rock guys are around 8-9%, and I have heard trail guys talking about 4-6%. I can't imagine with the speeds and weights of the rigs in 4400 that they would want more than a percent or two.

 

[arse_sidewards]

I can't think of a situation where it would be beneficial to overdrive the rear

Donuts in the parking lot.

 

[snivilous]

And just to throw this up there since the shitting on WEW Watt's link, coincidentally he just made a youtube video detailing the path he went down and why:

 

[mobil1syn]

That thing is a back breaker with negative ground clearance at full bump.

its scary how many u4s are like that. they look good for the full bump pics for the 'gram

 

[Isdtbower]

Over driving the front axle is getting more popular in the rock crawling scene to improve steering, take some bind out when forcing the front into big walls/boulders, and to "stretch" the chassis out to keep it planted and stable on big climbs. I can't think of a situation where it would be beneficial to overdrive the rear. It seems to me that the heavier the vehicle is and the more speed that's involved, the less overdrive you can get away with. With RC crawlers, it is pretty common to run 20-40% front overdrive, I think some of the WE Rock guys are around 8-9%, and I have heard trail guys talking about 4-6%. I can't imagine with the speeds and weights of the rigs in 4400 that they would want more than a percent or two.

Good Info. Some U4 and TT's are using front sprags to unlock the fronts on decel. Mainly when landing the jumps. This adds to the curmudgeon around the whole driveline wrap-up. I know it is a thing at the top of the food chain, but lockers would accomplish much of the same and also give you reverse. I'm not seeing Xfer cases being clicked out of front drive anymore (except some sxs?)

Any more on this?

 

[Bebop]

I'm not seeing Xfer cases being clicked out of front drive anymore (except some sxs?)

Loren said on video he was doing the desert in 2WD

 

[cdemart2]

isn't Loren running an SCS? or does he have some kind of one way front diff like a pro4?

 

[Bebop]

isn't Loren running an SCS? or does he have some kind of one way front diff like a pro4?

In the video I saw, he had an Atlas.

 

[Tech Tim]

And just to throw this up there since the shitting on WEW Watt's link, coincidentally he just made a youtube video detailing the path he went down and why:

In that video, his set-up looks like it is working fairly well and it looks well designed.

Much better designed than what was posted earlier:

All the travel

 

[Ghetto Fab.]

its scary how many u4s are like that. they look good for the full bump pics for the 'gram

Any idea what a good amount of clearance is? Obviously more is better, but that compromises other design goals.

 

[bdkw1]

Any idea what a good amount of clearance is? Obviously more is better, but that compromises other design goals.

Desert I like minimum 5" on an IRS car. By the time you compress the tires, that doesn't leave much for road crown. IFS can get a little closer due to impact angles. Solid axle rear fuel cell, 4".

 

[Jeffh555]

Over driving the front axle is getting more popular in the rock crawling scene to improve steering, take some bind out when forcing the front into big walls/boulders, and to "stretch" the chassis out to keep it planted and stable on big climbs. I can't think of a situation where it would be beneficial to overdrive the rear. It seems to me that the heavier the vehicle is and the more speed that's involved, the less overdrive you can get away with. With RC crawlers, it is pretty common to run 20-40% front overdrive, I think some of the WE Rock guys are around 8-9%, and I have heard trail guys talking about 4-6%. I can't imagine with the speeds and weights of the rigs in 4400 that they would want more than a percent or two.

Being able to vary the front overdrive based on terrain would be really interesting. I think there's systems that do that in road race or rally cars, but IDK.

This is something that might actually be easier to do if your front drive was electric.

I say interesting because who know if it'll be worth the effort/complexity until you try it. Horschel's 4ws car seems like it would be worth it, but hasn't proven to be yet.

 

[SLOWPOKE693]

Horschel's 4ws car seems like it would be worth it, but hasn't proven to be yet.

As bad ass as that car is its just way to complicated and fragile for what we do with them. Honest question.... Has that car even finished a race since it was built?

 

[Bebop]

As bad ass as that car is its just way to complicated and fragile for what we do with them.

Agreed.

He had a short course car that was simple and fucking badass. I think Loren bought it from him.

 

[Ghetto Fab.]

Being able to vary the front overdrive based on terrain would be really interesting. I think there's systems that do that in road race or rally cars, but IDK.

This is something that might actually be easier to do if your front drive was electric.

I say interesting because who know if it'll be worth the effort/complexity until you try it. Horschel's 4ws car seems like it would be worth it, but hasn't proven to be yet.

Not quite sure why he went 4ws in the first place. I get he is looking for an advantage, but rear steer seems out of place in racing. I think for a more dual purpose rig and not a racecar, then rear steer has more advantages, but at race pace I think its just a liability. If your doing IRS though, its real easy to add a steering system to it though.

 

[Jeffh555]

I've never driven anything with 4ws, just armchair engineering here. I could see a handful of reasons it's worth trying.

Journalists seem to have good things to say about Porsche's and other sports cars with 4ws.

4ws rock crawlers are clearly more capable.

We're talking about a car that's never finished a race, any publicity is good publicity. The crabwalk jump seems to have gotten some good coverage for FOX and Nitto.

People I know with play cars with 4ws love it, because it's more fun. Remember, basically everyone racing is a hobbyist and fun is ultimately the reason they do it.

 

[SLOWPOKE693]

At this point in the game I don't think IRS is even necessary. The IFS/SA rigs seem to be the best combo in KOH style racing at the moment and the simplicity of having a SA rear keeps the failure points to a minimum.

 

[SLOWPOKE693]

I've never driven anything with 4ws, just armchair engineering here. I could see a handful of reasons it's worth trying.

Journalists seem to have good things to say about Porsche's and other sports cars with 4ws.

4ws rock crawlers are clearly more capable.

We're talking about a car that's never finished a race, any publicity is good publicity. The crabwalk jump seems to have gotten some good coverage for FOX and Nitto.

People I know with play cars with 4ws love it, because it's more fun. Remember, basically everyone racing is a hobbyist and fun is ultimately the reason they do it.

How many actual go fast race cars that race in the dirt or on pavement have 4ws? I can't think of anything except monster trucks and cone dodgers and do those really count? I'd think if it was the "cats ass" for racing we would have seen it in F1 or other forms of high end on road racing by now.

Play cars and race cars are two very different things. I'd love to hear Paul's reasoning for it and why he implemented it into his KOH car

 

[Bebop]

I'd love to hear Paul's reasoning for it and why he implemented it into his KOH car

Some people like the tried and true tech (Bomber and Miller), some people want to push the envelope (rear TTB, rear steer and other special cars).
Horschel never really liked anything simple.

 

[CDA 455 II]

Memes of KOH | Facebook

www.facebook.com

 

[SLOWPOKE693]

Some people like the tried and true tech (Bomber and Miller), some people want to push the envelope (rear TTB, rear steer and other special cars).
Horschel never really liked anything simple.

Problem with the tried and true tech is that now that the bugs are being worked out of the "new tech" the tried and true stuff isn't able to keep up for much longer.

I also get trying to push the envelope but if what you do flat out doesn't work then trying the next idea would probably be a wiser choice than trying to polish a turd. I get the not liking anything simple part though, especially now knowing what he does for work.

 

[ridered3]

Agreed.

He had a short course car that was simple and fucking badass. I think Loren bought it from him.

If I recall correctly, Loren traded a toter home for that short course car

 

[94toytruck]

Hypothetically if Horschel got the bugs worked out and started placing well next season how long do you think till someone else tries it? That car wins a race and it'll get some attention for sure

If no one tries anything new it'll grow stagnant. We'll end up with a recipe for what works and no one will deviate from it. Hell look at the SA cars, it works but has been pushed so far it's at its limit. Now the IFS/IRS stiff is getting sorted out.

 

[ridered3]

Hypothetically if Horschel got the bugs worked out and started placing well next season how long do you think till someone else tries it? That car wins a race and it'll get some attention for sure

If no one tries anything new it'll grow stagnant. We'll end up with a recipe for what works and no one will deviate from it. Hell look at the SA cars, it works but has been pushed so far it's at its limit. Now the IFS/IRS stiff is getting sorted out.

There’s a twin to Paul’s current fancy car. I’m sure someone would quickly snatch that twin up with the tried a true method of a dump truck full of cash.

 

[Tech Tim]

Not quite sure why he went 4ws in the first place. I get he is looking for an advantage, but rear steer seems out of place in racing. I

It adds more complexity, more moving parts and more failure points. Look at how many people bow out because of power steering issues just with a front steer car. Now you're doubling the failure possibilities.

4ws rock crawlers are clearly more capable.

This right here! Having rear steer for the rock sections could potentially be huge, especially when you are trying to work your way through trail blockages. BUT, we've seen it time and time again, you need to know how to drive rear steer or it will get you into a bigger mess.

At this point in the game I don't think IRS is even necessary. The IFS/SA rigs seem to be the best combo in KOH style racing at the moment and the simplicity of having a SA rear keeps the failure points to a minimum.

It's been talked about for years. Look at the full suspension cars (IFS/IRS) out there now and it is not like they are stealing all the wins. Hell, look at desert racing, Class 1 is all about the unlimited full suspension rigs and they haul the mail, but the Trophy trucks with IFS and live axle are consistently the fastest.

Part of it is travel. You can set up a live axle rig to have way more travel than an IRS.

Another part is tire size. The TTs are running bigger tires, which make the holes feel smaller.

The TTs are bigger & heavier and continue to dominate. Maybe that's why we're going to seeing the bigger U4 cars dominate as long as they don't break and IF they get that formula down, they will be the TTs of U4.

Hypothetically if Horschel got the bugs worked out and started placing well next season how long do you think till someone else tries it? That car wins a race and it'll get some attention for sure

If no one tries anything new it'll grow stagnant.

Eggs-xactery!

 

[Treefrog]

It adds more complexity, more moving parts and more failure points. Look at how many people bow out because of power steering issues just with a front steer car. Now you're doubling the failure possibilities.



This right here! Having rear steer for the rock sections could potentially be huge, especially when you are trying to work your way through trail blockages. BUT, we've seen it time and time again, you need to know how to drive rear steer or it will get you into a bigger mess.




It's been talked about for years. Look at the full suspension cars (IFS/IRS) out there now and it is not like they are stealing all the wins. Hell, look at desert racing, Class 1 is all about the unlimited full suspension rigs and they haul the mail, but the Trophy trucks with IFS and live axle are consistently the fastest.

Part of it is travel. You can set up a live axle rig to have way more travel than an IRS.

Another part is tire size. The TTs are running bigger tires, which make the holes feel smaller.

The TTs are bigger & heavier and continue to dominate. Maybe that's why we're going to seeing the bigger U4 cars dominate as long as they don't break and IF they get that formula down, they will be the TTs of U4.



Eggs-xactery!

The trophy truck vs class 1 debate is somewhat tainted by SCORE requiring class 1s to use traditionally weaker transaxles instead of allowing a transmission and ifs diff.

 

[Bebop]

The trophy truck vs class 1 debate is somewhat tainted by SCORE requiring class 1s to use traditionally weaker transaxles instead of allowing a transmission and ifs diff.

Companies could build a bigger/better transaxle.

The TTs are way past TH400s and it didn't stop them from developing new stuff to keep pushing the envelope.

 

[Jeffh555]

I'd think if it was the "cats ass" for racing we would have seen it in F1 or other forms of high end on road racing by now.

Banned: Four-wheel-steering

Of all the exotic technologies to be banned from Formula 1 through the years, four-wheel-steering is perhaps be the only innovation to have been developed after it was outlawed.

www.racefans.net

 

[bdkw1]

Companies could build a bigger/better transaxle.

The TTs are way past TH400s and it didn't stop them from developing new stuff to keep pushing the envelope.

Bigger transaxle doesn't make up for the poor unsprung weight ratio in the front/the lack of straight line stability from heavy rear weight bias. There have been a couple 1 cars with front engine/rear transaxle, but they weren't well funded enough to make a real effort. There is an AWD 1 car being built. I doubt it will be as effective as a AWD TT for the same reasons.