Big Bird WS6

iTrader: (9)

sorry to hack. sam will you explain the unblanced torque are. never seen something like that. so basicly WTH

allmotor

De-coupled torque arm:






Sam, what IYO are the cons to decoupled torque arms? Thanks in advance
From my understanding, This basically acts as a short length torque arm under acceleration, moving the instant center rearwards for improved acceleration/traction. Under Deceleration, it acts as a long torque arm, moving the instant center forwards for improved braking. (Using short length torque arms such as BMR's cross member mount or UMI's tunnel mount can generate wheel hop / brake chatter under heavy deceleration). I remember hearing a pretty big con about the UE decoupled torque arm, but I forgot what it was.

Sam Strano

iTrader: (41)

First, it's complicated.

Second, while it's claimed to get rid of brake-hop I've driven 2 UE equipped cars, and 1 Herb Adams car, and brake hopped all 3. The claim was "not properly setup", which is fine but my car with a full length arm hardly ever brake hops anymore, and it goes back to being overly complicated.

Three, while I don't disagree the short side of the TA plants power better than a longer one it does it be moving the instant center backward. That unloads the front end, and suddenly it's hard to power out of corners (if that's your think like it is mine) and can causes a power on push. You can "fix" it with big springs and bars, but then you have more wheel rate which makes the car not as nice over bumps.

Four, I dislike floorpan mounted TA's as the sheetmetal is in no way intended for those loads.

z28bryan

iTrader: (7)

That pretty much right there was enough to convince me to not bother with the decoupled torque arm. And I was considering it.

squee

iTrader: (16)

So if setup properly, unlike the cars you drove, it should accelerate better than a full length torque arm and not brake hop? And again, thats if everythings setup properly? I was gonna get the best of the best when it came to it, and this and the Watts link setup you have are on the list, but I dunno from what you have said about them...

Big Bird WS6

iTrader: (9)

so on a high horse car

sam would a full lenght torque arm be best?

z28bryan

iTrader: (7)

Depends on what you want to do with the car. The rule of thumb seems to be for drag racing the short length arm is what you want. All other applications it's the long arm that you want.

Sam Strano

iTrader: (41)

In theory.... yes. But again, all 3 I drove brake hopped. Considering it's not "supposed" to and claimed to eliminate it, why did all 3 do it?

And again, I don't buy it. Brake hop, tramp, whatever you want to call it happens with a solid axle. Nextel cup cars have NO torque arms at all, and in 2007 *both* Jeff Gordon and Tony Stewart, who are both very good road racers brake hopped themselves out of the lead of the race @ Watkins Glen (going into turn 1). And it happens all the time @ Martinsville too.

I have no brake hop issues that cause me any sort of trouble, and I have a full length arm on my car. And my car turns in a variety of situations and corners.

allmotor

Yes, I agree with your points 3 and 4.

But what type of complicated are you talking about? ackermans theroem complicated or pro-touring forum complicated? Could you elaborate on the complexities please?

Ironhead

Well, there is a 13 page, 3-1/2 year old ongoing thread on FRRAX devoted solely to gettingg these things set up right.

There's nothing wrong with doing things differently and to some extent I understand the desire to "tinker" with stuff (hell, I do it myself sometimes) but I personally like driving and competing a WHOLE lot more than testing / tuning / tweaking / testing / tuning / tweaking.

I think that is what Sam was getting at.

allmotor

I tried searching on pro-touring forum for an explanation of why the de-coupled torque arm does or does not work, with no luck. I figured there would be an explanation there if anywhere. If you do have one then you should also post it there, Sam.

I suppose since no one on pro-touring has gone in depth on the de-coupled TA, and Sam has driven 3 cars with them or similar and experienced brake hop that it should be stayed away from. especially since there is a 13 page long thread just about getting it set up correctly. I was just curious about it since I like learning about such engineering issues and I figured someone would know. And complexity does not phase me, I'm an engineering student.

Sam Strano

iTrader: (41)

Korry hit the nail on the head. 3.5 years that thread has been going on and folks are still pissing with it.

Go over the frrax.com and read the thread, I think most would see the complexities involved.

Ironhead

In that case register, read and decide for yourself.

http://www.frrax.com/rrforum/index.php?showtopic=4630

Sam Strano

iTrader: (41)

Why? Pro-Touring (and I've never been there) has not lock on suspension parts. You get way more information from those that actually use parts for more than touring, even if they do it professionally.

allmotor

Because it's a lot of engineers and most people go in depth mathematically explaining pretty much everything about racing that is "complicated". Alot of it is over most anyone in this forums' heads, at least in the advanced forum there.

allmotor

"The error returned was:

Sorry, the link that brought you to this page seems to be out of date or broken."

Sam Strano

iTrader: (41)

That's great, but I'm not an engineer, and don't claim to be. You'll love frrax, there are plenty of mathematics over there.

I'm a trial and error guy. I have understanding of engineering, but in the end function is what matters to me, and a lot of things that have added up, don't always pan out.

And the link Korry posted worked for me, but I belong to the site.

Ironhead

Advanced mathematics and mechanical engineering is fine. Having it explained to you is fine. I appreciate and crave knowledge as much as anybody. But......

If getting a car to handle was only about theory and crunching numbers, why do the NASCAR teams struggle each and every single weekend to find and keep a handle on their cars? Surely with their enormous technical resources, both mechanical and human, they should be able to set the car up at the shop, unload at the track and run perfect laps at the very limit of adhesion, right? Doesn't happen, does it? Why not?

What drives the car? Theory? Math?

That stuff may explain why a car does what it does but it takes a human with experience to tune a car to their particular liking.




And once again I'm speaking for Sam.... sorry Sam.

Ironhead

Can't say for sure, but you may have to wait for Kevin approve your account before you're actually in with the cool kids.

I really don't know how he goes about it or what the procedure is these days.

Otto-813

iTrader: (1)