LR limiter travel

[mbaker76]

I have heard before that a good amount to let the LR drop before hitting the limiter would be like 4.5-5" at or just inside of the birdcage. I never thought about it before but is that with or without the driver in the car at ride height. I measured our car last night and found that without driver its right at 5" from ride height to limiter, but with driver in the car it settles more and drops almost 5 3/4 from ride height to the limiter.

[billetbirdcage]

Your LR ride heigth drops 3/4" when the driver gets in? that seems a little excessive, typically we see 3/8" on the LR. I also wouldn't get to catght up with the travel length, use what the car needs or wants. If it acts like it needs more try more if acts like it needs less try that. Just find a travel that works with your set-up or style.

Yes, 4.5 to 5.0 is a good general rule. Some will like more and some like less.

[mbaker76]

it may be closer to 1/2", i just measured quick last night before I loaded the car.

The only reason i ask is because after getting advice on some other topics about the RR bar angle I decided to raise the bars on the right side. But....

Then I got to thinking that maybe the reason the car liked so much LR bar angle is because it was putting so much rear steer in the car and it freed it through the middle (Billet you have mentioned this severl times). Basically what i am thinkgin is the fact that we had so little RR bar angle was making the car tight and getting more steer on the left side was compensating for it?? And then whenever we would take LR bar angle out he thought it lost bite off the corner and maybe it did, but maybe it also got tight in the middle from less rear steer and he broke it loose without realizing what he had done and that lost traction for exit. I just wonder if with the extra steer and drive now on the right side if the car will be too loose due to roll steer. When i laid it out on CAD that last 1/2" from 5 to 5 1/2" really cranks in the rear steer. Thats why I wondered if the car was a little loose like too much steer if we could take come chain out and help the car with out moving any bars. As a side effect it would calm the car down a little and not let it get so rocked up.

[Chris Steele]

I have done exactly what your talking about Mbaker...shortening my chain by one link because the car was hiking up, getting good bite, but was too loose because of the roll steer. I shortened my chain by one link before a feature and it made a world of difference. Car drove so much better and wasn't irratic anymore. Don't know how much travel we have, never measured it. What kind of car you got mbaker? Mine is a '04 GRT.

[wheel spinner]

Another question, Should a travel limiter on the left rear be connected to the frame through a dampening spring similar to a 6th coil?
I observe some cars hike up so fast that they seem to pull weight off the LR for a split second making an otherwise tight car loose for a moment. A car at maximun LR extension whether it is a chain or a shock would be converting some of its weight to unsprung weight on the LR.

[Chris Steele]

Another question, Should a travel limiter on the left rear be connected to the frame through a dampening spring similar to a 6th coil?
I observe some cars hike up so fast that they seem to pull weight off the LR for a split second making an otherwise tight car loose for a moment. A car at maximun LR extension whether it is a chain or a shock would be converting some of its weight to unsprung weight on the LR.

Jimmy Judd has exactly what your talking about, a spring loaded limiter.

[Rocket Bonehead]

Another question, Should a travel limiter on the left rear be connected to the frame through a dampening spring similar to a 6th coil?
I observe some cars hike up so fast that they seem to pull weight off the LR for a split second making an otherwise tight car loose for a moment. A car at maximun LR extension whether it is a chain or a shock would be converting some of its weight to unsprung weight on the LR.


Some guys run just a strap or chain, but I would suggest that IF you are going to run a limiter that is NOT a bar under the tube, I would highly recommend something along the lines of what JJ builds. I think Billet makes a similar version as well, but don't quote me on that.


RB

[mbaker76]

Well to follow up on my posts, when we put a little more bar angle in the RR we also took out 1/2" of drop on the LR and the car was great. I think it was like Billet has pointed out many times, the LR reached a point that we were gaining more steer than bite and the mroe we let it drop the better the car got simply because it wfreed up. Now with more bar angle in the RR, we gained a little steer and more drive there so we were able to take some of the chain out of the Lr and still have the car free enough through the middle but it came off better I assume from more equal loading of the rear tires.

Now the thing is the car was good through the middle but just a little tight off and then down the straight. Would taking some bite out help at that point on the track or what other adjsutment could be made. It wasnt bad but he said he that once the car turned through the middle and was really taking off he had to feather it just a little to keep from pushing up the track until he got to the straightaway.

[billetbirdcage]

If you laid that out in CAD, you should have seen that the last 1/2" of travel added almost 1" of rollsteer. Is that about what you came up with? I'm just going off memory and estimates on your bar angles and the cage and stop positions.

Yes, you are correct you were very likely at the point in which the car was being loosened because of excess rollsteer. You evaulation should be dead on, from the sound of it.

Less bite may fix that slight push, but I doubt it. If it is up on the bars it doesn
t know where the adjuster nut is. It will however effect the car anytime the LR spring has reasonable load on it (entry or intial throttle up). I would go another route instead of bite.


Chris, Mbaker has a MODIFIED!!

[mbaker76]

Thanks to Billet, RB and others for all the help. Even though it is a mod, its hard to find help except from the LM guys. I appreciate it all the different views.

Billet,
I cant remember what the exact number was but yeah it was pretty tame from 1-3" then 3-5 got a little faster and once you went past about 5" it got crazy. Thats why I originally asked about travel with or without driver. We made those changes last weekend when we ran at I80/NRP and the car worked as good as it ever had and prob turned better all around than ever and that seems to be a problem for us out there.

I guess I was thinking that taking bite out all aroudn the car would be putting more preload on the RR and taking it off the RF even though it was on the bars and would give the RR a little more drive, maybe not though. We have never really messed with bite that much.

What other adjustment would you look at?

Also he said he almost spun a couple times early because when he hit the gas the car would get up and steer so fast he almost didnt catch, we were going to try a stiffer rebound LR shock, would going from a 2 to a 3 be noticeable or should we just go to a 4?

[mbaker76]

Chris,

It is a mod, but its more or less copied from a LM. We run a limiter chain in place of the front shock, on the birdcage. I was told that was better than to the housing because when you hit the end of the chain on the housing it goes solid and could jerk the housing up for a second, but on the birdcage it will give a little because it is floated with everything else and will try to unwind the birdcage alightly just for a second,may not be much but it makes sense. The only thing youhave to remember is that when you make a bar change you have to recheck or adjust the chain to keep it stopping in the same spot.

[Chris Steele]

The one Jimmy sells goes right where the front shock would go. Click below for a picture of it.

[mbaker76]

yeah I have seen that before but we are only allowed 5 springs on the car so we couldnt technically run a spring on the limiter. Have thought about using a rubber bushing of some sort though.

The only thing is the limiter would vary depending on how much power you were putting to the ground and how much the spring compressed. With a solid chain its the same all the time no matter what.

[fourbar83]

I have a question concerning one of these limiters.
I have a spring loaded limiter that I was running on a latemodel and this year I tried it on a mod that I have. The mod was on the hook, and the limiter was attached to the housing, the car would get a hop in the turns when you hit the throttle. It was like it was picking the tire off the ground when it went up on the bars and loose traction causing it to sit back down then it would grab traction again, go up and then sit back down.....and so on and so on, hopping until it was straightened with the straight away
Would that be a sign that something on the set up was wrong or maybe....too weak of a spring in the limiter..........and ideas ?

Didn't hop until I added the limiter and stoped when I took it off, I never noticed it doing it on the latemodel

[Timmay]

fourbar,

Were you running a pullbar on the mod, or a 5th arm? I wouldn't run a spring loaded limiter with a pullbar. Run solid, or run a setup that doesn't run up on the limiter.

[billetbirdcage]

Jerking or POGOing is very common with any type of limiter that has something like a spring or bushing in it. It has something that is trying to pull the LR back up when it loses a small amount of traction then climbs back up. So it can osulate up and down or forward and back (depending on how hiked the car is). Some guys never have a problem with it, others once in a while, and some all the time. This is why I wouldn't use one.

If you have this problem and run a limiter like that remove it first as it is the most likely culpret. There is nothing wrong with something to slow the LR down before it hits the stop but shouldn't have anything that pulls back on it after that. There are other way to do this but are expensive and I haven't took the time to make one. I have however passed the idea along to the people that should be making them and after 3 years they still haven't.

[fourbar83]

The pull bar was something I haven't even thought about, I could see it being the problem. I did go solid and it stopped....thanks !

[billetbirdcage]

Mbaker,

I'd probably try something to gain back some rollsteer. Since you raised the RR bars which added rollsteer on entry, but is likely standing up more or not dropping as far as you are in the throttle as it was with the less RR bar angle. This is loosing some rollsteer during throttle, so taking all the static steer out may have been to much. You could also try adding some more angle to the RR bars, stagger, or move pulbar slightly to the right. There are alot of adjustments that could be done, I was just saying that I don't think I'd go with bite.

[mbaker76]

When I laid out the RR on cad teh way we had the RR before it ahd virtually 0 steer through 3" travel after 3 it would pull the RR forward. Now on the RR through 3" travel it pushes the RR back 3/16, so i think we have more steer on the RR than we had before all around. True, it looked like it didnt stay laid over as far on exit so it may be taking some of that steer out sooner and that is what is tightening it and maybe a little more trail would take care of that part.

I assume by static steer you meant trail/lead? We didnt take out any trail we only took out rollsteer ont he LR by shortening the chain. Again maybe a little more static trail would help now.

Who know what it will be like the next time we run, I thought about stagger but much more than 1 1/2" is hard to get, i never thought of the pullbar though, we havent messed with it much but that might also be a small adjustment just to add drive to the RR.

Can you get to a point when its tacky that with the car on the bars the steer in the rearend just naturally drives the car up the track, overpowering the front. Wherein more steer might make it worse? Maybe taking out some rear% would help the front end stick better? We picked up 60-70# mud mostly on the rear which is hard to avoid, but i guess we could have planned in advance for it better.

[billetbirdcage]

Sorry somewhere I thought you said you removed a 1/2' of trail from the RR, I can't find it now so I mush have misread that somehow. Forget That.

[billetbirdcage]

When I laid out the RR on cad teh way we had the RR before it ahd virtually 0 steer through 3" travel after 3 it would pull the RR forward. Now on the RR through 3" travel it pushes the RR back 3/16, so i think we have more steer on the RR than we had before all around. True, it looked like it didnt stay laid over as far on exit so it may be taking some of that steer out sooner and that is what is tightening it and maybe a little more trail would take care of that part.

Sorry I have forgotten, is this a 4 bar RR or a z-link. even with those low angles the RR should gain more then 0 rollsteer in 3" of compression

I assume by static steer you meant trail/lead? We didnt take out any trail we only took out rollsteer ont he LR by shortening the chain. Again maybe a little more static trail would help now.

Again a misread on my part, though somewhere you said removed some trail on RR also.

Who know what it will be like the next time we run, I thought about stagger but much more than 1 1/2" is hard to get, i never thought of the pullbar though, we havent messed with it much but that might also be a small adjustment just to add drive to the RR.

That is one adjustment that likely will only effect exit unless the pullbar is also the braking devise (two-way pull bar). I'd probably try that first, 1" should be noticable.

Can you get to a point when its tacky that with the car on the bars the steer in the rearend just naturally drives the car up the track, overpowering the front. Wherein more steer might make it worse? Maybe taking out some rear% would help the front end stick better? We picked up 60-70# mud mostly on the rear which is hard to avoid, but i guess we could have planned in advance for it better.

Yes, you can get loose rollsteer where the back end isn't loose (so to speak) but you chase the back end up the track with the front end. This is most noticable on small tracks or tight corners and you can't keep the car (on throttle) on the bottom to get under someone off the corner. The back end is steering so much it just drives up the track and you have to follow it with the front end drifting up to the top of the track. It doesn't really overpower the front end you just have to follow the back end up with the front end to keep the car tracking right.

[mbaker76]

It is 4 bar RR. my numbers frm static position with 14 upper -3 lower at 1" travel: back 1/16" 2" travel: back 1/16" 3" travel: 0. I guess it does move some but not much. AFter 3" it starts coming forward and the upper is almost leveled out. So it does move some but not much.


Chasing the rearend....Now that you say it thats kind of what it sounds like from the way he described it. Like it doesnt take off and push up hard he just cant keep it down under somebody without backing out. IT turns fine just wont stay straight. Even around the top he could gain ground on entry and through the middle but lost a little coming off because he couldt stay with it as hard coming off. This was at I80/NRP where its kidn of tight cornered ( i feel anyway) and there isnt much sweep to the straight. If he could get in front and round it out it would prob be fine. I hate to take steer out for fear of tightening middle, maybe more RR drive is needed for this condition?

FYI: I did notice that coming off the corner he would be steered to the right, then 1/3 the way down the straight you could sometimes see the car do a little dance (not sure how to describe it) then he would straighten out the front and go, now im wondering if that was the point where the RR cam up enough to pull some steer back out and it woudl drive straighter from there

[billetbirdcage]

How short are your bars? center of rodend to center of rodend?

Both sides LR and RR the same (both 17" and 15" excluding any trail) or are they different on one side verses the other?

[mbaker76]

I cant remember exactly but excluding any trail indexing etc. they should be 15 and 17 both sides, give or take a 1/4".

[billetbirdcage]

OK, was just curious as alot of mods are shorter because of the cage being so far back to get rear wieght. Alot used to be under 16" on the uppers.

[pinionangle]

Can Mods not run a dummy shock in front?

[mbaker76]

you can only have 5 shocks, 4 on the wheels and a damper on the rearend.

You can run a slider behind with a shock in front on the LR. We have done that before. It seemed like it slowed the car too much getting up or wouldnt let it roll up on its own, i know shock valving might take care of this though. The other problem is finding a slider that is free enough not to bind up when the car settles on entry. We have also torn up the insides of a shock by using it as the limiter and slamming against it all the time. We switched back to chain on front and coilover behind.

[pinionangle]

I see. I had forgot all about the one shock per wheel rule.

Years ago, I ran a slider made by Gearte and used a shock in front. I want to say it was just a dummy shock. It seemed to work good for us on a 4-bar dirtworks with the left rear on the "hook".