usra bmod set up

[cgs]

what are the shock and spring placements on a usra bmod?
ie shock and spring on front or do you guys separate them? also when the track goes slick how much lr bar angle will you use?

[hpontap]

A friend of mine runs LR spring in front on a slider with shock behind. RR spring on top of housing with shock in front.
Raise the LL bar up on chassis to add drive. Around 42 - 45 degrees LL bar angle at full drop.

[cgs]

thank you. what I'm also curious is how much is everyone using for drop? I have 4 in of drop at ride height which puts my bar angle at 38. is 4 in the ballpark and add angle or do I need to extend my drop to 6 in to get 45 degrees?

[hpontap]

I want to say you need 5" - 5-1/2" of drop should get you pretty close. Let out on your limiter chain until you get to around 43 degrees and see how much drop you have. Make sure that you dont over extend your shock in case you need a shock extension on it. And check that you dont over-index the birdcage and get it hung up.

[powerslide]

I want to say you need 5" - 5-1/2" of drop should get you pretty close. Let out on your limiter chain until you get to around 43 degrees and see how much drop you have. Make sure that you dont over extend your shock in case you need a shock extension on it. And check that you dont over-index the birdcage and get it hung up.

He is on a 2link.

[hpontap]

Forgot to add that your LL bar will probably already be in one of the upper chassis holes when using that much angle.

[cgs]

thanks. ya I'm almost to the top. I had it limited with a chain from my four link. I'm not actually a usra car. imca and two linked it cause it fits my driving style better. is there an advantage to putting the shock up front on the left side when it slicks off? right now I'm dominating heat races when its heavy and or rough. just need some help when it slicks off.

[hpontap]

One of the worst mistakes I ever made was to make too many changes at one time. If you increased you LR bar angle, I would try that and see what it does before changing anything else. One change at a time so you can see how the car reacts.

[cgs]

winner winner!! track was heavy rough. went right thru the ruts like they weren't there while all the 4bar cars jarred there teeth out. yes one change at a time. the car is close so I don't need to throw the kitchen sink at it.

[hpontap]

Glad to hear you are getting better and thanks for the feedback also. Give 'em Hell.

[cgs]

you're welcome. what I need help with is slick conditions with this two link. has anyone ran a really soft lr spring on a two link. to help it get on the bar and to also keep some kind of preload on the spring at full hike? like a 125?

[hpontap]

I have ran the soft spring/lot of pre-load deal in a few different class cars. What I found was after the spring is past a certain point , the effects start going the other way from how you intend. I had good luck with a Shaw Modified with a 150 spring on the LR with a LOT of pre-load in it. Some guys used to run soft ( 125-150 ) spring but 20" on the LR also.

[powerslide]

I would try a clamped swingarm LR if you want to get better traction in the slick.

[cgs]

I have ran the soft spring/lot of pre-load deal in a few different class cars. What I found was after the spring is past a certain point , the effects start going the other way from how you intend. I had good luck with a Shaw Modified with a 150 spring on the LR with a LOT of pre-load in it. Some guys used to run soft ( 125-150 ) spring but 20" on the LR also.

right now I have a 200 and with it jacked up i have an 1in between the spring and saddle. I was thinking a softer spring with more preload might help keep a little more pressure on the left rear when it's at the top of hike. I'll be at a slick track in a couple weeks and will give it a try. thank you

[cgs]

I would try a clamped swingarm LR if you want to get better traction in the slick.

spring on the arm and the shock on a clamp?

[powerslide]

I did a did the shock on the arm when i had a bmod. Your milage may vary. I also only ran about a 200, the motion ratio says thats really soft. But with all the stacks on LR 4bar stuff trying to make it soft as possible i'm not sure i was that far out to lunch

[Rockinduramax]

How much angle is needed to run a swing arm?

[powerslide]

How much angle is needed to run a swing arm?

Depends how long it is(thats what she said)

start around 18 degree on LR

[racing_kid]

My 3 link mod has 15 inch bars spring Infront shock behind lr 175 on top shock in front 20 inch pull bar 3 inch ahead of center line, the pull bar was a night and day difference in the slick from 3 inch behind to 3 inch ahead

[racing_kid]

Lr 43 degrees at drop with 4.75 in of drop and rr is10 degrees at ride height

[cgs]

thanks again guys. won again Friday night!!

[powerslide]

thanks again guys. won again Friday night!!

Hell yeah congrats man they aren't easy to come by

[cgs]

One of the worst mistakes I ever made was to make too many changes at one time. If you increased you LR bar angle, I would try that and see what it does before changing anything else. One change at a time so you can see how the car reacts.

Ya I just did that Saturday night. won Friday at one track and Saturday night went to another where it was their championship night. no heat races, just a main. needless to say I over thought it and threw all sorts of adjustments at it. no I know what not to try when I go back for their open show next weekend!

[dirtracer07x]

if running the soft lr preloaded do we need to go up on the rr? currently running a 150 lr and a 125 rr. Thinking about trying a 125 LR and a 175 RR. We have been playing around with the pullbar long and flat (10*) and has been working well. Anybody try chaining the RR down? Heard this will give tons of bite but is easy to mess up and go to far.