FOUR LINK BRACKET RACER

Suspension Tuning, Troubleshooting, Design and Discussion

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fat bastard
Posts: 10
Joined: Mon May 04, 2009 6:12 pm

FOUR LINK BRACKET RACER

#1 Post by fat bastard » Tue May 12, 2009 10:11 am

Hi everyone,

First timer here. I have a 65 ford mustang, 2+2 tubbed w four link. My instant center is at begining of front seats. I run a QA1 adjustable shock in rear, anti-sway bar hooked to rear axle[comp engineering]. Front suspension is stock [all brand new] comp engineering 90/10 shocks and morosso drag springs. Car is like a concrete block when pushing down and trying to lift up. It 60fts as good as 1:39 as bad as 1:45 normal is 1:41-2s. My pinion andgle is 5 degrees positive. Can I get better sixtys. or am I pipe dreaming. Car runs a 396 stroked 351 - est horse power 600-635..

car weighs 3150 with driver and fuel.

lft front 920 rt front 792

lft rear 716 rt rear 720


Vehicle launches straight, after I added a turn and half preload to top right bar. Car now sits at a strong angle down in the left?

I know Im leaving out a lot but hoping I can get this thing to hook a little harder. I added a 100 horse this year and sixtys stayed the same.


Thanks

Fat bastard

bracketracer
Posts: 329
Joined: Wed Oct 29, 2008 7:14 pm
Location: New Jersey

Re: FOUR LINK BRACKET RACER

#2 Post by bracketracer » Wed May 13, 2009 4:53 am

How big is the back tire??? You need to map out you IC locations on paper or a program. Did you remove the preload in the anti roll when you put preload in the 4 link?? What gear in the rear??? Have any video from the starting line...
Sounds like you just need to find a different location for the IC and possibly loose some spring pressure on the rear..Does the front pitch and rotate up??? What do you have for a trans??? More questions to come :scratch:

fat bastard
Posts: 10
Joined: Mon May 04, 2009 6:12 pm

Re: FOUR LINK BRACKET RACER

#3 Post by fat bastard » Wed May 13, 2009 6:20 am

http://www.youtube.com/watch?v=lFHv-BQ9DA8

http://www.youtube.com/watch?v=V7KuFniopm4

If this link doesnt help look up 65 mustng -big chippy on u-tube.

I hope I copied the link correct. This was last season before adjustments.

I am running hoosier 29.5x14-15 drag slicks on a 14" wide rim. Also running a 4;56 gear with a dynamic built c4 transmission
and lets not forget a 9" ultimate converter, stalling at 5400 rpm.

Lifting the front wheels looks cool, but wining races pays better.

Thanks
Fat bastard

DOTracer
Posts: 466
Joined: Tue May 24, 2005 11:12 pm
Location: Westminster, MD

Re: FOUR LINK BRACKET RACER

#4 Post by DOTracer » Wed May 13, 2009 9:11 pm

A turn and a half sounds like a TON of preload. We usually talk in flats of preload, not a turn and a half.

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sunsation540
Posts: 406
Joined: Sun Aug 20, 2006 11:32 pm
Location: Moore OK.

Re: FOUR LINK BRACKET RACER

#5 Post by sunsation540 » Wed May 13, 2009 11:10 pm

take the pre load out, dot racer is right 1 turn in my top R bar is 100 lbs to the LF,, the reason for preload is pushing left or right on launch if going straight put it back. where it was. is the pinion down or up positive 5 deg up would be a problem,, but never found 60 ft in pinion angle however it can eat HP...
make a plan and stick to it !!

fat bastard
Posts: 10
Joined: Mon May 04, 2009 6:12 pm

Re: FOUR LINK BRACKET RACER

#6 Post by fat bastard » Sun May 31, 2009 10:07 am

60fts I need some tips to bring down my sixtys. I thought 100 more rear wheel horse would have brought me at least a few hundreths, what gives.... Or am I just destined for 1.40s. Please I need some brain trust here.

I have been told by some racers my qa1 shocks.. _ _ ck, but what the shocks cost me I don't want to spend dough unless I can get some where. I put new springs in this year, 210s I started adjustment on shocks at 5. I also tried to loosen up the front suspension, [I see some cars bounce with one finger, you chevy guys no what Im talking about.] It is a mustang-buckboards go well with horses, right.

Please with all you sharp racers out there you got to have some Ideas....

Thanks
Fat Bastard

want-a-be
Posts: 189
Joined: Tue Feb 05, 2008 11:04 pm
Location: Southern Illinois

Re: FOUR LINK BRACKET RACER

#7 Post by want-a-be » Sun May 31, 2009 9:08 pm

What rear springs were you running before you put the 210s on? How did the car react to the new springs? I would think the 210s are a bit too heavy for this combination.

What spring rate are you running on the front? I think this car should be running in the mid 1.30s for 60' if not high 1.20s.

How far out is the instant center, and how high is it?

Don

bracketracer
Posts: 329
Joined: Wed Oct 29, 2008 7:14 pm
Location: New Jersey

Re: FOUR LINK BRACKET RACER

#8 Post by bracketracer » Mon Jun 01, 2009 5:36 am

Don, look at the 1st vid the back of that car don't move a bit....I agree way to much spring back there......

fat bastard
Posts: 10
Joined: Mon May 04, 2009 6:12 pm

Re: FOUR LINK BRACKET RACER

#9 Post by fat bastard » Mon Jun 01, 2009 12:41 pm

Guys,
I have 210 springs in the rear, front springs are moroso drag springs. I have about three threads of turns on rear springs. I have measurements of ic but what exactly are you looking for. I posted weights on each wheel after setting prload in chassis. This car is like pushing a cement block if you get my drift, I weigh 230 and car barely pushes down when I lean on it. Since I loosened up the front suspension I can push down a little bit more. But sixty foots are no better.

fat bastard

want-a-be
Posts: 189
Joined: Tue Feb 05, 2008 11:04 pm
Location: Southern Illinois

Re: FOUR LINK BRACKET RACER

#10 Post by want-a-be » Mon Jun 01, 2009 8:34 pm

This is going to take more time then I'm wanting to invest in a forum. Don't take that wrong though....I'm just meaning that I thinkn I could help you out better on the phone. If you're intrested then PM me and I'll send you some contact information.

But til' then,....are the 3 threads you have left on the bottom of the shocks or near the top? I'm betting near the bottom.

ON the IC,...I'm looking for it's length and it's height off the ground. Those 2 measurements make a wrold of difference.

Scaling the car should be done with no, ( zero ) preload on the rear end. This is achieved with one of the 4 link bars removed on one of it's mounts,...I like taking out the passender side one. If you decide to get ahold of me then you'll understand then.

As far as the car pushing like a dump truck....are you sure the rear end is in straight? How was it checked?

Are the brakes totally disengaging? Might have one locked up.

Are you sure you don't have a shock locked up?


Don

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