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Discussion Starter #1
I am looking for some suspension tuning tips for the strip. I have the stock Bilstein coilovers on the front, stock FFR uppers and Mustang lowers. The rear is a 4 link with Granatelli arms. I run 3.73's in the rear behind a TKO 500. The rear tires are 315/35/17 Nitto NT05r's. What adjustments (if any) can I make to get some more power to the ground?

My engine numbers were 576/550 on the Dyno.
 

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Pretty limited adjustments you can make with your set up. I assume that the Granetelli arms are adjustable so start with setting the pinion angle, conventional wisdom seems to point to 2 degrees down relative to the trans output. Also if you have a choice of holes for the upper and lower rear control arm attachment you want the front attachment points as close together as possible and the rear attachment points as far away from each other as possible. This will move the instant center back and provide more weight transfer to the rear. Tire pressure is also a big variable and with the NT05R you probably want to start at around you regular street pressure (~24psi to 26psi) and work down in pressure. I realize that this is pretty basic advise but each car is different but this is a good starting point and you will ultimately find what works best for yours.
 

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I agree, if you're adjustable, dial in the pinion angle first. That can make a world of difference. Mine set incorrectly, I could spin my tires at half throttle in 3rd gear, set correctly, hooking in 3rd with foot on the floor (same tires, same day, just a twist of the wrench).

Here's what was recommended to me:

2 degrees: solid bushings

4 degrees: solid and poly mix (my set up, UPR double adjustable, poly on one end, solid on the other)

6 degrees: poly on both ends

As mentioned, you may need to play with it to dial it in (fine tuning best done at the track). Not sure if I was lucky but I didn't have to touch mine once set to 4.


Taking it further, I've recently installed a rear Competition Eng. anti-roll bar (universal). It has to be welded in and adjusted correctly. It goes over the axle and is not visible. This changed the car dramatically.

I would STRONGLY recommend getting rid of the Bilsteins, at least in front. They have been known to break. Mine broke on the freeway, dragging my frame at 60 mph was not my idea of a party. Mine were properly installed. Head of the shaft snapped off. Factory Five took care of me but better to take care of it now.

If you wanted to take it even further (and were changing your shocks) you could get an adjustable drag race shock for the front which would allow the front of the car to lift higher transfering even more weight to the rear. They may not be the best for cornering though.

I don't have those myself but do have the adjustable Konis that FFR sells. All 4 adjusted to the softest setting. My 60 ft times at the track are now in the 1.40's through an auto tranny, no transbrake. Still handles like a slot car.

HTH

Tom
 

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Discussion Starter #4
Great tips. I think my initial pinion setup is one degree so that's a great place to start.

As far as the Bilsteins go, I sent them back and got the large shaft upgrade so I think they should be fine. I have a friend that manufactures coil overs so I will be replacing them at some point but he has been too busy for a low margin job.
 

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That's great to hear about the shocks!

I really believe that if you're set at 1 degree, by the time you stand on it your pinion is going to be pointing North, not where you want to be, even if you had solid bushings.

What kind of bushing do your arms have?

Tom
 

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Discussion Starter #6
That's great to hear about the shocks!

I really believe that if you're set at 1 degree, by the time you stand on it your pinion is going to be pointing North, not where you want to be, even if you had solid bushings.

What kind of bushing do your arms have?

Tom
The Granatelli's have poly bushings all around.
 

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That'll put you around 5 degrees North when the foot goes down if you start at 1.

I'd recommend starting at 5-6.

JMHO


You'll know when it's getting close when you step on it and the front raises up, even on the street.


Tom
 

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Sorry for the breif derail...

Tom, Does this math hold true for the 3-link also?

And if I read correctly, this means that I'm starting out by setting the pinion so it angles down towards the ground. When torque is applied this should jack the pinion up and I want to end up with the pinion pointing right at the trans output. Do I have this right?

Thank you for your patience, we now return you to your regularly scheduled program.

Les
 

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You are correct about the desired ultimate angle/direction of the pinion under load.

What I can't answer is where to set a 3 link to get there : ) No experience with those.

Tom
 

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Thanks Tom, I'll see if I can track down someone who has run the 3-link and knows what angle I need to start with.

Les
 

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Discussion Starter #11
OK, I have no adjustments on the control arms. I raised the rear of the trans as much as I could but am still only at about 2.5 degrees difference. I have looked into adjustable uppers and lower control arms. I am thinking of picking up the adjustable uppers only. Would that do the trick?
 

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add the adjustable upper arms. this will let you set the pinion angle to 3 down.
make sure to use the lower front holes on the chassis.
When changing the pinion angle
on the lower arms make sure they are in the rear lower holes of the axle brackets.
The drag sway bar is worth the cost.

As far as the three link when using it to drag race make sure it is welded to the housing. This is not an option, and should be done on all ffr's.
set the pinion angle to 3 down also with the control arms in the same position.

Later
Mark D
 

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Discussion Starter #15
I bought and installed a set of Edelbrock adjustae uppers and set the pinion centerline 4 degrees down relative to the trans output shaft. I mounted them in the lowest mount hole. These arms have bushings in the back and solid fronts. Does this sound about right or am I hearing I should adjust that back to 3 degrees? It's so easy to do now, I could try it where it is and then move it and try again.

I also installed a rev limiter so I can safely practice some power shifting.
 

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Try it and adjust as necessary. Every set up will be slightly different so what works for you may not work for the next guy.
 

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Discussion Starter #17
Who makes the drag sway bar and what does it do?


add the adjustable upper arms. this will let you set the pinion angle to 3 down.
make sure to use the lower front holes on the chassis.
When changing the pinion angle
on the lower arms make sure they are in the rear lower holes of the axle brackets.
The drag sway bar is worth the cost.

As far as the three link when using it to drag race make sure it is welded to the housing. This is not an option, and should be done on all ffr's.
set the pinion angle to 3 down also with the control arms in the same position.

Later
Mark D
 

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Yes, Competition Engineering. Get the universal kit if you get one.

It keeps the back tires planted evenly on the ground by eliminating twisting of the car (left side coming up) when you're foots in it, especially noticable on launch. The car hooks much better, stays straighter is easier to control.

The difference in my car was ridiculous. It now feels like the back end is glued to the ground or running through a slotted track when I'm at the drag strip.

I have an automatic now. I was really worried about shifting into second on the street with the hammer down, thinking it would go sideways. To my surprise, the opposite is happening. Even with the tires spinning some in first, when I hit second, the rear end drops, digs in, car straightens out and the tires hook. I even got in on video (fast forward to about 6:10):


I'm running drag radials of course, street tires wouldn't have a chance.

Tom
 

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Discussion Starter #20
OK, I am looking at installing the Competition Engineering anti roll bar this winter. I found 2 universal kits on Summit. Which one is the right one?


This one has a solid bar and says you mount it through the frame rails.

or


Hollow bar and it looks like it is set up for a square frame rail.
 
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