Make it handle

[NPilot1975]

Rob, Do you know anyone running Tilton master cylinders on the street? I saw an installation article in a mag and loved the look plus no booster, but not sure about use on the street.
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[robnolimit]

Originally Posted by NPilot1975

Rob, Do you know anyone running Tilton master cylinders on the street? I saw an installation article in a mag and loved the look plus no booster, but not sure about use on the street.
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Well, not tilton exactly. But I do know several guys running Wilwood and/or CNC set ups using two masters on a balance bar (no prop valve needed, just check valves), and some using the clutch masters also. They work good, but you have to get the bore size and pedal ratio correct. Wilwood has some good info on thier site. I will be running this type on my new C-10 project, (No Limit K-10) I'll try to get some picts up next week.

[NPilot1975]

Thanx. I will take a look at both of those. I have been following your K-10 build and love it.
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[Grimee]

I've run both and for my money I would stick with wilwood for you pedal assembly, master cylinders and bias valve . Tilton has it together when it comes to clutches and related parts

[NPilot1975]

I looked at both today and really like the wilwood pedals. I wish they had the drilled style pedal in a single pedal design. Might get it which would allow me to switch to a manual later if I decide.
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[robnolimit]

#2. Trailing Arms Lets look at these next, since many C-10's have them, and they're fairly simple. A trailing arm is a 2-link suspension. The arms control the front to rear axle placement, and the pinion angle. The front eye mount of the arms defines the 'Instant Center' or IC, the point where the tires traction pushes on the truck. A locator (panhard rod) is needed for side to side control. Coil springs, Air bags, or Coil-over shocks can be used as the 'spring' to hold up the weught of the truck.
We now have three component sets doing the 'jobs' required. With leaf springs, one part has to do all of the jobs. - not specialized. Now, we have some parts doing specialized jobs. Because of this, these parts can do a better job. The panhard rod's main job is to locate the rear axle, and it can do this very well if designed correctly. It also defines the rear Roll Center, or RC. The roll center hieght is the average of the two mounting points, the axle mount, and the chassis mount. Raising or lowering the RC can change the handling of the truck. The springs only hold up the truck, and provide the ride quality, and can easily be tuned for a better ride and handling. These are the trailing arm basics. More in a bit.

[robnolimit]

Lets talk Anti-Squat. For the most part, this is a comparison number. A way to say, "this is where the rear suspension lifts the truck". You may not know exactly where your 'anti-squat' is, but understanding it, and using it as a chassis tuning tool, will help. To understand anti-squat, we need to define a few things. CG (center of gravity), this is the balance point of the truck, both front to back, and top to bottom. As an estimate, say 58% of the wheel base (58% nose wieght) appx 68", and for hieght, say the center of the cam, appx 24" for a dropped truck. IC (Instant Center) this is the point where the suspension forces push on the chassis. For a leaf suspesion, we use the center of the front spring eye, for trailing arms, use the center of the front pivit. CC (contact Center) The center of the contact patch of the rear tire. Now that you have these 'points', draw a line from the CC, throught the IC, and contiue on that line until you pass the front/rear balance point. So, what do you do with it? First, you need to 'scale' your CG line. At the ground, you have 0% anti-squat. At the CG, you have 100%. You need to calculate where your 'force line' crossed your 'scale'. I try to set most projects up at close to 100%, with tuning room on either side. Below 100% = more lift on the front of the truck, the rear will sink some, more force pushing forward. Above 100% = more lift on the rear of the truck, the tires plant firm, but less force is pushing forward. The goal is to get all the downforce you need to keep the tires planted, and still push the truck forward as hard as you can.

[taank]

I am on pins and needles for the trailing arm conclusion.
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[jimmydean]

Originally Posted by taank

I am on pins and needles for the trailing arm conclusion.
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Me too! Man, Rob, leave a guy hanging why don't you.

Personally, I am sold on the trailing arm design for both ease of use and cost. After seeing the NASCAR style setup with the adaptability to variations in courses with the slightest adjustment, it just makes sense.

But I am waiting to hear what Rob has to say. Seeing how I blame him for me wanting to add more performance to my build.

[robnolimit]

OK, OK, - now that your all gettin a grasp of this, I'll throw in the curve ball. At the monent, these drawings are static, but in real life, Anti Squat (AS) in dynamic, it moves as the the truck moves up/down. Think about the pictures of old drag cars. Remember the long shackles to raise the rear? Well, this also raised the front leaf mount, or IC, and raised the AS. Not as dumb as it looked. Drag racers have evolved from this trick, but it did work. With trailing arms, The front eye of the arm is the IC, and it's pretty far forward. So, low trucks can have low AS %'s. I hear it comin', NASCAR uses these, and their mounts are low?? Yes, but their smart. They use air pressure to plant the rear tire, and the low IC give them more forward push, less energy waisted. BTW, ever see a cup car leave the pits? Smokes the tires without any hesitation, IE - not much bite on the tire from the suspension.

[jimmydean]

So from a NASCAR perspective, the suspension is set up so the air pressure created at speed by the aerodynamics is what creates downforce for traction and why they spin out so quick when they aren't doing 170.

OK, so what about the setup for a road course. Certainly they aren't creating nearly the downforce in a road course that they do in an oval. So do they raise the IC to create more AS at the lower overall speed?

<edit> Hey Rob, can you just set up an online course to cover all this material? Or better yet a weekend class with track days?

<edit2> Might be a dumb question, but do the bends in a trailing arm matter, or are you looking just at the mount points when drawing your lines? Or does the bend in the back of the arm only for mounting surface? I want to plot out my suspension now and see where it turns up on the scale.

[ambryatim]

Originally Posted by jimmydean

<edit2> Might be a dumb question, but do the bends in a trailing arm matter, or are you looking just at the mount points when drawing your lines? Or does the bend in the back of the arm only for mounting surface? I want to plot out my suspension now and see where it turns up on the scale.

Hello Rob, I was reading thru the thread and never saw where you might have answered this question....so does it matter??

I will be installing the trailing arm suspension on my 57 Chevy Truck and would like to know about the bend in the arms too. As for mounting them do you have to angle them in toward the center of the vehicle like the orginal set is...or can you make them straight.

And attach them to the outside of the frame?? Kinda like this.

http://67-72chevytrucks.com/vboard/s...1&postcount=59

http://67-72chevytrucks.com/vboard/s...4&postcount=52

Thanks

[taank]

So from a drag racing perspective what is the best way to get this heavy old ***** to hook?
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[68 TT]

Originally Posted by taank

So from a drag racing perspective what is the best way to get this heavy old ***** to hook?

Increase anti-squat until you get it to hook. Use as little anti-squat as you can to get it to hook so more of the force is used to move the truck forward instead of lifting the nose upward.

Move as much weight as you can to the back of the truck and lighten the front end as much as you can too. Put the weight as close to the rear axle as you can. It will react quicker this way. If you put it further back the reaction will be slower and the front end lift will be more profound wasting energy.

You need tires with the largest contact patch you can fit on the truck and the softest compound you can get your hands on to start with though. A set of rock hard street radials won't hook in a nose heavy truck even with 150% anti-squat.

You can make one of our trucks hook like it has claws on a set of 28x10.50 slicks but a set of 325/50-15 drag radials work pretty well too if you need to drive it on the street and the track. Slicks will also require aftermarket axles so that may influence your choice as well.

My favorite pic

[taank]

Originally Posted by 68 TT

Increase anti-squat until you get it to hook. Use as little anti-squat as you can to get it to hook so more of the force is used to move the truck forward instead of lifting the nose upward.

Move as much weight as you can to the back of the truck and lighten the front end as much as you can too. Put the weight as close to the rear axle as you can. It will react quicker this way. If you put it further back the reaction will be slower and the front end lift will be more profound wasting energy.

You need tires with the largest contact patch you can fit on the truck and the softest compound you can get your hands on to start with though. A set of rock hard street radials won't hook in a nose heavy truck even with 150% anti-squat.

You can make one of our trucks hook like it has claws on a set of 28x10.50 slicks but a set of 325/50-15 drag radials work pretty well too if you need to drive it on the street and the track. Slicks will also require aftermarket axles so that may influence your choice as well.

My favorite pic

how do you increase anti squat on a truck arm. i wouldnt mind lifting the wheels a bit

[taank]

Also who owns that truck?
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[68 TT]

Originally Posted by taank

Also who owns that truck?

djracer currently owns the truck. He has reconfigured and rebuilt the truck since he picked it up.

http://67-72chevytrucks.com/vboard/s...d.php?t=151718

Previously it was Tom Durham's truck which is from the time frame the pic was taken.

[hairlesshobo]

Originally Posted by 68 TT

Increase anti-squat until you get it to hook. Use as little anti-squat as you can to get it to hook so more of the force is used to move the truck forward instead of lifting the nose upward.

Move as much weight as you can to the back of the truck and lighten the front end as much as you can too. Put the weight as close to the rear axle as you can. It will react quicker this way. If you put it further back the reaction will be slower and the front end lift will be more profound wasting energy.

You need tires with the largest contact patch you can fit on the truck and the softest compound you can get your hands on to start with though. A set of rock hard street radials won't hook in a nose heavy truck even with 150% anti-squat.

You can make one of our trucks hook like it has claws on a set of 28x10.50 slicks but a set of 325/50-15 drag radials work pretty well too if you need to drive it on the street and the track. Slicks will also require aftermarket axles so that may influence your choice as well.

My favorite pic

It's very impressive to me to see a truck with a fat @$$ front end like our trucks have pull of something like that. Now I don't think that would be good to see while driving down the expressway but cool nonetheless

[69gmcc10]

Rob thanks for the "diagrams" to go with the words, it helps solidify the ideas you discuss. So for a vehicle that is at stock height or closer to stock it is less important to flip the trailing arm brackets, blocking the rear is just a tactic to maintain ride quality and the lower you go the more important these factors becomes correct?

[KQQL IT]

Truck Arm looks the easiest. Although leafs and cal trac bars do a great job...
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[robnolimit]

great pict. and right on the mark. Anti Squat is like carb jetting. You want just enough to get a good plant of the tires, too much will waste energy and run slower. With a trailing arm truck, there are only a few ways to do it. I'm going on the assumption (I know) that the truck will stay at it's current ride hieght. 1) move the front trailing arm mount up. You can flip the stock mounts or buy aftermarket. This is the easiest. 2) More work here. Shorten the arms appx 6", use a 'johnny-joint' style pivit ball, move the crossmember back 6", and use adjustable mounts. This is for the serious guys. 3) move the CG down. Lower the motor/trans, and everthing else you can find. BUT, moving the CG back, while helping weight balance, will lower your AS. So, if you move wieght back, you need to raise the IC farther. Sinking in yet?

[hgs_notes]

Originally Posted by robnolimit

great pict. and right on the mark. Anti Squat is like carb jetting. You want just enough to get a good plant of the tires, too much will waste energy and run slower. With a trailing arm truck, there are only a few ways to do it. I'm going on the assumption (I know) that the truck will stay at it's current ride hieght. 1) move the front trailing arm mount up. You can flip the stock mounts or buy aftermarket. This is the easiest. 2) More work here. Shorten the arms appx 6", use a 'johnny-joint' style pivit ball, move the crossmember back 6", and use adjustable mounts. This is for the serious guys. 3) move the CG down. Lower the motor/trans, and everthing else you can find. BUT, moving the CG back, while helping weight balance, will lower your AS. So, if you move wieght back, you need to raise the IC farther. Sinking in yet?

Oozing in like molasses is more like it. Wouldn't tire diameter also affect this? Taller tire would raise the IC point while keeping the CC in the same spot.

[robnolimit]

One more thing, if your going to do this right, you need to know where yor are. Its time to weigh and measure your truck.

[taank]

ok so to increase the anti-squat if i was to install something like this


wouldnt it change the driveshaft angle as well? would you have to add a drop block to correct it?.

if you flipped the brackets it would effectively do the same thing?


the higher the trailing arm is in the crossmember the higher the ride height in the rear would be?

[Grimee]

Raising the arms in the cross member will change the amount of anti squat and the pinion angle. the springs will set the ride hight