Make it handle

[69gmcc10]

How about polly bushings for shocks? are they a worthwhile upgrade or an upgrade at all?

[Rstone1]

I asked this question earlier and got no responce so I will ask again.

Inclination between the lower and the upper ball joint in the spindle. Is this needed, what is it used for and where is a good range to be in if it is needed?

[robnolimit]

Originally Posted by 69gmcc10

How about polly bushings for shocks? are they a worthwhile upgrade or an upgrade at all?

Shocks only work when the shaft moves. So, anything that soaks up the transfer of suspension movement from the shock shaft is bad. shocks are one of the components that when it comes to performance, I'd go straight to bearing mount. But, urathane bushings are a big + from stock rubber.

[GMC Canuck]

Please correct me if I'm wrong but I will try and answer.
The axis between the lower and upper ball joint that the spindle turns on if moved out or in is camber (moving the top of the tire out or in, out for positive in for negative). This sets the angle of the tire when you go into a corner. You want a little negative camber, like a motor cycle leaning into a corner.
If you move the axis forward or back (you won't see any change on the tire) you're changing caster. Move the top back you have positive caster, forward for negative. Positive caster will pull the steering back to centre (like a shopping cart caster has massive positive caster and will always snap back to centre)

[Rstone1]

Thank for responding. I understand why it there and what it's for. I guess I should have been clearer. I'm wondering what's the least amount of degrees diference between the upper and lower ball joint you can get away with.
Posted via Mobile Device

[oldspowered67C10]

Rstone1, The inclination your speaking of is there to control camber change through steering arc of movement. This is also influenced by ball joint offset fore and aft.

I don't really under stand what you mean but minimum allowable though. Do you mean in the design of the spindle or in the position of the ball joints relative to the frame?

[Rstone1]

Yes in the design of the spindle. If you were to build your own. Factory spindles at all on the conservative side.
Posted via Mobile Device

[Mechanic77]

Rob can correct me if I'm wrong, but I believe you're referring to what they call the king-pin inclination angle.....the angle you get when you draw a line through the upper and lower ball joints to the ground....if you're making your own spindles, and know your wheel and tire size, you can determine the ideal king-pin angle. Ideally, you want the imaginary line drawn through the ball joints to hit the ground at the center of the tread on the tire, that reduces the scrub angle when you turn and will also reduce steering effort.....clear as mud?
Rob might be able to explain it better than I can

[Rstone1]

This what I'm wondering how small an incline can you have and not loose all of your steering feel?
Posted via Mobile Device

[oldspowered67C10]

Rstone1, alot of variables to think about there. KPI(king pin inclination), included angle and scrub radius.

If you decrease KPI the car tends to lose stability and the steering has a harder time returning to center, great for low speed parking lot type stuff but not so great for a performance car. But keep in mind, caster also has a effect on this.

The more you decrease KPI the more wheel back spacing you'll need to keep scrub radius in check. Of course the position of the spindle on the upright in or outboard effects this.

The more you decrease KPI the the closer together the lengths of the upper and lower control arms become which effects camber curve. The position of the control arm mounts relative to the frame in or outboard influences this as well.

Anyways, it seems you already are aware of the principals of KPI but are wondering what effects too little would have and at what point would you encounter driveability problems. Since you would have to incorrectly engineer a part to find out, cant say for sure but typical KPI is around 5-6 degrees so if I had to guess Id say at half that spec you start to run into issues. I suppose you could put vehicles with wildly varying purposes, say a WW2 era Jeep and a new corvette on a modern alignment machine to get the numbers so you'd have a way to relate the numbers to how a vehicle drives but even then there are other variable in play there also so while it may give you a idea its not exactly a sound scientific method.

Just out or curiosity, why are you asking this?

[Rstone1]

Well I'm concidering building my own spindles. I've seen a camaro built recently that didn't had like 2 or 3 degrease of KPI. And also alot of prototype cars don't seam to have much. I would like to get as close to 0 scrub as possible. I've talked to the camaro owner a little bit and he says that his car handles real well. He's going to the autocross nationals. just looking to do something different than normal. There has to be a better way to make these trucks handle.
Posted via Mobile Device

[robnolimit]

KPI Hey, you guys did great sorting that out. Rstone1, if you are serious about fabbing your own set up, get a copy of "suspension geometry pro" from "autoware", it's way cheaper than buying extra steel. My HellBoy C10 has 7* KPA in the spindle. Just so you know. I wouldn't go much less than 5*. When it comes to scrub radius, there is a common belief that '0' is the goal. In this case, however, '0' is a comparison number that everyone can compare to and understand. Like a strarting point. In practical application, as you close in on '0' scrub, you start to loose all steering feel. Now add in power steering and you have no feel at all. In a performance build, I would aim for 2" scrub radius with a 10"+ wide front tire.

[hotrod1]

I dont think that this thread ever discussed braking systems, more specifically vacuum assist, hydroboost, manual master cylinders (dual and tandem).

Most of our trucks on this thread are maybe for autocross/protouring, handling, and do see street time as well. A play vehicle maybe? The majority would tend to have disc all the way around as well.

There seems to be a trend towards getting rid of the assist braking systems and going towards the manual systems; lack of vacuum, available space, not as safe as manual, etc. Are manual systems feasible on a vehicle that sees street time, a hot rod show, autocross?

If manual is the way to go, the question then becomes dual or tandem? What about the dual cylinder with balance bar vs tandem cylinder with a proportioning valve? How about pedal set ups? 6 1/4 to 1 or 7 to 1? Can manuals be placed on the frame using the stock pedal, or would putting it on the firewall better? If firewall, masters inside the cab or on the outside in the engine compartment. I would think masters inside is nothing but a pain in the neck. I maybe wrong.

Is all this worth considering, or leave the vacuum master alone and choose another thing to tinker with?

[Rstone1]

Just wanted to thank everyone for there input. It really helped. Rob thank again for your input. I drew it up in CAD and with a scrub right arount 1.25" I was at 5 degrees of KPI. I'm a parapaligic so I end up having to drive one handed all the time so I was going to go with a 16 to 1 box with a 2 to 1 quickiner on it so I was thinking I could get by with a little less than normal becasue of the faster ratio on the steering. I could be mistaken though. trying to get close to 1 turn lock to lock.

[robnolimit]

Originally Posted by Rstone1

Just wanted to thank everyone for there input. It really helped. Rob thank again for your input. I drew it up in CAD and with a scrub right arount 1.25" I was at 5 degrees of KPI. I'm a parapaligic so I end up having to drive one handed all the time so I was going to go with a 16 to 1 box with a 2 to 1 quickiner on it so I was thinking I could get by with a little less than normal becasue of the faster ratio on the steering. I could be mistaken though. trying to get close to 1 turn lock to lock.

It would be worth a few phone calls. I would call Lee engineering and talk with them about steering boxes, then I would call KRC and have a chat about pumps. These guys are at the top of their game, and very helpfull.

[robnolimit]

Brakes more specifically, the delivery system. That being the pedal, booster and master. If you have ever read about "the pogo incident" from my younger days, you know I have spent some time on brakes. The goal, for me anyway, is to create 1000 to 1250 psi of line pressure at the top end with the type of pedal feel that you want to match you intended driving style.
I have a great three car comparison. Three that are currently in my garage.
1. My trusty sled, 1946 ford convert. Has a 5.5-1 pedal ratio, hydro-boost and a 1 1/8" master. (4wd, oem type 11"ft, 11"rr) This car weighs in at 3400 lbs, and stops on a freekin dime with three cents to spare. I once put a set of really agreesive pads on it, and with Falken tires it stopped from 60-0 in 92 feet, out braking a Porsche! The pedal is very soft and smooth, BUT, in a track setting, or the roads up to Big Bear, the pedal feel is so light its hard to feel the pad contact.
2. The Bullit, 55 F-100, has big 14" 6 piston Baer brakes, the pedal is 6-1, and uses an 8" dual diapham booset and 1" master. This is a standard street/perf set-up. The motor makes good vacuum and it is very comfortable to drive. Stop and go is no problem. Pedal feel is great. It does take a bit more effort than my '46, but much less than a stocker old p/u. I like it. When the Bullit was fresh build, I had got a hold of a bad master right from the start, the fading master cost me three points at the first Truckin Throwdown. Had it not failed, I would have won by two points. Aaargh!!!, but, its an easy fix and now works perfect every time.
3. HellBoy. My goal was to eliminate anything that could fail, and to have lots of adjustment for tuning. I used a Wilwood hanging pedal at 6.5-1 with tandem masters. The front is a 3/4"bore, and the rear is 13/16". The diffenerce in bore size puts a lille more pressure to the front brakes. The balance bar assembly allows adjustment to the front and rear brake without a proportioning valve. It's a pain to bleed. It looks really cool. Yes, it works very well, and the pedal feel on the track is consistant. It is easy to feel the brakes, and modulate pedal input. But, it takes a firm push to stop it, so on the street you have to be used to it. Most of us are not used to manual brakes any more. It takes some getting used to.
I'll put together some info on this for you.

[hotrod1]

Originally Posted by robnolimit

Brakes more specifically, the delivery system. That being the pedal, booster and master. If you have ever read about "the pogo incident" from my younger days, you know I have spent some time on brakes. The goal, for me anyway, is to create 1000 to 1250 psi of line pressure at the top end with the type of pedal feel that you want to match you intended driving style.
I have a great three car comparison. Three that are currently in my garage.
1. My trusty sled, 1946 ford convert. Has a 5.5-1 pedal ratio, hydro-boost and a 1 1/8" master. (4wd, oem type 11"ft, 11"rr) This car weighs in at 3400 lbs, and stops on a freekin dime with three cents to spare. I once put a set of really agreesive pads on it, and with Falken tires it stopped from 60-0 in 92 feet, out braking a Porsche! The pedal is very soft and smooth, BUT, in a track setting, or the roads up to Big Bear, the pedal feel is so light its hard to feel the pad contact.
2. The Bullit, 55 F-100, has big 14" 6 piston Baer brakes, the pedal is 6-1, and uses an 8" dual diapham booset and 1" master. This is a standard street/perf set-up. The motor makes good vacuum and it is very comfortable to drive. Stop and go is no problem. Pedal feel is great. It does take a bit more effort than my '46, but much less than a stocker old p/u. I like it. When the Bullit was fresh build, I had got a hold of a bad master right from the start, the fading master cost me three points at the first Truckin Throwdown. Had it not failed, I would have won by two points. Aaargh!!!, but, its an easy fix and now works perfect every time.
3. HellBoy. My goal was to eliminate anything that could fail, and to have lots of adjustment for tuning. I used a Wilwood hanging pedal at 6.5-1 with tandem masters. The front is a 3/4"bore, and the rear is 13/16". The diffenerce in bore size puts a lille more pressure to the front brakes. The balance bar assembly allows adjustment to the front and rear brake without a proportioning valve. It's a pain to bleed. It looks really cool. Yes, it works very well, and the pedal feel on the track is consistant. It is easy to feel the brakes, and modulate pedal input. But, it takes a firm push to stop it, so on the street you have to be used to it. Most of us are not used to manual brakes any more. It takes some getting used to.
I'll put together some info on this for you.

Hey Rob:

Looking forward to more information on the brakes.

I just took a look on the internet for your truck "Hellboy" and found some pics. WOW, that thing makes my heart race. Where can I find more and more pictures? Hey, where is the radiator? In back? Tell us more about that as well. How well does it cool? I imagine that you dont drive this anywhere except for autocross.

[robnolimit]

Those in So Cal, the So Cal challenge is this weekend. A car show area has been added. Come check it out, in Riverside at Adams Motorsports Park. if your not local, follow the action on facebook at No limit Engineering.

[MrBlue]

Rob,
First thanks for all the information. I know that I read this somewhere between page 1 and this last page, BUT What shocks do you recommend. I am going to lower with springs, this is a street driver, not a racer. Thinking of 3-inch front and 4-5-inch in the rear
Thanks,
Victor

[gringoloco]

Originally Posted by MrBlue

Rob,
First thanks for all the information. I know that I read this somewhere between page 1 and this last page, BUT What shocks do you recommend. I am going to lower with springs, this is a street driver, not a racer. Thinking of 3-inch front and 4-5-inch in the rear
Thanks,
Victor

Start at post 1302...

[jlsanborn]

Originally Posted by MrBlue

Rob,
First thanks for all the information. I know that I read this somewhere between page 1 and this last page, BUT What shocks do you recommend. I am going to lower with springs, this is a street driver, not a racer. Thinking of 3-inch front and 4-5-inch in the rear
Thanks,
Victor

Victor,
I'm in the same boat and got some feedback a page or two back. I'm going with the Monroe shocks. Rob is in the process of developing some that are specific to our trucks but I'm not sure when he'll ha e those available or what the price point will be. He has the Monroe's on his site but ok not sure how to pick the right shock. There has to be a formula that he uses to determine the proper dimensions (extended length and collapsed length).
Posted via Mobile Device

[69gmcc10]

Found this thread half way down page 2 and I started feeling sad, so I am bumping it back to where it belongs!

Mr. Rob, do we have any more great info on brake systems?

[GMC Canuck]

Found this thread half way down page 2 and I started feeling sad, so I am bumping it back to where it belongs!

should be a sticky.

[AJohn6]

Rob,

I have a question about Sway Bars. I am certain it has been covered but sifting through 56 pages to find it is proving to be more difficult than I had imagined.

The truck is a '71 C-10 Stepper and I have your Fatbar 4-link w/ 6.9" single adjustable Shockwaves attached to a F@$d 9" and a 4x2 custom back half. I am looking at buying the Speedway Engineering swar bar but I'm not sure what bar I should get. Should I get a solid/hollow bar and what thickness should I get?

The front end is the Porterbuilt mild dropmember with their sway bar and RS-7 bags

Thanks in advance,

Adam

[robnolimit]

I'd go with a 1" splined bar and arms. I tried a 1 1/4", and even at .065" wall, it's a little stiff. Once you're set up with the 1" bar, you can change bars easy. I'd start with a 1" solid.