Make it handle

[AJohn6]

Rob,

I have a question for you. I am in the middle of rethinking my brake setup since the underdash pedal assembly I have isn't going to work for me. I had planned on using a 7" booster and a corvette style dual master cylinder and a pro-valve. My plan now is to use the Wilwood reversed brake pedal kit without a brake booster and with dual master cylinders, one for the front and one for the rear.

My question is how do I figure out what bore size would be best for me?

I have a '71 stepper, porterbuilt mild dropmember with bags, and a fatbar 4-link with Shockwaves. For the brakes I have the following Wilwood kit-

13" Forged Narrow Superlite 6R Big Brake Front Brake Kit
13" Forged Narrow Superlite 4R Big Brake Rear Parking Brake Kit

[C0UCH]

I've narrowed down my search for suspension. After talking to Porterbuilt on the phone for quite a while I'm going with a coilover touring dropmember front end and mild c-notch in the rear. I'd go lower but I don't want to raise the bed.

From what I've read the Hotchkis TVS (as I previously mentioned) kicks ass, but I don't want to mix and match parts between Hotchkis and Porterbuilt and I'd rather support PB anyways. Pulling the engine possibly today and starting the teardown as soon as my brothers S2K is out of the shop. Blasting the rails and will mockup everything once PB components arrive.

I'd like to order the wheels/tires asap though but without all the parts, I'd rather not risk it. Any luck with the backspacing chart mentioned above?

[robnolimit]

No luck yet on more wheel info. Does Nate have specs for his suspension?

[Can't kech me]

i don't really know if this fits in the suspension forum, but it does go along with handling.

for us auto tranny guys, would running a ratchet shifter with reverse lockout be hugely beneficial for us on an autocross course, but still be able to put it in drive and cruise? seems like something project JT needs. just curious, because being able to upshift/downshift one at a time knowing that it will be one gear, and keep it out of park, reverse, and neutral would be just as beneficial. anyone running one have any imput?

[robnolimit]

Well, this is the set up I use in the HellBoy C10. A nice thing here is the 'balance bar'. This takes place of the prop valve, and is easier to tune. I started with the recomended 13/16" bore rear, and 3/4" bore front. - also a 3/4" bore clutch. And, I run 4-piston superlights on all four, 1.75" bore front, and 1.625 bore rear. My wieght balance is 52% ft. - pretty good for a p/u. Our J.T. shop truck is 57% ft. So, it was OK this way, but I couldn't get the rears to lock up. Even with the balance bar max'd out. So, I switched to a 3/4" bore rear master. That worked good for me. The balance bar is close to center, which gives me some tuning room. Now, I am playing with pads to get the last little bit out. - haha, don't ever try 'A' pads on high $$ rotors. - they will have a 1000 mile lifespan. - just so ya know. Really agressive!!! lol.
So, try the same set up to start,(13/16" and 3/4") it may match your 6/4 piston set up well. But, don't be shocked if you want/need to change one or both later. For a softer pedal you might try a 3/4" and 5/8", but this will have more pedal travel. Oh ya, the one piece aluminum cylincers are the ticket inside. The plastic resivours seep just a tiny bit.

[AJohn6]

Originally Posted by robnolimit

Well, this is the set up I use in the HellBoy C10. A nice thing here is the 'balance bar'. This takes place of the prop valve, and is easier to tune. I started with the recomended 13/16" bore rear, and 3/4" bore front. - also a 3/4" bore clutch. And, I run 4-piston superlights on all four, 1.75" bore front, and 1.625 bore rear. My wieght balance is 52% ft. - pretty good for a p/u. Our J.T. shop truck is 57% ft. So, it was OK this way, but I couldn't get the rears to lock up. Even with the balance bar max'd out. So, I switched to a 3/4" bore rear master. That worked good for me. The balance bar is close to center, which gives me some tuning room. Now, I am playing with pads to get the last little bit out. - haha, don't ever try 'A' pads on high $$ rotors. - they will have a 1000 mile lifespan. - just so ya know. Really agressive!!! lol.
So, try the same set up to start,(13/16" and 3/4") it may match your 6/4 piston set up well. But, don't be shocked if you want/need to change one or both later. For a softer pedal you might try a 3/4" and 5/8", but this will have more pedal travel. Oh ya, the one piece aluminum cylincers are the ticket inside. The plastic resivours seep just a tiny bit.

Rob,

Thanks again for your advice. A couple questions so I can really understand this. Did you end up going to the 3/4" bore for the rear of JT or Hellboy? Also are you talking about the Wilwood solid aluminum M/C (has resevoir built on it)? My plan was to run a remote aluminum dual F/R resevoir on the firewall and I am not sure how to do that with the solid M/C.

Thanks again,
Adam

[robnolimit]

Originally Posted by AJohn6

Rob,

Thanks again for your advice. A couple questions so I can really understand this. Did you end up going to the 3/4" bore for the rear of JT or Hellboy? Also are you talking about the Wilwood solid aluminum M/C (has resevoir built on it)? My plan was to run a remote aluminum dual F/R resevoir on the firewall and I am not sure how to do that with the solid M/C.

Thanks again,
Adam

Oops, I was just giving the JT's weight balance. It has a 85 C10 booster/master. The Wilwood stuff is on the HellBoy. If you are using the low mount set up, then the plastic remote cans are good. Just keep your eye on them.

[AJohn6]

Originally Posted by robnolimit

Oops, I was just giving the JT's weight balance. It has a 85 C10 booster/master. The Wilwood stuff is on the HellBoy. If you are using the low mount set up, then the plastic remote cans are good. Just keep your eye on them.

I ended up getting the compact remote M/C 3/4" bore for the front and rear (p/n 26010372) and the brake pedal assembly (p/n 34012509).

Thanks for your help,
Adam

[hotrod1]

Originally Posted by AJohn6

I ended up getting the compact remote M/C 3/4" bore for the front and rear (p/n 26010372) and the brake pedal assembly (p/n 34012509).

Thanks for your help,
Adam

Hey Adam

Let us know how the 3/4 front and 3/4 rear works for you.

[derrickmanx1]

So From what I can tell it would be better to have the front part of my truck arms as low as possible to make the trailling arms as close to level at ride hieght? I have a cpp x-member and they recomended installing it with the pad-eyes in the upper pos. Should I flip that over modify if needed and try that? By the way have not installed the mounting pads for the rear-end so I can still adjust the pinion angle.

[jayman68]

Originally Posted by derrickmanx1

So From what I can tell it would be better to have the front part of my truck arms as low as possible to make the trailling arms as close to level at ride hieght? I have a cpp x-member and they recomended installing it with the pad-eyes in the upper pos. Should I flip that over modify if needed and try that? By the way have not installed the mounting pads for the rear-end so I can still adjust the pinion angle.

What part of the trailing arm are you thinking to be level at ride height? I would think you would want the part where the axle mounts level, not the forward part. Just that would be alot of drop in the front mounts.

[robnolimit]

The hieght of the front trailing arm mount will directly effect the "anti-squat", or "rate of rise" of the rear suspension. Raising the mount will raise the anti-squat value.
Here's what may happen.
For an A.S. value of 50%, the front would lift slightly, the rear would drop, or "squat", and a majority of the axle's rotating force would be used to push the truck forward. But, this will reduce the total tracion available.
At 100% A.S., the truck would appaer to lift evenly, ft/rr, during a launch, splitting the axle forces between a forward push and tire loading.
At 150% A.S., the rear of the truck would rise, with the majority of forces being used to plant the rear tire. But, this takes away from theforward push.

Ideally, you want the lowest A.S. value you can have, that still keeps the rear tires planted. For most of our trucks, that would be just above 100%, and that woul 'ideally' put the front trailing arm mount even, or just above the floor.

So, I think you should mount the CPP X-member as designed, with the mounts up.
BTW, the 'bend' in the factory arm was designed in for purposes of "packaging". As far as the axle is concerned, the arm could be straight. The axle saddle's rotation would change to keep the pinion angle the same. But, if the arms were straight, mounting a coil spring would be difficult. The bend in the stock arm was all about mounting the coil spring as efficiently ($$) as possible. The one thing that iI wonder about is the shock mounts, in this regard. It may have been cheaper to form the lower shock mounts right on to the end of the trailing arm, moving the shocks outboard, and improving the ride and stability. But, they need a stamped lower plate for the U-bolt nuts anyway. Hmm. Then there is the idea that the shock is more protected from rocks and road junk if its inboard. - we may never know.

[69gmcc10]

Rob,

I was noticed that you added a splitter and a spoiler to Hellboy and it got me wondering about mechanical vs. aero grip on these trucks. We spend most of our time working on mechanical grip, but what and where are the gains of a sleek 67 hood, tonneau cover, splitter and spoiler? Can you elaborate on the principles, you must have done those things for a good reason?

Thanks for your willingness to share your wealth of knowledge.

[robnolimit]

Originally Posted by 69gmcc10

Rob,

I was noticed that you added a splitter and a spoiler to Hellboy and it got me wondering about mechanical vs. aero grip on these trucks. We spend most of our time working on mechanical grip, but what and where are the gains of a sleek 67 hood, tonneau cover, splitter and spoiler? Can you elaborate on the principles, you must have done those things for a good reason?

Thanks for your willingness to share your wealth of knowledge.

I guess I should tell the truth. - Part of the reason for the splitter/spoiler was to pump up the look for SEMA, and to help get us in to the Optima Invitational. Looks does help create a buzz. But, There is a performance reason. Two weeks before SEMA we were at the "Return to the Coast" event in El-Toro, and that was the first time I had ran the HellBoy on a big coarse (100mph+) I was surprised to learn that I won the road coarse event, beating the #2 finisher (Karl Dunn in his 'Blu-Balz' camaro, who I raced with a few times and like and respect) by more than a full second. I laughed a bit at this. You go out for four 'hot' timed laps per session, three sessions per day. I know the exact lap I went that tfast, and I was a bit scared most of the way around. This was the first time I entered a corner at 80+ and the bach was more than a little loose. On the main and back straight I could feel the front bobble around a bit, and it took a little brake check to get it settled before a corner. WOW, that was interesting. Two weeks until SEMA and the road coarse at Optima is bigger and faster. Splitter/spoiler. It didn't need much, and they work very well, too well maybe. With the radiator in the back I need some air to cool it. The splitter kept so much air out from under the truck that the temps got into the 'nervous' region. But the feel on the track was great. My fast lap at Optima was good for 9th overall on the big track, fastest truck, and shocked the crap out of myself. I may lift the splitter appx 1", it looks cool, but it scrapes on everything. Again, trail and error, and a whole lot of fun.

[69gmcc10]

Originally Posted by robnolimit

I guess I should tell the truth. - Part of the reason for the splitter/spoiler was to pump up the look for SEMA, and to help get us in to the Optima Invitational. Looks does help create a buzz. But, There is a performance reason. Two weeks before SEMA we were at the "Return to the Coast" event in El-Toro, and that was the first time I had ran the HellBoy on a big coarse (100mph+) I was surprised to learn that I won the road coarse event, beating the #2 finisher (Karl Dunn in his 'Blu-Balz' camaro, who I raced with a few times and like and respect) by more than a full second. I laughed a bit at this. You go out for four 'hot' timed laps per session, three sessions per day. I know the exact lap I went that tfast, and I was a bit scared most of the way around. This was the first time I entered a corner at 80+ and the bach was more than a little loose. On the main and back straight I could feel the front bobble around a bit, and it took a little brake check to get it settled before a corner. WOW, that was interesting. Two weeks until SEMA and the road coarse at Optima is bigger and faster. Splitter/spoiler. It didn't need much, and they work very well, too well maybe. With the radiator in the back I need some air to cool it. The splitter kept so much air out from under the truck that the temps got into the 'nervous' region. But the feel on the track was great. My fast lap at Optima was good for 9th overall on the big track, fastest truck, and shocked the crap out of myself. I may lift the splitter appx 1", it looks cool, but it scrapes on everything. Again, trail and error, and a whole lot of fun.

I guess those are two good reasons! I wont lie the aero hardware looks mean! How beneficial is the tonneau cover vs an open truck bed, should we all be running one?

[moregrip]

was thinking about this thread today and front upper/lower a-arms......not sure if its been covered....is there an ideal relationship to the ground for best handling? i.e. flat (parallel to ground), pointed up, pointed down?

[robnolimit]

Originally Posted by moregrip

was thinking about this thread today and front upper/lower a-arms......not sure if its been covered....is there an ideal relationship to the ground for best handling? i.e. flat (parallel to ground), pointed up, pointed down?

I usually try to keep the lower A-arm level to the road. This would be the line from the center of the pivit bushing to the pivit center of the ball joint. - this ma bee a bit different than the arm itself. On street cars, I would want to just a bit more spring hieght, with the ball joint slightly lower than the bushing, and for a track set up, just the opposit, with the ball joint slightly higher. All of this would be within 5 degrees of being level.

[moregrip]

Originally Posted by robnolimit

I usually try to keep the lower A-arm level to the road. This would be the line from the center of the pivit bushing to the pivit center of the ball joint. - this ma bee a bit different than the arm itself. On street cars, I would want to just a bit more spring hieght, with the ball joint slightly lower than the bushing, and for a track set up, just the opposit, with the ball joint slightly higher. All of this would be within 5 degrees of being level.

[1970 C10 MJW]

SUB'D this is a awesome page a lil over my head but i am trying to learn how to make my truck turn a corner

[jimmydean]

I want to see these pics of Hellboy with the road course spoiler!

[C0UCH]

These wheels are amazing! Truck looks great Rob! Very impressed.

[Andy4639]

Originally Posted by C0UCH

These wheels are amazing! Truck looks great Rob! Very impressed.

I like the picture Rob! Very

[68Stepbed]

Originally Posted by C0UCH

These wheels are amazing! Truck looks great Rob! Very impressed.

Hmmm.............a BFGoodrich sticker.....................but with Falken tires mounted.

[jimmydean]

Rob, the pic you posted on Facebook of Hellboy in downtown Portland is one of my favorite truck pics. I love everything about that truck and to see it in my part of town is awesome.

[C0UCH]

I'd give my first born for those wheels.
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