starting in traffic on steep hills

[-8]

When starting on the middle of a long and steep hill in traffic what rpm would you want the torque to come on strong, ~500-rpm? And how many miles per hour, ~1-mph? Is there a camshaft for 250-rpm torque engagement? And do you recommend a 6.69:1 granny gear for hill starts?

How long of a trac bar do you recommend for 3-link front? Should the panhard bar be the same length or a percentage of the length of the lower arms that locate the axle?


Do James Duff shocks work in any position when used in conjunction with cantaleaver suspension? King shocks does not make a shock long enough and I wonder about the ratios of the rockers? Can I put the shocks in the middle of the chassis where the lower suspension arms mount to the frame? Maybe I should do steel air bags like the military?


If I use military portals on my dana 60 axles do I still need 38" tall tires to roll over large rocks?

 

[Justafordguy]

I got nothing.

 

[Toddpole]

My brain hurts.

 

[Timmy390]

When starting on the middle of a long and steep hill in traffic what rpm would you want the torque to come on strong, ~500-rpm? And how many miles per hour, ~1-mph? Is there a camshaft for 250-rpm torque engagement? And do you recommend a 6.69:1 granny gear for hill starts?

Lost me here. What kind of hills are you talking about? We talking rock climbing or street?

Your idle speed is going to be 650ish or higher. Torque will come in depending on cam but 1000rpm is about the lowest I've seen. Torque doesn't come in based on MPH. It's RPM based.

How long of a trac bar do you recommend for 3-link front? Should the panhard bar be the same length or a percentage of the length of the lower arms that locate the axle?

An adjustable one so you can dial it in. All the vendors sell them


I got nothing for the rest.......

Tim

 

[broncobilly72]

Lost me completely........what are we doing here?

 

[AZ73]

Your engine won't run at 250 rpm no matter what the cam. If you had a 250 rpm with a 6.69/1 ratio your rear tire would take one rotation every 10 seconds (assuming a 4:1 first gear manual) and that's a LONG time. Back of napkin, for a 33 inch tire, you'd be going 1/3 MPH. If you're running an automatic c6 (2.46:1 first), you'd be going nowhere as it's not enough RPM to kick in the torque converter.

So are you talking about the torque converter stall speed or torque on the motor?

 

[-8]

Ok so I should be starting at 1,000 rpm in granny gear while on the steepest parts of the Grand Tetons?

Does the exact MPH matter where the engine engages to the moving rear wheels at 1,000 rpm?

Or is it just about making massive amounts of torque at the crankshaft at 1,000 rpm to start on the hill?

Would the stock manual 3 speed start on the middle of the steepest road in the Grand Tetons with a turbo-diesel?

thanks



http://www.ruffstuffspecialties.com/catalog/PANKIT.html

I am thinking of using this longer panhard bar. I made my current adjustable heim-trac-bar from Rough Stuff parts.

 

[Nothing Special]

I don't know what's going on here either, but I just scanned back through his last 100 posts. 91 of them (I kid you not) were "bump..........."

To address some of the questions...

Ok so I should be starting at 1,000 rpm in granny gear while on the steepest parts of the Grand Tetons?

Granny gear is good. 1000 rpm might be a little low.

Does the exact MPH matter where the engine engages to the moving rear wheels at 1,000 rpm?

Not sure what you're asking here. If starting from a stop the exact mph is 0 and the wheels aren't moving. If you're rolling backward it's harder to get started, if your rolling forward it's easier.

Or is it just about making massive amounts of torque at the crankshaft at 1,000 rpm to start on the hill?

Big torque helps, but low gearing helps more. And knowing how to use a clutch well is important

Would the stock manual 3 speed start on the middle of the steepest road in the Grand Tetons with a turbo-diesel?

If you're talking about at least a maintained gravel road the stock 3 speed will work even with the stock engine (but a 4 speed with a granny low will work better). If you're talking off road trails, then you probably want to shift the transfer case into low range.

 

[Broncobowsher]

That is one of the oddest mix of questions I have ever seen compiled into a single post.

Starting on hills. Gearing and clutch abuse are huge variables. With some driving skill you can hold 1000 RPM and go as slow as you like, but the clutch will die on a weekly basis. Typically I can count the number of revolutions between when I start to engage the clutch to when it is fully locked up. With a bit of a low gear I can do it in probably a half dozen revolutions on flat ground and under a couple dozen on grades or a hard launch. Minimal slippage, minimal heat generated and minimal wear created. IT is one of those things you just get a feel for. Some people just can't drive a stick and should get an automatic.

Track bar needs to match the steering or you will have bump steer. So you have not provided enough information for a good answer.

You have a way of connecting some military portals (Humvee?) to a D60? Again a tidbit of into won't get you a good answer. Rolling over large rock. Depends on how large of a rock you are trying to clear. Maybe you can clear big rocks on smaller tires, maybe you still need taller, maybe you just need to take a better line. Not exactly a question that can be answered. If you tell us what size rock you are trying to clear, and what the offset of your mystery portal is we might be able to figure if you will clear or not. That's not figuring the fudge factor of you can scrape and still keep moving.

If you are debating Duff or King dampers, you probably shouldn't be trying to engineer a complex suspension. Just saying...

When finished I would love to see this. And let me know what trail you plan to run (I want to be on something else that day). But do get pictures.

 

[half cab]

Pour the coals to it

 

[Scoop]

I would not recommend you driving in traffic. Or on steep hills.

 

[Skiddy]

I would not recommend you driving in traffic. Or on steep hills.

may want to stay away from large rocks too, they tend to roll you backwards a bit especially if on a steep hill. if you do decide to go that direction may want to take the military portal

 

[AZ73]

You can ride a bicycle up the side of a building of you had a tall enough gear. Doesn't take much torque. Still not sure what you're talking about. If your rear wheel was turning at 1000 rpm, assuming it's a 33 inch tire, you'd be going, back of napkin, about 90 mph. How about at least confirming you talking about an automatic transmission.

MOTOR rpm can have MOTOR torque come on almost anywhere with a cam. My motor jumps to about 90% peak torque at 1200 rpm and is fairly steady to 5000. It has nothing above that or below 1000 rpm. That's a range of 3800 rpm. My gearing (trans/differential/tire size) is designed to have motor torque in the lower rpms. If I swapped the cam for a different design, like I was drag racing a mustang, I'd get Torque coming on at about 3000 rpm and peak around 7500 with a 4500 rpm range. I'd switch to an automatic and want my torque converter to stall below 3000 someplace, depending on gearing. The idea is to have the torque when you want it. So, you want to start crawling uphill in traffic. You can have rev your motor and slip your clutch until it grabs, you can have your torque converter come on almost any rpm and have your motor bring it's torque curve on almost any rpm. Diesels don't rev and have high torque at lower rpms. Gas can do either higher torque and low to mid, or mid to high rpms.

Skip the numbers, just tell us what you're trying to figure out. Start with your motor size, your transmission, and your rear wheel diameter.

 

[-8]

"Track bar needs to match the steering or you will have bump steer."
-So mount the trac bar parallel to the drag-link? Can the trac-bar be longer?


"My motor jumps to about 90% peak torque at 1200 rpm"
-So I should build a 6.9L IDI intercooled and turbocharged engine with a NV4500!
-Does the Diesel cycle start making its torque at lower rpms than a gasoline engine?

http://www.filthymotorsports.com/Axle_Tech_Portals_p/axletech-portals.htm

https://www.dynatrac.com/axle-assemblies/prorock-44-portal-axle.html

http://www.stazworks.com/axels.htm

 

[AZ73]

"My motor jumps to about 90% peak torque at 1200 rpm"
-So I should build a 6.9L IDI intercooled and turbocharged engine with a NV4500!
-Does the Diesel cycle start making its torque at lower rpms than a gasoline engine?

[

I'm running a gas 347 stroker. My torque comes from the stroke and my cam. You can stroke a 351 and get tons of torque and it would probably be easier than dropping in a diesel. Just a side note, Factory Bronco frames aren't really designed to take gobs of torque. I would guess once above 500 ft*lbs you're gonna have to start working with a new frame, or at least reinforcing your old one, but maybe some of the guys running 408's can chime in.

http://shop.broncograveyard.com/New-Mandrel-Bent-Ford-Bronco-Frame/productinfo/10810/

http://www.krawlersedge.com/custom-early-bronco-chassis/

 

[-8]

Thanks for the input. If I had a stroker of 408 CID and made 500ft/lbs of torque with a short duration/fast-ramp camshaft I would start making torque at 850-rpm. Would that be 80% of my maimum torque? Maybe that would be 400-ft/lbs of torque. Maybe that would get my Bronco started on Grand Teton hills. How many MPH should I be turning when the the torque is engaged at 850 rpm?

Now as for the frame. When I am done building I want to strip the frame down and take it to a black smith for heat treating and maybe cryo-treating. Maybe I can beef it up/thickening it.

I am open for changing the gear ratios of the NV4500. Is 7:1 low enough for the granny gear? What is the optimium gear ratio for use as an Alpine gear?

 

[Skiddy]

Thanks for the input. If I had a stroker of 408 CID and made 500ft/lbs of torque with a short duration/fast-ramp camshaft I would start making torque at 850-rpm. Would that be 80% of my maimum torque? Maybe that would be 400-ft/lbs of torque. Maybe that would get my Bronco started on Grand Teton hills. How many MPH should I be turning when the the torque is engaged at 850 rpm?

Now as for the frame. When I am done building I want to strip the frame down and take it to a black smith for heat treating and maybe cryo-treating. Maybe I can beef it up/thickening it.

I am open for changing the gear ratios of the NV4500. Is 7:1 low enough for the granny gear? What is the optimium gear ratio for use as an Alpine gear?

Alpine gear? as in gear for mountain climbing?:?

 

[Teal68]

-8
I don't know why so many are confused. The answer is simple, but you have two choices....
1. Go for dog at boat, or 2. Kentucky fried tongue clit cow

Hopefully my answers were as clear as your (fun) questions.

Your welcome,
Tyler

 

[langester]

I am totally lost but very entertained by this thread!

 

[Yeller]

I don't even know where to start with everything that is going on here........%)

So many scary issues....