anyone ever autocross/road race their truck?

[Driveway Dreams]

I agree 100%. Google search Nastruck. A shop in the Denver area built it. It is a 39 Ford. I talked to the guy about going to work for him but he was a little too arrogant for my type. But great work. The whole thing kinda followed a nascar theme like you mentioned. But it was on air, of course, still handled very well. This, I think is along the same sort of design path you are taking.

[tymbom]

That's a cool truck. I plan on using as many production parts as I can, since it is easier to find a caliper for a C-10 than a Wilwood 6 piston carbon fiber thing out in the middle of nowhere. Heck, my truck has the HD rotors on the front. 1.25in. thick by 12in. That should work well with some good pads and some duct work. Same thing with sway bars. 3/4ton 2wd has a 1 1/16th in. bar on it stock. That's bigger than an aftermarket performance sway bar. I've been looking into ball joints and bump steer kits from different suppliers and I think I might be able to use parts that are designed for full size Gm cars. I think some aftermarket tubular upper A-arms is about the only thing besides some dropped spindles are gonna be used. Eventually I'd like to get a 9in. but that can wait since I've got 3.73's in it now.

[ccreddell]

Theres a 64-5 SB step up here in southern Oregon that I see at the auto cross meets. He has a Lincoln IRS welded in and some trick stuff done up front. He seems to get it thru the course pretty well, and it looks good too.

[tymbom]

I plan on running mine in Medford area stuff and the Hoopa Hill climb since I live near Yreka.

[ccreddell]

Hope to see you run. Let me know when you come up.

[gchemist]

Evertime I'm on the street.

[stepside85]

Originally Posted by killthewabbit

I always wondered how the trucks were set up in the race in bigblock73's avatar:



Sorry to beat a dead horse, but the thing I don't like about drifting is that winning is subjective. It's like extreme sports and skateboarding - probably more fun to do than to watch.

I'd like to see more of these pics.

[tymbom]

If you go to 73-87chevy.com and look under the information heading, there is a circle track article that the picture is from. Right click, save as... I look at it about once a week.

[Frizzle Fry]

1st time out, sound gets out of sync, and the cameraman didn't know how to use zoom. But hey it was fun and I beat some little cars

http://www.youtube.com/watch?v=h1exT5n2zxU

http://www.youtube.com/watch?v=7HnobUEreOY&NR=1...

[Test Pilot]

I am glad to see I'm not the only one nuts enough to thinks this can work.

I've been driving and instructing at local road courses for nearly 5 years now.
Based on my experience in my various track cars over the years, I have some input that I think will help with the success of making this happen.

Some things that will need addressed to be successful on a course.

Suspension, this is more or less obvious.
Hotchkis offers the biggest sway bar I've been able to find for our trucks at
1 -7/16". I'm temped to try this, but for the same 225 for thier front bar I think I can put together a splined bar. The benefit would be more accurate sway control and the ability to adjust the rate of the bar.

Stiffer springs will be a must, it's not un common to see guys with 1000 in/lb springs in cars, so a truck could need more, but I'd hope not, that would make for a horrible ride. I'd hope that something in the 700 in/lb range would work, or be a decent compromise, any one know what spring rate big block springs are?

Rear springs are probably pretty decent as is, but a rear sway bar should be approaced with caution. What can actually happen with a rear sway bar if it's too stiff is that it will have a tendency to lift the inside wheel on a turn.
In my project I plan to run one but make it adjustable so I can increase or decrease the rate.

Steering, hands down rack and pinion will be best due to the feed back it gives, but only if it's properly engineered to fit. A fox body Mustang rack is very easily adapted to many vehicles and is used in a lot of aftermarket setups.

For those like me without a large budget I expect I'll have to get the best I can find for our trucks, being one of the only GM vehicles to have the box on the outside of the frame it doesn't have the ease of cross reference that a lot of GM parts do. It's possible something from the circle track industry may be able to be fitted. There are components to quicken the ratio, but the feedback is hard to get from a steering box.

Brakes, If you are serious about this, 4 wheel disc are a must and bigger brakes up front will be a plus. I don't know if I'd say manditory at this point, but my 03 Z06 will kill a set of rotors in 3-4 weekends with the stock cooling ducts. Proper cooling ducts double this time frame. I think the highest speeds one could expect to see with a healthy small block on a road course are probably in the 120-130 range, the lower the speed the less heat/braking energy it takes to stop. The less heat the better they will work.


Weight distribution, if these trucks can be easily moved to the 55/45 or less range than there is a decent chance they will do well. A lot of the guys that run 3rd Gen Camaros and Fox Body Mustangs are in the 53/47 to 55/45 weight balance area. The general rule of thumb in this situation is 1 remove weight from the heavy end, if that isn't possible, 2 shift weight from heavy end to light end, if that isn't possible, 3 add weight to the light end.


Aero, not much can be done here unless you are going all out race rig, get the truck low to reduce the amount of air it has to push, but likely it won't be a huge factor top speed on the 505 hp SRT-10 Ram was an aero limited 154.xxx. I think getting a C10 to 150 would be a feat, and a bit scary to drive at such speeds.


I'm not claiming to be an expert on all of this stuff, just sharing what I've learned about setup and part selection over the past 5 years.
I also know that this will be met with a little controversy, some of the older guys don't believe trucks belong on a track, and others think it's cool b/c you had the kahonies to think outside the box and act on it.

There is much more I could put in, and I'd love to continue the conversation if anyone else wants to.

[tymbom]

More!!! I'm planning on running the truck arms so I can adjust all four corners easier. I know a 3-link would be better in an all out race car, but I plan on keeping my truck on the street so I will use the heavier duty stuff. I don't need a rod end going bad on my way to work... With that in mind what spring rate would you suggest for some rear coils?? Does the diameter of the coil have anything to do with performance or mostly packaging??
I noticed that the Project Talledega in PHR is running a drag radial on all four corners. How do they work in corners... I would get some just to stick with 15in wheels, but I don't waste time and money on drag radials if they're useless in corners. The Basset 15x10s are only 21 pounds each, thats nice. I'd like to run some 17s but I've only found a couple I like.

[68 TT]

My plans for my 67 C-10 are to make it look like a late 60's trans am race car team put all their spare parts onto their parts hauler truck. I have enough spare parts from all the first gen Camaro's I have had over the years to do most of it. I just don't have the time to even get started on putting the truck together.

[Test Pilot]

With that in mind what spring rate would you suggest for some rear coils??

I would think something in the 400-500 range would work. It would be nice to know the spring rates of the lowering springs offered by our vendors as well as some Chevelle spring rates.

Does the diameter of the coil have anything to do with performance or mostly packaging??

The wire diameter, coil diameter and height all play a part in how the spring rate it calulated, beyond that it won't matter a great deal.

I noticed that the Project Talledega in PHR is running a drag radial on all four corners

This is about the 4th or 5th time I've read about someone doing this, the problem is no one has any results after the fact. I too would love to keep 15" wheels as I think they are part of the classic styling of these older trucks.

There is another option, but you would be looking at nearly 1600 per set of tires. Avon makes a high performance tire in P metric sizes that is DOT compliant.
http://www.sascosports.com/products/...php?type_id=39


With this being said, I expect I'll end up with 18" wheels in order to get a performance tire that is also of a decent diameter.

In my opinion anything under 26" in overall tire diameter is too small for these trucks.

As I browse more and more, I'm leaning toward just doing the best I can by carefully selecting bolt ons. I would like for my end result to get my 68 C10 to be able to match a 2004 Ford Lightning in performance, but have the classic styling of an old truck.

My plans for my 67 C-10 are to make it look like a late 60's trans am race car team put all their spare parts onto their parts hauler truck. I have enough spare parts form all the first gen Camaro's I have had over the years to do most of it. I just don't have the time to even get started on putting the truck together.

I think this is VERY COOL!!!!!!!!!!!!!!!!
I'm a huge fan of the Trans-Am Series of the late 60s-early 70s

[68Timber]

Originally Posted by Test Pilot

For those like me without a large budget I expect I'll have to get the best I can find for our trucks, being one of the only GM vehicles to have the box on the outside of the frame it doesn't have the ease of cross reference that a lot of GM parts do. It's possible something from the circle track industry may be able to be fitted. There are components to quicken the ratio, but the feedback is hard to get from a steering box.

This is one item near the top of my to-do list. My steering is 3.5 turns lock-to-lock and over-boosted. A buddy told me the quickest GM steering box he knew of (from the era) was from a 70's Trans Am - 2.5 turns lock-to-lock. He didn't know if it'd fit, but I'll find the quickest GM box that will bolt up. Same thing for the power steering pump - way too much boost. I have no idea what's best but there should be a much broader selection there so I can get some feedback and roadfeel in the steering wheel. I already have a 1 1/4" front sway bar (thanks texassquarebodies).

I don't intend to road race or autocross, just the changes I've mentioned should be enough to make it much more fun to drive.

[Test Pilot]

Originally Posted by BRUISER

This is one item near the top of my to-do list. My steering is 3.5 turns lock-to-lock and over-boosted. A buddy told me the quickest GM steering box he knew of (from the era) was from a 70's Trans Am - 2.5 turns lock-to-lock.

I think the issue is that a T/A box and any other car box for that matter bolts to the inside of the frame, not the outside like our trucks. So the struggle here will be making a bracket that will bolt up. If you are up for the fab work I strongly recommend a 600 series steering gear like from Detroit Speed and engineering. It's not cheap but has a nice spool valve on it that makes the road fell close to that of a rack and pinion. Something else that you can look at is a restrictor like used for running a mustang ii rack with a GM pump. Mind you it's flow not psi that makes the difference in the way the box feels in terms of being over or under boosted.

[68 TT]

Originally Posted by Test Pilot

I would think something in the 400-500 range would work. It would be nice to know the spring rates of the lowering springs offered by our vendors as well as some Chevelle spring rates.




The wire diameter, coil diameter and height all play a part in how the spring rate it calulated, beyond that it won't matter a great deal.



This is about the 4th or 5th time I've read about someone doing this, the problem is no one has any results after the fact. I too would love to keep 15" wheels as I think they are part of the classic styling of these older trucks.

There is another option, but you would be looking at nearly 1600 per set of tires. Avon makes a high performance tire in P metric sizes that is DOT compliant.
http://www.sascosports.com/products/...php?type_id=39


With this being said, I expect I'll end up with 18" wheels in order to get a performance tire that is also of a decent diameter.

In my opinion anything under 26" in overall tire diameter is too small for these trucks.

As I browse more and more, I'm leaning toward just doing the best I can by carefully selecting bolt ons. I would like for my end result to get my 68 C10 to be able to match a 2004 Ford Lightning in performance, but have the classic styling of an old truck.






I think this is VERY COOL!!!!!!!!!!!!!!!!
I'm a huge fan of the Trans-Am Series of the late 60s-early 70s

Too much spring rate in the back will make it over steer bad. That is part of the reason trucks handle so bad. To carry a load they need high spring rates.

Keep the rear in the 200 range with a decent size sway bar and you should do pretty well. Add supplemental air bags you can fill up if you need to use it as a truck.

My uncles 1990 454SS handles fairly well for how high it is off the ground and it is running 275/60-15's all the way around. 28" tall. With the right ride height they won't look too small in our wheel wells. Common drag radial size too. It will sacrifice some handling but you can keep classic looking rims on it then. I plan on using some spare Camaro rally wheels for now but want a set of Halibrand style 5-spokes.

The 15" rim limits your brake choices to 12" or smaller rotors. Quite a few options there though. 90's Impala SS & cop car 12" disc comes to mind.

I plan on using a spare 65 Impala 12-bolt I have sitting around and converting the front to 5 on 4-3/4 bolt pattern to match. It will weigh far less than my 70 Chevelle did (3900 pounds) so it will be able to handle what I am going to throw at it with a 1/2" stud upgrade no problem.

I am going to install a full set of C3 Corvette 11.75" x 1.25" brake rotors matched with some LS1 Camaro PBR aluminum calipers. The Vette rotors use inside the rotor hat drum style parking brakes. I will need to make a backing plate to fit them up to the car 12-bolt and will incorporate that into the rear brake caliper bracket.

The C3 rotors are the same part that was installed onto the 68 & 69 Trans Am series Z/28's so they can take a mountain of abuse. They are cheap too, NAPA sells American made rotors for under $40 each.

I won't use the C3 iron calipers because they suck air too easily and weigh a ton. The front LS1 Camaro and Vette calipers are the right 1.25" wide rotor design so they can be used at all four corners with the internal hub parking brake rotors. An adjustable proportioning valve will have its work cut out for it but should allow the brakes to be balanced for the truck.

[68 TT]

Originally Posted by Test Pilot

I think the issue is that a T/A box and any other car box for that matter bolts to the inside of the frame, not the outside like our trucks. So the struggle here will be making a bracket that will bolt up. If you are up for the fab work I strongly recommend a 600 series steering gear like from Detroit Speed and engineering. It's not cheap but has a nice spool valve on it that makes the road fell close to that of a rack and pinion. Something else that you can look at is a restrictor like used for running a mustang ii rack with a GM pump. Mind you it's flow not psi that makes the difference in the way the box feels in terms of being over or under boosted.

I have a late 80's vintage IROC 2-1/4 turn quick ratio 700 series gear box and I am going to try to find a 700 series truck housing if it exists and swap the guts.

I assume the mid to late 80's square body trucks got the 700 series box. Does anybody know?

[tymbom]

I just watched a video on the PHR website with the Project Talledega in it. Johnny makes it out like the drag radials make it handle really good. Maybe they would be an option for an auto cross. I imagine track day would require a dedicated racing slick...
On www.pro-touring.com there is a good thread about 15in tire selections in the tires and wheels forum.

[Test Pilot]

Too much spring rate in the back will make it over steer bad. That is part of the reason trucks handle so bad. To carry a load they need high spring rates.

Keep the rear in the 200 range with a decent size sway bar and you should do pretty well. Add supplemental air bags you can fill up if you need to use it as a truck.

I agree too much rate can be a bad thing, The reason I suggested the rate I did was due to what I ran in my Mustang. It was significantly lighter than a truck, but I also ran slicks so cornering load was greater than I anticipate you could get out of a truck on a streetable tire. So heavier vehicle, but less cornering load should be about the same ball park, no way to tell for sure without putting it through the calculations

Also if we are talking about leafs that changes things too. Thus far I've been referring to coils such as in the 72 and older trucks. Since the coil is forward of the axle, it will take a higher spring rate to yield the same wheel rate of a truck with leaf springs.
Something else that ties in is your front setup, with stock rate front springs 200 may be just fine.

A lot of this is subject to SOTP feeling. Ofen times what works best it what feels best so 200 for you may work great, but I may want more...someone else may want less.

If we were really going to get the calculators out and make this scientific, spring rate would just be a value to achieve the desired wheel rate.

On a side note a nice thing about being able to use the air over loads is you can add a little spring rate if you wanted to start on the low side with your coils or leafs you could increase it to your liking. Effectively you can change the rates without having to swap springs.

[68Timber]

Originally Posted by 68 TT

I have a late 80's vintage IROC 2-1/4 turn quick ratio 600 series gear box and I am going to try to find a 600 series truck housing if it exists and swap the guts.

I assume the mid to late 80's square body trucks got the 600 series box. Does anybody know?

For those interested but can't modify their steering box, I found these guys. I emailed them to see how much for a quick ratio steering box for my truck. Cost should be similar or the same for other square bodies. I'll put the price up when I hear back.

[68 TT]

[quote=Test Pilot;3635131]

Originally Posted by 68 TT

Too much spring rate in the back will make it over steer bad. That is part of the reason trucks handle so bad. To carry a load they need high spring rates.

Keep the rear in the 200 range with a decent size sway bar and you should do pretty well. Add supplemental air bags you can fill up if you need to use it as a truck.
QUOTE]

The reason I suggested the rate I did was due to what I ran in my Mustang. It was significantly lighter than a truck, but I also ran slicks so cornering load was greater than I anticipate you could get out of a truck on a streetable tire. So heavier vehicle, but less cornering load should be about the same ball park, no way to tell for sure without putting it through the calculations

Also if we are talking about leafs that changes things too. Thus far I've been referring to coils such as in the 72 and older trucks. Since the coil is forward of the axle, it will take a higher spring rate to yield the same wheel rate of a truck with leaf springs.
Something else that ties in is your front setup, with stock rate front springs 200 may be just fine.

A lot of this is subject to SOTP feeling. Ofen times what works best it what feels best so 200 for you may work great, but I may want more...someone else may want less.

If we were really going to get the calculators out and make this scientific, spring rate would just be a value to achieve the desired wheel rate.

On a side note a nice thing about being able to use the air over loads is you can add a little spring rate if you wanted to start on the low side with your coils or leafs you could increase it to your liking. Effectively you can change the rates without having to swap springs.

I have always preferred the lighter spring rate with larger sway bars method vs. high rate springs & smaller sway bars method of achieving the handling I wanted. I just like the more compliant ride to keep my fillings in place on our pot hole infested and frost cracked roads up here.

200 ppi is what I ran in the rear coils on my 70 Chevelle with 500 ppi in the front with 1-3/8" solid bars front & rear and it did pretty well at Auto-X even though it weighed close to two tons (3900 pounds). Any higher spring rate and it just rode too rough for my liking since it was primarily a street car.

[Test Pilot]

Originally Posted by BRUISER

For those interested but can't modify their steering box, I found these guys. I emailed them to see how much for a quick ratio steering box for my truck. Cost should be similar or the same for other square bodies. I'll put the price up when I hear back.

Good find, down near Charlotte NC, there are a lot of used NASCAR parts shops. They have all sorts of NASCAR Parts new and used. There may be something from that industry we can use. The last time I looked into this I found a mfg with 5 different ratios, but they were also selling thier boxes for $700 per.

[Test Pilot]

[quote=68 TT;3635168]

Originally Posted by Test Pilot

I have always preferred the lighter spring rate with larger sway bars method vs. high rate springs & smaller sway bars method of achieving the handling I wanted. I just like the more compliant ride to keep my fillings in place on our pot hole infested and frost cracked roads up here.

200 ppi is what I ran in the rear coils on my 70 Chevelle with 500 ppi in the front with 1-3/8" solid bars front & rear and it did pretty well at Auto-X even though it weighed close to two tons (3900 pounds). Any higher spring rate and it just rode too rough for my liking since it was primarily a street car.

Thats where I think most of this comes down to individual preference. If 200 worked for you, than that is what is correct for you. Ie I'm not trying to create an argument.

After all if we don't enjoy our rides what's the point. I prefer a stiffer ride comparable to that of my Z06 which is why I would start out at no less than 300 in/lb.

Also the setup for autox and road courses are different.

[68 TT]

[quote=Test Pilot;3635208]

Originally Posted by 68 TT

Thats where I think most of this comes down to individual preference. If 200 worked for you, than that is what is correct for you. Ie I'm not trying to create an argument.

After all if we don't enjoy our rides what's the point. I prefer a stiffer ride comparable to that of my Z06 which is why I would start out at no less than 300 in/lb.

Also the setup for autox and road courses are different.

No argument here. I have run both setups and it all achieves the same goal. It all comes down to personal preference.

I started off with 425 ppi rear and 800 ppi front on the Chevelle and it handled amazing but it was painful to drive so I went another route.

I still have the 800's so I might give them a try on the C-10 if they will fit.

[68Timber]

Originally Posted by Test Pilot

Good find, down near Charlotte NC, there are a lot of used NASCAR parts shops. They have all sorts of NASCAR Parts new and used. There may be something from that industry we can use. The last time I looked into this I found a mfg with 5 different ratios, but they were also selling thier boxes for $700 per.

I hope they don't cater to the NASCAR crowd, this is an item that I won't pay a NASCAR price. That's not right - there's nothing I'm doing to this truck where I can or will pay a NASCAR price.

But I do want a quicker ratio. I did several searches today but couldn't find a site that would cross-reference to show direct bolt-on options.