'71 GMC Track Day Video

[bovey]

Thought you might enjoy this video I shot in the summer.

It's my '71 GMC Longbox, rocking a LS427/t56, a basic lowered suspension, stock front brakes with HP+ pads and Willwood rears. It's more fun than the video shows.

https://vimeo.com/79890973

Cheers,
bovey

[Evaded]

Awesome.... Ive been into the AWD Subaru scene for the past 10 years. Track day any day in anything is cool! Great vid!

Eric (Evaded)

[RANDY COX]

Pretty Cool, I liked the different camera angles.

[elf w/capital T]

Thats awesome!!!

[Andy4639]

Nice video man. Cool seeing a LWB truck dooing that!

[bovey]

Thanks guys. I had no idea how it would work on a track, this was my first time out, other that autoXing. I'm hitting 110 mph + is a few areas of the video, did not expect it to work as well as it did with such simple suspension and brake upgrades. However, I was at the limit of my talent and suspension this day...

[NC_John]

Originally Posted by bovey

Thanks guys. I had no idea how it would work on a track, this was my first time out, other that autoXing. I'm hitting 110 mph + is a few areas of the video, did not expect it to work as well as it did with such simple suspension and brake upgrades. However, I was at the limit of my talent and suspension this day...

I used to hit 160+ on that track on the ninja....playing chicken with the braking markers on the back stretch was always crazy. Its been 15 yrs since I've played there but its a great track. Cool video- I'd love to see one of an entire lap.

[cericd]

Cool video. I like your other video too that discusses your trucks setup. I know you said it's the standard 4/6 drop but I was wondering, do you have a c-notch in the rear and is the 6" drop all spring or a combination of springs and blocks.

[Codez67Chevy]

What he said. lol. Also what wheel/tire size you running?

[bovey]

Originally Posted by Codez67Chevy

What he said. lol. Also what wheel/tire size you running?

Wheels are 18 x 9s with 5" back spacing - actually they are cheapo rock crawling wheels for a 2000s Jeep - they used 5 on 5 - who knew?

Tires:
Front - 255/35/18 Toyo 888 - stiff side wall
Rear - 275/40/18 Toyo 888

I want a different wheel and tire combo, but this was cheap.

[giles70chevy]

I like the "Trucky takes on autocross school. FUN." video too.... looks like a blast!!!

[bovey]

Originally Posted by cericd

Cool video. I like your other video too that discusses your trucks setup. I know you said it's the standard 4/6 drop but I was wondering, do you have a c-notch in the rear and is the 6" drop all spring or a combination of springs and blocks.

Hey Chris, yes, it is C-notched. The rear suspension is really simple at the moment. I've owned this truck for 25 years and when I originally lowered it the only company making drop springs was a lowrider company out Cali called Chrisholm, hell, I even had to make the drop block to get to 6".

Anyway, the rear suspension in all it's glory.

4" Chrisholm drop springs
2" homemade blocks
ECE shock re-locater kit - from when they first made them.
CPP pan bar - stock location
Beltech Nitrodrop shocks
CCP C-notch kit

That it, and I chase down some crazy new AWD with it.

This will be getting replaced moving forward as it's heavily taxed on my race days - this year was just sorting out if I liked autoXing/track days or not.

NC John, the video is 2 laps of the DDT track, however, yes - the monster track at Mosport is on my list to hit next year. My truck is way too fast, and way under suspensioned (new word) for those kind of speeds. I was even holding back on the DDT (Driver Development Track) to keep the paint side up.

[cericd]

Originally Posted by bovey

This will be getting replaced moving forward as it's heavily taxed on my race days - this year was just sorting out if I liked autoXing/track days or not.

What's getting replaced? The truck or the rear end setup? What's causing you to be heavily taxed. Sorry for the odd question. I'm an AutoX noob.

[bovey]

Originally Posted by cericd

What's getting replaced? The truck or the rear end setup? What's causing you to be heavily taxed. Sorry for the odd question. I'm an AutoX noob.

Replacing suspension parts, the truck is not going anywhere.

In my case, speed combined with the types of racing I'm doing is more than what my current suspension was ever designed to handle. Mix that with a race track that allows for a ton of speed and it can be dangerous.

A lot of the autocross you see at car shows are designed to keep the competition around 35 MPH - no helmet stuff. That is not the case with the groups I run with up here. 90% of my competition are Miatas, S2000s and Subarus and they are fast and nimble. To be able to compete with them I need to build a very specific chassis to be nimble and deal with all of my power, as I run a LS 427 making 600ish HP with a brick torque curve.

My design criteria for the next version of my truck must be:

1) Nimble to deal with tight autocross designs. i.e. front IFS with excellent caster/camber adjustment

2) Stable for high speed track use. Not to mention the idea of doing Cannonball Run style road rallies... but that is off in the future.

Who doesn't love the Big Red Camaro? Inspiring car.

[bbcmudtruck]

That looks like a dream come true! Awesome video!

[slow-1]

That's awesome!!!

[bovey]

Autocross school was a fun week-end. We had no idea what would happen and it worked amazing.

BUT, please note there have been two big changes between "Trucky takes on Autocross School" and "Trucky takes on DDT":

1) Full 14:1 AGR race box, custom built, custom valved, with matched AGR pump and power steering fluid cooler. Look into AGR before buying a stock replacement, their products are amazing and the prices are great for race proven parts.

2) 12.19" Willwood rear discs with 4 piston callipers, Willood 1" MC and the stock front brakes have HP+ pads. I also run a rear 10lb residual valve as a cheap bandaid to solve the typical GM rear-end pad knock back.

[Tom Vogel]

I also run a rear 10lb residual valve as a cheap bandaid to solve the typical GM rear-end pad knock back.[/QUOTE]
What is pad knock back?

[bovey]

[QUOTE=What is pad knock back?[/QUOTE]


Pad knock back occurs when you have end-play in your rear-end that pushed the disc brake pads off the rotor (even a few 1/1000ths) - the result is a spongy petal. It is very common with GM c-clip rear-ends when you put fixed callipers on. Worse yet, the pads are always pushed back in varying amounts (depending on cornering force) so you never have any clue how spongy the petal is going to be. Kinda annoying when your heading into a 180 corner at 100 mph.

If anyone is considering doing a disc brake conversion, you should understand this issue - or it will cost you time and money.

As I said, a residual valve is a bandaid fix, a proper fix would be a floater rear-end, floater callipers, or a c-clip eliminator kit, but it must be a "circle track" not a "drag racing" c-lip eliminator kit.

This is a huge subject - I'll post a new thread on the topic and expand on the proper solutions. I don't want any of you to go through what I did.

[sublime1996525]

That's sweet! I'd be pretty intimidated to see that thing coming up on my rear.

[Tom Vogel]

GREAT info, and a really fun video. Thanks Bovey!

[CaliLivn]

Great video!!