Jump to content
distributorguy

620 Land Speed Record

Recommended Posts

Well, we're still a long way from making it happen, but given that this truck build started only 12 weeks ago, we may still make Speed Week at Bonneville this year.  In the coming week, we hope to finish the roll cage, mount the steering column and get the brakes functional.  Then it can go out for vinyl wrap (to make it look the part).  

 

We're going for a production class record (currently 129 mph) so most of the truck has to stay original, with no aero modifications other than lowering it and adding a hood scoop.  Tons of safety add-ons, better brakes, and the all-encompasing roll cage that is taking a HUGE amount of time and man power to complete.  Not to mention we had to restore a truck, source a second truck we could steal the cab from, to alleviate major rust issues, and work out some front suspension issues that were a result of lowering it so far.  Our front crossmember just behind the steering linkage will ride roughly 1 1/4" off the ground.  The motor shows is for mock-up, as the real one is in the middle of being built.  We hope to have 250 hp at the flywheel in order to beat the current record, naturally aspirated, running over 14:1 compression.  

The biggest hurdle we have now is that we're out of budget, by a LOT.  Any rich folk out there who want to donate to the cause???  :w00t: datarms.JPGdatnose.JPGdatfilm1.JPG

Share this post


Link to post

This sounds awesome. I hope you get the pictures figured out so I can see them. How are you trying to add them? You have to use a photo hosting site like photobucket. 

 

 

Welcome to ratsun :D

Share this post


Link to post

250 from a NA L20B is..... ambitious.

  • Like 1

Share this post


Link to post

250 from a NA L20B is.....a pipe dream.

This

  • Like 1

Share this post


Link to post

I can see the photos.  They are linked to another website.  Does anyone else have issues seeing them?

 

250hp is a fair estimate given the work done and being done to the motor.  Ultralight connecting rods, domed pistons, peanut head heavily reworked, Manley valves, Schneider cam custom ground to my specs, one of my Datsun distributors (that's what I do for a living), all the trick stuff you can pack into an L20B and stay under 2.0L.  I can't give out any specifics on bore and stroke, but they don't need to stay stock.  

Here's a little math on the subject:

Flat Plate Area ----> 19.71 ft^2 
Est. Cd---------------> 0.4 
Drag Area-----------> 7.9 ft^2 

Bonneville Alt.------> 4219 
Temp------------------> 90F 
Alt Setting------------> 29.92 
Dew Point------------> 25F 

Abs Pressure--------> 29.632 
Density Alt------------> 7160 
Air Density lb/ft^3---> 0.0617 
Relative Density-----> 0.8067 

Flywheel Hp sea level--> 250 
Altitude Correction-------> -48.3 
Flywheel Hp Bonneville- 201.7 

Loss to rear wheels------> 15% 
Net---------------------------> 171 Hp 
Rolling Resistance-------> -50 Hp 
Net-Net----------------------> 121 Hp 

Max Speed-----------------> 131.2 Hp 

 

And Dolomite, its been done!!!

Share this post


Link to post

I can see the photos.  They are linked to another website.  Does anyone else have issues seeing them?

 

And Dolomite, its been done!!!

 

 

You have to add the link either with the tree icon or with tags. 

 

http://www.mgexp.com/phile/40/312671/datarms.JPG

 

datarms.JPG

 

 

 

 

and 220hp has been done. 

 

Datsun-620-does-the-Maxton-Mile-and-brea

 

 

According to JNC’s blog post, the Datto truck belongs to Barry Brown of Riter Automotive and was run at the Maxton Mile recently.  It runs in the F/PMP class (F = 2.01 – 3.0 liter, PMP = Production mini/mid pickup) with a 2 liter that makes about 220hp equipped with Nissan 50mm race carbs and a Nissan 5 speed.  The #1620 truck broke the class record of 119mph by running 123 in the standing mile.

 

http://www.myrideisme.com/Blog/datsun-does-maxton-bring-on-bonneville/

 

 

 

 

 

Speeds all a matter of money. How fast do you want to go?

 

 

Nice upper a-arm setup there, what parts are you using for the links and mount bar? 

  • Like 1

Share this post


Link to post

Actually Barry claims 230 hp.  Those a-arms are from Ebay - a guy in Oregon makes them and I modified mine to actually work in this low configuration, plus I raised them on the frame mount to correct ball joint angles.

test

datlow_zpskb4nroga.jpg

Dat%20aarm_zpstxhcwjaa.jpg

  • Like 1

Share this post


Link to post

I like the statement that all they need to go 10 MPH faster is a wheel or gear change. Doesn't work like that. Wind resistance and drag is the largest use of engine power. To double your speed you need 4 times the power to do so. It takes more and more to go less and less.

Share this post


Link to post

That's a completely 100% accurate statement.  130 mph has been unattainable for all these years, since the frontal area of any mini truck is going to be no less than about 19 square feet.  Its all due to the limitations of the 2 liter engine class.  Destroking a V6 in the 3 Liter class can get you up to the F class record of 154, but again, wind resistance is a brick wall.  Then there's the issue of altitude, which is a major factor, and traction driving on salt which has the same coefficient of traction an snow.  

 

The fact that 250 hp is a reach, well, we know that but we have a plan to achieve it. I own a flow bench, which is where we'll earn a lot of power from.  A great friend of mine and I can both design cams, and have many times.  Another friend owns a chassis dyno.  And a small army meets here weekly to work on the truck, most of whom are racers in one form or another and are graciously volunteering their time to help achieve this outrageous goal because they know we can achieve it.  All it takes is time, money, persistence, and enough knowledge to keep moving in the right direction.     :ninja:

 

Overall weight and weight distribution is also part of the game plan.  This is the only motorsport where heavier can be better.  Every 1000 lbs you add aids traction, but also has the possibility of killing off 1-3 mph top speed.  Its a balancing act (quite literally) of traction, top speed, and actual front/rear weight distribution. Part of our equation was to redesign the rear leaf spring package to be extremely stiff and track straight using bronze shackle bushings and 100% new springs, purpose built.  That was by far the most important suspension component and most expensive.  My intention is to add limiter straps to the front suspension and torque down the torsion bars to match the rear spring rate without increasing ride height, at least until we can afford to convert to the front coil-over spring/shock package I'm lusting over in the new QA1 catalog.  

 

Will we smoke the record on our first trip to the salt?  No.  Will we have fun trying?  Yes!!!  Will we eventually break the record?  YES!!!  Google "Guy Henson Engine Builder" to get an idea of who is making the power we need.  My name is Jeff Schlemmer, and build power with distributors and my 12 Sun distributor machines about 1500 times a year.  Some people want to visit the salt as a bucket list item.  For us that includes breaking a record or two.  

  • Like 3

Share this post


Link to post

I forgot to mention the wheel change idea - that it will gain 10 mph.  Barry actually tried 3 different tire sizes and gained something like 1/2 mph.   I'm impressed that they got over 120 in the first mile, but that will equate to 115 on the salt at best due to altitude.  We have 4:36 and  4:11  rear axles to chose from.  The lower (higher numerically) is probably better for top speed when wind resistance is a factor, but more dangerous due to driveline speeds.  I speculate with the 4:11 that our driveshaft will be rotating around 6200-6300 rpm, which will require a solid carrier bearing as opposed to the rubber diaphragm mount.  Barry runs a one-piece shaft, but that will have a tendency to "jump rope" in the center due to length, especially considering he's got a 'lil Hustler long box.  

 

You may note that I'm sharing a lot of design info, while others will not.  Our goal is to earn the record against the best possible competition, no tricks, no surprises.  This photo is only one of the obstacles we had to overcome early in the build:  a sandblasting outfit ruined the entire front clip and box.  blasted_zpsocgyq93c.jpg

Share this post


Link to post

jfkrice.jpg

 

We choose to go to 130MPH in this decade with an L20B NA 620, and do the other things, not because they are easy, but because they are hard,

  • Like 5

Share this post


Link to post

I forgot to mention the wheel change idea - that it will gain 10 mph.  Barry actually tried 3 different tire sizes and gained something like 1/2 mph.   I'm impressed that they got over 120 in the first mile, but that will equate to 115 on the salt at best due to altitude.  We have 4:36 and  4:11  rear axles to chose from.  The lower (higher numerically) is probably better for top speed when wind resistance is a factor, but more dangerous due to driveline speeds.  I speculate with the 4:11 that our driveshaft will be rotating around 6200-6300 rpm, which will require a solid carrier bearing as opposed to the rubber diaphragm mount.  Barry runs a one-piece shaft, but that will have a tendency to "jump rope" in the center due to length, especially considering he's got a 'lil Hustler long box.  

 

You may note that I'm sharing a lot of design info, while others will not.  Our goal is to earn the record against the best possible competition, no tricks, no surprises.  This photo is only one of the obstacles we had to overcome early in the build:  a sandblasting outfit ruined the entire front clip and box.  blasted_zpsocgyq93c.jpg

 

 

What in the actual fuck? That takes some skill to do that kind of damage. :( 

Share this post


Link to post

Sand blasting generates a lot of heat. Unfortunately the worker didn't know this.

  • Like 1

Share this post


Link to post

I was assured they had already blasted 4 complete cars this year, when they had done this in May.  I actually managed to get the front fenders, tailgate, and box straight.  Every other panel was replaced.  Doors, cab, hood, cowl, valance.  Jerks.  The blasting was free.  Yay.  And they wrote me a check to not disclose what blasting company in the small town of Mankato, MN  did the work.  

  • Like 2

Share this post


Link to post

Maybe they figured the golfball aero would make you faster...?

  • Like 1

Share this post


Link to post

Well, that was my thought doing paint.  I left all the factory spot welds visible down the top edge of the box and where the inner wheels wells are attached to the box.   :thumbup:

We were allowed to remove the box hooks and minor trim emblems, as well as side mirrors, but we have to leave the horn and side marker lights in place???? :confused:

Share this post


Link to post

Today's shop progress was better than most.  I installed the steering column, welding an adapter from the race column to the original steering shaft, bolted to the box & fabricated a dash bar in the roll cage from which to hang a custom column mount.

 

I also finished the basic 6 point cage, minus the door bars and helmet cage.  That includes the bars to mount the 6 point seat belt, the seat mounts and mounting brackets, the previously mentioned dash bar, and the rear cross brace.  

 

Then I had to move (fabricate) the brake and clutch pedals so there's room to actually fit your feet between them.  I had an issue with hitting the brake pedal when trying to apply throttle.  Not good.  

 

The passenger compartment is getting tight.  I'd better start stretching daily to be able to contort in and out of the cockpit wearing a Hans device & helmet, and fitting past the door bars to be added tomorrow.  Its difficult enough to squeeze in and out of the 15" wide race seat. Thankfully the steering wheel is removable, or it would be impossible.  

 

 datint2_zpsdjjehiww.jpgdatint1_zpsrcbljyyq.jpg

  • Like 3

Share this post


Link to post

Update:  the cage is almost done.  Probably 3 more hours work (a drop in the bucket considering there is nearly 150' of tubing in this small cab!)  I wish there was a way to photograph how much tubing is really in the cab, but even a fish eye camera lens wouldn't give you the feeling of how packed in it is.  The goal is to prevent death in the event of a rollover at 120+ mph, so its got to be more than a 4 point basic NHRA drag cage.  Hopefully its done tonight, painted tomorrow, then the doors can be installed.

 

At this point I can custom order the door net as required.  The tires and wheels should be here Thursday, so once the wheels are drilled and tapped for the Moon hubcaps, they can be painted, mounted, balanced, and installed.  Then the front fenders and hood can be installed.   Note the red, white, and blue drawing on the white board in the background.  That's roughly the goal for the final appearance, with some tweaks to have more blue and accent the great body lines!

 

 datinterior_zps7vvvas5f.jpg

  • Like 2

Share this post


Link to post

Hauling ass is serious business :devil: 

Share this post


Link to post

Looks good man, I cant wait to see this thong in action!

Share this post


Link to post

Mmm ... thongs..... in action......

  • Like 7

Share this post


Link to post

I'd rather see other thongs in action, but I'll put one on if you like? 

 

Here's the stance as it sits out in the sun this morning.  The back is a little high, with plans to drop in 500-1000 lbs ballast as needed to balance front/rear weight distribution.  The springs are designed to hold up to 1500 lbs in the box without negative handling.  The springs are 20% thicker and two additional leaves were added.  I figured we can remove them, but if we can't make them while at the salt.  

Hopefully the custom fornt wheels and new tires will clear the fender wells and allow at least some turning radius at this ride height?

 

dattruck_zps505jss3a.jpg

  • Like 2

Share this post


Link to post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×

Important Information

By using this site, you agree to our Terms of Use.