WELD/SUTTON DIRT MISSILE build

[jlwdvm]

For the interior sheet metal work: do you finish welding the joints completely, or use seam sealer between the tack welds?

[Ron Sutton]

Originally Posted by jlwdvm

For the interior sheet metal work: do you finish welding the joints completely, or use seam sealer between the tack welds?

We think of them as "spot" welds, but yes, we use a seam sealer, specifically 3M Fire Barrier Silicone Sealant 2000+. See it HERE.

[mfain]

Absolutely awesome build! Can't wait to see it on track. ABS? Traction control?

Pappy

[TrackMuscle]

What is the total weight of the car wet with no fuel? And as Pappy asked above, any ABS?

[craig510]

Please keep an eye on the T/C Rods on the lower control arms. The bend in them makes me nervous. They will be under compression under braking which puts a large bending moment on them and they are pre-yielded from the bending process.

With enough wall thickness and yield strength they could be fine but it is something to watch. If you have trouble with your caster alignment changing they could be bending further.

[Ron Sutton]

Originally Posted by craig510

Please keep an eye on the T/C Rods on the lower control arms. The bend in them makes me nervous. They will be under compression under braking which puts a large bending moment on them and they are pre-yielded from the bending process.

With enough wall thickness and yield strength they could be fine but it is something to watch. If you have trouble with your caster alignment changing they could be bending further.

Hey Craig! You are spot on correct. As you know, any time you pre-bend a tube, you make it more susceptible to bending easier. So you have to make it beefier or brace it.

We ran FEA analysis on these arms before we ever made any, just like I do with all my control arms. We build that curved strut (and the main LCA) out of 1.25" OD x .120" wall 4130 tubing. At 1.7G we have a 1.69 safety factor. We have had 1 or 2 DIY customers use .095" DOM, against our advice. They failed. That curved tube HAS to be strong.

[GregWeld]

Ya but.......... how are we going to slow it down!?!?! LOL

[Ron Sutton]

Originally Posted by TrackMuscle

What is the total weight of the car wet with no fuel? And as Pappy asked above, any ABS?

If it was a "Race Only Car" we would build everything on the edge of being too light & constantly inspect, repair & replace ... and it would be 2400#. We're building this to be Greg's "Track Car" that he races in NASA's TTU class some. So we built it much more durable ... and safer. It will be about 2600#-2650#.

[Ns RS]

Originally Posted by Ron Sutton

If it was a "Race Only Car" we would build everything on the edge of being too light & constantly inspect, repair & replace ... and it would be 2400#. We're building this to be Greg's "Track Car" that he races in NASA's TTU class some. So we built it much more durable ... and safer. It will be about 2600#-2650#.

So what you’re sayin is if he lays off the cheese balls he’ll even be faster??

[Ron Sutton]

Originally Posted by Ns RS

So what you’re sayin is if he lays off the cheese balls he’ll even be faster??

Nope. Greg's pretty light these days.

But learning how to drive one of these missiles takes a minute or two. (That's my slang for "awhile") The car will have so much downforce, the grip is amazing in the fast corners. It is confidence inspiring for sure. But the driver has to be smooth with the steering wheel & pedals, or you upset the air.

If the driver upsets the airflow over the car/splitter/wing/etc ... the downforce & grip evaporate for a bit.

So with high downforce cars you, or in this case Greg, need to work up to the limits a small step at a time. The car will be EASY to drive high 1:50's at Thunderhill (with Crows Nest). Mid 1:50's take concentration, but is still pretty comfortable. Low 1:50's take a lot of experience & skill. The driver has to hit their braking points the same every time, hit their turn in marks exactly the same every time & be smooth as glass with the steering wheel, as well as the throttle & braking.

That simply takes lots of seat time to achieve. Some drivers learn it in a year or two, some ten years & some never.

Most of you know I've worked with some pretty good talent. 413 of my wins were someone other than me driving. Greg has proven to be a very coachable & capable driver. Back when we first worked together in Old Yeller ... it was F&%$ing handful. His buddies were running 2:10's to 2:12's. Old Yeller's rear brakes had more force than the fronts. Greg was running 2:22's without spinning out and trying to go faster led to spin outs.

Once I got the brake bias right, so the car wasn't trying to kill him, he & I worked on his driving. Man! Did he improve a ton in one weekend. Once we fixed the brake bias, Greg worked his way all the way down to 2:08 to 2:10. Now Greg runs 2:04's in the car with improvements we made. 1:50's is another time zone.

Looking forward to our shake down of the Mustang on June 28th. We'll post photos.