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PKRWUD · 11-09-2001, 10:34 PM

TJR-
Both Sprint car classes (VRA & VRA Seniors) here run 360 wingless Sprints (wings are for faries). 410's are just too expensive, and not very much faster on our track, because it's a 1/5 mile oval. The SCRA guys come and race at Ventura 2 or 3 times a year, and they are awesome, but they are so much more expensive to run. A decent 410, complete, will set you back $35k just for the engine, and only yield 150 - 200 more horsepower. That sounds like alot, but on a 1/5 mile dirt oval, 700 horsepower is enough. Well, okay, so you can never have "enough", but you know what I mean. If you've inherited a fortune, or have some big name sponsors, 410's would be a blast, but when you're born a poor white boy, 360's are just perfect.

We did go up north and ran at Santa Maria one night when we weren't scheduled at Ventura, and there were 360 winged cars running that night as well as wingless 360's (separately, of course). That track is almost twice the size of ours (1/3 mile), and those cars just plain flew. Those wings, on a big track, just plant those tires. Those cars were running like they were on rails. Still, though, their best qualifying time was just over a second faster than the best wingless sprint. Speaking of which, when the SCRA 410's come to Ventura, the top locals take their 360's out and run with them. You can see the power difference, but it's pretty close. The qualifying times are nearly identical.

Now then, on a 1/2 mile oval, 410 winged Sprints are incredible.

5.0 HO-
What helps is the fact that they are such fast revving engines and that we can use such big tires. There aren't any transmissions, which means less mass to turn by the engine (think flywheel). They can go from idle to 7500 rpm faster than you can say your name. Chassis set up is critical, too. That's something that I'm still learning. The pro chassis guys can walk out onto the track prior to racing, feel the mud, and come back in and adjust the suspension for ideal running. It's really pretty tricky, and involves rear gears, ride height (front and rear), torsion arm setting (all 4 are set different), stagger (the difference in circumference between the two back tires, the tire offset (how far in or out from the frame the tires sit, the shocks (different expand and retract rates), and tire pressure. Tire pressure, believe it or not, is probably the single most important factor for hooking up, and requires a tire pressure gauge that reads in half pound increments. When we go out for the Main Event, we never run higher than 3.5psi in the left rear, or 8 psi in the right rear. Any more and the tires would act like baloons, and the car would become too bouncy. What really makes chassis set-up tough is you need to change it as the track condition changes. As the night goes on, the track dries out, and can become "dry-slick". That's the toughest to drive on. Muddy and tacky is the best. Both require totally different set-ups, and can mean spending alot of time wrenching inbetween the heat races and the main event. Right now I make the changes. I'm good enough to make suggestions, but not good enough to insist on them. I'm learning, though.

Take care,
-Chris

------------------
Retired Moderator
MustangNet

My site: Peckerwoods Pit Stop

My teams site: Jim Porter Racing

RACECAR spelled backwards is RACECAR

HEY !!! Are you ASE Certified ??? If you are, ask me about iATN.

11-09-2001, 10:34 PM	#16
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	TJR- Both Sprint car classes (VRA & VRA Seniors) here run 360 wingless Sprints (wings are for faries). 410's are just too expensive, and not very much faster on our track, because it's a 1/5 mile oval. The SCRA guys come and race at Ventura 2 or 3 times a year, and they are awesome, but they are so much more expensive to run. A decent 410, complete, will set you back $35k just for the engine, and only yield 150 - 200 more horsepower. That sounds like alot, but on a 1/5 mile dirt oval, 700 horsepower is enough. Well, okay, so you can never have "enough", but you know what I mean. If you've inherited a fortune, or have some big name sponsors, 410's would be a blast, but when you're born a poor white boy, 360's are just perfect. We did go up north and ran at Santa Maria one night when we weren't scheduled at Ventura, and there were 360 winged cars running that night as well as wingless 360's (separately, of course). That track is almost twice the size of ours (1/3 mile), and those cars just plain flew. Those wings, on a big track, just plant those tires. Those cars were running like they were on rails. Still, though, their best qualifying time was just over a second faster than the best wingless sprint. Speaking of which, when the SCRA 410's come to Ventura, the top locals take their 360's out and run with them. You can see the power difference, but it's pretty close. The qualifying times are nearly identical. Now then, on a 1/2 mile oval, 410 winged Sprints are incredible. 5.0 HO- What helps is the fact that they are such fast revving engines and that we can use such big tires. There aren't any transmissions, which means less mass to turn by the engine (think flywheel). They can go from idle to 7500 rpm faster than you can say your name. Chassis set up is critical, too. That's something that I'm still learning. The pro chassis guys can walk out onto the track prior to racing, feel the mud, and come back in and adjust the suspension for ideal running. It's really pretty tricky, and involves rear gears, ride height (front and rear), torsion arm setting (all 4 are set different), stagger (the difference in circumference between the two back tires, the tire offset (how far in or out from the frame the tires sit, the shocks (different expand and retract rates), and tire pressure. Tire pressure, believe it or not, is probably the single most important factor for hooking up, and requires a tire pressure gauge that reads in half pound increments. When we go out for the Main Event, we never run higher than 3.5psi in the left rear, or 8 psi in the right rear. Any more and the tires would act like baloons, and the car would become too bouncy. What really makes chassis set-up tough is you need to change it as the track condition changes. As the night goes on, the track dries out, and can become "dry-slick". That's the toughest to drive on. Muddy and tacky is the best. Both require totally different set-ups, and can mean spending alot of time wrenching inbetween the heat races and the main event. Right now I make the changes. I'm good enough to make suggestions, but not good enough to insist on them. I'm learning, though. Take care, -Chris ------------------ Retired Moderator MustangNet My site: Peckerwoods Pit Stop My teams site: Jim Porter Racing RACECAR spelled backwards is RACECAR HEY !!! Are you ASE Certified ??? If you are, ask me about iATN.