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Royal Purple Raceway

Jeff

Nitro Member
#3
Our experience at the Houston divisional was that the new pavement was not smooth. In fact one night they had a crew of 10 or so guys out there working to try a diminish a huge "ramp" out of the left lane at about 900 feet (they worked on it until 10:30pm). I wish I could show a pic of my wife's Racepak laser ride height sensor comparing Ennis to Houston (our last two divisionals) .... the two tracks are not comparable. Ground concrete is just dang smooth and tends to stay that way!

It may be that the nitro cars have so much downforce that they don't care, but I'm interested to see if any grinding work was done to the track after the divisional and to see how the pro cars take to the new surface. It clearly takes a fair amount of skill to put pavement down smooth enough for a 200 or 300 mph car to see it as smooth, and most of the time it seems they have to come back and grind it to get the thing really good.

Our class is not invited this year, so I will just be a pro mod & pro stock spectator.
 
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tx_trojan

Nitro Member
#5
I grew up in SoCal going to Pomona twice a year for years, lived in Vegas for five years going to LVMS twice a year those five years, and now live outside of Houston with RPR as my latest home track. I will say the Friday Q2 session at RPR trumps all the other sessions, hands down. The conditions are always stellar and the runs are always legit. Can’t wait for this Friday....!
 

Cliff

Nitro Member
#6
I sure hope they got that lane fixed! My old home track was San Fernando drag Strip, in the LA area. The track was uphill off the starting line and then about half way down, it went downhill. You couldn't tell it by looking at it. but if you had a clutch car, you had to be careful coming off the line. You could still red lite though....
 

tx_trojan

Nitro Member
#9
Saturday won’t be a rain out. There may be a passing shower, but any sizable rain will be overnight. Weather looks pretty damn good all weekend long...
 

Reese

Nitro Member
#10
Maybe they shouldn't have cut out so many classes this year. Seems like a lot of dead time and it's only 12 noon. Maybe it's just me missing all the top classes and comp. But we do have Redemption cars (yea right).
 

Dave

Nitro Member
#12
Our experience at the Houston divisional was that the new pavement was not smooth. In fact one night they had a crew of 10 or so guys out there working to try a diminish a huge "ramp" out of the left lane at about 900 feet (they worked on it until 10:30pm). I wish I could show a pic of my wife's Racepak laser ride height sensor comparing Ennis to Houston (our last two divisionals) .... the two tracks are not comparable. Ground concrete is just dang smooth and tends to stay that way!

It may be that the nitro cars have so much downforce that they don't care, but I'm interested to see if any grinding work was done to the track after the divisional and to see how the pro cars take to the new surface. It clearly takes a fair amount of skill to put pavement down smooth enough for a 200 or 300 mph car to see it as smooth, and most of the time it seems they have to come back and grind it to get the thing really good.

Our class is not invited this year, so I will just be a pro mod & pro stock spectator.
It looks like there are some mean bumps in that left hand lane even before 900 foot. The Pro Mod cars really show it off nicely.
 

Jeff

Nitro Member
#13
No question watching pro mod that the bump is still pretty bad. Below is an overlay of our recent runs at Ennis and Houston. The red or pink lines are all Houston. The lowest line at the back half of the racetrack is our ride height sensor cycling much more than the green line right over it from Ennis. One set of lines up you can see the wheel speed jump when the car exits the first hump. .... and a lot of people will notice the fuel issues I'm having at the one second mark in the run .... believe it or not that yellow line is for a 6.12 last week in Ennis before the crank decided to detach from the flexplate.....

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#15
Considering the conditions and normal runs made on Fridays in Baytown, especially in Q2, there was an abnormal amount of fuel cars that didn’t make it down the track. Real oddity for Baytown....
 

Jeff

Nitro Member
#16
Armand, I got the ride height sensor last year in large part to deal with the bumps at No Problem (both lanes) and Houston (right lane) in our rigid dragster. Since we used to try to avoid the right lane in Houston, I don't have many runs to compare. This year we all started trying to avoid the left lane because the hump (roughly 750 ft) had the tire gaining 700 rpm after exiting the hump (and this is with a lot of wing in the car to combat it .... and sacrificially blister tires because of the large wing angle). The Houston concrete has never been super smooth (say like Topeka) or super rough (say like Atlanta, pre repaving), Houston's excitement tended to start with the transition to asphalt just after the 1/8th. Their track base and drainage shortcomings just make it hard to keep the track super smooth. Don't get me wrong a street car at 100 mph would see this as a sheet of glass .... but a car using the tires as the primary suspension and still accelerating hard doesn't take much at all to upset. The ride height sensor graphs for the left lane of Houston lay right on top of each other year to year up to the 1/8th mile (every up and down is the same), but from roughly 700 ft to almost 900 ft my ride height sensor says the track is noticeably less smooth this year vs last year. It only takes one hump or dip to induce these kinds of oscillations ... and for the wing set ups we run in our top dragster where we try to somewhat minimize downforce to minimize tire blistering) a hump is much harder to deal with than a dip. I think that is why you see the pro mods being the easiest to upset too, those cars likely also don't like a hump that launches the car up and causes almost nonexistent suspension to have to cycle while trying to accelerate with that same suspension (the tire).
 

Cliff

Nitro Member
#17
Jeff, thanks for the info. I thought Houston surface would be better, but I guess not. Hope they could laser grind it to smooth it out. It's really interesting to me that your tires blister if you have the wing set to give more down force. I thought that happened in T/F and T/AD, but not T/D. But, you are running low 6's, and that is quick. Just asking, but would you do better without a rigid chassis? I've seen some T/D with a flex frame that you can see the rear of the chassis go "up" as the car launches. I think Chuck Phelps has a 6.20 car & it has that chassis. Love the T/D cars!
 

Paul

Staff member
Nitro Member
#18
With the air temps and track temps we saw this weekend, the fuel cars should have been flying. Sucks the track spent the $ to lay down new pavement and it's not up to par. I remember Maple Grove in the mid 90's put down new pavement and the minute the fuel cars got off the concrete they were hazing the tires through the finish line, pretty sure that was the year Arend won. Hope they can fix it before next year.
 

Jeff

Nitro Member
#20
Jeff, thanks for the info. I thought Houston surface would be better, but I guess not. Hope they could laser grind it to smooth it out. It's really interesting to me that your tires blister if you have the wing set to give more down force. I thought that happened in T/F and T/AD, but not T/D. But, you are running low 6's, and that is quick. Just asking, but would you do better without a rigid chassis? I've seen some T/D with a flex frame that you can see the rear of the chassis go "up" as the car launches. I think Chuck Phelps has a 6.20 car & it has that chassis. Love the T/D cars!
Cliff, a lot of people don't understand one of the most common ways tires blister. Down track the wing makes the tire D shaped (with the flat part of the D being on the track), the tracks are very sticky nowadays so when the tire gets ripped off the track after being pressed down so hard for "so long" (because of the wing angle making the flat part of the D longer) is exposes places within the tire where the tire body is not as well attached (glued) to the exterior of the tire, so they separate. The wing also helps to increase the severity of the angle that the tire gets ripped up at, putting more pressure on the tire interior to exterior attachment.

Yes, I know on top fuel video the back part of the tire is what looks flat .... that is caused by the tire being pressed down so hard on the track, after it gets ripped up, it's got to rush back around to keep up with the bead.

Cruz properly said yesterday that people need to stop complaining about the track and "tune their clutches" .... and I totally agree with this. Bumps and humps give crew chiefs more to do and are part of the racing environment ... anybody can go fast on flat smooth tracks. I get that, but fans seems to like record numbers in record conditions, and I was of the opinion that while the repave probably greatly improved any track weeping problem, I don't think it did anything to make it a faster, better place to race for the fans. In my view it used to have a left lane preference (except for 20 minutes when the sun is setting) and now its a right lane preferred track all of the time.

On TD chassis .... rigid chassis are about 130lbs lighter that shocked chassis. Shocked chassis are easier to run on very bumpy tracks, but rigid chassis are easier to get to consistently launch hard. I say this because we see shocked cars launch hard 10 times great, then rattle once bad .... just lots of moving parts and hard to get into the middle of a tuning envelope. Its all preference, and many of the best drivers still choose the suspended route ... they are clearly safer if your driving style involves hard breaking. A good set of electric shocks on a 260" suspended TD is probably the optimum chassis set up for TD.
 
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