Raceway Results

pciley · 08-07-2004, 10:44 PM

Got in 3 runs today (Saturday 8-7-04) at Carlsbad Raceway in lovely north county San Diego, CA.

Here's all 3 slips.
The first run I had the tailgate up and the mirrors out... and my head up my a$$. NO SPIN though. 15.31

Second run, I tucked the Big Tow mirrors, and opened the tailgate. Had just a BIT of tire spin, maybe a couple of rotations before hookup. ran a 15.16

Last run, I launched too high, around 1800 rpm, and had a bit more spin and ran a 15.18.

I will really try to work on my launch, as it seems to shave a cuople of tenths off when you do it right. 1500 rpms seems to be about right for my setup.

I have a KC XE, BUT I put on the LE wheels/tires with the 1.2" increase in overall diamater and a few inches longer roll out. I know this slows the truck down, but I think the XE's tires are over an inch narrower making for a smaller contact patch which would only add to tire spin anyways.

Only performance upgrades are Banks exhaust and Volant CAI (no ram air yet..).

I will try for a 15.0 flat next Saturday if I can keep from spinning the tires. Maybe I'll drop the spare and just floor it when the light turns green instead of doing a brake stand at 'xxxx' rpm. Not having the spare will drop over 60 lbs, good enough for one tenth if you ask me. I should have tried dropping the spare today, didn't think about it though.

DOH!! check engine light turned on. Maybe the octane boost? I will put on the O2 simulators in the morning and reset the ECU to see if that turns it off.

First run was against an Integra, won. Second run was against a WRX turbo with some engine mods, lost. Third run was against a 68 Camaro SS clone, LOST!! by 3 seconds... that guy smoked me the whole way down the track, starting from when he lifted his front tires off the ground at the green.

Maybe I'll see some other pickups next Saturday, I felt like an idiot being the only truck there.

The only people who came over to check out the truck were the Honda/Nissan/Subaru import guys. All the rednecks with the "heartbeat" stickers on their big blocks just gave me the evil eye.

PS not sure why the time slip computer was printing 1-3-1980..? maybe they didn't set the date on their 25 year old computer.

Temp outside was 82 degrees on the first run, dropped to 80 by the last run.

phillipyang · 08-07-2004, 10:51 PM

Very nice, you should try taking off the spare tire and repair kit for less weight? You can even take the darn tailgate off for more of a reduction. Also have 1/4 quater full of gas also with a higher octane? Its your call. Nice time, i can't get my truck to spin for some reason. I just push the darn pedal to the max when i start and i don't know if thats the correct way =/. I'm such a stupid driver trying to race from the line. My tires never spinned before...only when raining of course.

pciley · 08-07-2004, 10:55 PM

The repair kit (jack, tools, etc) is out of the vehicle. I just keep a can of fix'o'flat and a AAA card handy.

Also, I only had 5 gallons in the tank, yes it was 91 and also poured in some cheap octane boost from Wal Mart, although I'm not sure how effective it was.. if at all.

I debated dropping the tail gate, but with the tire spin, I wanted the extra weight hangin off the back to keep the tires diggin' in.

If you look at the MPH at 1/4 mile, you will see with the tail gate up I ran FASTER at the end of the track.... CAN'T FIGURE THIS OUT!! WTH??
With the tail gate down, I had a faster time, but was limping in the last 1/16 mile and had a slower MPH at 1/4.
Maybe having the tail gate down is adding a bunch of drag, even though it obviously reduces wind resistance...??

Titan Power · 08-08-2004, 12:01 AM

There is something realy wrong with their timing equipment. Unless the installed an aircraft carrier style catapult launcher, I doubt you really pulled a .5 sec 60 foot time!

I also wouldn't read too much into the MPH. The only way you could be running low 15's at 81mph would be if you let off or hit the brakes before the line. If you didn't do that, I'd say it was also a timing screw up.

Great times though. It's too bad you don't know your real 60' times, they are a great way to tell how effective your launches are. With cooler weather, I think you could break into the 14's.

As for the tailgate, I've heard it explained that leaving the tailgate up creates less drag then putting it down. The theory is the the air in the bed is fairly stationary, with relation to the air around the truck. At speed, turbulent air bounces off the stationary air, kind of like an invisible tonnue cover. I guess it would be fairly easy to confirm or refute. Maybe tape some streamers on the insides of the bed and go for a ride. See what they do with the tailgate up and down.

Jason K.

pciley · 08-08-2004, 12:27 AM

Thanks Jason.
I think that first run's 60 ft time is erroneous. Has to be.
As for the bed air, trucks aren't exactly renowned for their aerodynamics. I think the addition of a light soft tonneau cover like the Truxedo Low Pro. will help with the turbulence issue. It might create some un needed down force, however, at higher speeds.

TITAN21 · 08-08-2004, 01:46 AM

damn good times paul. i think the hemi boys are heading out to the california speedway on the 21st, you gotta get out there. they'll be ****tin their pants when they see you in the 14's!

Nissan Junkie · 08-08-2004, 04:00 AM

pciley,

Not trying to be offensive here... those are GREAT times...

But dude... you gotta quit sleeping at the tree man...

.500 -> perfect
.600 -> acceptable
.700 -> practice
.800 -> ummm... yeah
.900+ -> pack it up and go home

again... I am not trying to be offensive here... and I mean nothing against you...

But you need to work on it... considering the size (mind you I have only test driven a titan, and have never ran a "sissy stick" through the traps) you may want to hit the accerator as the last yellow is lighting up...

and which brake are you using when you are power braking?

not that the parking brake is going to work well for this situation, seeing as how it is a push to enguage and push to release (atleast in the one I test drove)...

the more I think about it... the harder it is to launch this truck... not like my focus... or other cars that I have taken down the strip... they all had the lever type of e-brake.. which allows me to hand control the brake at the light and launch harder

...

but try launching a bit sooner, if you see green you are allready too late

...
fyi my persional best light is a .507 and my average light is in the mid .5's...

hell I may come down there and run with you next time... just for the hell of it!!!...
tho it would be me in my focus

peace!

37L1 · 08-08-2004, 06:28 AM

Paul,

Have you tried the JetTech leaf spring helper/cheap trac bar mod???

For $30 probably will eliminate most of your wheel spin.

Just a thought.

37L1

the head · 08-08-2004, 06:41 AM

Awesome runs. Yeah it looks like the 60' was fubar. So was the MPH in every run but the first timeslip. Odd that it worked the first time and then didn't every run after that - in the same lane no less. 80 degrees!! Man, I would give up body parts for that right now. You'll lose roughly 0.1 sec for every 100 pounds you can take off.

IMADOGMAN · 08-08-2004, 08:15 AM

Quote:

Originally Posted by pciley

The repair kit (jack, tools, etc) is out of the vehicle. I just keep a can of fix'o'flat and a AAA card handy.

Also, I only had 5 gallons in the tank, yes it was 91 and also poured in some cheap octane boost from Wal Mart, although I'm not sure how effective it was.. if at all.

I debated dropping the tail gate, but with the tire spin, I wanted the extra weight hangin off the back to keep the tires diggin' in.

If you look at the MPH at 1/4 mile, you will see with the tail gate up I ran FASTER at the end of the track.... CAN'T FIGURE THIS OUT!! WTH??
With the tail gate down, I had a faster time, but was limping in the last 1/16 mile and had a slower MPH at 1/4.
Maybe having the tail gate down is adding a bunch of drag, even though it obviously reduces wind resistance...??

What makes it obvious? Have you done any wind tunnel testing, or is it just that you think that the tailgate is a drag inducing item when it is up? I don't know if anyone has had their Titan in a wind tunnel, but all of the other trucks that I have seen tested in the past...had LESS drag with the tailgate up. The air inside the bed acts as a cushion, allowing the airflow to pass over the tailgate where it joins the air from the sides and bottom with less turbulence than with it down. Eyeball aerodynamics assumes that it has less drag, but tests have shown otherwise. Maybe someone who has access to a wind tunnel, or who has a friend in a college engineering class could have them do a wind tunnel test on a model Titan...any takers?

pciley · 08-08-2004, 09:41 AM

Quote:

Originally Posted by Nissan Junkie

pciley,

Not trying to be offensive here... those are GREAT times...

But dude... you gotta quit sleeping at the tree man...

.500 -> perfect
.600 -> acceptable
.700 -> practice
.800 -> ummm... yeah
.900+ -> pack it up and go home

again... I am not trying to be offensive here... and I mean nothing against you...

But you need to work on it... considering the size (mind you I have only test driven a titan, and have never ran a "sissy stick" through the traps) you may want to hit the accerator as the last yellow is lighting up...

and which brake are you using when you are power braking?

not that the parking brake is going to work well for this situation, seeing as how it is a push to enguage and push to release (atleast in the one I test drove)...

the more I think about it... the harder it is to launch this truck... not like my focus... or other cars that I have taken down the strip... they all had the lever type of e-brake.. which allows me to hand control the brake at the light and launch harder

...

but try launching a bit sooner, if you see green you are allready too late

...
fyi my persional best light is a .507 and my average light is in the mid .5's...

hell I may come down there and run with you next time... just for the hell of it!!!...
tho it would be me in my focus

peace!

hehe.. yeah, the parking break idea is DEFINITELY out. I really have to stand on the break so the truck won't get away from me and false start when I was launching at just 1500 rpm. I was trying my best to launch at the last amber so I was across the line when it hit green. THOUGH IT DOESN't AFFECT TIMES!!! because the individual lane timers don't start until your nose moves forward. For instance, I could sit at the start line until the other guy has finished, and still beat him if my 1/4 mile time is less... know what I mean?

Keep in mind dude, the trucks being drive by wire don't let you think for yourself. From the second I let go of the break and hit 3/4 throttle (because full would actually shut it down a bit) it takes a moment for the truck to decide to move. I haven't had a vehicle before that did that, and all my previous cars had a throttle linkage directly from the pedal to the throttle body so I have to assume that the wire/servo setup is "the weakest link."

Quote:

Originally Posted by 37L1

Paul,

Have you tried the JetTech leaf spring helper/cheap trac bar mod???

For $30 probably will eliminate most of your wheel spin.

Just a thought.

37L1

Search is not my friend today. Tried both those descriptions and searched by JetTech's username and nothing came up regarding leaf springs.. do you have a link? I am open for any mod that increases traction for $30. Thanks.
-Paul

Quote:

Originally Posted by imadogman

What makes it obvious? Have you done any wind tunnel testing, or is it just that you think that the tailgate is a drag inducing item when it is up?

Well, I don't have any wish to take my truck to a wind tunnel... its just a pickup truck, not an indy car. This track racing is just a weekend thing to keep me out of trouble.. in a way.
What I 'thought' made it obvious that having the TG down had less wind resistance was that I get better milage that way. With the tail gate up the truck has a harder time passing at high freeway speeds and doesn't get as good of fuel economy. I guess that is how I came to that conclusion, but I am NO rocket scientist, so if there is an imaginary cushion of air inside the bed then....

Hope I have answered all questions. I POSTED THIS BECAUSE I AM OPEN FOR SUGGESTIONS!!! but mostly to brag

so the HEMI guys can stop saying "Show me the time slips" and all that about us.

All criticism is welcome, don't feel bad to knock my reaction times or anything. This is only my second time to a race track to be the one racing, and these runs were my 3rd, 4th, and 5th runs ever. The first two runs I had at California Speedway in Fontana were over 15.6 because of me not knowing how to drag race. I'm still learning.

IMADOGMAN · 08-08-2004, 09:54 AM

Drive train clunk

Look at 7/13/2004 post

Mike H. · 08-08-2004, 10:46 AM

Quote:

Originally Posted by IMADOGMAN

[/i][/b][/color]
What makes it obvious? Have you done any wind tunnel testing, or is it just that you think that the tailgate is a drag inducing item when it is up? I don't know if anyone has had their Titan in a wind tunnel, but all of the other trucks that I have seen tested in the past...had LESS drag with the tailgate up. The air inside the bed acts as a cushion, allowing the airflow to pass over the tailgate where it joins the air from the sides and bottom with less turbulence than with it down. Eyeball aerodynamics assumes that it has less drag, but tests have shown otherwise. Maybe someone who has access to a wind tunnel, or who has a friend in a college engineering class could have them do a wind tunnel test on a model Titan...any takers?

I did exactly that in Senior Design back in college, around 13 years ago. Actually tested a 1/24 scale late-80's Nissan 4x4. With only tailgate, with bed cover, with a few different shaped toppers, and final test was to cut out the tailgate from the back. I don't recall all the numbers. Problem was with a 1/24 scale model, we were not able to simulate actual highway speeds in the 80 mph tunnel we had. We would have needed to run about 200-300 mph air to have an equivalent Reynolds number, due to the small size of the model. I also researched other full-sized tests too. The bottom line is that it depends on the size of the truck and the length of the bed. With a full-sized truck with very short bed, opening the tailgate hurts. With a long bed, it can help. Some of the truck mags have tested this before when the tailgate nets were popular. It depended on the truck as to whether it helped or hurt. Flat bed covers always help. Rectangular toppers hurt (bad). With toppers, the more sloped the rear is, the better. The absolute best setup was a triangular topper that was sloped from the top of the truck cab to the top of the tailgate. Much better than any other.

pciley · 08-08-2004, 11:47 AM

Sounds like a soft tonneau is in order. Would removing the tailgate hurt in a wind tunnel study? I would like to remove the TG for weight, but not if it is going to somehow slow me down

Mike H. · 08-08-2004, 12:13 PM

We tested tailgate removal in our study. I don't remember the level of impact. But if I recall correctly, it was a little worse.

There is a definite difference between OPENING the tailgate and REMOVING it. Opening is better than removal (from the standpoint of drag) in that the added "bed" length (the horizontal tailgate) keeps the upper and lower airflows separate longer, allowing them to straighten better and merge together with less turbulance. Air does not like to do things abruptly, whether it be dividing, coming together, or changing direction.

Removal of the gate may hurt your coefficient of drag, but that may be offset by the weight reduction. Only fullsize testing can really qualify the differences.