Raceway Results - Page 2

WIS-key · 08-08-2004, 01:47 PM

Grab the latest issue of R&T, and turn to p.156 - they've got a very enlightening article about pickup trucks and drag.

The report cited in the article is SAE Paper No. 2004-01-1146.

They tested the coefficient of drag (Cd) of a 2002 F-150 CrewCab.

The results (lower is better, of course):

Tailgate up: 0.5304
Tailgate down: 0.5425
Tailgate off: 0.5596
Partial tonneau cover: 0.5072
Full tonneau cover (estimated): 0.5023

There is a point where drag becomes a huge resistive force. I've seen it in fuel mileage in normal driving. I can get around 18-19 mpg under normal freeway driving (65-75 mph). When I drove down to Key West, I kept it between 45-55 mph on US 1. I saw an honest 21+ mpg on that stretch of road! I'm sure many factors played a role in that exceptional mileage, but I'm guessing drag (or lack thereof) was a big part of it.

In 1/4-mile racing, with a tonneau cover and tailgate, I'm guessing you'll lose some acceleration off the line, but start gaining it back after 50 mph.

I'd put a tonneau cover on the truck, leave the tailgate on, and fold the mirrors in - then give it a shot.

All in all, good job going out there and giving the Titan a run.

-Rob

pciley · 08-08-2004, 02:30 PM

Wow, never would have guessed having the TG off would slow you down...

It sounds like the effects listed above would be much more dramatic on my KC since the bed is over 1.5 feet longer than an F150 crew cab.
Maybe when I get the soft tonneau I'll take off the TG for the 1/4 mile. Whether or not the TG is there under the tonneau cover is not an issue for the air passing over the cover, unless it would effect rigidity on that back portion.

juma · 08-08-2004, 03:34 PM

what I am struck by is that you have a banks and volant and you are running about the same as "the head's" almost stock truck. seems like you should have a better timeeven given all the variables between locations and equipment. wondering if the mods don't really help....??

juma

the head · 08-08-2004, 07:58 PM

Well look at the mph. I only average in the 90s with the stock muffler and PC is in the 91s, consistently. PC would be smoking me if he would lose the spare and the tailgate. I run without either (take them off at the track). The #1 main reason is because 99% of the trucks out there are all doing it. Next time I go out I'll weigh them on a real scale to see what it drops. A lot of people are of the mind that "you should run it the way it is on the street". That's OK but if you are seeking the best ET then lose the dead weight. I guarantee you that EVERY truck that was at the Chevy meet that I went to with the Hem-eyes had the spare and tailgate gone. Some of the Chevy guys were removing one headlight for better airflow to their airboxes. I also don't have an ounce of tirespin.

juma · 08-09-2004, 04:58 AM

Quote:

Originally Posted by the head

Well look at the mph. I only average in the 90s with the stock muffler and PC is in the 91s, consistently. PC would be smoking me if he would lose the spare and the tailgate. I run without either (take them off at the track). The #1 main reason is because 99% of the trucks out there are all doing it. Next time I go out I'll weigh them on a real scale to see what it drops. A lot of people are of the mind that "you should run it the way it is on the street". That's OK but if you are seeking the best ET then lose the dead weight. I guarantee you that EVERY truck that was at the Chevy meet that I went to with the Hem-eyes had the spare and tailgate gone. Some of the Chevy guys were removing one headlight for better airflow to their airboxes. I also don't have an ounce of tirespin.

ok, I see what you mean. still, a hundred pounds of tire and tailgate would add a little top end, maybe, but its not like he's gonna run away from you that much for having 700 bux worth of mods. 1 mph means he got about 10-15 hp out of the mods....muttering....still doesn't seem like much diff. I've invested close to the same in the hope I could rip off sub-15's at 93 mph. looking more like it ain't gonna happen. juma

the head · 08-09-2004, 07:12 AM

I'm planning on ordering the Banks today. After that it'll be something else, I'm sure. I'm pretty sure the Banks will put me into the 14s. Even with the Dynomax choking it down, my ETs are pretty much the same. If I'd a had the stock muffler last time out, it would have run 15.1s and 15.0s, maybe.

I'm considering the electric fan but I think if I have any kind of overheating issues I'm sure Nissan will point the finger. This is also why I have decided against dumps on the exhaust - no reason to have them other than racing. I think there is a lot of time in the wheels, more specifically the rear. I need to figure out if a 16" wheel will fit the back. I'd like to run as short of a tire as I can to increase the gearing a little to get the thing going. If a 16" wheel will fit (like off a Pathfinder) then we could run drag radials and/or other sticky tires if there was a traction issue.

GETSOMZ28 · 08-09-2004, 08:13 AM

So, who is gonna be the first to shoot some juice throught their engine? It is only a matter of time...Screw 15's and 14's, go straight to 13's!!!

juma · 08-09-2004, 08:55 AM

Quote:

Originally Posted by the head

I'm planning on ordering the Banks today. After that it'll be something else, I'm sure. I'm pretty sure the Banks will put me into the 14s. Even with the Dynomax choking it down, my ETs are pretty much the same. If I'd a had the stock muffler last time out, it would have run 15.1s and 15.0s, maybe.

I'm considering the electric fan but I think if I have any kind of overheating issues I'm sure Nissan will point the finger. This is also why I have decided against dumps on the exhaust - no reason to have them other than racing. I think there is a lot of time in the wheels, more specifically the rear. I need to figure out if a 16" wheel will fit the back. I'd like to run as short of a tire as I can to increase the gearing a little to get the thing going. If a 16" wheel will fit (like off a Pathfinder) then we could run drag radials and/or other sticky tires if there was a traction issue.

fans and tires -- good choices.

overheating - I ran electric fans on a '96 caprice making 300 hp and weighing about 4400. It never overheated, ever. In fact, I'd look for the plastic fan brackets off a '96 copcar caprice or impala and order new chevy fans for it and use that with a napa temp sensing switch. you can get two different watt fans for that combo and I'd probably get the higher watt just to be safe. someone already has done that or planned it as I saw it on the this forum awhile back.

juma

juma · 08-09-2004, 08:57 AM

Quote:

Originally Posted by GETSOMZ28

So, who is gonna be the first to shoot some juice throught their engine? It is only a matter of time...Screw 15's and 14's, go straight to 13's!!!

clearly this is the only way to attack lightenings today. just wonder though what the ECU will do???

juma

JMC · 08-09-2004, 08:57 AM

Quote:

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

Always leave on the last yellow light!

pciley · 08-09-2004, 09:42 PM

about the wheels... I'll leave mine stock. I think they look good. I guess I'm not as hard core racers as you guys, I will try dropping the spare (60 lbs) and the tail gate (66 lbs... yes I just went outside and weighed it

).
Also I bought those add-a-leafs to install in front of the axle. Will post strip results as soon as I can get back there on a weekend.

Should be interesting to see if replacing the resonators with 3" pipes helped or hurt me.. not sure yet, I didn't have them installed on Saturday. opinions of experts here go either way.