RE: RE: attn.Steven. tailgate up or down

From: Stlaurent Mr Steven (STLAURENTS@mctssa.usmc.mil)
Date: Tue Jul 11 2000 - 15:32:13 EDT


I throw a sheet in the back and see at what MPH will the sheet do the
whirlwind dance. It started around 75MPH. This is why I was asking.

Hmm! Maybe a 150HP shot and that should put you in the high 12s or low 13s.
He He

-------------------------------------------
Steven St.Laurent
Test Engineer
Test Branch, GSD, MCTSSA
MARCORSYSCOM, USMC
760-725-2506 (DSN 365-2506)
Work:mailto:stlaurents@mctssa.usmc.mil
Home:mailto:saint1958@home.com

 -----Original Message-----
From: Barret, Matt [mailto:MATT_BARRET@earthtech.com]
Sent: Tuesday, July 11, 2000 12:21 PM
To: 'dakota-truck@buffnet.net'
Subject: DML: RE: attn.Steven. tailgate up or down

No, .25 to .50 seconds in the quarter mile is alot of time. Would normally
take 20 to 50 HP for those gains, or 200 to 500 lbs of weight reduction. I
really don't believe in the theory of drag from a tailgate at highway speeds
90 mph or less. The design engineers take that into consideration when
designing the aerodynamics of the truck. They engineer the roof lines to
deflect most air up over the tailgate. I won't say there is no air drag
from a tailgate, but I believe the significance of it is a non factor under
normal speeds.
Now, in older trucks, like anything older than say 1990, they probably
didn't do any aero work on the design, so the tailgate down theory may apply
to these designs. But by todays standards they are tweaking fuel economy as
much as possible.
I have raced with the tailgate on and off, and observed no difference in
ET's.

The subject of the tailgate up or down and its effects on fuel mileage and
drag has always been a hot topic . Most people are either in one side of the
fence or the other. I have had 3 trucks, 84 Ram, 85 F-150, and now the Dak.
I have experimented with the tailgate down/up and have never seen any
increased MPG with it down.

Lockhead Aircraft did wind tunnel testing on trucks in the 90's with
tailgate up and down and actually found that leaving the gate up created
less drag than putting the gate down!! A "separated air bubble" forms in
the bed of the truck at highway speed which lets the air flow freely over
the tailgate.

I'm sure this will spark some interesting comments :)

matt

-----Original Message-----
From: Stlaurent Mr Steven [mailto:STLAURENTS@mctssa.usmc.mil]
Sent: Tuesday, July 11, 2000 2:17 PM
To: 'dakota-truck@buffnet.net'
Subject: DML: RE: RE: RE: RE: Re: RE: attn.Steven. was Richmond D'way

I wonder if any air turbulence is occurring while drag racing and if you can
gain a .25 to .50 of a second time with a cover over the bed.

-------------------------------------------
Steven St.Laurent
Test Engineer
Test Branch, GSD, MCTSSA
MARCORSYSCOM, USMC
760-725-2506 (DSN 365-2506)
Work:mailto:stlaurents@mctssa.usmc.mil
Home:mailto:saint1958@home.com

 -----Original Message-----
From: Barret, Matt [mailto:MATT_BARRET@earthtech.com]
Sent: Tuesday, July 11, 2000 10:29 AM
To: 'dakota-truck@buffnet.net'
Subject: DML: RE: RE: RE: Re: RE: attn.Steven. was Richmond D'way

Nope, no Tonno cover on my truck, I even leave the tailgate up when racing.

matt

-----Original Message Follows -----

~From: Stlaurent Mr Steven [mailto:STLAURENTS@mctssa.usmc.mil]
~Sent: Tuesday, July 11, 2000 1:05 PM
~To: 'dakota-truck@buffnet.net'
~Subject: DML: RE: RE: Re: RE: attn.Todd/Tim. was Richmond D'way

~Are you running with the tonner cover on when drag racing?~

-------------------------------------------
Steven St.Laurent
Test Engineer
Test Branch, GSD, MCTSSA
MARCORSYSCOM, USMC
760-725-2506 (DSN 365-2506)
Work:mailto:stlaurents@mctssa.usmc.mil
Home:mailto:saint1958@home.com

 -----Original Message-----
~From: Barret, Matt [mailto:MATT_BARRET@earthtech.com]
~Sent: Tuesday, July 11, 2000 9:56 AM
~To: 'dakota-truck@buffnet.net'
~Subject: DML: RE: Re: RE: attn.Todd/Tim. was Richmond D'way

~Yea Todd that would be alot of fun, maybe we could bet together at VMP,
~would be 50 miles closer to ya than Richmond Dragway. Although Richmond is
a
quicker track. Tim and I have been trying to get together somewhere so he
could borrow my slicks. What times have you been running lately?
These truck are pigs when it comes to weight, my little RC weights 3670 with
out me, and 3870 with me. Not much you can do to trim weight off the truck,
spare tire weighs 50 pounds and the tailgate about 40. To be honest, I have
run just as quick with the tailgate on!

Hey Tim, lets get something together, Todd sounds like he's ready to go in
the low 13's!! In a 4XXX lbs truck, no less!!! hee heee

Matt

-----Original Message-----
From: Todd Flummer [mailto:mustang@netunlimited.net]
Sent: Tuesday, July 11, 2000 11:23 AM
To: dakota-truck@buffnet.net
Subject: DML: Re: RE: attn.Tim B. and Injectors installed... was
Richmond D'way

You guys let me know when you plan to race again and I'll come up that way.
I plan on dropping as much weight as I can and maybe even going with the big
150 shot. I think that would put me low to mid 13's.

Todd
Mustang@netunlimited.net
www.netunlimited.net/~mustang/

----- Original Message -----
From: Barret, Matt <MATT_BARRET@earthtech.com>
To: <dakota-truck@buffnet.net>
Sent: Tuesday, July 11, 2000 9:29 AM
Subject: DML: RE: attn.Tim B. and Injectors installed... was Richmond D'way

> yea, It will be close to the same, but I bet you'll see about a 2 mph drop
> or so in trap speed if the 60' times drop by .2's or more. I've got a
> spreadsheet of 70+ runs that you can compare all the info and see the MPH
> fluctuate. I'm talking about strictly 60'. Your Bro spinning 1st and 2nd
> was probably more along the lines of 100 feet or more, that will
definitely
> kill your ET and MPH!! Traction problems for our trucks is only in the
1st
> 60', generally no problem with traction after 60' unless your on some real
> bad radials :).
>
> Yea, bring that ride up here to Richmond Tim and we'll put the
> Hoosier-(daddys) on there and watch your truck stab deep in the 14's :)
> hee heee I'll keep my radials on and run ya ;-) !!
>
> Matt
>
>
> -----Original Message Follows -----
>
>
> From: Tim Berry [mailto:coolva1@home.com]
> Sent: Tuesday, July 11, 2000 8:48 AM
> To: dakota-truck@buffnet.net
> Subject: DML: attn. Matt B. and Injectors installed... was Richmond
> D'way
>
>
> Matt... I think MPH will stay close to the same...
>
> My bro spun 1st and 2nd at the track on his first time, last run, and
turned
> a 14.4 @101
> (normally 13.5 @ 105)
>
> btw, I installed a set of 24# injectors yesterday.. It seems to be
catching
> on (the puter)....
> Now... When do I get to slap them slicks on my truck??? =-)
>
> I feel the injectors MAY have lost a little torque down low, and gave me
> some extra HP, but I cant tell... it seems the speed-o-meter rises to 60
in
> a blink of the eye.... but... only VMP will tell me that =)
>
> Tim Berry
> Chesapeake, VA
>
>
> > Hey Wayne, once you get that rocket hooked up, say, in the 1.8-1.90
range,
> > hee heee, That would almost be 12's!! At any rate, mid 13's in a truck
> is
> > flying!!
> > That high MPH is a good indication of tire spin, I would bet that when
you
> > do hook up your MPH will be right around 100 mph even. Congrats!!
> >
> > Matt
>



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