How the heck do I quote just part of a post? I am refering to the part about the pitot tube. A pitot tube is used to "traverse" a duct to measure velocity pressure (Total pressure-static pressure) using both the + and - ports on your manometer. You then convert velocity pressure to velocity, and velocity to cfm. This is a very acurate way to measure cfm in a duct, but would be very impracticle for what you are doing. You want to measure just static pressure and use with ernest's table.

 

See post #11 above in this thread for links to my threads, and then my threads give links to other threads where the accuracy issues are discussed. If it's more convenient to chat on the phone, we never get close to using all our cell minutes, and I can call your land line so it doesn't cost you! You can let me know a good time (not early AM, I'm retired for a reason) by email, or give me a call, and I'll dial you back.

 

I do it as follows... 1) click on quote and get that window up on FTE... 2) copy and paste that entire window into a blank email window, I use Outlook Express... 3) Hit the back button on Internet Explorer to return to the main thread on FTE.. 4) Within the email window you can chop up the quote into as many pieces as you want by replicating the QUOTE=....."piece you want"...QUOTE designators as many times as needed, and then respond to each piece at a time, as I'm doing with your post. 5) Recently I've been trying to remember to use "..." before and after the piece to signify that I'm just quoting back a "... piece ..." of the original post... 6) copy and paste the email window into the "go advanced" FTE window, hit preview to make sure it looks ok, and hit submit. You can close up the extra white space by running the pieces "nose to tail" in the FTE edit window if the preview doesn't look quite right.

Here's a link to a site that shows a pitot tube inserted into the intake tube of a 7.3L turbo! I'm going to call him sometime and discuss this approach and compare it to mine, and see if he's getting more accurate measurements. The accuracy of my approach is sensitive to how dirty the filter element is, but the advantage is that your air flow gauge is always monitoring the performance of the filter, so you definitely know when it's time to change it.

EDIT... Another advantage of my approach is that it doesn't disturb the air flow pattern as a pitot tube might, and since the experiment that Tenn is doing is to see if a vortex forms in the inlet tube with an open element symmetrical air filter, introducing a pitot tube into the inlet wouldn't be a good approach!

Since I've recently removed my Zoodad baffle as I discussed here...The Zoodad Mod https://www.ford-trucks.com/forums/636400-the-zoodad-mod-2.html#post4978830 and I'm concerned about bugs, etc... getting into the filter box, I'll probably keep my current setup so I can know if my element gets clogged. I always carry a hot spare, and with the AIS it literally only takes a few minutes to change the element.

 

That's good to know. Ive got my eyes open for hotrod PSD's everywhere I go....I guess I'm just aalways in the wrong place at the wrong time to hook up with those folks.

Where is the "bottoms"?....guess it doesn't matter....I'm too old to go cruise.

 

Centerville is 1000'!
9's or 10's with a 7.3 in the quarter mile and everyone would know your name.

The 'bottoms' is on the east end of Little Rock behind the airport. It's notsolegal 1/4 mile racing but the guy that owns the land is all about it, AND it's 5500 feet length is all pavement, it mind as well be a legitimate dragstrip.

I'm not looking to build a race truck. I'm a self proclaimed horsepower junkie. I want a respectable 12 second 1/4 street truck.

 

You might want to check with phil6608 who posted these times on one of my drag threads here... https://www.ford-trucks.com/forums/634998-whats-the-correct-way-to-interpret-drag-race-ets.html to see what all he's done to his truck. He discussed some things on the referenced thread. See post #5 & #11.

60' = 1.681
330' = 4.859
1/8 = 7.514 @ 92.31 MPH
1000' = 9.816
1/4 = 11.762 @ 116.17 MPH

 

He has an f150 with a lightning motor (gas). Thanks for the explanation on "quoting" part of thread. Unfortunatly I am not computer literate enough to do it.

 

I checked that thread again, and I was confused because phil6608 who posted the fast times seems to lists a PSD on nitrous, and S_Harvey lists the F150, but he didn't post his times when he realized that my aerodynamic drag model was only for a PSD. Now I see that phil6608 lists a "blower" which doesn't sound like a PSD after all! Are these two different F150's?

phil6608
DE Chapter Board Member--New Castle County
2003 SuperCrew
DSS Built Lightning block/Stage 2 heads and cams
L-conversion/Kenne Bell upgrade blower at 18 PSI
100 shot nitrous/Best 1/4 to date
1.68 60 foot time/11.76 @ 116.17

S_Harvey
1999 F150 Lightning (my work truck!)
- Built long block, Whipple charged!

 

Sounds to me like he has a Kenne Bell Whipple Charger which would be installed in a 351 or 5.8 Windsor engine. That would be a supercharger in a gasser.

 

phil6608
DE Chapter Board Member--New Castle County
2003 SuperCrew
DSS Built Lightning block/Stage 2 heads and cams
L-conversion/Kenne Bell upgrade blower at 18 PSI
100 shot nitrous/Best 1/4 to date
1.68 60 foot time/11.76 @ 116.17

"Super crew" is an F150 thing, "DSS Built Lightning block" lightning engines are gas. And he lists "cams" as in two. Kenne Bell makes super chargers for gas engines, not sure if they make turbos for diesels. I would say he has two F150's

 

you can just delete what you dont want when you hit the quote button, you can delete anything in the body of the quote you want just dont touch the [quote] part of it......here I just highlighted some of your message and deleted whatever, lots easier than copy paste somewhere else etc etc.......

 

I have seen models that say to take your 1/8th mile times and multiply by 1.54-1.58 and you will get a good idea of your 1/4 mile times. The 1.58 is a slower vehicle running 17+ second 1/4 mile times, so I figure on your truck 1.56 or 1.57 is about right. That puts your truck at a 15.1 1/4 mile when multiplied by 1.57 and 15.01 when multiplied by 1.56. Does that seem about right to you?

 

To get an accurate result for drag race ET's, one needs to have an accurate model for the RWHP required to overcome the truck's rolling resistance and aerodynamic drag for each fraction of a second, as the truck speeds down the track, and this model is different for each vehicle body style. Without knowing these rolling resistance and aerodynamic drag RWHP numbers from one instant to the next, you won't know how much of the engine generated RWHP is actually available to accelerate the truck at each instant of time. My model calculates rolling resistance and aerodynamic drag for each fraction of a second, to see how much RWHP is left over to accelerate the truck between these fractional second intervals, and then updates to the next fractional second interval. This type of computation is the ONLY way to get an accurate result.

To match a known run, like I'm going to do for the best set of ET's reported by Tenn, I can input engine generated RWHP estimates into the model, for each fractional second, until I get the model ET's to match the measured ET's at the track for each distance, 60', 330',660',1000', and 1320'. And then my model will give the MPH at each distance, along with the engine generated RWHP vs RPM that is necessary to achieve the set of ET's that were measured at the track. My model shifts through each gear to the 3200 RPM redline (or one of your choosing), and applies the appropriate engine generated RWHP vs RPM, that is available to accelerate the truck, after accounting for rolling resistance and aerodynamic drag.

 

Wow, never noticed this thread. I'm not on the nets but a couple of times a week. When I come here I usually look only at the first page of posts (you know, the active stuff).

Yes, that was us at Centerville, no not me at the 'bottoms' but yes, Chris and Ron race down there often. I don't because my job is a driving job, I NEED my license.
FWIW, Ron's truck (the one that ran a 9.6 in 1000') is a built 6.0!

Robby, I sent you a PM with my number, call me, I'll be around for a couple of days, I'd be more than happy to let you check out our trucks. Mine, Chris' and the shop truck will be here if you call today. You can get a perspective of different power levels and driveability in three different 'built' 7.3's.

-JE