T-100 Performance Update

[aerohead]

September 10 came,and I left home with the trailer project in pieces.I left an update at the full boat tail trailer thread.--------- To make the best of a bad situation I went ahead and ran out to New Mexico to check out the new "racing" tires and any affect they might have on mpg.------------- I ran without the 24" boat tail to simulate the truck at standard length as a future comparison to the trailer rig now scheduled for Christmas holiday testing.------------- The new tires are 70 aspect ratio compared to 75 for what came off the truck.RPMs were affected,turning as much as 400-rpm higher at 80-mph (129 km/h ).------------ Results at 80 mph were within 1.5% agreement with numbers achieved in earlier testing, @ 26.767 mpg.------------ Results at 70-mph ( 113 km/h )were within 0.2 mpg from one earlier test,returning 30.32 mpg ( 7.748 L/100 km ).------------ The most interesting run stretched from Cloudcroft,New Mexico to home,which I ran at the old double-nickel 55-mph speed limit,which approximates more closely the EPA HWY testing.At a steady 55-mpg ( 88.6 km/h ) the truck averaged 32.813 mpg with one leg at 39.05 mpg ( 6.014 L/100 km ).This is the highest mpg I've recorded for the T-100 at highway speed and is same run where CRX recorded it's best mpg.-------------- Had I been running the boat tail I might have broke into 40-mpg territory.--------------- This coming December I'll run this same leg with the trailer and see just how far I can push mpg.--------------- P.S. looks like losing the boat tail cost me about 1.7 mpg on the interstate.

[orange4boy]

Congrats on the new record. Got one myself this summer. Looks like you are-o-headed for another.*Ouch* Sorry.

Do they switch to winter gas in Texas? It's always a bummer here when your numbers drop like a stone when the winter gas hits.

[aerohead]

Originally Posted by orange4boy

Congrats on the new record. Got one myself this summer. Looks like you are-o-headed for another.*Ouch* Sorry.

Do they switch to winter gas in Texas? It's always a bummer here when your numbers drop like a stone when the winter gas hits.

orange4boy,thanks for the thumbs up and congrats on your own fuel-stretching.
As far as I know they do a winter fuel formulation switchover.The overall Btu content isn't supposed to be affected,just vapor pressure and some other gee-whiz chemical engineering stuff.Numbers will tell.Don't ya just love variables?!

[itsmedc]

Thanks for the update and inspiration; have been reading all the info old and new on the T-100 and a lot of other materials. Look forward to the next update.

Have a question for you.
I have a 72 Dodge D100 Shortbed which is the first year of the redesign after the style from the late 60's and was used in its basic form up into the 80's. This is a 3rd vehicle used for some hauling and occasional pulling of a pop up camper. I check every tankful of gas but it does not get driven a lot. Also have picked up several sheets of aluminum sign material, for FREE, since they were throwing the old signs away. After a lot of reading, thinking, and studying that includes "SAE 881874 Pickup Truck Drag Reduction...Without Limiting Truck Utility" my plan is to combine a
- 24 inch long cab width wing at 8 degrees down angle
- with a partial bed cover.
The truck came with a 24 inch long over the rail toolbox behind the cab that I use; also has tubular bed rail protectors attached to the box.
The bed cover plan includes a removeable 12 inch extension past the tailgate in the up position, with sides and bottom similar to the bed extension you did but, with an open back. This is after looking at the ATDynamics Trailer Tail for Class 8 truck trailers. Will also be working on a tray to go under the rear bumper and forward to the back edge of the rear wheel well.

My question, finally, is about the length of the tail extension;
? based on your experience, is a 12 inch open back extension, with the proper angles likley to provide a measurable benefit or would it need be longer?

Note I am also planning several other mods before the tail extension including the previously mentioned wing and bed cover as well as:
- partial grill blocks, angled from the bumper to the hood, that includes improved control of the air flowing to radiator
- and a front tray / splitter from bottom of bumper back to the low hanging frame / suspension points with deflectors for the front tires
- and partial belly pans from the edges of the cab and bed over to the frame running from front wheel wells all the way back to the rear wheel wells.

[aerohead]

Originally Posted by itsmedc

Thanks for the update and inspiration; have been reading all the info old and new on the T-100 and a lot of other materials. Look forward to the next update.

Have a question for you.
I have a 72 Dodge D100 Shortbed which is the first year of the redesign after the style from the late 60's and was used in its basic form up into the 80's. This is a 3rd vehicle used for some hauling and occasional pulling of a pop up camper. I check every tankful of gas but it does not get driven a lot. Also have picked up several sheets of aluminum sign material, for FREE, since they were throwing the old signs away. After a lot of reading, thinking, and studying that includes "SAE 881874 Pickup Truck Drag Reduction...Without Limiting Truck Utility" my plan is to combine a
- 24 inch long cab width wing at 8 degrees down angle
- with a partial bed cover.
The truck came with a 24 inch long over the rail toolbox behind the cab that I use; also has tubular bed rail protectors attached to the box.
The bed cover plan includes a removeable 12 inch extension past the tailgate in the up position, with sides and bottom similar to the bed extension you did but, with an open back. This is after looking at the ATDynamics Trailer Tail for Class 8 truck trailers. Will also be working on a tray to go under the rear bumper and forward to the back edge of the rear wheel well.

My question, finally, is about the length of the tail extension;
? based on your experience, is a 12 inch open back extension, with the proper angles likley to provide a measurable benefit or would it need be longer?

Note I am also planning several other mods before the tail extension including the previously mentioned wing and bed cover as well as:
- partial grill blocks, angled from the bumper to the hood, that includes improved control of the air flowing to radiator
- and a front tray / splitter from bottom of bumper back to the low hanging frame / suspension points with deflectors for the front tires
- and partial belly pans from the edges of the cab and bed over to the frame running from front wheel wells all the way back to the rear wheel wells.

itsmedc,being that your's is a shortbed truck,I think the extension is a good idea.Since you're starting from"square"architecture,and she's not very long,you're not going to alter the wake significantly,as 12-inches won't support much curvature,although you will approach the long-bed length with better chop off.Sepp reports from Europe that an open tail loses some mpg vs a "closed" unit with a back.---------If you stay within 10-degrees for your downslope and say 7-degrees at the sides,and 2 1/2-4-degrees coming up from below you should have attached flow if you run at least a 1/2-tonneau ahead of the tailgate.Your partial bellypan will help your underside flow.--------- As to estimating an improvement,calculate the new wake area of the added tail and compare to the present area of your tailgate/rails/bumper valance/spare-tire and support structure.------------ Your rule of thumb will be a 5-6% mpg improvement at 55-70mph,respectively,for any 10% wake area reduction,as drag is an arithmetic function of wake area.Obviously,the longer the tail the greater the wake reduction but then length can be an issue.24-inches is good for 1.7-mpg,interstate with the T-100.------------- I have a 1962 D-100.I swapped a 4-spd OD and 3.50 rear axle out of a 1977 Dodge and pushed mpg from 11,up to around 18.6 mpg at 70-mph.A 6-inch nose extension with fractional airtight radiator inlet,plex headlight/turn signal covers;partial front wheel well gap-fillers,hubcaps,and aeroshell allows 21.5 mpg @ 70 mph,with a very weak six-banger.

[itsmedc]

Originally Posted by aerohead

Sepp reports from Europe that an open tail loses some mpg vs a "closed" unit with a back.

I read about both versions of Sepp's aeroshell but missed his info on open tail vs closed... Will have to a bit more digging around.

Originally Posted by aerohead

10-degrees for your downslope and say 7-degrees at the sides,and 2 1/2-4-degrees coming up from below

Thanks for confirming my thoughts on angles; and the info on calculating the potential improvement.

Originally Posted by aerohead

I have a 1962 D-100. I swapped a 4-spd OD and 3.50 rear axle out of a 1977 Dodge and pushed mpg from 11, up to around 18.6 mpg at 70-mph. A 6-inch nose extension with fractional airtight radiator inlet, plex headlight/turn signal covers; partial front wheel well gap-fillers, hubcaps, and aeroshell allows 21.5 mpg

The one photo I have seen of the 1962 D-100 is what gave me the path for some of the mods I am planning;
Would love to see more detailed photos of the nose on it.

As for a tranny swap and gearing... I am running the original 3-speed auto (727 TorqFlite) and original 3.23 gears; with a reworked V-8 (318 2-barrel) and a bit of electrical and ignition curve work have managed to get from 11 mpg to 14 mpg at 50-55mph while pulling the pop up camper. Best tankful without the camper at 50-55mph was 16 mpg and is typically around 11-12 mpg for mixed driving. For a transmission upgrade, when the money falls off a tree or the original trans dies, I would love to put in a later version auto with overdrive and also gain a lockup torque converter but will more likely end up overhauling a non-lockup 904 TF I already have and swaping it in. The 904 uses a bit less power and should hold up fine under my driving.
I am familiar with the 4-speed manual with overdrive from a Plymouth Duster that had one behind a 225 slant 6 and with 2.93 gears would knock down 27 mpg at 55-65 mph traveling around the Texas / Oklahoma area when I was stationed out by Abilene.

[aerohead]

Originally Posted by itsmedc

I read about both versions of Sepp's aeroshell but missed his info on open tail vs closed... Will have to a bit more digging around.



Thanks for confirming my thoughts on angles; and the info on calculating the potential improvement.



The one photo I have seen of the 1962 D-100 is what gave me the path for some of the mods I am planning;
Would love to see more detailed photos of the nose on it.

As for a tranny swap and gearing... I am running the original 3-speed auto (727 TorqFlite) and original 3.23 gears; with a reworked V-8 (318 2-barrel) and a bit of electrical and ignition curve work have managed to get from 11 mpg to 14 mpg at 50-55mph while pulling the pop up camper. Best tankful without the camper at 50-55mph was 16 mpg and is typically around 11-12 mpg for mixed driving. For a transmission upgrade, when the money falls off a tree or the original trans dies, I would love to put in a later version auto with overdrive and also gain a lockup torque converter but will more likely end up overhauling a non-lockup 904 TF I already have and swaping it in. The 904 uses a bit less power and should hold up fine under my driving.
I am familiar with the 4-speed manual with overdrive from a Plymouth Duster that had one behind a 225 slant 6 and with 2.93 gears would knock down 27 mpg at 55-65 mph traveling around the Texas / Oklahoma area when I was stationed out by Abilene.

This is a shot in the dark,but B&M Hydro used to offer an aftermarket full lockup torque converter.I've no idea if they still do.You might check HOT ROD Magazine or GOOGLE B&M.---------- Your 318 is a sweet engine and I've known van owners who routinely saw 22-mpg at the old double-nickel speed( with more frontal area).I think you could easily push into the 20s range.--------- I have some shots of the Dodge's nose although nothing digital.If you don't mind waiting I'll try and dig 'em out and scan.I originally mocked-up a front end for the truck with cardboard and masking tape and drove test runs at 50 mph ( that's all it would do with 3-speed and 4:56 gears)between Lubbock and Hereford,TX in college,and it held together long enough for the testing.If you were to mimic any of the modern truck noses,I'm sure you'd be rewarded.

[itsmedc]

Originally Posted by aerohead

This is a shot in the dark,but B&M Hydro used to offer an aftermarket full lockup torque converter.

I did a little searching, and will dig around some more, but according to a seasoned chrysler dealer mechanic I know lockup converters also have a different valve body and even different input shafts. So you can't simply stick a lockup converter in a non-lockup trans.

Originally Posted by aerohead

Your 318 is a sweet engine and I've known van owners who routinely saw 22-mpg at the old double-nickel speed (with more frontal area).

That is some impressive numbers. I owned a short wheel base full size van that also had a 318 and rolled up a lot of miles in it as a field service tech driving all over Georgia but, have no recollection of the fuel mileage. Do not think it was that high. The closest I ever came to those kind of mileage numbers with a 318 was in a 72 Dodge Demon (same basic shape as the Plymouth Duster) with a TF-904 and 2.76 gears... managed 21mpg on the highway by either 55-60 mph DWL or DWL with 45 mph at the top of hills and well over the speed limit at the bottom of hills but never moving the throttle position. Dad did one tankful his way and I did one my way on a trip from TX to SC and we were within a tenth of a mpg on back to back tankfuls.

Originally Posted by aerohead

I have some shots of the Dodge's nose although nothing digital.If you don't mind waiting I'll try and dig 'em out and scan.

I have plenty of time with all the rain we are getting here in the Atlanta area lately... Would love to see the photos... If it would be easier I will PM you with my mailing address and you can send copies in the mail... although I imagine there are others on here who would love to see them.

Originally Posted by aerohead

If you were to mimic any of the modern truck noses,I'm sure you'd be rewarded.

Have been studying aero on all the late model trucks. Looked at some videos talking about the aero on the 2009 Ford F150.
Video on new F150 aero http://video.tiscali.it/canali/truveo/2867473023.html

Part of the talk about the nose was how the lower part angled back before turning the air flow down... seems like I have seen something similar to that on the front of a white T-100. Also talked about how the back top of the cab rounded over before coming to a "chisel" line to trip the airflow... Funny how the back edge of the cab on my old Dodge does the same thing... unlike the 87 Ford they used in the SAE 881874 paper which has a cab trailing edge that is almost as square as cardboard box.

I even spent a day wandering around in a mall parking deck so I could get a good look at the undersides of the noses by walking along the ramps.
Had first noticed the bottom of the noses being angled back as part of the bottom of the front bumper on the newest Honda CR-V. Also, all the little deflectors hanging down in front of the inner third of the tires.
One little detail I did notice on the newest Toyota Tundra's was that only the front passenger wheel well has a set of small louvers in the front part of the wheel well. Was not able to figure out the purpose of those.

[aerohead]

Originally Posted by itsmedc

I did a little searching, and will dig around some more, but according to a seasoned chrysler dealer mechanic I know lockup converters also have a different valve body and even different input shafts. So you can't simply stick a lockup converter in a non-lockup trans.


That is some impressive numbers. I owned a short wheel base full size van that also had a 318 and rolled up a lot of miles in it as a field service tech driving all over Georgia but, have no recollection of the fuel mileage. Do not think it was that high. The closest I ever came to those kind of mileage numbers with a 318 was in a 72 Dodge Demon (same basic shape as the Plymouth Duster) with a TF-904 and 2.76 gears... managed 21mpg on the highway by either 55-60 mph DWL or DWL with 45 mph at the top of hills and well over the speed limit at the bottom of hills but never moving the throttle position. Dad did one tankful his way and I did one my way on a trip from TX to SC and we were within a tenth of a mpg on back to back tankfuls.





I have plenty of time with all the rain we are getting here in the Atlanta area lately... Would love to see the photos... If it would be easier I will PM you with my mailing address and you can send copies in the mail... although I imagine there are others on here who would love to see them.




Have been studying aero on all the late model trucks. Looked at some videos talking about the aero on the 2009 Ford F150.
Video on new F150 aero | tiscali.video

Part of the talk about the nose was how the lower part angled back before turning the air flow down... seems like I have seen something similar to that on the front of a white T-100. Also talked about how the back top of the cab rounded over before coming to a "chisel" line to trip the airflow... Funny how the back edge of the cab on my old Dodge does the same thing... unlike the 87 Ford they used in the SAE 881874 paper which has a cab trailing edge that is almost as square as cardboard box.

I even spent a day wandering around in a mall parking deck so I could get a good look at the undersides of the noses by walking along the ramps.
Had first noticed the bottom of the noses being angled back as part of the bottom of the front bumper on the newest Honda CR-V. Also, all the little deflectors hanging down in front of the inner third of the tires.
One little detail I did notice on the newest Toyota Tundra's was that only the front passenger wheel well has a set of small louvers in the front part of the wheel well. Was not able to figure out the purpose of those.

Could it be that B&M took the valve body and input shaft into consideration for their converter and it's the later model electronic lockup MOPAR converters that won't fit? I wouldn't know.------------ With respect to the Tundra's wheel well louvers,could that be the site for combustion air to enter the airbox/air cleaner? I've seen that done before.It's out of the way,there is no way jetsam can clog the inlet( as a plastic bag might with a grille inlet) and it's in a fairly high pressure regime.