My new way of measuring on-road drag

[freebeard]

According to them's that do:

You know the rain may blow, snow may snow, and the turnpikes they may freeze
But that don't bother ol' Speedball, he goin' any damn way he please
He got a broomstick on the throttle to keep his throttle foot a-dancin' 'round
With a cupful of cold, black coffee, and a pocketful of west Coast turnarounds

Jim Croce: Speedball Tucker

[Piotrsko]

Figure out where and what the throttle settings are, disconnect the harness and measure the result at that point.

It will either be a resistance or a voltage and one side should increase while another will decrease in cadence believing you have 2 for a safety check.

Make and install resistive device or another TPS in parallel but pre set to whatever value you desire. I believe there are home positions that disable the original, BUT since the second fixed position one is in parallel, it should come online. Viola and easy peasy

[M_a_t_t]

Originally Posted by Cd

If I understand correctly, if you suddenly needed to quickly pass someone in an emergency situation while testing, you could do so by pressing the button on your parking brake lever and this would release the lever, and give more length to the cable connected to the gas pedal ?
Did you have to disconnect the actual parking brake and make it nonfunctional ?

The cable is setup so that the pedal can't return to idle. So to pass I would just have to push the gas down. When I have the lever engaged I rest my hand on it in case of a quick release, but usually I only do testing on a 2 lane (one each way) road or when there is no traffic. I don't live in a large town though so traffic is never an issue for me.

I added a second parking brake lever from a metro I scrapped. I put it next to the shifter (auto) so it's easy to reach. I don't have a picture handy right now to share.

[Cd]

It's too bad a cruise control setup can't be modified to hold a certain throttle position ( instead of speed )

[gumby79]

Originally Posted by Cd

It's too bad a cruise control setup can't be modified to hold a certain throttle position ( instead of speed )

This is a common mod on 1st and 2nd gen Cummins/ rams . They use it for high idle insted of stedy state cruse. Due to no computer to program in a high idle for warm ups(obviously not on eco modder )

[freebeard]

duckduckgo.com/?q=hand+throttle&iax=images&ia=images

[Cd]

How long must the test take in seconds to be accurate, and what is a minimum speed for an accurate test ?
I have a road nearby that has a good flat stretch, but then has lots of hills and stop lights.
Speed limit is 50 MPH.
If i go through the flat section of the road at a steady 50 mph, I will get 1 - 2 seconds of speed change data to work with.

I will be using a GPS app on my phone to give exact speed. I have two and use them in unison.

I plan to tap the 'reset' feature as I enter the target zone, and 'pause' as I exit, so that the data is not skewed as I begin to drive towards a hill, or slow for a stop light.
This is pretty cumbersome since it's just me in the car.
Ideally, i need a second person to do this and watch the speed readout.
Any ideas on how I could do it different ?
I think i could maybe just video the phones display and verbally mention as I hit a target and exit.

Regarding hand throttles, that is overly complicated and costly for me.
Thank you for the links though guys !
I have some mushy clay ( pottery clay ) that is very easy to form. It keeps its' shape after you release it.
I'll have that in a small plastic bag under the gas pedal and just featherfoot the pedal till I get to target speed.
I'll then be able to make the wooden throttle stop with a screw and use that.

If i suddenly need to accelerate, i will have an eye hook in the side of the plank hooked to a line that I can pull sideways and yank it out.

I'm eager to see some posts of how you all have done your testing, and ideas you had on performing the test safely and accurately.

[redneck]

.

Hand throttle.

https://ecomodder.com/forum/showthre...yle-26101.html


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[gumby79]

Cd
Time is not so much a factor in throttle stop testing. Only top speed achieved and MAINTAINED with the Artificially reduced max power.

How long/ min test time. 2-3sec at peak to verify you are truly at max. Just has to be long enough to have multiple data points to average your speed value and confirm max is achieved.

How much is needed?
The higher you set the speed/ throttle stop(TS) for the, test the higher the resalution( smaller things will show better with more speed) .

Smoke in the tunnel is done at ~30-35 mph to prevent thinning the smoke too much to see the evadence. Fuel log records for others with OBD2 port access indacate that commutes under 45mph are less about Cd or A and more about RRC and the nut behind the wheel.

I might suggest setting your TS @
<35 for RRC testing
>45 mph for CdA

2nd peraon?
Using the camera on the 2nd gps phone should work a dandy.


Only issue I see with you using this segment of your commute is installing the TS block enroute. And possibly RRC temperature based discrepancies if this point in your community is not far enough to be at full operating temp for grease and oils.

[freebeard]

redneck: In-ter-est-ing.

I tend to drive with my left hand on the steering wheel spoke and my right hand on the hand brake, a habit I picked up driving Beetles. The thinking is that you can get rear-wheels-only braking before the hydraulic pedal is depressed.

The only thing I see that could use updating from 2013 would be a 3D printed adapter block to replace the stock handbrake sleeve.