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Convert my Cadillac ETC into so-called A-tractors.


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Hi, In Sweden you can convert cars into so-called A-tractors. The requirement that they must not go faster than 18.64114 mph. How do I throttle my Cadillac ETC so it doesn't go faster?

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I am not sure if you are joking.  Adding a reduction gear box in the drivetrain is apparently the solution with an automatic.  Also you would need to address how to limit to 2 passengers, removing the rear seat and reducing the cabin area, which would seem a major undertaking.

Bruce

2023 Cadillac CT4-V Blackwing

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16 minutes ago, Bruce Nunnally said:

I am not sure if you are joking.  Adding a reduction gear box in the drivetrain is apparently the solution with an automatic.  Also you would need to address how to limit to 2 passengers, removing the rear seat and reducing the cabin area, which would seem a major undertaking.

Not kidding. It is very popular with young people from the age of 16 to convert a car into a tractor. Can drive it until they turn 18 for a driver's license.
Just need to insert grilles behind front seats so the back seat is closed. Then remove the tailgate and insert a flatbed. No big jobs except to reduce the speed. On new cars, it is possible to set the control box so that it does not go too fast, but problems with older ones.

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Northstar Performance offers tuning for the early northstars: http://www.northstarperformance.com/tuning.php

I think a speed limiter for 18 mph would be an unusual request but it would be an elegant solution versus adding reduction gearing.

They appear to be swapping the entire PCM, so there would be a cost to get it to Sweden etc. 

Bruce

2023 Cadillac CT4-V Blackwing

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In Sweden, the Cadillac Eldorado Touring coupe is very cheap and almost impossible to sell. However, if I convert it to an A-tractor,  I can earn 2-3 times more.

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God morgon Göran,

Inte svårt få den godkänd om den håller hastigheten och är plomberad så den inte går att ändra utan stora ingrepp. 

Priset på en -93 med 20000 mil  behäftad med olika problem ligger inte högt i kurs.

Kommer inte ge mig in på projektet, var en liten fundering som grabben hade att vi skulle ha ett vinterprojekt i garaget.

Har kontaktat northstarperformence för att höra om dom kan tuna pcm så den inte går fortare än 30. 

 

Mvh

Eilert

 

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On 9/2/2022 at 5:08 PM, Bruce Nunnally said:

Northstar Performance offers tuning for the early northstars: http://www.northstarperformance.com/tuning.php

I think a speed limiter for 18 mph would be an unusual request but it would be an elegant solution versus adding reduction gearing.

They appear to be swapping the entire PCM, so there would be a cost to get it to Sweden etc. 

Got a reply from northstar performance,"I would need to know the maximum RPM (gear ratio, tire size) of the tractor and then I would set a speed limiter on the engine to not exceed that RPM." Looks like it is possible to limit the rpm.

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That surprises me; in hptuners there is a specific speed limiter, the top speed limiter.  The transmission can also be tuned to not shift out of 1st gear, and to limit speed in gear. 

I suspect with the 4 speed automatic 1st gear maxes out at 25 mph or so at 3000 rpm.

To determine exactly, we would take the gear ratio x final drive ratio x the revolutions per  mile of the tire/wheel combo at 18 mph.  For my ATS-V this would be 3170 rpm.

RPM of limiter = Final Drive: 3.71:1  x first gear 2.96:1 x Rev per mile 18 mph limit*63360/(Wheel+Tire Diameter*PI()*60) where wheel+tire diameter is in inches.  

Example diameter: 225/60-R16 would be .6 sidewall ratio*225 mm /25.4 mm/inch x 2 sidewalls in diameter + 16 in wheel diameter = 26.6"
Also, wheel+tire circumference divided by PI would work if you want to measure the actual wheel & tire.  I include the formula in case you have different wheels/tires.

So RPM of limiter = 3.71 final drive * 2.96 first gear * 18 mph max * 63360 / ( 26.6 diameter * PI * 60 min/hr) = 2498 RPM.

Bruce

2023 Cadillac CT4-V Blackwing

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