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Does anyone know of a company that makes different tooth sprockets for the Slingshots. Would like to get much better MPG. My car gets 36 and my diesel pickup gets 25. Why does a 1600 pound vehicle get only 28.
 

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The Slingshot is about as aerodynamic as holding up a sheet of plywood going down the highway. Most Slingshots will obtain a faster top speed in 4th gear than 5th for the same reason. A higher final drive ratio would probably not help the gas mileage, maybe even hurt it. You would also probably have to have the ecm recalibrated.
 

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I can't guarantee it will work, but both the 1st and 2nd Gen Slingshots use the same 62 tooth rear pulley, but the 1st Gen Slingshot uses a 39 tooth pulley on the angle drive, providing a 1.59:1 final drive ratio (39/62). The 2nd Gen Slingshot uses a 32 tooth pulley on the angle drive, resulting in a 1.77:1 final drive ratio (35/62) based on the angle drive pulley vs the rear pulley. I believe the 2nd Gen transmission actually uses different gearing to take advantage of the higher rpm redline of the Polaris motor, so the engine is likely turning faster than a 1.77:1 final drive ration would indicate. The angle drive pulley on both the 1st and 2nd Gen is attached to the angle drive with the same part numbers for the parts, so swapping out the 2nd Gen angle drive pulley for the 39 tooth pulley from a 1st Gen Slingshot should allow the motor to run at lower rpms at any given speed and hopefully produce slightly higher gas mileage at the expense of slightly slower acceleration. The 1st Gen Slingshot angle drive pulley is identified as SPROCKET, 39T pn 1333869 with a price around $350. The 2nd Gen mounting parts should hopefully work, but a 2st Gen Service Manual should be consulted as far as part re-usability when replacing the pulley is concerned.

Looking at recommended rear drive ratios for best performance for 4-wheel converted Slingshots, most 1st Gen Slingshots can use a 3.27:1 differential, with 3.45 or even 3.91 for better acceleration, while the higher-revving 2nd Gen Polaris motor seems to work best with a 3.91 or 4.11 differential with a 3.45 probably being the last choice for acceleration (source - PLUS 1 Quad Conversion Kit, V2, Polaris Slingshot, (Deposit)).

Note - Hopefully, someone more knowledgeable than i with respect to final drive ratios will verify my math as I tend to get confused when calculating final drive ratios. :unsure:
 

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The Slingshot is about as aerodynamic as holding up a sheet of plywood going down the highway.
Correct, Somebody else here has also compared the Slingshot to a parachute. The SlingShot is designed more for fun, not economy! Also, at least the first generation SlingShots have a minor issue of the knock sensor requiring early replacement if a rider tends to run higher gears and lower RPMs “lugging” the engine. I believe keeping above 2000 RPM at highway speeds to be a good practice.
Oh, while talking about fuel economy, the MPG decrease even further when we install the top.
Just saying………….
Bill
 

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Along the same lines, my 2015 S was getting around 30 mpg when first purchsed. Adding a TD Top and CAI brought that down to around 28 mpg. Adding my Hahn Stage 2 Turbo dropped it to around 26, but significantly upped the enjoyment factor.
 
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