sol4me

Hi,

I am a new owner of a 1997 Del Sol 5 spd. A friend has a 93 auto and while we were driving together we noticed that my 5 spd ran at higher RPMs, at the same highway speed, than their auto, is this normal (5-spd 60MPH @ 2800RPM)? If so, how does a 5spd get better gas mileage?

Thanks

Hanmin

its because of the tranny, if your at a higher rpm than he is at 60 mph in 5th gear, then your gears are shorter than his. This means you will accelerate faster than him, but he will hit a higher top speed, if everything else is equivalent. He will also get better gas mileage since hes at a lower rpm at cruising speeds.

5 speeds can get better mileage by the shift points, shifting at 2k will increase your gas mileage, and not giving more gas than is needed just to accelerate the car slowly.

sol4me

Thanks for your reply. Both I thought that the 5-spd would get getter MPG (assuming both are stock) am I wrong, does auto get better highway miles than 5-spd?

Hanmin

not all the time, Im assuming you have the z6 engine? the d16z6 comes with a short geared tranny, if you swapped with a vx/cx/hx/dx/lx tranny then you would get better mileage because those trannys have longer gears than the z6 one. The cx,vx,and hx will get you the most, I'm not sure which one is the best though, or if some are the same or not.

sol4me

I understand now. Thank you much. Poeple like you makes having a Del Sol all the more fun. Thanks again

94EG8

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Theres a lot more to it then just what RPM your at, at any given speed. Automatic transmissions are heavy. I can lift the tranmission thats in your car with one hand about a foot off the ground, It takes two people to lift the automatic your buddy has (I've had to move both before), Automatic transmissions use a torque converter to transfer power from the engine to the transmission, they slip by design, its a fluid coupling and its only something like 70% efficient if my memory serves me correctly, a manual transmission on the other hand uses a clutch which when fully engaged should be 100% efficient or very close to it as there is no slippage, just a solid coupling. All this said if you drive like you're at the track all the time your mileage will suck. If its mileage you crave upshift early and be light on the gas pedal. As someone else stated if you have the D16Z6 engine you have the short geared close ration transmission, it will give you the best acceleration possible, at the expense of some fuel mileage, you could swap in something geared longer, but it really takes some of the fun out of the car IMO.


Edit, forgot to add, the torque converter will look up at highway speeds for better mileage, but around town its always gonna be slipping somewhat.