Slacker buys a Tercel

[Toby]

Hello ecomodders,

I returned to the USA from disaster relief work in Sudan about a year ago in pursuit of my wife.

I finally found a job in my field (engineering), but it involved a 40 mile commute suitable to neither my preference of cycling, nor my trusty Nissan pickup.

In response I recently purchased a 1996 Toyota Tercel DX. It's a sweet ride with 94 hp, 85k miles, a couple dents, and wicked pink "graphix" reading "sport." With mild hypermiling, I ran 38 mpg over my first tank in this car. Basically, I love it.

Since my commute is 95% highway, I'm really interested in aero mods. I'm also very interested in taller gearing for this car. If anyone has gone down that road, I'd love to hear about it.

I have decent mechanical skills. I'm a fair welder and machinist with access to a good shop at work. I love problem solving. The downside is that I can be a real slacker about personal projects.

I have enjoyed many of the ideas and projects I've read about here. Great work, people.

[Daox]

Welcome to EM Toby.

You and I share very similar cars. My Paseo is built on the same chassis as the Tercel and they also share the same engine. Unfortunately for me, the Paseo has shorter gearing than the Tercel. As it is, if you have the 5 speed transmission, you have the tallest stock transmission possible. The only option for going taller is to check if the 4 speed differential fits in the 5 speed bellhousing. But, even then, it will only drop your rpms roughly 100 @ 55 mph, so not much of a gain there. The other option would be a custom 5th gear. A few guys have tried this on various other cars and have had good success with it. Since you have access to a machine shop, you might have good luck doing a reversed 2nd gear (you'd need a donor transmission) as a new 5th gear. I know I'd love to do that myself.

Other than that, I'd definitely pump the tires up to maximum sidewall and focus on aero mods. An upper grill block would be an excellent start.

[Toby]

Thanks for the amazingly quick response. In fact, I have the four speed manual transmission. Oddly, the EPA rating for the model with the 5 speed is slightly worse. I will definitely be looking into the possibility of the 5 speed in my car, though.

I've read several of your posts about your Paseo. I hope I can make half your progress.

[SentraSE-R]

Welcome to EM, Toby. Thanks for your humanitarian assistance in Sudan!

How fast do you drive on the highway? You don't need aero mods if you keep your speeds <=55 mph. The 1NZ-FE engine in the Tercel/Echo/Yaris is capable of ~50 mpg at slow cruising speeds.

[Toby]

After only a week in this car, I've settled to cruising around 57 mph. This seems to be a sweet spot that keeps me just above the speed at which you get run over by pickups and H2's on the highway I frequent.

My car has the 5E-FE engine. I know I should be getting better milage than I have, but my numbers are also suspect so far.

I'm running on Missouri winter gas in pretty harsh winter weather. And I'm calculating my fuel consumption by pump top off, which is subjective at best.

[Toby]

This car, by the way, is the second worst winter driving vehicle I have ever experienced. It has the 155 tires, and the handling and breaking are just poor in the extreme on anything but bone dry conditions.

[Daox]

Originally Posted by SentraSE-R

You don't need aero mods if you keep your speeds <=55 mph.

Sorry, but this is completely untrue. At just over 35 mph, half of the power to move the car is going towards overcoming aerodynamic drag. At 55 mph, 70% of the power required to maintain speed is going to overcome aero drag. Aerodynamics are a huge factor at all but very slow speeds.

Here is the break down using the numbers for a Tercel.




I also calculated the regearing effect of swapping to a 5 speed (from a 95+ Tercel, the earlier ones had shorter gearing). At 55 mph, the 4 speed puts you at roughly 2550 rpm. The 5 speed will drop that down to 2200. Not a huge drop, but its something. If you put your 4 speed differential in your 5 speed, you'd be down to 2080 rpm. FYI, I'm not 100% sure that the differential does actually fit in the 5 speed bellhousing.

[MetroMPG]

Welcome to the forum, Toby.

The numbers don't lie: if highway driving is your thing, aero modding is your friend.

Looking forward to your projects.

Darin

[SentraSE-R]

I apologize for the misstatements in my previous post. I engaged my typing fingers before turning on my brain.

[MetroMPG]

No biggie: it's a common misconception that aero doesn't matter except at high speeds. If fuel economy has the equivalent of urban myths, that would be one of them.