engine and drivetrain Fuel Economy

[Slavs]

The 02 is a versatile car, and there are many different ways to build one.

The mpg factor, therefore greately varies.

But, I'm one of those who hates bad mileage unless the car is a purposs built race car or weekend road racer.

That being said, I have several cars:

1. An engine stock 69 1600 (Granada) and the other

2. A 1967 1600 with stock 2002,Weber 32/36 and 5 speed OD

3. A 75 02 with Top End engine including 32/36 Weber, 284-292 duration cam, 9.8 JE pistons, header, Volvo breaks, 4 speed Metric Mechanic gearbiox, strut braces etc.

4. A 70 2002 stock with Weber 32/36.

I don't consider the 75 as an extremely built motor, but it is a fuel guzzler at 15mpg average city/highway. MY stock motored 02s with the 32/36 gets 18mpg city/highway. It got 21-22 mpg city/highway with the single barrel Solex. The 1600 with the stock single barrel gets a consistent 22-24mpgcity/highway. I can't get it under 22mpg even if I try driving it like a maniac.

The Top-End motored 02 has a longer power band, but is less streetable with the header and free-flow exhaust. The 67 1600 with the 2 liter motor is most fun to drive. It has the 4.10 gears and OD 5 speed. Even though the motor is stock, it has the most torque with those gears, and it is quiet.

And, it gets better mpg, especially with the stock carb.

I'm really not a fan of modifying these motors too much. THE TRADE-OFF IS JUST NOT WORTH IT.

I do reccomend stiffening the chassis and suspensions though. This really transforms even your stock car into a real road warrior.

If you are building a race car, go for all the engine modifications, but otherwise I would stay away. Longer Duration Cams seem to really kill your mileage. Forged pistons add to this along with increased oil consuption. Add a header and free flow, and you burn another 1-2 mpg.

The 5 speed overdrive is nice in 5th, but they don't seem to shift as nice.

In addition, I have a size 14 shoe, and the loss of space at the accelerator pedal ,caused by banging out the transmission tunnel to accomodate the 5 speed, is really annoying. I have to operate the accelerator pedal with my toes or the side of my foot. A lot of propaganda has been published about the advantages of the OD and especially the modified engine components. I'm not impressed. You have to be crazy to trade in your well shifting 4 speed (especially if it is the early 02 Porsche-synchroed 4 speed in good condition for a 5 speed OD.

I had to reset the alignment of the driveshaft on the 5-speed OD to smooth out the driveshaft vibration caused by misalignment.

Mahle pistons RULE. There is a good reason why the factory used them. I have gotten in excess of 140,000 miles on a rebuilt before the rings on my Mahles started to deteriorate, and I got any significant smoking. Try that with forged pistons. The JE's are already staritng to smoke on the motor with less than 20,000 miles.

I've been driving 02s as daily drivers since I got my license in 1982.

Another one of my 02 cents-worth,

Slavs

[Pinepig]

Magasquirt those bad boys and you could probably get your millage to double.

My stock 71 motor ( in my 75 ) with 24# injectors gets about 24 in town. I've never run it on a long trip so I have no idea what it would get on the freeway. BTW 3.64s with 4 speed.

[dubois]

when I had to rebuild the engine on my 02, we purposely chose Mahle piston 9.5 CR, we basically could have gone higher and build a race engine. I decided I wanted a driver, that would be extremely balanced and smooth, instead of a monster with an on/off button.

I agree with much of what you mention, there are some many intangibles that can make your car enjoyable or a total misery. It is not all in the numbers, there are a multitude of factors that are also so important.

I my journey for "more horsepower" I have found out that I personally would give up 30 hp for smoothness, quietness, finesse, precision, feel, lightness, comfort, progressive acceleration, efficiency etc.

It is funny you mention this, because I have too became fixated on making my cars more efficient and enjoyable.

[jgerry2002]

Your mileage is interesting. I have a Metric mechanic motors in both my cars. They are both the 2200 hiflo sport (10:0:1 compression, mild cam, 2.2L displacement, custom pistons....somewhere around 155hp mark).

My '76 with a 40/40 downdraft can get 27/28 on the highway at a steady 70mph/4100 rpm under the right conditions (little wind, around 75F, low humidity) with the 3.90 and a 4-speed. Usually no worse than 24mpg if there is a strong headwind. Around town I think I am somewhere around 20mpg, not a 100% sure because I have not really checked it lately.

Check your jetting on the motors you are only in the mid teens with. It seems very high to me. CDiesel definitely has the best ideas about tuning the 32/36 (but the ideas can be applied to 38/38 and 40/40).

The only experience I had with my tii (another metric hiflo motor) is ~24mpg on the way back in the middle of snow storm last year. This is prior to the whole car getting rebuilt, and the injection getting some badly needed linkage parts, hoses, and tuning. I've also added a 5-speed, which combined with the 3.64 should give me very good (hoping for 28mpg-30mpg) at a steady 70mph.

[jerry]

slavs, i appreciate your discussion on this topic. there are a lot of threads on how to make a snorting, monster engine but it's nice to hear the perspective on how these cars can behave in stock configuration.

because of threads such as this i am looking forward to trying out the single barrel solex carb that the PO fortunately saved when he converted to weber after the engine rebuild. i resisted 'upgrading' to bilstien struts and installed the new Boge struts that were in the trunk when i bought this car.

the only upgrades i plan are Crane ignition, 5spd and battery relocation.

i don't recall any shifting differnce between the 5spd and 4spd, btw but i will try to compare when i get the opportunity.

my one concern is that the PO mentioned he installed a mildly upgraded cam during the rebuild (i'm guessing 284, perhaps). will the single-barrel solex be able to keep up with that?

[winstontj]

i don't recall any shifting differnce between the 5spd and 4spd, btw but i will try to compare when i get the opportunity.

my one concern is that the PO mentioned he installed a mildly upgraded cam during the rebuild (i'm guessing 284, perhaps). will the single-barrel solex be able to keep up with that?

IMO the only gearboxes that shift poorly are old tired ones and ones that were put in poorly. I spent an extra day during my 5-spd install making sure the driveshaft was perfect and that everything was lined up properly. People often overlook the details of balance and tolerances.

As for the foot thing.... I'm not as well endowed as you (9) but I too find myself stepping on it with the outside of my foot. With that said, the 5-spd was one of the best things I have done to the car. The only thing that will rival it will probably be MegaSquirt.

I was fortunate enough to buy a car with a 3.45 gearset. I get ~25+ while Megan consistantly gets over 30mpg (driving styles if you didn't guess). I have a tuned stock motor with 32/36 - tuned means I keep it in tune. It's old and tired but still runs like a top.

I hope that the addition of MegaSquirt will improve mpg by two to five mpg (with an engine build too)

The 3.45 gearset is a wonderful thing.

As for the solex single - its an amazing carb and highly underrated. it would probably keep up with a 292 depending on other factors (CR).

[Chris_B]

I have single 45 DCOE on a motor with 9.5:1 pistons, Motorsport 300 cam and tii manifold with a custom 2" exhaust system. This motor makes power all over the place (right, Dubois?) and pulls strongly past 7K RPM. I have a 4 speed on a 3.64 diff.

While tuning this carb (repeated WOT runs), I never got worse than about 15MPG. In normal driving (mixed freeway and city) I had been averaging about 19MPG. Recently, I got an AFM with a wide band sensor, and found I was running way rich at part throttle. I have tuned some of this out and am now getting 20+ MPG on average. However, I have a ways to go before I am at optimal part-throttle mixture, so I anticipate getting my mileage up to the low 20s.

My point is that it is possible to make a streetable motor with ample power that has relatively good mileage with a carb (or two...). Weber carbs can be quite efficient in light throttle driving, if jetted properly.