if you could build the perfect mpg festy.......

[loknlode]

what would you put together drive train wise? from which year car or/engine/trans? carbey with a later model 5 speed, FI with a 4 or 5 speed? I would think if you were a mostly urban driver and 4 speed would do a better job than the 5 IF you rarely got to use 5th. what say the gear nerds?

[Grey Vw]

Mk3 Jetta tdi engine.

[KingFish]

Five speed MTX has same gearing as Four. Just added another OD gear.

[Movin]

Gasoline and diesel are crazy expensive. I would build LPG or CNG and build the
engine to take advantage of the 114 plus octane. A diesel/CNG hybrid is a great
way to do this. Car would be stripped of anything it didn't need for light weight.
I would really consider 16" high pressure scooter tires, and maybe narrow the rim
even more than stock festy. Oils and lubes, greases would all go to the lightest weight
possible and be synthetic to protect the parts even though every thing is too thin.
Car would be lowered. Early festy 5 speed would be used, or better, any of the 5 speeds
used with gearing designed to keep engine speed between 1500 and 1800 rpm as much
as possible.
Every effort would be made to speed up the atoms and expand the molecules of the
CNG or LPG immediately prior to entering the cylinder. Conversely every effort to slow
the atoms and condense the molecules of the air charge would also be made both for
throttle limited situations and full throttle situations.

Aerodynamics and modern cars are far from being in the same school of thought,
the festy is very poor for speeds above forty mph. A tremendous improvement
could be made here but it would not look like a festy, it would like a missile.

[zoom zoom]

What IS the gear ratio of a Festiva 5 speed and an aspire 5 speed? Everyone says an aspire is geared higher but who has taken one apart and counted the teeth?

Honestly, I think Karl, saftey guy, has the right of it. He's building an mpg Festiva.

Id make it a gasket matched polished (not ported) intake/exhaust straight na motor, maybe ITB's for a little more power, with the lowest geared transmission I could find. Maybe even shave the head .03 and get a PnP ms to fine tune it as good as it gets(even turns off the egr system). Maybe even use a g series xr2 tranny(3.85:1) with the 626 5th gear swap? Straight pipe with a resonator to the muffler? Maybe some better injectors than stock (not bigger, better)

Head work= power= efficiency.

Of course, after all that work and $ you'll probably be driving the car for 5 years before it pays for itself, and by then parts are probably worn in enough to make the milage difference negligible vs driving a stock car, but it would be pretty sweet to hit and average 60 mpg..if that's possible.

[loknlode]

maybe I should have been a little clearer. how about if you could take stock parts from ANY year festy/aspire and mate them up for mpg. lets say you have 20 parts cars ( 1 -3 from every year) in the well and you can put together ANY combo you would want.

stay with the drive train - not this mirror/? from this year and this trim from this year, etc., just the drive train.

[FestYboy]

here's the issue with alternate fuels: they don't have the BTU count that gasolene or diesel has and an IC engine is a HEAT and air pump.... need to have high BTUs to make power and MPG.

[htchbck]

Aspire motor (or at least head). Festiva 5 speed. Tall skinny tires if we're looking for highway MPGs, not so much so for the city though. But def Aspire head and a festiva 5 speed. Other than that, not much really available to change if we're sticking with only stock parts.

[Movin]

Aspire motor (or at least head). Festiva 5 speed. Tall skinny tires if we're looking for highway MPGs, not so much so for the city though. But def Aspire head and a festiva 5 speed. Other than that, not much really available to change if we're sticking with only stock parts.

Yes that is a game changer! I would still go with the lightest synthetics
I could get away with. I would still use CNG at .83 per 40 something miles
unless this is a numbers race, then I would use the most expensive no
alcohol gasoline, Or would be forced to use it as CNG or LPG were not stock
options.

[blkfordsedan]

I would start with an EFI and a Festy 5-speed. Use the Aspire cam and roller follower, clean up the casting mis-match in the intake and exhaust ports and polish the combustion chambers...but not grind any material out. Then, mill the head .020" and install a MLS head gasket. This should get the compression up to around 10:1. The polished chambers will help alleviate spark knock issues. Then, advance the cam about 4* to raise dynamic compression and enhance the lower RPM. Install a stock Festy exhaust manifold and stock Festy exhaust with modern hi-flo cat. Advance the timing as close to the knock limit as you can and install a multi-spark ignition. Install the lightest 13" wheels I could find with 155/80R-13 tires. If I could, I would rebuild the short block for the tight side of the factory tolerances and run 5W-20 Synthetic oil as well.


EDIT- I guess I would do the compression math first. It may be best to just run a MLS gasket and not mill the head. Sometimes reducing chamber volume can have an adverse effect on mixture motion. If you could get to around 9.7:1 or 9.8:1 then I think it would be a good compromise.

[zoom zoom]

I really wish I could get the hang of polishing :/ I might be going at it all wrong tho, I don't know..

[blkfordsedan]

Oh yeah...forgot the most important part

Install one of those miraculous fuel line magnets from Harbor Freight!

It may also be interesting to go aftermarket fuel management so you could fine tune the A/F ratio at cruise for near stoich. I've also wondered if adding a heater plate that circulates antifreeze between the throttle body and intake plenum would improve MPG as well. It may make for quicker warm-ups and help atomize the fuel as well.

[zoom zoom]

^ I was looking at those awhile back, I thought..man that inventor is genius, if only it actually worked!

My guess is its about like wearing a magnetic bracket. Doesn't matter how much you think it helps, and it doesn't matter if you think its cool, at the end of the day there's only one type of guy that wears a bracelet... :p

Disclaimer:
I'm just kidding about the bracelet, I don't need another group of man-bracelet wearing festivers mad at me, the old guys already hatin'

[fujioko]

I worked at an independent automotive emissions laboratory many years ago.

We tested the fuel magnet and no benefits could be found.

Buyer beware on some gimmicks.

[Advancedynamix]

I've often thought about building a b3 turbo diesel. I know the block and head are strong enough, pretty sure the crank would hold up and rods are cheap. Custom
pistons and some combustion chamber work would be needed, but it's not that far fetched. I'm pretty sure Mazda had a diesel version of the b6. With the right management you could get upwards of 70 mpg, especially with water methanol injection.