Project 100mpg - Page 5 - Fuel Economy, Hypermiling, EcoModding News and Forum

Christ · 10-03-2009, 11:35 PM

Quote:

Originally Posted by TOOSTUBBORN2FAIL

Well, the car started, im going to replace the rest of the timing components, then test the compression, if its good were back on.

good thing too, as i have 1200 miles of driving on my vacation.

Unfortunately, that means my next tank will have a huge jump in mpg, and i wont be able to pinpoint which items helped the most. Oh well, im at 43mpg now, we'll see what 44psi vs 32 in the tires, a little more grillblock, drivers mirror delete, cleaning up the half blocked egr, and the 25% reduction in cruising rpms and 6.25 pound lighter clutch/flywheel do for it

47 highway. (Tank average for your whole vacation trip.)

fusion210 · 10-04-2009, 12:37 AM

Good luck with the compression check!

TOOSTUBBORN2FAIL · 10-23-2009, 09:32 PM

44.5 mpg, average, without changing the transmission, grillblock, or doing anything else really. Was able to coast a lot with 4 people at luggage in the car, and never really got less then 18 mpg uphill.

Car is losing oil (burning it after the timing belt issues), doing a compression check tonight, and we'll go from there.

Christ · 10-23-2009, 10:45 PM

If you're burning more oil after the change than you were before the timing belt failed, it's one of two things:

The timing belt isn't installed correctly, in which case you'd be running poorly -
Or
Damage was done when the belt gave out.

If you need a new head, you can swap on a 2.0SOHC without changing anything else.

fusion210 · 10-23-2009, 11:40 PM

It definitely takes a lot more to swap on a sohc head. Head bolts, head gasket, intake manifold, exhaust manifold, coolant temp pigtail, egr tube, throttle position sensor, timing belt/covers, passenger side engine bracket and filing down the edges of the piston domes? A whole list of stuff, unless you were just thinking that would be obvious, or maybe you were just kidding.
I'm not even sure that's CA legal.

I looked into why the sohc just feels to have more low low end torque under 1500rpm, especially in my sohc/3.55 final drive trans vs my dohc/3.94 final drive trans (apart from the intake manifold). Maybe it's partially due to the sohc having 9.8:1 compression instead of the dohc's 9.6:1. Otherwise the older dohc head also has larger valves. The new style dohc head has sohc sized valves. More low end? Maybe. They did use the new style dohc head for boats like the pt cruiser and minivan after all.

My scangaugeII says my sohc neon uses .27-.31 gallons per hour at idle (calibrated) vs .35-.4 gallons per hour from my dohc (loosely calibrated). Really cuts into my ICE on pulse and glide.

Christ · 10-23-2009, 11:48 PM

Most of it is obvious. Also, some don't have EGR, manifolds will swap between heads, the bolts and gasket would have to replaced anyway, TPS is part of the OEM TB, so it's a moot point, timing belt and covers are obvious, since they're the whole point of the head swap anyway, passenger side engine bracket, I didn't know made a difference, and I've never heard of anyone modifying their pistons to swap heads.

Do you frequent Neons.org?

Oh - the fact that the SOHC has smaller valves is the reason it has better low-end torque. Higher intake/exhaust velocity. The .2 compression difference does something, but it wouldn't be anything you could feel.

The Minivan w/ the 2.4 is DOHC, but I'm not sure what size the valves are. I know it sucks for torque, though. It doesn't pick up until somewhere just south of redline, butt-dyno. Then again, the van weighs like 3500#, too. I'm sure it would feel better w/ a 5 speed in a Neon.

TOOSTUBBORN2FAIL · 10-24-2009, 02:35 AM

I have lots of dohc parts, and a cleaned up dohc mani, so ill probably stick with it for now. Fusions a long time and very well versed neons.org member, including a huge list of the weights over over 100 parts on neons.

Some people get away without filing the pistons, some dont. The throttle position sensor is also different between dohc and sohc, and the manifold wont interchange without some heavy modification.

did a compression check, nothing weird, 185 to 190 on all cylinders. Also noticed that from fresno to disneyland and back, about 450 miles a driving, i lost about half a quart. From fresno to vegas, i lost about 2/3 a quart, again about 450 miles. From vegas to fresno, i lost less then half a quart. At no time have i lost any on the ground, and the exhaust smells horrible. As far as timing, its dead on now, or at least its timed to stock settings.

Not sure whats going on with the oil, but for now ill be watching and checking out the exhaust.