Hemispherical cut heads

[tundrawolf]

What are the specs of your 2276 motor?

FK89 cam, Scat 1.5:1 rockers, 48x38 Comp Eliminator heads, 12.5:1 CR, 1 7/8" merged header with 3" muffler, custom home-built intake system. Wasn't built with economy in mind at all, but the MS3 v3.0 crank fire with coil on plug ignition controling fuel and igntion i'm able to tune it for it. 91 octane from the pump too.

What Jon did back in the 80's was pretty incredible, I don't want to take that away from him. But thirty years later we have people getting huge praise for hitting mid 30 mpg figures and I don't get it. It's not 'that' great, we're capable of so much more. Wonder if I need to develop a 1600 solely for mileage, and sell it as a turnkey complete engine. Maybe that's where my focus should be instead of getting my car ready for the track next season......

Are you monitoring your CHTs? Do you think people with similar specs to your motor are getting 70 MPG for 50MPH? Out of a motor twice the size of Karceys, that is difficult for me to wrap my mind around. So if you drove at 50MPH with a full tank, you could go 700 miles in your VW?

Marc, sorry, I sometimes miss the obvious.

Very interesting about squish, I never thought about that small volume rushing into that smallish portion of the head, I thought it was kinda pushed in, not rushed in. I talked with my machinist today and he agrees, we won't hemi cut the heads (Thank God he didn't already, I guess).

I will try and have it set up for a .45 deck height, if possible. He already cut the case to even out the cylinders because there was some sort of metal warpage occurring. I have a set of rebuilt German 1300 SP heads I will be using.

I am going to run hydraulic lifters, along with the 91 grind (Which is a hydraulic grind). I am debating a multispark ignition, but the cost is prohibitive.

[Marc]

1300SP heads have somewhat smaller chambers than 15/1600 (~3½cc less IIRC) so they won't need as much flycutting for a given static C.R.
Glad to hear you have some, their smaller valves and inlet tract will help your mileage. Years ago (when 1300 heads weren't so hard to come by) we built quite a few 1585 and 1641cc engines at my shop, all very near stock except for those heads. Even with a single carb they got significantly better mileage than any "normal" 1600. Pleasantly torquey/responsive in the midrange, but not much reason to go past the red lines on the speedo when shifting (15/30/45MPH in 1st/2nd/3rd). My dad ran one for years; he was obsessive about logging his fuel mileage and usually got close to 40MPG (87 octane, 7.75:1 with "too much" piston deck, ~.072") in his `69 Bug - and that was with an 009 distributor, too.
You'll want to CC the chambers to see what you're starting with. A "rule of thumb" for stock chambers is that they'll be reduced by approximately 1cc for every .010" flycut. You can also level the head and put the desired volume of surface-tension-free liquid (solvent, light oil, water+detergent) in the chamber and then measure down to it; subtract the measurement to the existing flat surface to estimate how much to flycut.

[Eaallred]

Are you monitoring your CHTs? Do you think people with similar specs to your motor are getting 70 MPG for 50MPH? Out of a motor twice the size of Karceys, that is difficult for me to wrap my mind around. So if you drove at 50MPH with a full tank, you could go 700 miles in your VW?

There's no way a carbureted engine will do what mine is doing. 32x16 fuel and ignition maps have allowed me to fully control every aspect of this engine running in all loads and conditions. It took me a while to get the tune dialed in and I won't lie, it is running on the edge of saftey.

Head temps while doing 70mph were 350-375.

Theoretically, it could go 700 miles on a tank of gas. But the reality is the harsh valvetrain wouldn't survive that long i'm sure, and there's no way I could drive this thing 700 miles at 50mph. I could barely stand the 60 miles non-stop that I did do. Half the intake system is inside the car with me, it's very loud, and the ride is horrible (6" narrowed beam up front, 30mm torsion bars out back). But hey, it's built to be a drag car. The mileage thing was just to see what I could do for fun.

[supaninja]

what are your AFR's at cruise? That's friggin awesome, programable FI/ign is where it's at, especially for fuel mileage.

[Ol'fogasaurus]

A couple of years ago I was filling my car up with gas and there was this girl bragging that she was getting over 75 mpg in her Honda (or Toyota). After listening to her talk for a few minutes I figured out that she was turning the engine off at stop lights, turning it off when going down hills (very illegal and very dangerous to her and others), rock hard tire pressure, narrow tires, backed off her rear brakes, drafting cars and trucks (sometimes the trucks with the engine off) and so on. Her boyfriend and the group of guys he ran with were doing it and he had told her how to do it. It was all stuff they used to do in closed course, extreme fuel mileage tests paralleling the old Mobil Economy Runs (http://en.wikipedia.org/wiki/Mobil_Economy_Run) held during the mid 30’s through ’68 (excluding the war years).
Extreme fuel mileage gurus (some kind of auto performance sub culture) have taken the fuel mileage to extreme measures and not much (if any) of this stuff is street legal stuff either http://www.fueleconomy.gov/feg/extremeMPG.jsp Running on hydrogen, the PAC-Car II achieved the equivalent of 5,385 km per liter of gasoline [12,665 MPG!.
When I was interested in reading about it they were using Opal chassis and (among other changes) I seem to remember a ’25 Chev engine with an Olds head: they took the accelerator pump out of the modified carb, a heavy flywheel, rock hard tires, backed off or no brakes and rolled on a Plywood surface (but this could be two different cars too but I do remember one being a modified Opal and I remember the Chev 4 banger also). They would slowly accelerate to a set speed then turn the engine off and coast until they got to a minimum speed then repeated it until they had run the gallon of fuel out). By-the-way, the prewar (WWII) fuel record was around 50 mpg http://automobileandamericanlife.blogsp ... art-i.html.
As I said before, I am not easily convinced when I hear of a lot of high mileage claims as there is often a lot of information left off or not completely true. In some of the high mileage claims, the person making the claim was unwilling to substantiate their claims in a controlled test but the word had gotten out and was taken as the truth (like the big three and the oil companies buying and quashing the 100 mpg carburetor).

There are certain things like parasitic drag of components, weight, tire drag and the effect of air on the car when moving that limit a car’s fuel mileage and although there have been a lot of movement in fuel mileage, using older inefficient cars w/o upgrading to the newer components kind of unnerves me..

Lee

[tundrawolf]

There's another dynamic to all of this old fashioned points and condenser, carbureted stuff, and that is that hard times may be coming. What are you going to do when your hall effect sensors windings burn up during an electrical surge and you're stranded? You can't repair potted human hair sized wiring on the side of a road. I guess it's the zombie apocalypse side of me that wants something that can be fixed. The vehicle itself is being completely rebuilt suspension wise.

Dual rear spring plates, reindexed rear, lifted front suspension, forged reinforced link pin spindles, and a cutting brake are some of the things I am doing. So this vehicle should survive offroad use, and if it can do it getting 40+ MPG I will be very happy.

[supaninja]

I like your thinking

I have been carrying an extra COP with me. My VR sensor is mounted somewhere safe from the fan belt, but I have to pull the shroud to get to it. The fuel pump is just a regular walbro with 3/8" fittings, fairly standard. I carry an extra 40a relay. My electronics are all mounted high (incase I take on water) and on rubber vibration mounts.

I should put together a anti-zombie kit: spare plugs, butane soldering iron, spare VR, spare TPS, spare CHT, spare IAT, spare fuel pump, spare fuses, relay, COP, misc wire, shrink tubing, JB weld, duct tape, and various sizes of zip ties... That's not a bad idea.

[Eaallred]

All my parts are readily avaliable at any local auto parts store. Not always true with stock VW ignition stuff. There's plenty of stock stuff that can't be fixed on the side of the road as well.

[tundrawolf]

Yes that's true. When I look out of my window I see this:



Having something break on me when I am "out there" in the Mojave could cost me my life.

I like your ride, supaninja. That "patina" is just about the coolest you can get. What made you go with the gixxer intake?

[supaninja]

I used to live out in the mojave, summers there were hotter then the summer I spent in Iraq. Thanks dude, I got that throttle body off ebay for $30. That sealed the deal, I'm about to make a new manifold for it.

[tundrawolf]

I used to live out in the mojave, summers there were hotter then the summer I spent in Iraq. Thanks dude, I got that throttle body off ebay for $30. That sealed the deal, I'm about to make a new manifold for it.

Thank you for your service to my country. I appreciate it.

One or two years when I was babysitting 600 acres for some friends, I had no electricity and no drinkable water, no a/c and no swamp cooler. But I survived

[KillerGreenBug]

How are you guys passing emissions if you are all doing this on California roads?

Oh..You don't live in California!

Or ....As soon after you passed emissions, you swapped the hot motor back in for another 364 days of that year?