Better fuel efficiency through vapor carburators?

[hitssquad]

Cylinder deactivation in the LS2, or a lack thereof

I understand that GM wanted to incorporate DOD into the LS2 but found that it decreased the maximum RPM and so left it out (something about the added moving parts interfering with the free running of the engine at high RPMs; I do not recall where I read that). Apparently, GM http://www.roadandtrack.com/article.asp?section_id=7&article_id=1556&page_number=4&preview= where the DOD mechanicals would attach if they were installed:

• The LS2's cylinder block is an entirely new casting with LS6-inspired openings in its main-bearing bulkheads for chamber-to-chamber airflow. There are also DOD (displacement-on-demand) bosses in its valley that did not have to be used.

Popular Hotrodding reports GM attained 35 MPG in testing of an experimental C6 equipped with DOD:

• ...an early prototype C6 Corvette with an LS2 running DOD provided equal power and acceleration to an LS2 without DOD, but produced 35 mpg instead of 30 mpg. When applied over a large volume of vehicles, GM could have the choice to pocket the improvement in economy and reduce the need to import small outside-sourced cars, or it could build a larger V-8 with more power (say a 6.5L V-8 with 430hp) and keep the same 30 mpg.

 

[racprops]

Truck vers Car motors, I have found that the truck motor came with flat lifters not the roller lifter/cams that the cars got, and normally have taller gears, like 307s and 343s where cars like my 79 Caddy has 243 gears, so that would account for a lot of it.

I am building a car motor with the roller cam and lifter system, and do not plan on ever hauling a full ¾ ton load.

Darn they are doing the DOD correctly now.
Too bad refitting one will be so hard.

I take it as good news that I am on something of the right track.

Rich

 

[racprops]

Darn has this thread run out of gas...?? Pun intended.

I hope more will jump in and fill-in the missing information.

I am really building this setup, I have the motor to build, all work done but final assembly, preoiler and filter on hand, modified 3 speed on hand, and I am building the coupling and adaptor to join the two transmissions.

I have the TPI injector system with wiring and computer.

I also now have two Propane bottles and will be ordering the propane injection kit.

I am building a custom dash with a ton of SW gages to monitor everything. And I have the 87 Chevy LWB Van.

I have the Cold Vapor injection unit and will try it as well.

And I have a old (their last version) Edlebrock water injector and may see if that adds anything to the mix...

I will have the rear end gearing changed if needed to match the power and gas mileage findings.

The tech questions have not been completely answered, what happens to gas vapor in the combustion chamber? What does water ad to combustion? Will the two transmissions work?

And what air control will help the boxy Van get though the air the best?

I am hoping to get more information on these questions, my building and running all of the above will only answer some, but if I can be convinced that any line of work is running up a blind alley, it will save me time and money.

And as I lack a wind tunnel I cannot test the Van.

So if you can help, please jump in.

Once done, I hope to share all these findings with everyone. After all not everyone can afford nor wants a very costly new SUV.

Rich

 

[Cliff_J]

what happens to gas vapor in the combustion chamber?

Any matter will be a solid, liquid, or gas at certain temperature AND pressure. Given that the fuel should be atomized by the injector and that its 7% of the mixture by weight there is a slight possibility that it could start to condense but (guessing) since the temperature quickly rises hundreds of degrees during compression its very unlikely.

What does water ad to combustion?

It will help absorb some of the heat of compression which should lower the chance of detonation. Most applications for water injection seem to be for boost applications. The additional heat from the boost process raises the starting temperature and the additional charge means the compression process makes more heat - both mean detonation is that much more likely to occur. Like having aluminum heads that can remove heat faster (and actually hurt efficiency a little because of it) the extra heat control to prevent detonation is better in the overall scheme of things.

Will the two transmissions work?

It will get the van down the road if you implement it properly. Whether or not you can use it to get better mileage remains to be tested I guess. In the end a 3.07:1 gear or 3.23:1 is probably going to work the best by guessing but there are plenty of factors like the loading (weight and drag) and so on.

And what air control will help the boxy Van get though the air the best?

A big cow-catcher (like old locomotives) mounted to the front would help a lot and is like an upside-down boat hull if you think about it. Seriously though, the boat example is useful since we're talking about traveling through a fluid - the front is where the most rewards are to be found, the rest is mere icing on the proverbial cake.

Just the testing equipment alone to measure the effects of aero aids would be too expensive to justify unless gas prices multiply a few times. Maybe a local college would have some students who could use some of the schools equipment to find out. The tailgate example above shows how common sense is contrary to empirical data.

Lets say the ground effects cost $500 and you drove 15,000 miles a year and gas is $2 a gallon. If it increased your mileage from 10 to 12 then it would pay for itself in a year, not bad ROI. It if increased your mileage from 10 to only 10.2 it'd take over 16 years to pay for itself since it'd save less than $30 a year - what's that, one fillup?

There's a couple other gearheads who have posted in the past but I haven't seen them here lately, must be busy with school or work. Oh well, hope at least I answered part of your questions...

Cliff

 

[Cliff_J]

Oh, and if you really wanted efficiency and if propane is available easily enough, a diesel would be a strong canidate. The old 5.7L has a bad reputation but that was mostly because of the timing problems caused by poor fuel filter care. One of those or a 6.2L would be cheap and should have little problem with the loads. Trick would be finding a good mechanic that could get it all setup for you with a propane retrofit kit and diesel ability as well.

Cliff

 

[hitssquad]

Ideas for aero testing sans wind tunnel

And as I lack a wind tunnel I cannot test the Van.

My understanding is that most companies that do wind testing of their products similarly lack wind tunnels. You don't need one in order to test your vehicle and come up with valid results. In fact, the artificial nature of the breeze produced in wind tunnels can give numbers that don't mean much in the real world.

I have read that most companies simply test their aero engineering ideas out on an open road on a calm day. Unpowered rolling tests on the flat are supposed to be popular, but I think for an automobile that rolling it unpowered down a downgrade starting at a freeway speed would provide results that are more distinct.

For your van, I would pick a favorite downgrade stretch of a nearby freeway. After selecting a starting speed that can easily be remembered (say, 60 MPH; a higher starting speed should be better in regards to the distinctiveness of the results since air resistance rises logarithmically but I wouldn't want to get pulled over, of course) so it can be used by me in future testing at that spot, I would also select begin-test and end-test points on that stretch that are next to easily recognizable and easily remembered landmarks. Then, on a calm day or night with preferably little or no traffic, I would drive the van down the highway toward the testing stretch and bring the van up to my preselected start-test speed. At the moment I was passing the begin-test landmark, I would dump the transmission into neutral. Then I would keep one eye one the speedometer and one eye on the next landmark. As soon as I passed the next landmark I would memorize the speedometer reading at that moment as that particular run's result.

I would think that if your vehicle is typical, your speed should drop significantly from 60 MPH, even if you pick a nice, steep (and the steeper the better, in my opinion) freeway downgrade.

One caviat here is that air density will affect your numbers and air density changes with air temperature. Part of your testing data should include air temperature. Wind speed and direction, I think, would also be potentially critical data to have recorded, though of course you would optimally be testing only on the calmest days/times possible.

 

[racprops]

Thanks for all info.

Gas condensing back into liquid, very unlikely, thanks I will work on the gas vapor injection system as it may work.

Water sounds like poor idea but for the hot dry air here in AZ, other wise turn it off.

Two Trannies, your gearing sound like my idea as well, thanks.

Streamline the front end first…

Well I needed more room in front of the motor anyway so that is a possibility.

I passed on diesel as being too costly to buy, too costly to run and way too costly to repair.

I CAN and am building my own gas engine. And there is so many more ways to fuel it.

Rich

 

[racprops]

Wow this has been such a trip though the rabbit hole.

Claims and counterclaims:

That you can get up to 200MPG.

That you CANNOT get any more than what the stock fuel injection gives you…!

That you can run your car on water...

One page said that the total possible power out of gas would produce is 100 MPG IF there were no friction losses, not in the engine, drive line or tires, MAX Possible.
And only IF you burned every atom of gas AND uses ever erg of power, and lost none of it to heat.

All write great pages, all seem to have science to back their claims, most seem reasonable and real.

I am hoping like a lot of things, the truth falls somewhere in-between, SO:

OK Here is what I hope and expect to get. 20 to 30 MPG, In a long wheel base 87 Chevy van, and be able to go up mountains faster than the Trucks. (More will be gladly used)

I think it is a reasonable hope and goal.

I know that there are new trucks getting this mileage, but I would then have to spend $30,000+ and that is the sale price before insurance and payments, these will add costs of thousands more…

I hope to get this out of a $1000,00 Van (bought for) with a $1500.00 motor (Rebuilt for) and about $1000.00 more in fixups (Hoses, belts, the TPI ect.) and at worst $1000.00 in extras like the propane system.

I all ready have the Vapor injector and the water injector and the modified three speed with over drive, so I guess those would add in for an extra $1000.00 all ready spent.

So for a about $4500.00 to $5500.00 I will have a custom Chevy Van that get great power and great mileage and does all the other things I need a van for, like camp outs and going on cross country road trips.

And almost all the parts are easy and cheap to get in nearly any wrecking yard any where, should I suffer a breakdown, AND I personally can make these repairs.

And last IF I want to change something, the ride, (Shocks and springs) the rear end, the transmission, the tires the wheels, I can.

I like it.

On the wind testing on the road: good idea, but I can just drive and see what happens to the mileage as well, problem is I will have to spend a few hundreds of dollars adding the ground effects sides and the rear wing air deflector and NOT know until after I road test if any thing worked, I was hoping to find out before all the money goes out…

Rich

 

[Cliff_J]

Rich - thought of one more thing you might want to try. The lockup for the torque converter is easy to control externally, all it needs is electricity supplied to a solenoid inside the tranny. You can access the wire right at the diagnostic port (GM service manuals tell which pin) and if you used a couple diodes to keep the computer output separate from your switch you could prematurely lock up the converter.

Depending on how efficient your converter is (most factory ones are like 80%, bad afermarket ones are like 60% and some good ones are 90%) and how good your lockup clutch is, this might mean significant gains in MPG for around town driving. The converter will not lock in 1st but will in every gear after that. One of my old cars with wiring problems would not lock the converter anymore automatically so I wired up a switch to lock it up manually. Pretty nice going up hills and just letting the motor work instead of slipping the converter like mad...but it was a 3200lb f-body so one can cheat a little more there too.

Just a thought.
Cliff

 

[racprops]

I am very much aware of the Lock up torque converter and I also know I will need a heavy-duty version for my Van.

That can work both ways, unlocked and the engine can rev up into the power curve and you get the toque converter’s multiplier.

Locked and you have less power loses and a cooler running transmission.


Your preaching to the choir.

I have already installed 200r4 in my older van and in a 79 Camaro that got 19-highway mileage with a Quad….

My 87 Van came with a computer controlled truck 700r4.

And I just switched out the old TH400 for a 200r4 in my 79 Seville and as it is a CA version FI that will run in closed loop, I expect even better mileage.

Once the repairs and a setoff full gauges are installed, I will drive it stock and get the base lines of its performance and then see if I can improve on it.

Any thing that works will then be put on the Van.

Rich