Cam for fuel economy

[scrounger]

thanks Bob
I found it, Old guy Old Rabbit---both Happy. 170 pages long.

[theman53]

I still think you build a diesel to run as efficient as possible and then don't use it if you want mileage.

You were only asking about a cam, but if the over picture is looked at then I would use all synthetic grease and lube oils. Engine and trans. If you are getting 55mpg then the brakes and other parasitic draws are probably ok. It is good that it will coast a mile in neutral, but if you are coasting leave it in gear. The IP will continually inject less fuel if you use the engine for braking while coasting. You said you have boost. The #1 thing I did in my car to get more mileage was add an intercooler. I went from 38-40 mpg to 44-47mpg and the only mod I did in that time was add my IC. <-I didn't change cam shafts, but this tells me that the more cooler air you  have in the cylinder the better it is. This was a 1.5 year deal and I had the car non IC and IC about equal time in all weather and driving conditions. It wasn't one tank is what I am saying.
The last thing I noticed is my car will gain a few MPG with BP diesel. I have ran marathon, speedway, Duke, and more that I cannot think of but I consistantly get 2-4mpg better mileage with the BP diesel than anything else. I dont' run it much at all but Cetane booster will help get you more bang out of your fuel. If you goal is to lessen fuel costs adding it maybe more than the gains.

I hope you do well with the cam. It may help. It may get the same ammount of air in, but just move the power band. If that power band matches your driving better then I think you could pick up a mpg or two. Please let us know.

[theman53]

thanks Bob
I found it, Old guy Old Rabbit---both Happy. 170 pages long.

Be prepared for some of the hardest to read english since CRSMP5 and a guys inability to read a Bentley Manual...Oh of course the never ending use of EH

[scrounger]

I read the first page and could barely read it. I thought perhaps that I did not have enough coffee.

I agree what I am after is the most efficiency at light loads. Having the rack open half way is not what I am doing. I assume that I will be over fueling the engine at high loads. Perhaps I can literally smoke anyone behind me

As far as fuel I am using my fuel from a commercial supplier delivered to my tank in bulk. The best part of it is that it is consistent for the entire bulk tank. Whether it is the best for mileage I don't know.

Impressive improving your mileage that much with an intercooler. I assume that you were able to turn around the intake elbow on top of the intake manifold. My car stills. has the original AC condenser installed. Probably a good place to mount the IC.

Fuel is the biggest expense any more of owning a car. Even with 40 mpg at $4 a gallon that is $.10 a mile or 1500 dollars a year for an average amount of driving. Purchasing fuel in bulk I feel the pain about once a year.

I'll keep rattling at you guys as long as there is some interest.

[theman53]

Yeah I just flipped the intake cast elbow. Had pics somewhere on here...found in the build thread page 23 or something.



This is what I said about it at the time.
"EGT is still an issue, but it was 110F the other day. I can take it up to around 1500-1600F and then it stops. It climbs much slower over 1300F than it does before that point. Now that I have been driving it for 2 months with intercooler on I have never dipped below 42mpg and have 3 tanks at 47mpg. I can only make 21psi boost now. Overall I like it now."

[scrounger]

PM sent

[R.O.R-2.0]

I wouldn't give much gravity to the feedback on aesthetics.

60mpg @ 55mph is probably achievable with the current aero mods and fine tuning of timing and break pressures.

65mpg will take a bit more effort (laws of diminishing returns, yadda...).

it takes aerodynamics to get awesome smileage..

look at the porsche 356 that was on our forum a couple years back, AND in diesel power magazine..

it got like 68mpg IIRC? but a porsche 356 is SUPER AERODYNAMIC!! and it had a custom geared transmission for the diesel.

i would lower my break pressures to 125 bar, i believe andrew or someone said worked the best, between good atomization, and low break pressures..

i think part of my consistent good smileage, is the fact that i run 135bar (N/A) injectors in my turbo engine..

if you change from TD injectors to NA injectors, you WILL notice a difference in power (artificial timing advance) and economy from the lower pumping losses..

BTW.., it only takes 10hp to turn a 14mm bosch VE pump.. our pumps are super efficient, as compared to other similar pumps of the day..

most normal VE pumps, you can get away with a 5hp test fixture..

[homerj1]

Yeah I just flipped the intake cast elbow. Had pics somewhere on here...found in the build thread page 23 or something.



This is what I said about it at the time.
"EGT is still an issue, but it was 110F the other day. I can take it up to around 1500-1600F and then it stops. It climbs much slower over 1300F than it does before that point. Now that I have been driving it for 2 months with intercooler on I have never dipped below 42mpg and have 3 tanks at 47mpg. I can only make 21psi boost now. Overall I like it now."

Sorry for the hijack, although I like your engine compartment.

I have the same fuel filter on my mk1. I was going to order some car stuff on line - but am not sure of the actual fuel filter type.

My choices are
http://www.autopartsway.ca/PartList.cfm?Volkswagen/1984/Jetta/Base/1.6L_L4/allB/Air_and_Fuel_Delivery/Filters/Fuel_Filter/pagenum1/tabS

the one with the nipple end or the one that looks like an oil filter with a h20 drain. I suspect it is the latter?


thanks

[Blownoiler]

Thanks for the insight blown oiler.
My tach isn't working so I can't say exactly what my shift points but I am shifting if the next gear will pull smoothly, Typically I am into 5th at 30-40mph. If someone wants to pass me then so be it. It will cruise at 60 at 2-3psi. The car will run 95 mph now. I would be happy with 70-75 max speed if the fuel economy is improved some. Like you said. it is reversible if I don't like it.  Maybe a few degrees of stock cam timing advance would be a good thing to try.

Except for you, no one has said anything about personal experience with this subject. My first test will be running stock industrial cam timing.When I read your two recent posts I got two messages. One was to improve efficiency by building a new intake. Your next note was more positive to try the industrial cam. Perhaps you gained insight as to what I was trying to do.

Yep you have it there with aerodynamics short timer. The easy stuff has been done. I drive like a turtle.  My tires are rock hard. The car will coast a mile in neutral I have changed the shape of the back end, had  grill covers. The car has been mired at 55 mpg for the last year using aero mods.  Am looking to put it past 60, 64 to be precise, that is 2oz/mile. I had a post a while ago about some changes that I have made to aerodynamics. It was not well received.

I made a few other changes looking for power and found that better economy was a side benefit, basically anything that improved VE improved mileage. One mod that worked well at part load was putting a divider into the log exhaust manifold, creating 2 smaller exhaust manifold volumes rather than the one large turbulence producing factory design, I think that the gain comes from harnessing  the pulse energy of the exhaust blowdown ,  keeping gas velocity higher on its way to the turbine resulting in better v.e.  Another gain was found when trying to reduce the intake noise which was much too loud for my liking, I removed the standard inlet pipe that went from the airbox to behind the headlight and replaced it with some flexible plastic pipe, and plumbed the inlet to a cold air area behind the grill, my first attempt at this resulted in a slight drop in power, after some theorizing and experimenting I found that different lengths of pipe gave differing power/economy gains/losses at certain revs.  The Helmholtz effect is easy to take advantage of here, I wanted a gain at 3000 revs, so eventually found that a pipe length of approx. 36 inches from airbox to the bellmouthed air inlet gave a noticable result, plastic flexible pipe is cheap, you will have to experiment a bit to see what length works for your engine/rev level, and don't forget to whip up a bellmouth for the opening, I used a 2.25 inch diametre section of exhaust pipe, and flared the end by forcing it (with a large hammer) over an old large size towball (wrecked the towball too!) , though I'm sure that you will be able to find, build or buy a more pleasant looking finished product!

[theman53]

Yeah I just flipped the intake cast elbow. Had pics somewhere on here...found in the build thread page 23 or something.




This is what I said about it at the time.
"EGT is still an issue, but it was 110F the other day. I can take it up to around 1500-1600F and then it stops. It climbs much slower over 1300F than it does before that point. Now that I have been driving it for 2 months with intercooler on I have never dipped below 42mpg and have 3 tanks at 47mpg. I can only make 21psi boost now. Overall I like it now."

Sorry for the hijack, although I like your engine compartment.

I have the same fuel filter on my mk1. I was going to order some car stuff on line - but am not sure of the actual fuel filter type.

My choices are
http://www.autopartsway.ca/PartList.cfm?Volkswagen/1984/Jetta/Base/1.6L_L4/allB/Air_and_Fuel_Delivery/Filters/Fuel_Filter/pagenum1/tabS

the one with the nipple end or the one that looks like an oil filter with a h20 drain. I suspect it is the latter?


thanks

Yeah, it is just the MK1 filter. Thread on with the water drain on the bottom.

[8v-of-fury]

cheapest ones to get, and you can buy bigger elements for them too if I am not mistaken.

[nathantheengineer]

Good to see that you are still trying to crack the self-imposed mpg barrier.  Going back to the car aerodynamics, have you thought about a long nose front end, something akin to the DTV droop snoot Firenza we got in the uk?

http://blu.stb.s-msn.com/i/E9/881C92E8EC90EF8428375AA6A1C77E.jpg

Would definitely help. Also have you changed the side mirrors? i cant remember?  some bullet type or even better if you removed them ( if legal where you live?)

[bbob203]

there's a guy on tdi club who put a tdi into a saturn and gets close to 70mpg. I bet a 1.6 td into a saturn would get you at least 60.

[TylerDurden]

Going back to the car aerodynamics, have you thought about a long nose front end, something akin to the DTV droop snoot Firenza we got in the uk?

We have the easy-peasy MK2 "big bumpers" and the mirrors (gotta have two in most states) on the >89(?) series are a bit more aero than the 86 version.




I'm all for aero mods, best bang for the buck.

[scrounger]

Who can argue with the appearance of the more compact bumper and below bumper valence. I can't put my finger on it but have read that the big front bumper actually helps some.

A friend of mine gets in the 60's with a 1.6 na  and extensive body molding. He is running stock mirrors. They are far enough back that the air is pretty turbulent. 

It shows how stock my car is.
and

The back window, trunk lid and center support have been removed. He uses it like a minicamper.

I talked to him about my new cam, He is very interested.