Fuelly Forums

Fuelly Forums (https://www.fuelly.com/forums/)
-   General Fuel Topics (https://www.fuelly.com/forums/f8/)
-   -   saturn mileage (https://www.fuelly.com/forums/f8/saturn-mileage-5376.html)

lovemysan 07-12-2007 07:50 PM

saturn mileage
 
Well it seems I've hit a wall or maybe my perceptions have changed. I've got some 50mpg gallon tanks under my belt and it really wasn't that hard. But I've been getting lack luster mileage the past few months and have been increasingly disappointed. So wedsday I decided I'd go for broke and see what the car was capable of. My typical church trip is 80 miles round trip. This is how it broke down

trip out
42miles
55.7 mpg 55mph

trip back (slightly altered route)
first leg
9miles
64.6mpg 40mph

second leg
40 miles
58.5mpg 50mph

So at this point I'm disappointed because I feel there is no silver bullet. The only way to get good mileage is to slow down. My goal for the car is 50mpg at 70mph. Lets face the facts I live 8.5 hours from my home town. I don't want to drive 58mph all the way home. With baby stops thrown in it equates to a 12 hour ride in a small car with baby and another baby on the way(and some of you guys know what that means).

Don't get me wrong I think the car gets fine mileage for what it is but I had hoped that I could intelligently modify the car for more mileage. I'm also realizing that I'm very ignorant on the subject of aerodynamics. I'm further hampered by my lack of education and general mathematical skills.

At this point it still seems to me that the largest gains for me could be made in aerodynamics. I've been reading aero articles and I'm starting to understand some mistakes I made with my belly pan. Look at my mods and tell me where I can improve. Pics in below link

https://s75.photobucket.com/albums/i3...emysan/saturn/

skewbe 07-12-2007 08:47 PM

I always loved the name of your car, I was thinking of it all the while trying to climb a few hills on vacation with the trailer :)

Anyway, COZX2 just posted some pics, https://www.gassavers.org/showthread.php?t=4200

Just armchairing it here (I don't get anywhere near 70mph in my commute): I think your wheels are chewing on a lot of air (might want to fill them in), and you could lower the car and/or add a front air dam.

usedgeo 07-12-2007 08:47 PM

I think I am where you want to be and your belly pan looks better than mine. Mine is not full length. I have the front half of the car and the rear third. I did not go over the muffler. I have rings around the front wheels and the mirrors moved inside. I have not documented the effect of all the changes. I think mirrors add a spot of drag.

I run 60 psi in my tires and real 180 degree IAT, no resistor for now. I think that is the main difference between mine and yours. My grill block is just blocks of foam stuffed into the grill. Yours looks a lot better than mine.

I am pretty sure mine would get your goal of 50 @ 70 but I have not driven that fast for several months now :rolleyes: . Actually my current goal is 60@60 and I think I am getting very close to that. I want to drive a bit faster too.

lovemysan 07-13-2007 09:23 AM

Quote:

Originally Posted by usedgeo (Post 63243)
I think I am where you want to be and your belly pan looks better than mine. Mine is not full length. I have the front half of the car and the rear third. I did not go over the muffler. I have rings around the front wheels and the mirrors moved inside. I have not documented the effect of all the changes. I think mirrors add a spot of drag.

I run 60 psi in my tires and real 180 degree IAT, no resistor for now. I think that is the main difference between mine and yours. My grill block is just blocks of foam stuffed into the grill. Yours looks a lot better than mine.

I am pretty sure mine would get your goal of 50 @ 70 but I have not driven that fast for several months now :rolleyes: . Actually my current goal is 60@60 and I think I am getting very close to that. I want to drive a bit faster too.

I think the belly pan in its current state doesn't help enough, simply because its not sealed correctly. After reading the autospeed aero articles and studying the mercedes pans I've discovered that the vents I installed, slow the air under the car significantly. I think it really need skirting inside the the wheels underneath to keep the air at higher velocity. This would also reduce the lifting affect caused by the poorly radiused rear glass and short trunk. I'm considering a trunk extension and vortex generators on the roof. But not before I figure some way to instrument it and test its affect.

Bill in Houston 07-13-2007 10:38 AM

Quote:

Originally Posted by lovemysan (Post 63290)
I think the belly pan in its current state doesn't help enough, simply because its not sealed correctly. <snip>I've discovered that the vents I installed, slow the air under the car significantly. <snip>

Hey all the pictures in your old belly pan thrash thread are blown out. Can you show some pictures of what you are talking about?

usedgeo 07-13-2007 01:05 PM

I forgot to mention that I am not running an alternator. That is not a functional idea for a 10 hour trip.

However, preliminary results suggest that Somender Sing grooves might be good for a 10% gain on a SOHC Saturn. I ran 63.5 mpg today at 60 mph for a bidirection test and around 55 mpg for a short bidirectional test at 70-75 mph.

You might put some valley metal over the exhaust system. I think that would help. I don't think the exhaust heat is going to be a problem.

cfg83 07-13-2007 01:27 PM

usedgeo -

Quote:

Originally Posted by usedgeo (Post 63243)
I think I am where you want to be and your belly pan looks better than mine. Mine is not full length. I have the front half of the car and the rear third. I did not go over the muffler. I have rings around the front wheels and the mirrors moved inside. I have not documented the effect of all the changes. I think mirrors add a spot of drag.

I run 60 psi in my tires and real 180 degree IAT, no resistor for now. I think that is the main difference between mine and yours. My grill block is just blocks of foam stuffed into the grill. Yours looks a lot better than mine.

I rarely see my real IAT much over 140 degrees F. Do you have a picture/description of how you did it? I looked around on the GasSaver forums, but couldn't find a specific post from you that pictures/describes it.

Quote:

I am pretty sure mine would get your goal of 50 @ 70 but I have not driven that fast for several months now :rolleyes: . Actually my current goal is 60@60 and I think I am getting very close to that. I want to drive a bit faster too.
Are you still using your block heater? That would take the edge off the startup from home.

It would be cool if you did a thread on your car like "Peakster's Geo Thread".
(https://www.gassavers.org/showthread....t=peakster%27s)

CarloSW2

Zvolen 07-13-2007 02:21 PM

I need to pay attention to this thread as I only get 30MPG if I am lucky, however it is ALL city driving and I have a AT. Any advice would be helpful, or a list of mods that you have done to help the most. My immediate goal is 30MPG without slowing down to a snails pace.

usedgeo 07-13-2007 03:02 PM

I am still using the block heater most of the time. I did not this morning and I started out quite well but got into slow traffic for a couple miles. I need space to pulse and glide effectively. I don't see how MetroMPG can go so slow.

My intake temp is a function of the belly pan, grill block and something I forgot to mention. I used weather stripping the full width of the hood to keep air from going in under the hood lip. The intake hose is tied up so it pulls air behind the exhaust manifold. My intake temp runs about 20 degrees below water temp. Most of the intake heat is coming from the water.

I aint sure my car is worth a thread yet. Some of these college kids have too much time on their hands :) . I will think about it. Maybe I should start a web page.

The lovemysan links show better pictures than mine for heated intake air.



Quote:

Originally Posted by cfg83 (Post 63343)
usedgeo -



I rarely see my real IAT much over 140 degrees F. Do you have a picture/description of how you did it? I looked around on the GasSaver forums, but couldn't find a specific post from you that pictures/describes it.



Are you still using your block heater? That would take the edge off the startup from home.

It would be cool if you did a thread on your car like "Peakster's Geo Thread".
(https://www.gassavers.org/showthread....akster&#37;27s)

CarloSW2


CO ZX2 07-13-2007 05:00 PM

Quote:

Originally Posted by Bill in Houston (Post 63301)
Hey all the pictures in your old belly pan thrash thread are blown out. Can you show some pictures of what you are talking about?

Pics here:
https://s75.photobucket.com/albums/i3...urn/?start=all

lovemysan 07-13-2007 05:26 PM

CO ZX2, I was hoping you would weigh in with your thoughts about the belly pan. Also do you think my wheel skirts are fine as they are.

lovemysan 07-13-2007 05:32 PM

Quote:

Originally Posted by usedgeo (Post 63341)
I forgot to mention that I am not running an alternator. That is not a functional idea for a 10 hour trip.

However, preliminary results suggest that Somender Sing grooves might be good for a 10% gain on a SOHC Saturn. I ran 63.5 mpg today at 60 mph for a bidirection test and around 55 mpg for a short bidirectional test at 70-75 mph.

You might put some valley metal over the exhaust system. I think that would help. I don't think the exhaust heat is going to be a problem.

You make me feel horrible.

So tell me more about your car. What power options does it have P/S, a/c etc. Do you think I should pull the resistor leave the HAI as it is. I'd like to see your pics of your belly pan, skirts, and especially the front rings.


COZX2

I'd like to know how you keep your front skirts from bowing back in and rubbing the wheels.

skewbe 07-13-2007 05:46 PM

Also note that our MPG Leader CO ZX2 still has belly pan on his todo list. I'm guessing that huge piece of lawn edging hanging off the front bumper has a lot to do with it :)

CO ZX2 07-13-2007 06:20 PM

Quote:

Originally Posted by lovemysan (Post 63419)
CO ZX2, I was hoping you would weigh in with your thoughts about the belly pan. Also do you think my wheel skirts are fine as they are.

I remember your belly pan thrash and admired the determination you put into getting it done. I thought I remembered that you had a gain at the time. You also inspired a lot of people to get up and do something.

On my own car I had an underpan that covered everything back to the front of the front tires. That had been a definite improvement for me. I couldn't wait to add to it. I added a 4 foot section to the rear of it and my pressure/flow gauges immediately showed me it messed up the gain I had made on negative pressures at the rear of the car. After rechecking my gauges and tubing, I removed the new piece alongside the road. My pressure readings were back where they were. I do not totally understand why this happened but it did. These pressure gauges have been my most important discovery recently. See pic in my garage(link below my sig.).

Your skirts look real nice but I wonder if they may be bulged out too far. On my car I had mine bulged more than they needed to be. I have rearranged my skirts to clear the closest part of the wheel by 3/4 inch. They are considerable more flat to the body than before. I also proved that is better with the gauges. If you have interest, I may have an extra gauge to spare. All it takes to use it is a couple fittings and some plastic tubing to run to the spots on the car you want to check. Gauge is inside the car and just read at speed(I use 60 mph).

You might also look at my front end pic in my garage. I would never have believed that big air dam would work. It has and I've even added 3" to it. That was the item that worked best to reduce negative pressure at the rear of the car.

One more thing I will mention. Sealing the belly pan around the front and sides as much as possible made a difference for me. Sealing my grille block and fender skirts is also important to me. Without a tight fit, I was not getting all there was out of these mods.

Don't be discouraged with having to drive slower to do your best. Do that when you can, but if you need to speed up, just do it. A while back we were taking the cat to the vet and wanted to get there as soon as we could. I didn't worry about FE much even though I got 20 mpg less than usual.

Keep a good attitude and we all know you're a worker.

usedgeo 07-13-2007 06:20 PM

I wasn't trying to make you feel bad. I was trying to say your goal is realistic. I think your car is very close to mine and you have done nicer work than I. My belly pan looks like yours except I put up no framework. Mine is just coroplast and tie straps with a few screws. You did a very nice job. My middle is actually hanging on the exhaust system with heavy wire. There are pictures on the site but I will find later.

My car is not even an SL1 it is just an SL. It has AC, PS, PB and CD player but windows and locks are manual, no cruise. I am running an NAPA belt that runs between the crank-AC-and water pump. I just got lucky and this belt fit. I roll it on but it is too loose to run the AC. CO's system of turning the alternator off internally is better. If I get caught out somewhere I will need to install the belt that is in the trunk.

I have my mirrors inside. I think that helps. Did you see CO's clear mirror streamlines? I would never have thought of that. I think blocking the air that enters full width at the front of the hood matters too. My car did not have a molding there though there were holes for it. I just used foam tape weather strip. I know I have not documented like many here have.

I will take pictures of my front wheels and rings. Most of the skirt clears the tire by less than 1 inch. This will have to be a bit later. If VW can get 300 mpg without front skirts I decided I would do what seemed easier to me.

At this time I don't believe in IAT resistors. I may go back there in the future. I relocated the sensor into the body of the intake box. I had to tap a hole but it was just in plastic. I was not the first to do that. I like heated intake air.

60 psi makes a difference but it is beyond sidewall recommendations and does affect traction a bit. The tires will slip a bit easier on uneven surfaces.

Skirt pictures later.

CO ZX2 07-13-2007 07:01 PM

Quote:

Originally Posted by lovemysan (Post 63424)
You make me feel horrible.

So tell me more about your car. What power options does it have P/S, a/c etc. Do you think I should pull the resistor leave the HAI as it is. I'd like to see your pics of your belly pan, skirts, and especially the front rings.


COZX2

I'd like to know how you keep your front skirts from bowing back in and rubbing the wheels.

The plastic I use has some stiffness and I bow it slightly to the outside when I put it on. I have a half inch plastic ball on the inside of the skirt that barely contacts the center of the hubcap. The ball also takes some load off the rubber inserts when the wheel turns. The screw in the middle of the skirt holds the ball in place.

usedgeo 07-13-2007 08:29 PM

Here are some pictures but please bear in mind I just did what I thought looked nice and have not done any real testing. I will just post the links this time. Other wise it might take a while to load.

Right rear pant only about 1/4 inch clearance with 1/4 inch spacer at front.
https://xs.to/xs.php?h=xs117&d=07286&f=rrpant.JPG

Right rear pant again
https://xs.to/xs.php?h=xs117&d=07286&f=rrpant_2.JPG

Right front pant. Tight at back . Open at front. Just trying to control imagined air flow through wheel well. I was trying to get a radius for the air coming out of the wheel well. I reasoned that the tire formed a nice radius at the front. Anyway that fit the length of hose I had cut off at that time ;) .
https://xs.to/xs.php?h=xs117&d=07286&f=rfpant.JPG

Right front pant again showing spacer block at back. This is not a smooth transition to the car body.
https://xs.to/xs.php?h=xs117&d=07286&f=rfpant2.JPG

Plastic vacuum hose used for radius. Tie strapped on. Yes it rubs and makes noise when I hit bumps and turn. Yes those are screw holes in my fenders. I paid for the car and I put the holes in it :) . The plastic is not going to rust either.
https://xs.to/xs.php?h=xs117&d=07286&f=flexradius.JPG

Rear pan
https://xs.to/xs.php?h=xs117&d=07286&f=rearpan.JPG

Front pan
https://xs.to/xs.php?h=xs117&d=07286&f=frontpan.JPG

Front pan installed. Pardon the low resolution. It is not so smooth after a few thousand miles.
https://xs.to/xs.php?h=xs117&d=07286&f=frontpan_on.JPG

Hope this answers more questions than it raises. Again I have not tested any of the aero stuff. I really want to test the front skirts on a hill roll down. I just have not done that yet. They are the only part of the aero package that I could not easily tell it helped. Please note my belly pan is not continuous front to rear. The middle bottom of the car looked substantially flat to me and only the easy part was covered. I am not covered near the fuel tank for about 40 inches.

Bill in Houston 07-13-2007 09:09 PM

Quote:

Originally Posted by CO ZX2 (Post 63413)

Thanks!

Lovemysan, what part are you unhappy with?

cheapybob 07-14-2007 09:31 PM

>> My goal for the car is 50mpg at 70mph. <<

I think I need to slow to about a steady 65 mph or less on level to get 50 mpg out of my SC1. At 70 mph it drops to about 47 or 48 mpg if I remember right. That is with just me in the car, no a/c.

BTW, I had zero luck doing aero mods. They looked more aerodynamic, but any mpg increase was not enough to notice on my standardized test runs. I never did try a belly pan or skirts, though.


All times are GMT -8. The time now is 09:23 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.