Project Del Sol Kammback Dead; New Ideas

[MetroMPG]

Denis - note his location. Likely less of a seasonal temperature effect in California.

Jedi - FYI, in my not entirely rigorous A-B test, I measured a 2.2% improvement with the undertray on my Firefly/Metro:

http://ecomodder.com/forum/showthrea...9.html#post873

[jedi_sol]

Originally Posted by groar

Your last 10 tanks are since 2010-10-13 while the 10 previous one were from 2010-04-19 to 2010-10-01, ie automn-winter vs spring-summer, so the 2.8% improvement is certainly lowered by lowered temps.

Do you feel the car behavior different ?
I know that with the rear wheel skirts my car accelerates stronger and is more difficult to keep at a steady speed, as it want to accelerate rather easily...

Denis.

EXACTLY! Getting a slight increase in MPG during winter months vs. warmer temps means the underbelly tray is working.

As far as driving behavior, yes the car accelerates easier, I can eoc MUCH longer. (Even though I did this mod for FE reasons) My favorite improvement is the dramatic decease in wind noise.

Darin -
Yeah, i've seen your posts regarding your undertray, the amount of labor going in vs. the amount of FE improvement is a little disappointing. But every little bit helps, right?

[MetroMPG]

That was my exact take on it. A bit bummed that it wasn't as big an improvement as the numbers show is possible (on other vehicles, admittedly). But I'll take what I can get.

Aside from a few major mods (Kammback/boat tail, alternator delete, transmission re-gearing) this is a game of a few percent at a time.

[jedi_sol]

Nothing official yet, but with the warmer temps arriving, i just hit 225 miles and I am still a few "ticks" above the half tank mark = I'm on track to hit 45mpg (assuming I don't make any un expected trips from my normal weekly commute)!

[jedi_sol]

Last 3 tanks

45.02
44.62
45.22
====
44.95 avg.

I know the car is easily capable of 45mpg now, however, I know it can do better if not for the fact i get out of work right smack dab in the middle of rush hour traffic every day.

Anywho, I've got the itch for more mpg's. Removed the power steering belt tonight. Will check back with updates.

[Joenavy85]

Just curious, why do you post the temps at time of fill up on your fuel logs?

[tiderfish]

Great work here. Your Del-Sol looks slick! Those MPG numbers are fantastic!

What did you use on the underbelly? I thought I read chloroplast, but then it looks like you heat shrank it to ft the form of the under-body. Is that true? Did you go back in and cover the holes for the exhaust? I know it's pricey, but you could wrap the exhaust with that insulator that will keep the heat trapped in the pipes, and then out the back. Thus keeping your engine bay cooler, and protecting the chloroplast. Keep up the good work!

PS is there any way you can re-post the old pictures? Their links are broken. (Damn photobucket!)

[jedi_sol]

Originally Posted by Joenavy85

Just curious, why do you post the temps at time of fill up on your fuel logs?

When I first joined ecomodder, I just followed the assumption that you should "fill up when temps are cooler." So i've been keeping track on the temperature to see if there is a correlation mpg vs. temps vs. fillups.

But since you've asked, I've been doing research on this topic and I just learned that underground gas tanks do not flucuate in temperature very much. So i guess tracking temperature is a waste of time?

One question though. Since temps do not fluctuate very much for underground tanks, will temperature flucuations have a significant impact on the gas in my fuel tank, in terms of volume? Or are the changes so miniscule, it's not even a factor?

For example, assume i fill up when the outside temperature is 90*, the gas in my tank will have expanded a great deal, taking up more room in the fuel tank. Will that affect how much gas I can fill up? Would this cause underfill/overfill?

[jedi_sol]

Originally Posted by tiderfish

Great work here. Your Del-Sol looks slick! Those MPG numbers are fantastic!

What did you use on the underbelly? I thought I read chloroplast, but then it looks like you heat shrank it to ft the form of the under-body. Is that true? Did you go back in and cover the holes for the exhaust? I know it's pricey, but you could wrap the exhaust with that insulator that will keep the heat trapped in the pipes, and then out the back. Thus keeping your engine bay cooler, and protecting the chloroplast. Keep up the good work!

PS is there any way you can re-post the old pictures? Their links are broken. (Damn photobucket!)

Thanks! I actually got a "thumbs up" on the freeway yesterday.


The underbelly is made out of coroplast. The outside edges (front bumper, side skirts, rear bumper) are all screwed in using self tapping screws. The "inner" parts of the underbelly are held on using a combination of "Hanger straps" and self tapping screws. No special heat shrinking used, just good old "eyeball/cut/screw" method.

(Oatey 3/4 in. x 10 ft. Copper Coated Steel Hanger Strap - 33918 at The Home Depot).

No, the exhaust is still exposed. However, the coroplast directly underneath the transmission has melted and warped. So i need to go back under there and replace that section with aluminum flashing.

as far as the older pictures, its nothing special.
Battery relocation in the trunk/replaced with deep cycle battery:


Inner bubble mirror:


Rear skirt planning/construction:

[jedi_sol]

Again, its only preliminary. Just finished my weekly drive to los Angeles, been driving this route for 2 years and I've never cracked 50 mpg.

This trip with the power steering delete, 51.06 mpg. Yeah!