35 MPG 1966 Chevelle

[aerohead]

Originally Posted by 67-ls1

Yeah, the more I follow this the more I get concerned about the aero aspect of my project. Looking at it from the front and below, it is anything but smooth. I will add an air dam to the front and try to close up the grill as best I can without cooling problems. I don't think a belly pan is in the cards given everything that is under there, so I will concentrate on keeping as much aid out as I can.
Has anyone ever "vented" the under car area?

The big dogs would say don't do it.If anything,build an airtight fence around the perimeter,as low as the bottom of the naughty bits,and let the air pool inside it,upside down.The free stream will skim over this dead air as as if it were a virtual belly pan.(airdam-to-rocker panel extensions, all the way, and a lowered rear valence to match).

[sgtlethargic]

Originally Posted by aerohead

...

Thank you for taking the time to write a very detailed reply- I appreciate it.

It looks like I'll have to start with another car, or modify the Ranchero more than I originally thought.

[The_Jed]

This build is definitely relevant to my interests. I'm looking to do something similar with my '92 Mark VII. I want to make improvements without losing the character of the car and hopefully hit a repeatable 30 mpg without p&g or eoc.

Best of luck to you!

[cosmick]

Now I realize the Monte SS being discussed had the L69, I can chime in, as I had one I played with. Those L69s did like a lot of RPM at cruise, and then they did give better MPG than the more boring versions of the 305. Getting 27 MPG from a 305 with no OD was impressive, and did happen back in '84, but 305s never were MPG engines, I had a 350 give 25.1 with the centrifugal advance not working, at 65 MPG, in the mountains, in a '78 Camaro with the 5" rear spoiler. That one had 3.08:1 gears and a 700R-4. If I ever copy it, I'll tweak it until I get 30 MPG. Anyway, the LB9 used the same cam specs, and did 27 MPG with a 3.45:1 x 0.73:1, while the L69 did it with 3.73:1 x 0.73:1.
As for the curved fastback drawing, it's so false. I'fe played with a SuperFlow 1020 and a Serdi enough to know that air indeed will flow over a 15 degree angle as well as a perfect radius. And the air will follow the angle partly because the transition is nearer being abrupt. Only a long-box pickup can have a 15 degree cone behind the rear window, anyway.
Many times many people have called me a liar over my MPG accomplishments, but I've come to realize that some people just can't drive for mileage, and will consistently get 20% worse than me in any car under any conditions.
I can believe a '94 F150 getting 18.5 MPG, but I had a '94 Chevy C1500 repeatedly return 23 MPG, with a best of 26 more than once, with a 3.73:1 rear instead of the preferred 3.42:1 or the lame 3.08:1. On the other hand, I had a 1.9L Escort return 44 MPG.
The '66 Chevelle is a beautiful car, and the 3.6L is good power for the size.

[67-ls1]

Realistically, I am not the type of person who will drive to eek out the last .1 MPG. I would like to get this car to the point that I COULD get 35 MPG, but would be very happy if my 90 day average was above 30.
That said, there is a ton of fascinating stuff on this site that will probably show up on my other vehicles and affect the way I do drive on a daily basis

[malovich]

to preserve the nose lines turn the front end into a ducted hood/grill: integral radiator/intercooler not required. The v6 should be shorter and mounted farther back anyways right?

[67-ls1]

The weird thing about this particular V6 engine is that one cylinder head is longer than the other. I don't know of another V engine that the heads are not interchangeable right-to-left.
The left head (drivers side) head is longer to the rear to drive the high pressure pump for the direct injection. I also allowed room to get the pump out without removing the engine.
For this reason, the engine is not set back any further then with a V8. There is about 10" from the front of the engine to the core support.

[RCB]

Out of curiosity, is there a reason you skipped over the 6.5TD? It's not uncommon and many people get right around 30mpg without any aero mods in hot rod applications and it's relatively straight forward (as long as you're comfortable with the electronics).

I'm guessing cheap access to the v6 and 6 speed?

[jodydewey]

Originally Posted by jcp123

I disagree. I lived in the South Bay long enough to know that while you have pretty mild temperatures in Walnut Creek, your nightly lows get cool enough for a block heater to matter. I had a low here in east Texas of 39 last night and a high in the 50s. My FE got slaughtered. A block heater would have gone a long, long way. +30*f coolant temp when you start the car makes a BIG difference.

I have a 1999 F350 Crew Cab with a powerstroke diesel. I run the block heaters year round. In the winter it is a must to start but in the summer I get 2 mpg better because the engine is already warm and runs much better.

With a gas motor running a block heater in the summer your engine would start and immediately go into closed loop mode and get much better gas mileage.

[67-ls1]

I actually love diesels. I worked for Cummins for 33 years.
But the diesel I considered for this project was a VW TDI. Small, powerful, clean running. The 6.5 is unnessasarily large for me.
The issue is I did not want an old, mechanical fuel system with tons of miles on it and I could not find anyone that could help with reprogramming the VW ECM.
Maybe the TDI will be my next swap.....